MINISTRY OF EDUCATION
MINISTRY OF AGRICULTURE AND
AND TRAINING
RURAL DEVELOPMENT
VIETNAM ACADEMY OF AGRICULTURAL SCIENCES
-------------------------------
ĐINH THỊ DINH
RESEARCH ON AGRONOMIC AND BIOLOGICAL CHARACTERISTICS AND
TECHNICAL MEASURES OF GROWING AND CARING FOR RHYNCHOSTYLIS
GIGANTEA (LINDLEY) RIDLEY IN NORTHERN VIETNAM
Major:
Code:
Plant sciences
62.62.01.10
SUMMARY OF AGRICULTURE DOCTORAL THESIS
Ha Noi, 2015
The thesis was completed at:
VIETNAM ACADEMY OF AGRICULTURAL SCIENCES
Supervisors: 1. Dr. Dang Van Dong
2. Prof. Dr. Tran Duy Quy
Judge 1: Dr. Pham Thi Minh Phuong
Judge 2: Prof. Dr. Nguyen Thi Kim Ly
The thesis was protected in the grassroots review panel meeting at:
Fruit and Vegetable Research Institute
8.30 am in 17th December, 2014
The thesis can be found in:
Library of Vietnam Academy of Agricultural Sciences
LIST OF PUBLISHED ARTICLES RELATED TO THE THESIS
1. Dinh Thi Dinh, Dang Van Dong and Chu Thi Ngoc My (2013), "Evaluation results on the growth
and development of several Rhynchostylis gigantea (Lindley) Ridley varieties in Gia Lam Hanoi", Journal of Vietnam Agricultural Science and Technology, 3 (42), p.81-88.
2. Dinh Thi Dinh and Dang Van Dong (2014), "The research results on morphological and
anatomical characteristics of several Rhynchostylis gigantea (Lindley) Ridl prospective varieties
in Northern Vietnam", Journal of Agriculture and Rural Development, Vol 1 - 1/2014, p.33-40.
3. Dinh Thi Dinh, Dang Van Dong and Tran Duy Quy (2014), "The Impact of the ecological zones
and treating Gibberilin (GA3) on the growth and flowering of purple-spotted white
Rhynchostylis gigantea (Lindley) Ridley", Journal of Science and Development, Vietnam
National University of Agriculture, Thematic plant physiology, vol 12, No. 7-2014, p.10491057.
4. Dinh Thi Dinh, Dang Van Dong and Tran Duy Quy (2014), "Research on the impact of technical
measures on the growth and quality improvement of Rhynchostylis gigantea (Lindley) Ridley",
Journal of Agriculture and Rural Development, 22/2014, p.10-18.
INTRODUCTION
1.1 Rationale
Orchids are one of the objects of nature, the art masterpieces that nature bestowed on human. Its
beauty exotically attracts flower growers. We can say that orchids have all of the valuable features of
flowers such as beautiful and varied colors, diverse and delicate flower structrue, long flower durability
and especially attractive to flower growers by seductive scent. When admiring the beauty of orchids, the
human soul is in harmony with nature. The ancient elders said: orchids bring all the noble characters of
the gentleman that are humanity, formality, integrity, mentality and credibility.
Due to the valuable characteristics, orchid production industry has constantly developed and
increasingly expanded throughout the world, bringing great benefits to the nations that invest in
research and production of orchids such as China, Thailand, Taiwan. Vietnam has suitable climate
conditions for growth and development of numerous orchids and the source of a lot of orchid
species recorded by the orchid researchers.
Rhynchostylis gigantea (Lindley) Ridley is one of native and rare orchid species of Vietnam. This
flower has pendulous flower clusters, aroma and long durability. It has several tranditional names: Nghinh
Xuan in the Central (since the spring bloom), Ngoc Diem in the South, Dai Chau in the North (since
looking like string of pearls) and also Me orchid as a folk name. Rhynchostylis gigantea (Lindley) Ridley
has high economic value because of blooming in the Lunar New Year. Its usage is quite various such as
putting on a pots, decorating in the living rooms, hanging on the balconies and windows, grafting on dead
woods and growing trees or on the rockeries forming a very beautiful landscape and a natural appearance.
With the development of economy and society, the demand for ornamental plants has been increasing and
requiring highly, Rhynchostylis gigantea has increasingly won the hearts of consumers. However, the
indiscriminate exploitation of wild orchids have been made Rhynchostylis gigantea decreasing in number
and in danger of extinction, while conservation and development of Rhynchostylis gigantea are not really
popular in Vietnam. One of the limitations in the production of this orchid is extremely slow growth,
especially in Northern Vietnam, leading to the time from planting to flowering takes several years. On the
other hand, agronomic and biological characteristics of the plant have not been fully evaluated. Researchs
on the cultivation and care in order to overcome the disadvantages and promote the advantages of this
flower have not much and no application in production. For the purpose of conservation and wide
development of Rhynchostylis gigantea in Vietnam, we conducted the thesis: “Research on agronomic
and biological characteristics and technical measures of growing and caring for Rhynchostylis gigantea
(Lindley) Ridley in Northern Vietnam”.
1.2 Objectives
The research on agronomic and biological characteristics of Rhynchostylis gigantea and
technical measures aims to increase the growth, flowering early, flowering rate and flower quality
and improve technical procedures to widely develop this orchid in production.
1.3 The significance of science and practice
1.3.1 The significance of science
The thesis was to provide scientific data on agronomic and biological characteristics such as
anatomy, relative growth and development of Rhynchostylis gigantean varieties. Based on the
research results, effective technical solutions in the cultivation and care of Rhynchostylis gigantean
were released to build the technical process of producing this valuable flower.
Results of the study are the valuable references for teaching, researching and producing of
orchids, especially Rhynchostylis gigantean.
1.3.2 The significance of practice
Purple-spotted white Rhynchostylis gigantea that has been determined are suitable for
ecological conditions in Northern Vietnam. This variety is durable, beautiful, strong growth and
development to meet the requirements of production.
The thesis has proposed technical measures for planting and caring to increase the growth
and development, early flowering, flowering rate and high-quality flowers in Northern Vietnam
conditions. These technical measures are feasible, capable of application to the production of goods
and effective for florists.
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1.4 Novelty
This is the first systematical study on Rhynchostylis gigantea characteristics of morphology,
anatomy, growth and developmet from housing to flowering (3 years old).
The thesis researched the correlation between the growth length of leaves and length of
flower stems that releases measures to increase plant growth in the nursery stage in hot and humid
summer conditions and improve the growth, flowering rate and flower quality in production garden;
consequently 2 years plants flowering 47% (1 year earlier than control), 3 years plants flowering
80% in the Northern Vietnam conditions.
1.5 Scope
The thesis determines agronomic and biological characteristics and technical measures of a
number of Rhynchostylis gigantea (Lindley) Ridley varieties in Northern Vietnam. Implementation
period is from 2011 to 2014.
CHAPTER 1. LITERATURE REVIEW
Rhynchostylis gigantea has aesthetic and high economic values and development potential in
Vietnam as well as in the world. There have been several studies on Rhynchostylis gigantea. The
new researchs focused on breeding methods. The authors have identified that the materials used for
propagation are immature seeds, mature seeds and meristems. Furthermore, they have determined
the culture medium, the fast propagation and creating mature plants; after housing seedlings are
healthy and possible to meet the production.
There have been a number of studies on agronomic and biological characteristics and
technical measures of Rhynchostylis gigantea over the world such as temperature, light, GA3 spray
to enhance the growth and development of plants. However, the studies of anatomy, growth
correlations between vegetative and floral organs have not been mentioned. Especially, there have
been very few studies on Rhynchostylis gigantean in Vietnam, people rely on traditional experiences
to plant and care for plants leading to slow growth and flowering, poor flower quality.
To widely develop Rhynchostylis gigantean in production, the research on agronomic and
biological characteristics, cultivation, care and flowering control are needed to improve the process
for serving the needs of production and increase income for orchid growers and toward export in the
future. The results of previous studies will be the basis for reference and inheritance of the thesis,
which results in comprehensive and effective follow-up studies.
CHAPTER 2. MATERIALS, CONTENT AND METHODOLOGY
2.1 Materials
- Experiments conducted on four Rhynchostylis gigantean varieties, including: one
indigenous variety and 3 imported varieties from Thailand. Other materials are substrates,
fertilizers, biological pesticides, and GA3 growth stimulants.
2.2 Research Content
2.2.1 Research on agronomic and biological characteristics of Rhynchostylis gigantean
- Assess the growth and development of some Rhynchostylis gigantean varieties in Gia Lam Hanoi
- Research morphological characteristics of roots, stems, leaves, flowers and fruits; anatomy of the
vegetative organs of Rhynchostylis gigantean
- The correlation between the growth of leaves, roots and flowers of purple-spotted white
Rhynchostylis gigantean.
- Growth and development characteristics of the purple-spotted white Rhynchostylis gigantean in
some ecoregions
2.2.2 Research on the effect of several technical measures on plant growth in nursery period
- Effect of subtrates and watering times on plant growth after housing
- Effect of fertilizers and fertilizing times on the growth of seedlings
2.2.3 Research on the effect of some technical measures on the growth and development of plants
in the producing garden
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- Effect of planting season on the growth and development of plants
- Effect of water quality on the growth and quality of flowers
- Effect of growing media and watering times on the growth and development of plants
- Effect of fertilizers and fertilizing times on the growth and development of plants
-Effect of GA3 concentrations on the growth and flowering ability of Rhynchostylis gigantean
- Effect of the shading levels reducing light in the summer season on the growth and
development of plants
- Effect of temperature treatment in the winter on the growth and development of Rhynchostylis
gigantean
- Effect of biological pesticides on occurrence and development of diseases and pests on
Rhynchostylis gigantean
2.3 Methodology
2.3.1 Method of experimental designs
- The experiment evaluating the growth and development of plants in Gia Lam, Ha Noi is
arranged in randomized complete block (RCB) with three replications, 30plants/ formula.
Experiment evaluates four Rhynchostylis gigantean varieties: Red, spotted Red, White, Purplespotted White. Experimental plants that are tissue culture plants eligible for housing.
- Research on morphological characteristics of roots, stems, leaves, flowers and fruits by
observing, describing and measuring randomly some indicators of roots, stems, leaves, flowers and
fruits of 10 plants/variety, 4 varieties, 3.5-year-old plants.
- Research on anatomical characteristics of roots, stems and leaves of 4 Rhynchostylis gigantean
varieties, 3-year-old plants. The method of making anatomical templates carries out the following
steps: treating sample, cutting templates, bleaching sample, double dyeing, observing and
photographing by a microscope. Analysis of anatomical structure of vegetative parts: roots, stems
and leaves according to documents of Tran Cong Khanh (1981).
- Research on the correlation between the growth of roots, leaves and some indicators of
purple-spotted white Rhynchostylis gigantean flowers: randomly sampling 30 plants grown and
cared in the same conditions in Gia Lam - Hanoi. 3-year-old plants are in bloom period. Measuring
the indicators of the leaf length, root length, flowering shoot, number of flowers/inflorescence.
Counting Pearson correlation coefficient (r), the determination coefficient R2, the regression
equation by means of correlation analysis on Excel 2010. Assessing correlation coefficient.
- Experiment of assessing characteristics of growth and development of plants in several
ecological zones, experiment of planting time (experiment 4.7) are arranged in a not repeated
sequential method, 30 plants/formula.
- Experiments of technical measures implement on purple-spotted white Rhynchostylis
gigantean, arranged in a randomized complete block (RCB) with three replications. In nursery
period a formula experiment is 2 m2 (100 plants), in the period of production garden a formula is 3
m2 (corresponding to 54 plants). Tracking plants follows 5 points of cross angle method, 2
plants/point, tracking 10 plants/replication. Tracking 30 days/time.
- Method of pests and diseases investigation follows national technical regulations of survey
method detecting plant pests (QCVN 01-38: 2010 / MARD).
2.3.2 Experimental conditions (non-experimental factors)
- Experimental plants were cared following temporary process of Fruit and Vegetable
Research Institute:
+ Plants were grown in a simple net house. 2 layers of black net covered the net house in
summer (from June to August). Nursery period: plants were grown in soft plastic, transparent pots;
size 8.5 (height) x 8cm (diameter). Growing media used Seaweed + charcoal + coarse bark (ratio 1:
1: 1). Charcoal and coarse bark size is 0.5-1.0cm. Spraying Growmore 1 - NPK ratio = 30:10:10),
the fertilizer concentration is 0.05%, a time/week.
+ Production garden (1 year and older): Plants were grown in square wooden pots, an edge
length of 25 cm, 3 plants/pot, the growing media were seaweed + charcoal + coarse bark (ratio 1: 1:
1). Size of charcoal and coarse bark was 2-3cm. Spraying Growmore 2 - NPK ratio = 20:20:20, the
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fertilizer concentration was 0.1%. Fetilizers were sprayed by hand sprayer on leaves, stems and
roots. Watering a time/day by rain shower nozzle.
+ Disease prevention: periodically spraying 10 days/time Daconil concentration of 0.1%.
Spraying Selecron 500EC 35ml/16 liters sprayer, Reasgant 3.6EC 10ml / 16 liters sprayer, 10
days/time to prevent leaf-eating insects, caterpillars, aphides. Preventing slugs and snails by
sprinkling lime powder to create protective strips around the experimental zone.
2.3.3 Location and time
- The experiments were conducted in the Center for Flowers, Ornamentals Research and
Development – Fruit and Vegetable Research Institute - Trau Quy, Gia Lam, Hanoi.
- The anatomical experiments were conducted in the laboratory of Plant Department,
Faculty of Agronomy, Vietnam National University of Agriculture.
- The experiments that evaluated the ability of growth and development were in some localities
such as Gia Lam - Hanoi, Van Giang - Hung Yen, Moc Chau - Son La and Sapa - Lao Cai.
Research time: from January 2010 to February 2014
2.3.4 Data Processing Method
The data were processed by the analysis method of the standard deviation and variance
analysis on the softwares Excel 2010 and IRRISTAT 5.0.
CHAPTER III. RESULTS AND DISCUSSION
3.1 Agronomic and biological characteristics of some Rhynchostylis gigantea varieties
3.1.1 Assessing the growth and development of some Rhynchostylis gigantean varieties in Gia Lam - Hanoi
3.1.1.1 The percentage of live plants and green recovery time after housing
The results showed that the green recovery time of varieties was from 12-15 days (the time
from planting to having new roots), in which purple-spotted white Rhynchostylis gigantean had the
shortest green recovery time and red Rhynchostylis gigantean had the longest time. Survival rates of
varieties after planting were relatively high (90-95%) in which indigenous variety had highest
survival rate, 95%.
3.1.1.2 Leaf growth characteristics of Rhynchostylis gigantean varieties
Table 3.2. Leaf growth dynamics of Rhynchostylis gigantean varieties (From 2010 to 2012, in Gia Lam - Hanoi)
Surviva
1 year
2 years
3 years
Characteristics l rates
Number Leaf Leaf Numbe Leaf Leaf Number Leaf Leaf
(%)
of leaves length width
r of length width of leaves length width
(cm) (cm) leaves (cm) (cm)
(cm) (cm)
Varieties
Red
90
2.8
8.8
1.5
4.1
15.8
2.8
5.3
21.0
4.2
Spotted Red
90
3.0
8.5
1.5
4.0
15.3
2.7
5.1
21.6
4.0
White
92
2.6
8.1
1.6
3.9
15.0
2.9
5.2
20.3
4.4
Purple-spotted
95
3.9
10.5
1.7
4.9
18.3
3.0
6.0
24.5
4.5
White
CV%
4.3
6.1
5.2
LSD0.05
0.6
2.4
0.23
The growth rate of the number of leaves of Purple-spotted White indigenous variety was
fairly fast, after 3 years the number of Purple-spotted White leaves was highest 6.0, the lowest was
5.1 leaves in spotted Red Rhynchostylis gigantean. Leaf size was also different in varieties. White
Rhynchostylis gigantean had the shortest leaf length 20.3cm, but leaf width had good size reaching
4.4cm. Purple-spotted White variety had the biggest leaf size, leaf length was 24,5cm, and leaf
width was 4.5cm.
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3.1.1.3 Stem growth characteristics of Rhynchostylis gigantean varieties
Table 3.3. Growth dynamics of stem height and diameter
(From 2010 to 2012, in Gia Lam - Hanoi)
1 year
2 years
3 years
Characteristics
Stem
Stem
Stem
Stem
Stem
Stem
height
diameter
height
diameter
height diameter
Varieties
(cm)
(cm)
(cm)
(cm)
(cm)
(cm)
Red
2.1
0.54
3.8
0.65
6.2
1.18
Spotted Red
2.1
0.60
3.7
0.72
6.3
1.20
White
2.0
0.61
3.9
0.73
6.0
1.23
Purple-spotted White
2.5
0.78
5.1
0.89
8.8
1.39
CV%
7.3
4.5
LSD0.05
1.24
0.14
Stem height and diameter of varieties after planting a year were a little difference, stem
height reached from 2-2.5cm, stem diameter reached from 0.54-0.78cm. However, these characteristics
had a clear difference between 2 years and 3 years plants. After 3 years of planting, stem height of
varieties reached from 6.2 to 8.8cm, Purple-spotted White indigenous variety gained 8,8cm, while
exotic Rhynchostylis gigantean varieties only got 6.0-6.3cm. Stem diameter of Purple-spotted White
variety also reached the highest value (1.39cm), while the other varieties only got 1.18-1.23cm.
3.1.1.4 Root growth Characteristics of Rhynchostylis gigantean varieties
The number of roots after planting 1 year reached 3-3.2 roots, two years plants got from 4.1
to 4.6 roots, 3 years plants reached 4.8 to 5.1 roots. There was a difference in the root length of
varieties: after planting one year the root length of varieties was from 14.6-18.8cm, 2 years plants
was from 23.2 to 28.0cm, and 3 years plants was 35.2-41.2cm. Root length of Purple-spotted White
variety reached the maximum value, 40.8cm, and the remaining varieties was 35.2-37.1cm.
Table 3.4. Root growth dynamics of Rhynchostylis gigantean varieties
(From 2010 to 2012, in Gia Lam - Hanoi)
1 year
2 years
3 years
Characteristics
Number Root
Root Number Root
Root Number Root
Root
of roots diameter length of roots diameter length of roots diameter length
Varieties
(cm)
(cm)
(cm)
(cm)
(cm)
(cm)
Red
3.2
0.25
15.2
4.6
0.56
23.2
5.0
0.77
36.6
Spotted Red
3.0
0.24
14.6
4.1
0.55
25.2
4.8
0.76
37.1
White
3.1
0.24
16.0
4.1
0.67
24.1
5.1
0.86
35.2
Purple-spotted White
3.2
0.32
18.8
4.3
0.62
27.3
5.1
0.87
40.8
CV%
4.50
4.70
7.30
LSD0.05
0.31
0.11
2.80
3.1.1.5 The harmful level of main pests and diseases on varieties
Generally harmful levels of main pests and diseases on varieties were from mild to moderate
levels. Soft rot disease caused heavy damage to white Rhynchostylis gigantean variety than other
varieties; leaf damage rates were 5-25% (Level 5) in the spring/summer season. In all Rhynchostylis
gigantean varieties, Purple-spotted White variety had mild harmful levels of some main pests and
diseases, pests appear very scattered and diseased leaf rates were below 5% (Level 3).
Rhynchostylis gigantean orchid started flowering after planting 3 years, each plant had one
flowering shoot and it was uniform in all varieties. The flowering percentage was from 40-51%,
highest in Purple-spotted White variety and lowest in White variety.
Flower quality of varieties differed: The number of flowers per inflorescence of the varieties
reached from 21.5 to 26.3 flowers/ inflorescence, flowering shoot length was 12.6-16.8cm,
flowering shoot diameter of varieties gained from 0.45-0.59cm, flower durability ranged from 19 to
24 days. In particular, Purple-spotted White Rhynchostylis gigantean variety had the highest quality
indicators compared to remaining varieties. Flower diameter of varieties had no difference. Flowers
of all varieties had beautiful color and fragrance; especially flowers of Purple-spotted White variety
were fragrant and the remaining varieties had light fragrance.
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3.1.1.6 The quality and time of flower development of Rhynchostylis gigantean varieties
Table 3.6. Flowering rate and flower quality of Rhynchostylis gigantean varieties
(11/2012-2/2013, in Gia Lam - Hanoi)
Flowering Number of Flowering Flowering Flower
Flower Flower Fragrance
Char. rate (%)
flowers
shoot
shoot
diameter durability color
/ìnlorescence length diameter
(cm)
(days)
Varieties
(cm)
(cm)
Dark
Light
Red
45
21.5
14.2
0.45
2.37
21
Red
fragrance
RedSpotted
Light
47
23.4
13.7
0.47
2.33
22
spotted
Red
fragrance
White
Green
Light
White
40
24.3
12.6
0.52
2.30
19
White fragrance
PurplePurplespotted
51
26.3
16.8
0.59
2.33
24
spotted Fragrance
White
White
CV%
6.5
6.7
4.3
5.4
LSD0.05
1.8
2.1
0.06
0.07
Rhynchostylis gigantean orchids usually bloom in the Lunar New Year so are also known as
Nghinh Xuan in Vietnamese (Welcome Spring in English). However, depending on weather
conditions the flowers can bloom sooner or later. In the weather conditions of the Red River Delta,
flowering shoots often appear in November (from 14th to 23th November). Different varieties had
different time of appearing flowering shoot. Results of monitoring in 2013 showed that the
flowering shoots were appeared earliest in Purple-spotted White variety and latest in White
Rhynchostylis gigantean 23th November.
Table 3.7. The flower development time of Rhynchostylis gigantean varieties
(11/ 2012 - 2/2013, in Gia Lam - Hanoi)
Characteristics
Date of
Development Flowering Flowering
Total
appearing time of flower
time
shoot
development
flowering inflorescence
(days)
durability
time of
Varieties
shoots
(days)
(days)
flowers (days)
Red
19/11
54
14
32
86
Spotted Red
20/11
53
13
34
87
White
23/11
55
12
30
85
Purple-spotted White
14/11
55
16
38
93
Development time of flowering shoots of varieties ranged from 53 to 56 days, the shortest
was Spotted Red Rhynchostylis gigantean and the longest was Purple-spotted White variety.
Flowering time was from 12-16 days. Flowering shoots durability of all varieties ranges from 30 to
38 days, the longest was Purple-spotted White variety and the shortest was white Rhynchostylis
gigantean. The total development time of flowers was between 85 and 93 days and Purple-spotted
White variety had the longest time.
Comments: The results assessing the growth and development of Rhynchostylis gigantean
varieties in Gia Lam - Hanoi showed that: In 4 Rhynchostylis gigantean varieties, Purple-spotted
White indigenous variety had healthy growth and development: after growing 3 years a number of
leaves were 6, leaf length was 24.5cm, a number of flowers/inflorescen reached 26.3, shoot length
was 16.8cm, flower durability was 24 days, pests and diseases were mild level. Beautiful color,
fragrance were favored by consumers.
3.1.2 The morphological and antomical characteristics of vegetative organs of some Rhynchostylis
gigantean varieties
3.1.2.1 Morphological and anatomical characteristics of roots
- Morphological root characteristics
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The roots of Rhynchostylis gigantean varieties generally is cylindrical and white-gray. On the
surface of roots of 4 varieties has very thick velvet, this layer is responsible for transporting water
and mineral nutrients into the roots and then those are transported to the stem organs, leaves.
The root tips that are green express the plants are growing, these root parts are capable of
making photosynthesis and root elongation. Colour of root tips tend to flower color, in which the root
tips of red and spotted red flower varieties are purple, root tips of white flower varieties are yellowish
blue, root tips of Purple-spotted White flower varieties are blue, and this is the basis for identifying the
varieties when the plants have not bloomed yet. All indicators about the number of roots, root length,
and root diameter reached the highest value in Purple-spotted White variety. Thus, all Rhynchostylis
gigantean varieties typically have morphological characteristics of roots for each variety, in which
Purple-spotted White variety have morphological characteristics of roots that are favorable for plant
growth such as the largest and longest roots in four varieties.
- Anatomical root characteristics
Components of Rhynchostylis gigantean roots include the velamen, exodermis, cortical
parenchyma, stele, and inner stele having the vascular bundles. Root transection shows that root
cover contains single epidermis covered by large and thick cells that are arranged in format of radial
wall, followed by a layer of polygonal cells, in which cross-section is the ellipse or rectangle. This
cell layer that is capable to absorb water easily and avoid the loss of water from the roots. Root
cover also works to reflect light and be fastened to the surface of other coarse bark; this is the
characteristic of epiphytic plants. Under the cover (the epidermis) is the cortical parenchyma
including many layers having chloroplasts and tubular cells. It is formed by round cells in different
sizes and thin-walled.
Chloroplast cells of roots may photosynthesise and this is typical for the orchid roots.
Cortical parenchyma layers are able to reserve water and nutrients for the plants and can change
shape when climbing (cylinder converted into hemisphere) is typical for epiphytic plants. The
endothelial cell layer wraps around the stele roots, inner stele roots have many vascular bundles
conveying water and the products of photosynthesis.
Apart from the research on anatomical structure, we also measured the size of cover layer,
stele size, a number of vascular bundles and size of vascular bundles. In particular, the Purplespotted White variety reached the highest value: Stele size was 1232.50μm, a number of vascular
bundles were 27.05, and bundle width was 80.5μm.
Table 3.9. Anatomical root characteristics (in 2011, in Gia Lam - Hanoi)
Number of Size of vascular bundles
Characteristics
Size of cover
(µm)
Stele size (µm) vascular
layer (µm)
bundles
Varieties
Thickness
Width
Red
1510.00±102.7 1196.25 ± 55.2 26.95±0.8 193.50±15.3 48.50 ±4.6
Spotted Red
1323.75±84.0
958.75 ± 35.5 26.35±1.4 200.50±12.3 72.00±7.1
White
1580.00±126.0 1228.75 ± 52.0 26.70±2.1 197.50±14.8 67.50±6.6
Purple-spotted White 1463.75± 69.5 1232.50 ± 56.2 27.05±2.2 202.50±10.7 80.50±8.9
Through an assessment of morphological and anatomical roots, Rhynchostylis gigantean
orchids are very specific to monocotyledons and able to adapt to the epiphytic conditions. In which
root characteristics of Purple-spotted White variety have more advantages for the growth and
development of plants such as big roots, thick parenchyma, able to absorb and store water, good
nutrition and high drought tolerance.
3.1.2.2 Morphological and anatomical characteristics of stems
- Morphological stem characteristics
The stems of Rhynchostylis gigantean varieties that were observed are single; their stems are
capable of carrying a lot of leaves. Therefore, perennial plants have the more pairs of leaves and
high flowering capacity because of flower shoots growing from the leaf axils, so a plant can have
multiple flower shoots that make more value of plants.
The stem colors of varieties tend to follow the color of the flowers, but the expression is not
clear as the color of root tips. Red flower variety has purplish green stems and the remaining varieties
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have green stems. Stem height of Red flower variety was highest (8.98cm) and the lowest was the
White flower variety (6.62cm). The stem diameter was largest in Purple-spotted White variety
(1.38cm) and smallest in the Red flower variety (1.17cm).
- Anatomical stem characteristics
Anatomical cross-section of the stems, the outermost layer is a single epidermis, followed
by two rows of thin-walled cells forming a layer of cortical epidermis having multiple stem layers.
Under these epidermises, rows of thin-walled cells formed are the cortical parenchyma with air
spaces in the cells that are responsible for reserving nutrients, transfering gas and reducing the
weight of stem, this demonstrates the adaptation of epiphytic organisms. Stele has numerous
vascular bundles messily arranged between light and soft parenchyma. Vascular bundles include
sclerenchyma, phloem and xylem vessels arranged in sealed superposition type to transport water
and products of photosynthesis.
Observing some indicators such as: The total of vascular bundles, size of vascular bundles,
sclerenchyma size were highest in Purple-spotted White variety.
Table 3.11. Anatomical stem structure of varieties (2011, in Gia Lam - Hanoi)
Parenchyma Number
Large vascular bundles
Small vascular bundles
Characteristics thickness
of
Quantity
Size (µm)
Quantity
Size (µm)
(µm)
vascular
Width Sclerenchyma
Width Sclerenchyma
bundles
thickness
thickness
Varieties
707.50
404.40 155.20 229.38
139.38
249.20 152.50
73.75
Red
±107.75
±38.80 ±23.28 ±18.25
±10.25
±15.52 ±7.75
±9.00
997.50
406.80 137.20 228.75
113.75
269.60 148.75
82.00
Spotted Red
± 122.0
±29.76 ±13.52 ±26.00
±10.75
±22.40 ±8.00
±12.50
745.00
447.20 143.60 227.50
116.25
303.60 145.75
67.00
White
± 95.25
±23.04
±6.08 ±17.00
±11.50
±16.96 ±10.25
±11.75
Purple-spotted
961.25
525.60 239.60 255.00
146.25
286.00 153.25
86.25
White
±73.75
±22.48 ±18.24 ±20.75
±23.25
±4.24 ±8.00
±11.50
Thus, Purple-spotted White variety had the largest stem diameter (1,38cm), the total number
of vascular bundles (525.6), the number of large vascular bundles (239.6) and size of vascular
bundles (Large bundles: 255,00μm; Small bundles: 153,25μm) also reached the highest value;
therefore, the ability transferring water and minerals are better than 3 remaining varieties. This
variety also had the largest sclerenchyma size (big bundles: 146,25μm; small bundles: 86,25μm)
leading to the best mechanical resistance in 4 researched varieties.
3.1.2.3 Morphological and anatomical characteristics of leaves
- Morphological leaf characteristics
The leaves of Rhynchostylis gigantean varieties have some general characteristics such as:
leaf shape is hollow, the leaf tips that are divided into two deflected lobes have spiky or round
thorns, leaf veins are parallel and deep in leaf cells except the midrib, and leaf shape grows erectly.
The leaf colors of varieties tend to follow the color of the flowers, but the expression is not clear. Red
flower variety has dark green with purplish red leaves, Spotted Red flower variety has dark green
leaves with red dots at the base of the petiole, White flower variety has light green leaves and
Purple-spotted White flower variety has green leaves.
The number of leaves of researched varieties generally had no differences and reached 6
leaves. However, the leaf size depends on varieties: The leaf length ranged from 22.57cm to 25.09cm,
leaf width reached from 4.10 to 4.25cm, in which Purple-spotted White variety got the highest value
in all indicators.
- Anatomical leaf characteristics
Structure and the number of stomata of leaves were observed under a microscope on the
peeled epidermis leaves. The stomata that are transformed by the epithelial cells are responsible for
exchanging gas with the environment. Stomata include: stomatal cells, stomatal slots in the middle,
outside stomatal cells having two subordinate cells parallel to stomatal cells. The number of stomata
8
on the upper side of leaves are fewer than the underside of the leaves and stomatal density of the
Rhynchostylis gigantean leaves are lower than the other species of monocotyledon, this proves that
Rhynchostylis gigantean orchids have high drought tolerance.
The mesophyll cells (assimilation tissues) and the vascular bundles are between the upper
and lower epidermises. Mesophyll includes parenchymal cells containing chloroplasts to
photosynthesise. Vascular bundles of midrib and blade are parallel and responsible for transferring
water and products of photosynthesis.
Table 3.13. The number and size of stomata on the upper side of leaves of Rhynchostylis
gigantean varieties (2011, in Gia Lam - Hanoi)
Size of stomatal cells (µm) Size of stomatal slots (µm)
Characteristics Quantity/
Varieties
mm2
Length
Width
Length
Width
Red
10.40 ±0.93 58.58 ±4.29 20.25 ±3.23 24.08 ±2.67 10.30 ±1.70
Spotted Red
10.27 ±1.26 60.70 ±2.62 26.63 ±2.23 25.93 ±3.52 11.58 ±2.41
White
10.17 ±1.02 58.83 ±6.08 25.95 ±2.38 23.38 ±2.59 10.80 ±2.24
Purple-spotted White
12.30 ±1.62 61.93 ±2.99 26.08 ±3.35 25.83 ±3.03 11.93 ±2.49
The length of stomata on the upper side of leaves ranged from 58.58μm to 61.93μm, in
which Purple-spotted White variety was longest and Red variety was shortest. The width of the
stomata also changes in varieties. White variety was widest (26.63μm) and Red variety was smallest
(20.25μm). Size of tomatal slots depends on the size of the stomata, the difference of stomatal slot
size in varieties were negligible.
Table 3.14. The number and size of stomata on the underside of leaves of Rhynchostylis
gigantean varieties (2011, in Gia Lam - Hanoi)
Characteristics Quantity/ Size of stomatal cells (µm) Size of stomatal slots (µm)
Varieties
mm2
Length
Width
Dài
Rộng
Red
15.37 ±1.52 52.93 ±3.83 23.80 ±2.19
23.83 ±2.15 10.08 ±1.64
Spotted Red
13.47 ±1.87 61.33 ±3.87 24.18 ±2.96
25.08 ±2.58 11.63 ±2.23
White
15.57 ±1.63 59.33 ±4.84 24.43 ±2.38
23.63 ±2.14 10.70 ±1.82
Purple-spotted White
17.10 ±1.88 62.43 ±4.02 25.43 ±3.35
26.18 ±3.13 12.68 ±2.17
The number of stomata on the upper side of leaves in varieties was from 10.17 to 12.30
stomata/mm2. The number of stomata on the underside of the leaves was from 13.47 to 17.10 per
mm2. The number of stomata on the upper side of leaves in varieties was less than the underside of
the leaves, in which Purple-spotted White variety had the highest number of stomata (upper side:
12.47 stomata/mm2; underside: 17.10 stomata/mm2). Size of stomata and stomatal slots also reached
the highest value in this variety.
Table 3.15. Anatomical structure of Rhynchostylis gigantean leaves (2011, in Gia Lam - Hanoi)
Varieties
Red
Spotted Red
White
Purple-spotted
Characteristics
White
102.50±9.00
98.75±19.50 107.00±17.00
88.75±7.75
Epidermis
Leaf upper side
thickness (µm)
91.88±7.25
88.25±15.50
99.50±16.50
79.38±9.25
Leaf underside
Assimilation tissue thickness (µm) 2436.25±165.00 2446.25±146.25 2617.50±112.50 2705.00±219.50
328.13±15.25 399.50±82.25 362.50±75.50 503.75±10.75
Size of vascular
Length
bundles of midrib
210.00±22.00 223.25±10.25 209.50±25.50 275.63±25.00
Width
(µm)
12.55±1.05
12.30±1.17
11.60±1.50
13.30±1.75
Large vascular
Quantity
bundles on blade Size Thickness
278.75±70.00 312.00±53.50 345.00±53.50 351.88±35.25
(µm)
188.25±17.50 187.00±16.00 197.00±19.75 236.88±16.00
Width
28.50±1.79
25.50±1.93
27.40±3.61
31.10±1.37
Small vascular
Quantity
bundles on blade Size Thickness
161.25±15.50 155.75±27.75 170.75±27.75 193.75±18.50
(µm)
125.63±11.50 110.00±17.50 122.00±17.50 138.75±13.25
Width
Epidermis thickness of the blade in varieties ranged from 88.75μm to 107.00μm. Under
epidermis thickness was thinner than upper epidermis, ranging from 79.38μm to 99.50μm, in which
Purple-spotted White variety had thinnest epidermis and White variety had thickest epidermis.
9
Assimilation tissue thickness, the number and size of vascular bundles were largest in Purplespotted White variety.
In brief, Purple-spotted White variety had the longest and widest size of leaves (respectively
25.09cm and 4.25cm), assimilation tissue thickness was also largest (2705.0μm), so the ability of
synthesizing and reserving leaf organic materials of this variety are better than 3 remaining varieties.
Purple-spotted White variety also had the largest vascular bundles of midrib size, the highest number of
vascular bundles on blade and the largest size of vascular bundles compared to 3 remaining varieties.
Therefore, the ability of transporting substances in the leaves of this variety is the best.
3.1.1.4 Morphological characteristics and size of reproductive organs
- Morphological characteristics and size of flowers
The common characteristics of Rhynchostylis gigantean flowers are large, bisexual; grow
around the floral axes (flowering shoots), thick sepals and petals, petal lips divided into three lobes.
Table 3.16. The characteristics of flowering shoots and flowers of Rhynchostylis gigantean varieties
(2011, in Gia Lam - Hanoi)
Number of Flowering Flowering Flower
Flower
Flower
Fragrance
Char.
flowers
shoot
shoot
diameter
shoot
durability
Varieties
/inflorescen diameter length (cm) (cm) length (cm)
(days)
(cm)
Red
21.00 ±8.16 0.46 ±0.07 12.61 ±2.93 2.4 ±0.12 2.37 ±0.18 21.30 ±1.89 Fragrance
Spotted Red
23.90 ±6.17 0.47 ±0.07 12.64 ±2.93 2.3 ±0.11 1.60 ±0.17 21.20 ±1.81 Fragrance
White
23.40 ±3.63 0.49 ±0.06 11.98 ±2.05 2.3 ±0.13 1.62 ±0.12 20.60 ±1.78 Fragrance
Purple-spotted
Strong
26.80 ±5.65 0.49 ±0.08 12.74 ±1.65 2.4 ±0.08 2.27 ±0.20 23.10 ±2.13
White
fragrance
Overall, all varieties had a flowering shoot per a plant and quite large number of flowers
/inflorescen (over 20 flowers/inflorescen), flowering shoot length varied from 11.98cm to 12.74cm,
flower stem length reached from 1.60cm to 2.37cm and flower durability ranged from 20.6 to 23.1
days. In particular, all indicators reached the highest numbers in Purple-spotted White variety.
Flowering shoot and flower diameter of all varieties had no difference. The 3 imported varieties had
light fragrance; however indigenous variety was fragrant (Purple-spotted White variety).
Apart from the indicators of flowering shoots, durability and fragrance, we also assessed the
size and color of flower petal lips, sepals and petals.
Table 3.17. Size and color of lips, sepals and petals of Rhynchostylis gigantean (2011, Gia Lam Hanoi)
Sepal size
Petal size
Characteristics
Lip size (mm)
Sepal
(mm)
(mm)
Petal color Lip color
color
Varieties
Length Width Length Width Length Width
20.30 10.63 15.52 9.87 14.05 6.98
Red
Dark red Dark red
Dark red
±0.60 ±0.59 ±0.59 ±0.56 ±0.50 ±0.44
White
21.12 11.02 14.18 10.30 14.63 6.63
White with
Spotted Red
with red
Red
±0.87 ±0.62 ±0.62 ±0.55 ±0.74 ±0.60
red spots
spots
20.72 10.13 13.62 10.55 13.43 6.57
White
White
White
White
±0.72 ±0.43 ±0.88 ±0.75 ±0.84 ±0.65
White
White with White with
Purple-spotted
20.80 9.27 14.40 9.37 14.53 5.87
with
purple
purple
White
±0.96 ±0.69 ±0.80 ±0.99 ±0.61 ±1.00
purple
spots
spots
spots
The Purple-spotted White variety produced not only the smallest-sized lips but also the
smallest sepals (14.40 mm x 9.37 mm) and petals (14.53 mm x 5.87 mm). The longest sepals belong
to the Red variety (15.52mm); the shortest but widest sepals were produced by the White variety
(13.62mm x 10.55mm). The variety of Spotted Red obtained the longest values of petals
(14.63mm), meanwhile the Red variety produced the widest (6.98mm).
10
Accordingly, despite insignificant difference in diameter values of the flowers, size of other
floral parts, including lips, sepals and petals, varied amongst different varieties in the experiment.
- Morphological characteristics and size of fruit
Color of fruit also varied amongst different varieties, as the color of their root, stem and
leaves. The Red variety produced fruit of purplish green, particularly, of which purple color
concentrated in the area of stalk base; fruit of the Spotted Red variety also saw purplish green color
in the stalk base area and along the fruit veins; the fruit of both the White and Purple-spotted White
varieties were green in color. The fruit length varied from 2.43cm to 3.42cm, in which the greatest
value belongs to the Red variety and the smallest value belongs to the Spotted Red. The fruit width
of the varieties in the experiment fell in the range from 1.19 to 1.30cm.
The results of morphological study on the Rhynchostylis gigantean varieties suggest that the
Purple-spotted White obtained advanced characteristics in growth, development and tolerance to
pests and diseases since the variety produced large roots with thick cover layer (1463.75± 69.5µm);
great-in-size stele (1232.50 ± 56.2µm); large number of root and stem vascular bundles
(27.05±2.2µm and 525.60 ±22.48µm, respectively); thick leaves (assimilation tissue thickness of
2705.00±219.50µm), with large vascular bundles of midrib (503.75 ±10.75µm long, and
275.63±25.00µm wide). Therefore, it was proved that the Purple-spotted White was potential for
vigorous growth, development and tolerance to pests and diseases, which is in accordance with the
results interpreted above. Accordingly, Purple-spotted White was selected for further research and
understanding.
3.1.3 Correlation of the growth of leaves with roots and flowers of purple-spotted white
Rhynchostylis gigantean
Table 3.19. Correlation of the growth of leaves, with roots and flowers of purple-spotted white
Rhynchostylis gigantean (2012)
Characteristics
Leaf length
Root length
Rachis length
No.of
(cm)
(cm)
(cm)
flowers/
inflorescence
(Flowers)
Leaf length (cm)
1
Root length (cm)
0.4562
1
Rachis length (cm)
0.9075
0.4659
1
No.of flowers/inflorescence
0.9012
0.3676
0.8644
1
(flowers)
35
y = 0,4148x + 30,597
R 2 = 0,2081
30
25
20
15
10
5
30
20
15
10
5
5
10
15
20
Chiều dài lá (cm)
25
30
35
20
15
10
0
0
0
25
5
0
0
y = 0,8609x + 4,9414
R2 = 0,8121
35
Số hoa/cành (hoa)
40
Chiều dài cành hoa (cm)
45
Chiều dài rễ (cm)
y = 0,7433x - 1,5837
R2 = 0,8236
25
50
5
10
15
20
Chiều dài lá (cm)
25
30
35
0
5
10
15
20
25
30
35
Chiều dài lá (cm)
Figure 3.6. Correlation of leaf Figure 3.7. Correlation of leaf Figure 3.8. Correlation of leaf
length with root length
length with rachis length
length with No. of flowers per
inflorescence
The results indicate the correlation between the length of leaves and roots (R2<0.5).
Meanwhile, the correlation of leaf length with florescence length and number of flowers per
floresecence were strong (R2>0.5, a>0).
Accordingly, in order to improve the flower quality of purple-spotted white Rhynchostylis
gigantean (length of florescences, number of flowers per florescence), techniques to increase the
length of leaves would play a vital role. Such recommendation is in line with previous study of Jean
Cardoso et al. (2012) on Phalaenopsis FSNT 'Dai-Itigo [47].
11
3.1.4 Growth and development characteristics of the purple-spotted white Rhynchostylis
gigantean in different ecoregions
3.1.4.1 Growth characteristics of the purple-spotted white Rhynchostylis gigantean in different
ecoregions
Table 3.20. Growth characteristics of the purple-spotted white Rhynchostylis gigantean in some
ecoregions (2012)
No.of
Leaf
Leaf
No.of
Root
Root
Characteristics
leaves
length
width
roots
length
diameter
Locations
(leaves)
(cm)
(cm)
(roots)
(cm)
(cm)
Gia Lam - Ha Noi
6.2±0.29 24.5±0.39
4.5±0.14 5.2±0.32 40.7±0.49 0.86±0.01
Van Giang - Hung Yen 6.0±0.21 24.6±0.44 4.6±0.15 5.3±0.30 41.0±0.64 0.87±0.01
Moc Chau - Son La
5.1±0.35 20.4±0.35
3.7±0.13 4.4±0.30 34.9±0.20 0.71±0.02
Sa Pa- Lao Cai
5.0±0.30 19.5±0.40 3.8±0.14 4.0±0.26 29.3±0.45 0.69±0.02
The growth indicators of Rhynchostylis gigantean in the Red River Delta were greater than
those in the North moutainous regions. Ability to grow of the plants in Gia Lam - Ha Noi and Van
Giang -Hung Yen were statistically similar, with number of leaves of 6.0-6.2 (leaves), leaf length of
24.5-24.6cm, number of roots of 5.2-5.3 (roots), and root length of 40.7-41.0cm.
In the North mountainous regions, Rhynchostylis gigantean in Sapa - Lao Cai and Moc ChauSon La reached the same level of growth, which was inferior to that of the plants in the Red River
Delta. The main reason of the difference was due to low temperature in winter season in the
mountainous regions that caused significant reduction in plant growth.
Figure 3.10. Growth dynamics of root length
Figure 3.11. Growth dynamics of leaf length
of Rhynchostylis gigantean in different
of Rhynchostylis gigantean in different
ecoregions
ecoregions
Rhynchostylis gigantean in the Red River Delta produced vigorous growth of leaves and roots,
which lasted 8 months from March to October. In the mountainous regions, the plants obtained inferior
growth to those in the Red River Delta, which began later (in April) but finished earlier (in September).
3.1.4.2 Flowering characteristics of purple-spotted white Rhynchostylis gigantean in different ecoregions
Table 3.21. Time of flowering and flower quality of Rhynchostylis gigantean in different eco-regions
(November 2012 – February 2013, purple-spotted white Rhynchostylis gigantean )
Char. Time of Percentage Length of
No. of
Diameter Diameter Flower
flower
of plants flowering flowers per of rachis
of
durability
bud
producing
shoot inflorescence (cm)
flowers
(days)
Locations
initiation flowers (%)
(cm)
(flowers)
(cm)
16.7±
Gia Lam –
7/11
50
26.2±0.20 0.59±0.01 2.33±0.02
24
Ha Noi
0.22
Van GiangHung Yen
Moc Chau - Son
La
Sa Pa - Lao Cai
7/11
51
16.9±0.12
26.4±0.27
0.58±0.01 2.31±0.01
24
3/11
30
13.6±0.14
20.3±0.33
0.44±0.01 2.29±0.01
27
3/11
25
12.7±0.12
18.4±0.30
0.46±0.02 2.30±0.01
27
12
The appearance of flower buds in the North mountainous regions (on 3rd November 2012)
was earlier than that in the Red River Delta (on 7th November 2012). The percentage of plants
producing flowers was highest in the Red River Delta (50-52%) and lowest in the North
mountainous regions (25-30%).
Flower quality described by three typical characteristics of flowering shoot length, number
of flowers per inflorescence, and rachis diameter of the plants in Hung Yen and Ha Noi was
statistically similar. Meanwhile, flowers of Rhynchostylis gigantean in regions of Moc Chau – Son
La and Sapa – Lao Cai were of lower quality. However, flowers of Rhynchostylis gigantean in
mountainous regions were more durable than those in the Red River Delta. The flowers lasted 27
days and 24 days, respectively.
3.2 Effect of technical measures on growth of Rhynchostylis gigantean seedlings 3.2.1. Effect of
growing medium and times of watering on growth of nursery seedlings
Table 3.22. Effect of growing medium and times of watering on growth of nursery seedlings (2011,
Gia Lam - Ha Noi)
Media
Times of
Survival Number
Leaf
Leaf
Number Root Diameter
watering
rate
of
length
width of roots length
of roots
(%)
leaves
(cm)
(cm)
(cm)
(cm)
(cm)
GT1
75
3.8
10.1
1.7
3.4
18.5
0.32
GT2
82
4.1
11.2
1.8
3.6
19.6
0.35
GT3
82
4.1
11.3
1.8
3.6
19.4
0.34
LSD0,05 medium
0.11
1.07
0.12
0.12
1.05
0.17
Twice a day
78
3.9
10.4
1.8
3.4
18.3
0.32
Once a day
82
4.1
11.7
1.8
3.6
19.6
0.34
Once / 2 days
82
4.1
11.8
1.8
3.6
20.3
0.35
Once / 3 days
76
3.9
10.5
1.7
3.4
19.6
0.33
LSD0,05 watering times
0.12
1.20
0.23
0.14
1.22
0.20
Twice a day
80
4.0
11.0
1.8
3.6
18.8
0.30
Once a day
76
3.8
10.6
1.7
3.5
19.5
0.32
GT1
Once / 2 days
73
3.8
10.4
1.7
3.2
20.2
0.33
Once / 3 days
70
3.7
10.3
1.6
3.2
20.0
0.31
Twice a day
75
3.8
10.4
1.7
3.2
17.0
0.32
Once a day
81
4.1
11.0
1.8
3.6
18.8
0.34
GT2
Once / 2 days
89
4.4
12.0
1.9
3.9
21.1
0.37
Once / 3 days
83
4.2
11.5
1.9
3.6
20.0
0.35
Twice a day
79
3.9
10.6
1.8
3.5
19.0
0.33
Once a day
88
4.3
12.2
1.9
3.8
20.5
0.36
GT3
Once / 2 days
85
4.2
11.8
1.9
3.7
19.5
0.34
Once / 3 days
76
3.8
10.5
1.7
3.5
18.7
0.32
LSD0,05 medium*watering
0.22
2.15
0.40
0.24
2.11
0.35
times
CV%
3.30
6.60
5.20
4.10
6.50
4.30
Note: GT1 (control): charcoal + coarse bark (ratio 1:1), GT2: seaweed + charcoal + coarse
bark (ratio 1:1:1), GT3: Cocopeat+ charcoal + coarse bark (ratio 1:1:1)
Types of growing media and times of watering had different influence on growth of
Rhynchostylis gigantea at level of 95% confidence. The treatment GT2 -with one watering every 2
days, and the treatment GT3 – with one watering a day were recorded to be the most appropriate
for growth of the seedlings.
3.2.2 Effect of fertilizers and times of fertilizing times on growth of nursery seedlings
The results indicate interaction amongst fertilizers and times of application. Increase in times of
fertilizer application - from once every 7 days to once every 3 days - promoted gradual increase in the
plant growth. The treatment of Fish Emulsion fertilizer (5:1:1) with one application every 5 days
(concentration of 0.05%) produced the highest results with 4.7 leaves of 13.2cm long, and 4.0 roots of
13
22.0cm long. At level of 95% confidence, he same level of growth was recorded in the treatment of
one application of the same fertilizer every 3 days. Such increase was due to high content of nitrogen
in the fertilizer that was suitable for Rhynchostylis gigantea during vegetative growth period.
Table 3.23. Effect of fertilizers and fertilizing times on growth of nursery seedlings (2011, Gia Lam - Ha Noi)
Fertilizers Fertilizing times No. of
Leaf
Leaf
No.
Root Diameter
leaves length
width
of
length
of roots
(cm)
(cm)
roots
(cm)
(cm)
PB1
3.9
10.7
1.7
3.1
18.9
0.32
PB2
4.4
12.9
1.8
3.7
21.0
0.35
PB3
3.9
11.1
1.7
3.1
18.9
0.34
LSD0,05 Fertilizers
0.10
0.67
0.10
0.11
1.00
0.18
Once / 9 days
3.8
11.0
1.6
3.1
18.2
0.32
Once / 7 days
4.0
11.1
1.7
3.2
19.0
0.33
Once / 5 days
4.3
11.9
1.8
3.5
20.2
0.34
Once / 3 days
4.3
12.1
1.9
3.5
20.7
0.35
LSD0,05 Fertilizing times
0.11
0.78
0.10
0.12
1.16
0.21
Once / 9 days
3.7
10.0
1.7
3.0
17.5
0.32
Once / 7 days
3.9
10.6
1.7
3.1
18.8
0.32
PB1
Once / 5 days
4.1
11.0
1.8
3.3
19.3
0.33
Once / 3 days
4.2
11.4
1.9
3.3
20.0
0.34
Once / 9 days
4.1
12.5
1.8
3.4
19.1
0.33
PB2
Once / 7 days
4.3
12.8
1.9
3.6
20.9
0.35
Once / 5 days
4.7
13.2
1.9
4.0
22.0
0.36
Once / 3 days
4.7
13.3
2.0
4.0
22.1
0.36
Once / 9 days
3.8
10.5
1.6
3.1
18.0
0.33
Once / 7 days
3.9
10.8
1.7
3.1
18.7
0.34
PB3
Once / 5 days
4.1
11.6
1.8
3.2
19.0
0.34
Once / 3 days
4.1
11.7
1.8
3.3
20.1
0.35
LSD0,05 Fertilizers* F. times
0.20
1.35
0.20
0.22
2.01
0.37
CV%
3.00
6.90
6.80
3.90
6.10
6.50
3.3. Effect of technical measures on growth and developmennt of Rhynchostylis gigantea in the
net-house
3.3.1 Effect of transplanting time on growth and development of Rhynchostylis gigantea
Above-mentioned results of the research on growth characteristics of Rhynchostylis gigantea
suggest that the plants have distinct seasons for vegetative growth. Therefore, research on time of
transplanting is necessary.
Table 3.24. Effect of transplanting time on growth of Rhynchostylis gigantea (20112012, Gia Lam – Ha Noi)
1 year after transplanting
2 years after transplanting
Char.
Time of
Survival
No. of
Leaf
No. of
No. of
Leaf
No. of
rehabilitation
rate (%)
leaves
length
roots
leaves
length
roots
Treatments
(days)
(leaves)
(cm)
(cm)
(leaves)
(cm)
(cm)
Feb 15th
81
25
4.9±0.21 15.7±0.12 4.0±0.21 6.1±0.18 25.1±0.1 5.3±0.1
Mar 15th
85
17
5.1±0.1
17.6±0.1
4.2±0.1
6.4±0.1
26.6±0.1 5.9±0.2
Apr 15th
97
10
5.4±0.1
19.0±0.2
5.6±0.2
7.0±0.2
27.4±0.1 6.8±0.1
May 15th
92
13
5.0±0.2
18.1±0.1
4.7±0.1
6.3±0.1
25.4±0.1 6.2±0.1
14
The results describe high rate of plant survival after transplanting, ranging from 81 to 97%,
of which highest result belongs to the plants transplanted on April 15th. The earliest rehabilitated
plants were also observed in the treatment (10 days after transplanting); meanwhile, plants in the
other treatments required 13-25 days to rehabiliate. At different time of transplanting, the strongest
ability to grow belonged to the plants transplanted on April 15th, indicated by number of leaves (7.0
leaves), leaf length (27.4cm), number of roots (6.8 roots), and root length (43.2cm) - which were
different from those of the other treatments at level of 95% confidence. The difference was because
of low temperature in the mountains, which resulted in poor growth of the plants transplanted on
15th of February and Mach. Vegetative growth of the plants transplanted on May 15th was also
negatively affected since the temperature in the season highly increased.
Table 3.25. Effect of transplanting time to flower quality
(November 2012 – February 2013, Gia Lan - Hanoi)
Flowering
Length of
Flowering No.of flowers
Rachis
Flower
Char.
rate (%)
flowering
shoot
per
length
durability
shoot (cm)
diameter
inflorescence
(cm)
(days)
Treatments
(cm)
(flowers)
Feb 15th
47
16.3±0.1
0.59±0.1
25.1±0.3
11.2±0.1
24
Mar 15th
54
16.5±0.1
0.61±0.1
26.0±0.2
11.4±0.1
24
Apr 15th
17.5±0.1
0.67±0.1
28.5±0.1
12.3±0.1
25
56
May 15th
50
16.8±0.1
0.60±0.1
26.4±0.3
11.7±0.1
24
According to the observation of flower quality amongst the treatments, the rate of flowering
varied from 47 to 56%, of which the highest value was obtained by the plants transplanted on 15th
April. The length of flowering shoot, and number of flowers per inflorescence of the treatment was
also of the highest values, with 17.5cm and 28.5, respectively. Values of flowering shoot diameter,
flower diameter and flower durability of the treatments indicated no significant difference.
3.3.2 Effect of water quality on growth and development of Rhynchostylis gigantea Table 3.26. Effect
of water quality on growth of Rhynchostylis gigantea
(2012-2013, Gia Lam – Ha Noi)
Characteristics
1 year after transplanting 2 years after transplanting
Survival
No.
No.
Leaf
Root
Leaf
Root
rate No. of
of
No. of
of
length
length
length
length
Treatments
(%) leaves
roots
leaves
roots
(cm)
(cm)
(cm)
(cm)
(cm)
(cm)
Well-water without
87
4.8
16.8 4.1 26.4
5.7
23.0
4.9 38.4
filtration
Filtered well-water
95
5.0
18.3 4.4 27.5
6.2
24.7
5.2 40.9
Tap-water
80
4.7
16.3 3.9 25.8
5.5
22.1
4.5 34.7
Rain-water
98
5.6
19.1 5.0 31.6
7.3
27.6
6.7 44.3
CV%
2.90 5.70 2.30 3.90 2.40
6.10 2.90 4.10
LSD0,05
0.26 2.20 0.27 2.02 0.28
2.79 0.28 3.02
Results of the study on water quality suggest that the plants produced vigorous growth when
rain water was used for watering, followed by the plants that were applied with water obtained from
wells with filtration and without filtration. The least vigorous growth was observed in the treatment
with use of tap-water. At level of 95% confidence, the plants in the experiment produced 5.5-7.3
leaves of 22.1- 27.6cm long, 4.5-6.7 roots of 34.7-44.3cm long. Indicators of leaf width and root
diameter in the treatment of rain-water were higher than those in the other treatments; meanwhile
the indicators of lowest values belonged to the treatment of tap-water.
The highest rate of flowering plants belongs to the treatment of rain-water (58%), followed
by the plants with filtered well-water (52%), then well-water without filtration (49%); and finally
the plants with tap-water (47%). The results of flower quality were of the same ranking.
15
Table 3.27. Effect of water quality to flower quality
(November 2013 – February 2014, Gia Lam – Ha Noi)
Characterisitcs Flowering Flowering Flowering
No. of
Rachis Flower
Treatments
rate (%)
shoot
shoot
flowers/
length durability
length
diameter inflorescence (cm)
(days)
(cm)
(cm)
(flowers)
Well-water without
49
16.9
0.59
25.5
11.3
23
filtration
Well-water with filtration
52
17.0
0.60
26.5
11.8
24
Tap-water
47
16.2
0.57
24.3
11.0
23
Rain-water
58
18.5
0.69
29.7
13.5
27
CV%
4.10
5.70
8.30
6.50
LSD0,05
1.26
0.08
4.00
1.30
Hence, it is obvious that water quality had influence on growth and development of
Rhynchostylis gigantea. Rain-water was proved to be the most suitable for the plants, followed by
well-water with and, then, without filtration; tap-water was the least suitable for the plant
development. The explaination was due to level of pH and EC in different sources of water. Low
EC and pH of rain-water, which were 0.04 and 5.55, respectively, together with the fertilizers
applied constituted a favorable condition for the plants to absorb water and nutrients, producing
vigorous growth and development. Although filtration reduced pH of well-water, EC remained at
high level that required further adjustion for watering Rhynchostylis gigantea. Well-water without
filtration and tap-water should not be used for plant watering since these sources of water had high
level of pH and EC, particularlly tap-water with too-high pH value of 7.52 and EC of 0.45,
inhibiting the plant growth and development.
3.3.3 Effect of growing media and times of watering on growth and development of
Rhynchostylis gigantea
Different constitutions of growing media and times of watering caused different effect on
the growth and development of Rhynchostylis gigantea. Treatments of GT1 (mounted on wood
trunks of longan trees) with one watering a day, and treatment of GT2 (seaweed + charcoal +
crushed wood) with one watering every 2 days were observed to be the most suitable. Growing
medium in treatment of GT3, even with different times of watering, maintained high moisture
since the cocopeat composition had high potential of water adsorption that led to unpleasant
airless environment, thus, inhibiting the growth and development of Rhynchostylis gigantea.
Study on the effects of growing media and times of watering suggested that the drier the
environment was, the faster the plants produced flower buds. The earliest emergence of flower buds
was recorded in the treatment of well-drained medium (GT1) with one watering every 3 days, of
which flower buds appeared on 5th November. Similar situation was recorded in the observation of
flower quality. The treatment of GT1 with one watering a day produced flowers of highest and the
same quality of those in the GT2 treatment with one watering every 2 days at level of 95%
confidence. The longest flowering shoots were 18.6cm and 18.5cm, with highest number of flowers
per inflorescence (29.8 and 29.5 flowers). Therefore, reduction of watering times (once every 3
days, and less amount of water) at stage of flower buds initiation would stimulate the plants to
produce inflorescence and at higher flowering rate.
16
Table 3.28. Effect of growing media and times of watering on growth of Rhynchostylis gigantea in
production garden (2012-2013, Gia Lam – Ha Noi)
Media
Times of
Survival
1 year after transplanting
2 years after transplanting
watering
rate
No. of Leaf
No.
Root No. of Leaf
No.
Root
(%)
leaves length
of
length leaves length
of
length
(cm) roots (cm)
(cm) roots (cm)
(cm)
(cm)
GT1
94
5.2
18.2
4.9
28.7
6.6
26.3
6.5
42.6
GT2
94
5.3
18.3
4.7
28.8
6.7
26.4
6.2
42.9
GT3
93
5.0
17.2
4.6
27.5
6.1
25.2
5.9
40.9
LSD0,05 Medium
0.10
1.00
0.10
1.05
0.11
1.07
0.12
1.06
Twice a day
94
5.1
17.4
4.6
27.3
6.5
25.1
6.0
39.7
Once a day
96
5.2
18.7
4.7
28.2
6.7
26.4
6.2
41.6
Once / 2 days
95
5.3
18.6
4.8
29.0
6.7
26.0
6.3
43.1
Once / 3 days
91
4.9
17.3
4.9
29.5
6.1
25.1
6.5
44.2
LSD0,05 watering times
0.12
1.20
0.13
1.00
0.13
1.24
0.14
1.22
Twice a day
96
5.4
18.5
4.7
27.5
7.0
26.4
6.2
40.2
Once a day
4.8
28.4
6.4
42.0
97
5.4
18.6
7.0
26.6
GT1
Once / 2 days
93
5.1
18.0
5.0
29.2
6.4
25.4
6.7
43.5
Once / 3 days
90
4.9
17.8
5.1
29.9
6.0
25.0
6.9
45.0
Twice a day
94
5.1
17.8
4.7
27.7
6.4
25.1
6.1
40.5
Once a day
95
5.4
18.4
4.8
28.6
7.0
27.0
6.3
42.4
GT2
Once / 2 days
4.8
29.4
6.3
43.9
98
5.7
19.1
7.5
27.7
Once / 3 days
92
5.0
18.1
4.8
29.8
6.2
25.6
6.4
44.8
Twice a day
93
5.0
18.0
4.4
26.7
6.1
25.5
5.5
38.5
Once a day
95
5.0
18.2
4.6
27.6
6.1
25.8
5.9
40.4
GT3
Once / 2 days
94
5.1
17.8
4.6
28.4
6.3
25.0
6.0
41.9
Once / 3 days
92
5.0
17.7
4.8
28.8
6.2
24.9
6.3
42.8
LSD0,05
0.20
2.01
0.21
2.00
0.22
2.15
0.24
2.12
Medium*watering times
CV%
2.00
4.00
2.00
2.04
2.00
5.00
2.30
3.00
Note: GT1: Mounted upon a trunk of longan tree of cylinder shape (40cm high x 20cm (diameter)),
GT2: Seaweed + Charcoal + crushed wood, GT3: cocopeat + charcoal + coarse bark, GT2, GT3:
nestled in wood baskets with a layer of 2-3cm of charcoal, coarse bark, crushed wood.
Table 3.29. Effect of growing media and times of watering on flowering ability and flower
quality of Rhynchostylis gigantea (November 2013 – February 2014, Gia Lam – Ha Noi)
Media Times of
Date of Flowering Flowering Diameter Number of
Flower
watering
flower
rate (%)
shoot
of
flowers per durability
bud
length
Flowers inflorescence
(days)
initiation
(cm)
(cm)
(flowers)
GT1
6/11
58
17.5
0.64
27.8
24
GT2
7/11
56
17.6
0.65
28.1
24
GT3
9/11
52
16.8
0.62
27.7
23
LSD0,05 Medium
0,72
0,39
1,22
Twice a day
9/11
53
17.0
0.63
27.5
22
Once a day
8/11
56
17.8
0.65
28.5
24
Once / 2 days
7/11
57
17.5
0.64
28.3
24
Once / 3 days
5/11
57
16.9
0.63
27.3
23
LSD0,05 Watering times
0.82
0.45
1.41
Twice a day
8/11
55
17.7
0.66
28.0
23
GT1 Once a day
7/11
0.67
59
18.6
29.8
25
Once / 2 days
6/11
59
17.0
0.61
27.5
24
17
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