Zhejiang native species Prunus zippeliana as the test material, effect of substrate selection and different types of container root control on Prunus zippeliana container seedlings was studied. The study not only established a scientific and rational cultivation technology system for Prunus zippeliana container seedlings, but also achieved agricultural and forestry waste recycling. This is a great significance for reducing environmental pollution. The main results are as follows:These five kinds of waste materials–shells of Carya cathayensis, sawdust; twigs and defoliation, mushroom residues, drug waste were collected, after fermentation and disinfects processing, and were mixed into 8 different light cultivation substrates according to different ratio. Determining their physical and chemical properties, compared with daily light substrates (peat and pearlite=7.5∶2.5) of cultivation container seedlings. Results showed that 8 different light cultivation substrates’bulk density, total porosity, aeration porosity, pH and Total N showed significant differences(α=0.05); water-holding porosity, A/W ratio, total P, total K(except the 6th and 7th substrates), available K showed highly significant differences(α=0.01). It is showed that each mixed substrate has good physical and chemical properties; has rich nutrient elements like total N, total P, total K and available K for container seedling cultivation.The variance analysis method analyzed 8 group substrates on Root and shoot part morphological indicators, biomass accumulation indicators, physiological indicators of Prunus zippelian seedlings. It suggested that the 2nd substrate (sawdust∶twigs and defoliation∶carya cathayensis shells∶perlite=4∶2∶3∶1) was the best substrate for Prunus zippeliana container seedlings, followed by the 1st substrate(sawdust∶twigs and defoliation∶peat∶perlite=2∶4∶2∶2) and the 3rd substrate (sawdust∶Carya cathayensis shells∶mushroom residues∶perlite=6∶2∶1∶1).Two root control containers 20cm×19cm light black non-woven bag and plastic root control container were compared with the plastic pots on the growth of Prunus zippeliana container seedlings. The results showed that both root control containers had significant effect on Prunus zippeliana container seedlings. Light black non-woven bag had significant difference on first class lateral root, root surface area and project area compared with the plastic root control container. Therefore the light non-woven bag for root control of Prunus zippeliana container seedling was better.
Study on Physiology Characteristic and Landscape Application of Elsholfizia Argyi
Elsholfizia argyi belongs to Labiatae family, Elsholtzia genera. It is a kind of herb with beautiful flower posture, and unique color of flowers, and it can resistant to heavy mentals.Therefore, it has high potential value of landscape application.The article focused on the study of seed germination characteristics, water stress, shade treatments and landscape applications of Elsholfizia argyi.The conclusion of this research as follows:（1）Seed germination:The result showed that the seed germination rate of Elsholfizia argyi is lower in the natural condition. According to different concentrations of GA3, IAA and NAA soaked for 24 hours compared with those treated with water, as well as sifferent soaking time of anhydrous alcohol and 30 %H2O2, the conclusion of promoting effect on seed germination is:IAA 100 mg/L>NAA 200 mg/L>GA3 150 mg/L> H2O2 90 min>anhydrous alcohol 40 min.（2）Water stress:With the water stress increasing, the leaves of Elsholfizia argyi went to hairy,wilting and yellow.While chlorophyll content increased,the leaf relative water content dropped. The physiological indexes including relative conductivity rate,MDA, SOD activity,POD activity and soluble sugar all changed as the increasing of the relative water content of soil, which emboied 20 %>45 %>65 %>80 % >95 %, but soluble protein content dropped. In the later time of stressing, chlorophyll fluorescence parameters such as NPQ, Fm, Fv/Fm, qP, Yield and ETR dropped, but Fo increased. Along with the extension of the water stressing time, leaves of Elsholfizia argyi changed to yellow and dry gradually, even fell off, and the height of plant dropped substantially, and some plants died when the relative water content was higher than 92 %. It was good for Elsholfizia argyi’s growthas the relative water content of soil was 65 %～80 %. When the relative water content of soil was during 20 %～65 % ,the growth was limited , while it can’t grow well when the realative water content of soil were less 20 % or higher than 92 % .（3）Shade treatments: With the increase of shading extent, the chlorophyll content increased, while the Chla/b decreased;chlorophyll fluorescence parameters such as Fo and NPQ dropped firstly and then rose,but Fm,Fv/Fm,Fv/Fo and qP rose firstly and then dropped. The content of MDA reduced. It can be found that the water content and relative conductivity of leaves increased but when shade was 75 %, they dropped, while the changes were opposite on the contents of soluble sugar and protein.It also can be found that POD activity performed as rose-fell-rose,and its minimum appeared in the shade of 75 %. In conclusion, the most suitable growth light condition of Elsholfizia argyi was in the shade of 75 %. While in the shade of 25 % and 50 %, it can grow normally. Moreover, it can endure the shade of 93 %, but the growth suffocated. And the full sunlight was unsuitable for Elsholfizia argyi.（4）Landscape application: Intergrating the ecological and ornamental characteristics of Elsholfizia argyi, it can be applied to the curb, waterfront, forest edge and woodland environments, etc. to enrich the level and color of plant landscape. It can also be used as functional plants in the copper, zinc and other heavy metals pollution areas to improve the soil environments.
The Study Onappraisal Andapplication of Ornamental Leaf Vegetables
Ornamental vegetables are plants of annual and biennial or perennial, which have certainly ornamental value and can be used as vice-food, suitable for indoor and outdoor layout, landscaping and enrich people’s lives. Ornamental leaf vegetables are plants that use the leaves, leaves ball, foliage, abnormal leaves and petioles as the product. Ornamental leaf vegetables, as one of a large class of ornamental vegetables, are fast growing, strongly ornamental and rich in species. A series of studies of this paper contained two aspects of ornamental leaf vegetables,the appraisal and application. The main results are as follows:(1) Through the collection of common types of ornamental leaf vegetables, we discussed the features of types and ornamental, and we build a mathematical model to evaluation and analysis the 28 varieties of ornamental vegetables by Analytic Hierarchy Process (AHP).(2) Effects of different light intensities (10%, 30% and 100%) on the growth of 6 kinds of leaf vegetables were investigated in the present studied. The results showed that the leaf color was fading and the whole plant was looses under lower light intensity. Plant height, leaf number, the net photosynthetic rate, chlorophyll contents and fresh and dry weight were reduced with the decline of light intensity.(3) Effects of different low temperature(0℃,-5℃,-10℃,-15℃and -20℃) on 4 kinds of leaf vegetables were studied. Relative conductivity, semi lethal temperature, soluble protein content, MDA content, SOD activity and POD activity were measured. The semi lethal temperatures of the 4 vegetables were increasing gradually with decreasing of temperature,while the soluble protein content, MDA content and the protective enzyme system had no obvious rule.(4) Carried out the research of application of ornamental leaf vegetables; introduced the cultivation and management technology of leaf vegetables, analyzed the leaf vegetables’planting styles which are suitable for the performance of ornamental, such as: container planting, raised bed planting, open field cultivation and hydroponics. And introduced the application place for the cultivation of leaf vegetables, such as: courtyard, roof, indoor, parks and agricultural sightseeing garden.(5) Through the questionnaire survey, we can understand the basic level of understanding to ornamental leaf vegetables among the respondents. In the survey we found that most people did not show a growing desire. There are two reasons that one is the lack of leaf vegetables, another one is the limited of environment. However, it is generally agreed that ornamental vegetables has the edible and ornamental features, and in the process of planting can harvest fun.
The Study on Cultivation and Drought Resistance of Hypnum plumaeforme
By split-plot and the broadcast sowing method of stem-cutting, the influence of light and substrate on the growth of Hypnum plumaeforme was studied. Furthermore, the drought stress response in the substrate of peat under different shading was explored. The purpose of the study was to provide theoretical evidence for the large scale cultivation, garden development and utilization of bryophytes. The main conclusions were obtained as follows:1. Study on cultivation: The effect of light and substrate had a highly significant difference on the coverage of H. plumaeforme(P<0.01), while the interaction of them was not significant(P>0.05). As for the light effect, there was significant difference between the full daylight and shading, and 60% shading was the most beneficial in which the coverage of H. plumaeforme among each substrate was up to 93% or more(except in sand ). The best combination for the growth of H. plumaeforme was 60% shading and peat. The branch length and number of H. plumaeforme varied under different light and substrate. The branch length was the shortest under full daylight, and increased with the enhancement of shading, while the branch number among different substrates from high to low was sand > saw powder > peat > pine bark > garden soil > clay.2. Study on physiological characteristics: Under drought stress, the leaves of H. plumaeforme were back-curling and the leaf color changed from green to yellow green or brown. The relative water content of tissue and chlorophyll content all decreased, especially in the first 10d when the relative water content reduced the fastest. The relative conductivity reached to maximum after drought stress for 10d and it was high up to 48.3% under the full daylight and down to 31.7% under the 60% shading. With the prolongation of drought stress the MDA content increased, which reached to peak under different light conditions after drought stress for 20d. Under the drought stress, the content of soluble sugar and soluble protein increased firstly and then decreased, while the content of soluble sugar of 60% shading was remarkably lower than that of the 40% shading. SOD activity and POD activity changed similarly, both of which increased firstly and then decreased. The relative water content and chlorophyll content increased within 24h after re-watering, while relative water content increased the fastest. Meanwhile, the relative conductivity, the content of soluble sugar, the content of soluble protein, SOD activity and POD activity all went up again within a narrow range and then decreased, but SOD and POD still kept higher activity. The MDA content decreased gradually, while 120h after re-watering the MDA content of 60% shading decreased to 93.1% of that at the initial experiment stage. From comprehensive comparison,we concluded that the H. plumaeforme under the 60% shading had the strongest resistance to drought stress.By comparison and analysis, we concluded that 60% shading and peat substrate were the most suitable condition for the growth of H. plumaeforme by the gametophyte breeding way. Moreover, H. plumaeforme in 60% shading had a stronger resistance and adaptability to drought stress than that in other light conditions.
Studies on Industrial Production Techniques of High-Quality Cultivars of Cymbidium
In the paper, through studying several key cultivation techniques, and investigating the popular varieties of Cymbidium cultivars and cultivation management technology in the production of Cymbidium, the species selection and cultivation techniques were studied in the process of industrial production of Cymbidium, in order to improve cultivation level and the quality of Cymbidium, ultimately improve the economic efficiency. The results can be summaried as follows:1. The quality evaluation standard and model of Cymbidium were established in the research, and 30 popular Cymbidium cultivars were evaluated using AHP method, from the aspects of quality traits, quantitative traits and ecological characteristics.Then according to the distribution of the comprehensive evaluation value and intuitive experience, the cultivars were divided into five grade, and the results showed that 23 cultivars have had better quality, were suitable in production and sales promotion.2. Through analyzing and summaring production technology of Cymbidium in Yunnan, from the aspects of site construction, cultivation media and containers, cultivation management technology at different stage, flower control and pest control technology, the mature cultivation technology industry of Cymbidium was formated. Then the questions in commercial culture of Cymbidium as well as the improved counter measures and suggestions of the related problems was put forward.3. With cultivation management pattern that using single-layer nets shade from 11:00 to 15:00, the tempreture was higer and the light was stronger in the environment, and the flower bud formation time was earlier, its quantity was more, its flowering quality was better, but the color was shallow; with the patterns that using single-layer shady nets all day and using double-layer shady nets all day, the differences of tempreture and light in envoriment between its was not significant, the growth performance and flowering of Cymbidium was ordinary, but the coler was darker.4. Four different fertilizer application on annual Cymbidium plant, make the impacts on the growth of primary and new shoot, the amount of lateral bud germination, and the root volume of Cymbidium reached a significant level, but leaves’chlorophyll content did not reach significant level. The fertilizer of”Hyponex (600ppm)”and”Scotts (2000ppm)”was most effective for growth of annual Cymbidium, the fertilizer of”potassium dihydrogen phosphate+carbamide(600ppm)”had second effect,a nd the fertilizer of”potassium dihydrogen phosphate”had least effect. 5. In the process of water deficiency, leaf water content gradually decreased, relative permeability of cell membranes and content of MDA gradually increased, activities of protective enzyme increased firstly and then decreased, physiological index above all can be used as appraisal index of water deficiency. And the results showed that the plants suffered serious intimidation from water deficiency 12d～21d.In production, the maximum water interval cannot exceed 12d, with 3～4d advisable, otherwise plant growth would be severely affected.
Tissue Culture and Cultivation in Haplocladium Microphyllum
By field inspection and the comprehensive analysis, the growth conditions for Haplocladium microphyllum tissue culture and soil cultivation were suggested, that is to say, the illumination intensity was 1500-3000lx, the moisture was 50-90%, and pH was 5.96-8.00. By means of spore culture, protonema culture and gametophyte culture, the development process of H. microphyllum were discussed, and fast reproductive system of H. microphyllum were established.The result showed that the spore was easy to sterilize, after washed the spore in 70% alcohol for 6 min, sterilized the spore in 20% NaClO for 5 min the contamination rate was 0. By orthogonal test design for the screening of the disinfection methods for the gametophyte, the results showed that the best way of the gametophyte sterilization was as followed: Explants gotten from intersection of branch were washed in 70% alcohol for 5s, and then washed in 2.5%NaClO for 60s, the survival rate was 70%.By means of spore→protonema→moss plant, spore→protonema→callus→moss plant, gametophyte→callus/bud→moss plant, the results showed that the optimum medium was MS+30g?L-1 sugar + 6.7 g?L-1 agar+pH 7.0. Added 1mg?L-1IBA in the medium for the protonema could get the most number of moss plant, and the moss clump was the highest, the color of the protonema was deep green, the comsistency of protonema was compact. Added 0.5 mg?L-1KT in the medium for the gametophyte was best to the induction and growth of bud. Added 0.3 mg?L-16-BA is best for the callus induction. Added 1mg?L-1IBA in the MS medium is best for the callus differentiation.Effects of different soils on growth and development of H. microphyllum was studied, and the soils which used to cultivated H. microphyllum were yellow upland soil, yellow sand soil and white clay. The experiment was been tested in illumination incubator. Cover degree, branch length, branch number, biomass, relative moisture content and photosynthetic pigment content had been evaluated on growth and development of H. microphyllum. The study showed that yellow upland soil was the best for growth and development of H.microphyllum, 50ds later after cultivated in yellow upland soil, H. microphyllum cover degree reached 84.33%, branch length was 4.80cm, level 1 branch number was 11.87 and level 2 was 5.13, fresh weight and dry weight increased 38.15 times and 17.69 times respectively.
Study on Establishment of System of Tissue Culture Regeneration and in Vitro Flowering of Stranvaesia Davidiana Var. Undulata
In this paper, obtaining aseptic plant by means of aseptic seeding, using parts of the plant stems as explants, We studied on the effect of factors which affected the in vitro culture and in vitro flowering of S. davidiana var. undulata, such as plant hormones, carbon sources, basic medium, active carbon, etc at the stage of proliferation culture, rooting culture and flower induction. As a result, the best mediums of every stage were screened out, tissue culture system for S. davidiana var. undulata was established, and flower bud induction was explorated. In addition, the landscape application of S.davidiana var. undulata was preliminary discussed. In this study, it can provide the efficient breeding to the the oretical and experimental basis for wild plants resources.The main results as following:1 Establishment of rapid propagation system. After disinfection treatment with 0.1 % HgCl2, disinfection time 15 min, survival rate of mature embryos was 90 %.Adding 6-BA(0.52.0 mg·L-1) was beneficial to the adventitious buds production, 1.0 mg·L-1 was able to achieve the best effect, and growth coefficient was 3.94. Adding TDZ(0.050.20 mg·L-1) was beneficial to the adventitious buds production, 0.2 mg·L-1 was able to achieve the best effect. Though growth coefficient was 3.94, the plant growth status of TDZ was obviously inferior to the 6-BA. Sucrose was the best carbon source of the proliferation medium, and the best concentration was 30g·L-1. The optimal medium for propagation were 1/2MS + 0.10 mg·L-1NAA and 1/2MS + 0.20 mg·L-1IAA, rooting rate were 88.33 %、86.67 % respectively, average root number were 10.28、7.81, and average root length were 0.32 cm、0.83 cm after 30 days. Besides, MS + 0.20 mg·L-1NAA and 1/2MS + 0.10 mg·L-1IAA can be selected. There was obvious promotion to average root length of S.davidiana var. undulata by adding active carbon into medium. The best time of hardening plantlets was 10d, transplanted in the artificial mixture with the ratio of perlite︰vermiculite︰peat （1︰1︰1）, and survival rate was the highest.2 Flower bud induction exploration. S. davidiana var. undulata can bloom in three years under natural conditions, but it can bloom after three months by means of aseptic seeding or one month by sterile materials induced. As a result, different types and concentrations of cytokinins on flower induction played an important role, the concentration which was too be high or too be low was not beneficial to the flower bud induction, 6-BA1.0 mg·L-1 and TDZ2.0 mg·L-1 were the best, and flower bud induction rates were 10.0% and 5.0%, while, the common use of cytokinin and auxin was not conducive to the flower bud induction. Carbon sources also played an important role on the flower bud induction, Sucrose was the best carbon source, and the best concentration was 30 g·L-1 compared with other concentrations, flower bud induction rate was 10.0%. In addition, the induction of different nitrogen to phosphorus ratio had no effect on the flower bud.3 Landscape application discussion. The leaves、flower and fruit of S. davidiana var. undulata have high ornamental value, which could be developed as ground cover plant; colorful; plant hedge, lower fence, and fruit fence; molding plant and so on.
Study on Genetic Diversity of the Plants of the Leaf Containing Aromatic Compounds in Chimonanthus
Based on the surveyed and collected resources in the main distribution area, and the morphological and microscopic features, molecular markers and the major secondary metabolites were studied on the plants of the leaf containing aromatic compounds in Chimonanthus. The major results were as follows:1. The plants of the leaf containing aromatic compounds in C. were collected and protected, 400 germplasms of 21 populations from 6 provinces which were Anhui, Fujian, Jiangxi, Guangxi, Hunan, Zhejiang province were collected and preserved effectively.2. The classified of the plants of the leaf containing aromatic compounds in C. was confused. Through consulting the literature and specimen, investigating the morphological features in the natural resources and the garden of the plants of the leaf resources and observing the microscopic characteristics, Zhang Ruohui’s view that the species containing aromatic compounds in C. were classified as C. salicifolius S. Y. Hu, C. Zhejiangensis M. C. Liu, C. nitens Oliv and C. grammatus M. C. Liu were supported and the distribution of four species were cleared. The C. salicifolius were mainly distributed to the junction area of Zhejiang, Jiangxi, Anhui provinces and the northern of Jiangxi province. The C. Zhejiangensis were mainly distributed to the junction area of Zhejiang and Fujian provinces. The C. nitens Oliv were mainly distributed to the areas of Yangshuo of Guangxi province, Xinning of Hunan province and Yichang of Hubei province. The C. grammatus were only distributed to the border region of Anyuan and Huichang of Jiangxi province.3. In use of AFLP molecular marker technique, the genetic diversity of 21 populations of the plants of the leaf containing aromatic compounds in C. was analyzed. The result showed that the plants of the leaf containing aromatic compounds in C. were low in genetic diversity. The total genetic diversity, Observed number of alleles, Effective number of alleles, Nei’s genetic diversity index and Shannon’s information index were respectively 0.1998, 1.992 6, 1.306 5, 0.199 2 and 0.325 1. Therefore, the protection of species resources should be more valued. Form the molecular level, the studies demonstrated the correctness of the result by Zhang Ruohui that the plants of the leaf containing aromatic compounds in C. were divided into C. salicifolius S. Y. Hu, C. Zhejiangensis M. C. Liu, C. nitens Oliv and C. grammatus M. C. Liu.4. With the material of C. salicifolius S. Y. Hu, the study on the chemical compositions of the plants of the leaf containing aromatic compounds in C. were conducted preliminarily. The results showed that there were rich volatile and non-volatile substances in these plants. The volatile compounds were mainly eucalyptol, borneol, bornyl acetate, furan, （E）-3-（4,8-dimethyl-3,7-nonadienyl）-, and （E,E）-Farnesol etc. The non-volatile substances were scopoletin （1）, scopoletin-7-O-β-D-glucoside （2）, kaempferol-3-O-β-D-glucoside （3）, kaempferol-3-O-β-D-rutinoside （4）, kaempferol （5）, quercetin （6）, and Emodin-8-O-β-D-glucopyranoside （7）. The compounds 1, 5 and 6 showed more obvious antioxidant activity than positive control Trolox with IC50 values of 8.72 mmol·L-1、1.53 mmol·L-1 and 0.56 mmol·L-1 respectively.
Breeding and Cultivation of New Ornamental Plant Varieties on Lycoris Herb.
Lycoris Herb. is one of the most important flowering bulbs, widely distributed in the southern subtropical regions of China,and has great potential for the development and utilization because of its unusual flower and numerous variation. Conventional breeding and molecular marker-assisted breeding methods were carried on the breeding of new varieties in this article. SSR molecular marker analysis protocol was established and was used on the correspondence analysis of fancypoints in L. chinensis.Tissue culture of L.sprengeri and the bulb cultivation techniques of L.radiata were studied respectively. Results are as follows:1. A number of clones with special ornamental value were selected as follows: 61 L. chinensis, 37 L. radiata, 24 L.sprengeri and a small amount of L.longituba, L. straminea, L. houdyshelii, L. aurea, L. albiflora, and a total of 138. First-hand information of these clones was obatianed through observations which provide support for cultivar assessment.2. Inter-species hybridization among 5 species was carried out. Results showed that: hybridization among fertile diploid hybrid parent groups was easy. And its seed between 0.862.92 on average, which was below compare with fertile diploid hybrid parent groups except L. chinensis. Analysis of reciprocal cross experiments showed that the number of hybrid seed depends on its female parent.3. An SSR molecular marker analysis protocol was established in L. chinensis, which had a total volume of 20μL containing 0.5 U of Taq DNA polymerase, 1.5 mmol·L-1 Mg2+, 0.125 mmol·L-1 dNTP, 0.5mmol·L-1 primer and 50 ng of template DNA. This protocol had been applied to an analysis of 8 species of Lycoris and 35 clones of L. chinensis with 7 and 9.5 polymorphic loci per primer on average obtained, respectively, which reflects a good performance in universality and stability of this protocol. Analysis of the corresponding relation between SSR loci and such traits as scape height and flowering time had preliminarily shown that loci Ly 97 and Ly 98 were correlated with late flowering time‘Oct’as well as that loci Ly 84, Ly 87 and Ly 97 with scape heights‘Mid’and‘Low’.4. The leaf blades and embryo of L.sprengeri were cultured in vitro.The results showed that high induction frequency, 75.8% on average, was obtained on embryo culture. The most ideal callus induction medium of embryo culture was MS+6-BA 2mg·L-1+2,4-D 2 mg·L-1+ Sucrose 60g·L-1,while the most ideal clustered shoots induction medium was MS+6-BA 2mg·L-1+2,4-D 1 mg·L-1+ Sucrose 30g·L-1. The results of leaf tissue culture showed that the induction frequency of young leaves was 65.8% on average which was higher than that of mature leaves（13.5% on average）. The most ideal induction medium of young leaves tissue culture was MS+6-BA 20mg·L-1+NAA 1mg·L-1+Sucrose 30g·L-1。5. The effects of fertilizing amount on L. radiata were studied, including the soil nutrient, blade nutrient, bulb weigh and circumference. The result indicated that the bulb weight and circumference increment trends of change in different fertilizing amount treatments present unimodal curve. The maximum bulb growth was higher than control group with 15.7%, while, excessive fertilizing amount stunted the growth. A fertilizing model was evaluated on the basis of soil fertility. Leaf analysis was studied on nutrition diagnosis method. The result showed that the critical concentration of leaf nutrient element was 3.05%、19.40%、31.29% respectively on N、P2O5、K2O,above which was necessary on ensuring a high output.
Isolation and Characterization of a Doritaenopsis Hybrid GIGANTEA Gene, Which Possibly Involved in Inflorescence Initiation at Low Temperatures
Doritaenopsis, abbreviated Dtps. in the horticultural trade, is an intergeneric hybrid between the orchid genera Doritis and Phalaenopsis. These hybrids are becoming more and more popular for their multiple flowering spikes, longer flowering period and more color than the traditional parents. For most grown orchid species and hybrids, flowering is influenced by temperature and light. However, compared to photoperiod, low temperature is a more important environmental signal than other factors induced inflorescence in orchids. The requirement for low temperature in inflorescence initiation of the orchid species increases the cost of their industrial production. Therefore, to determine the best method to reduce production cost of artificial regulation of flowering, understanding the physiological and molecular mechanism of flowering is necessary. In this paper, clone plantlets of Doritaenopsis‘Tinny Tender’had been studied under different temperature treatments (high temperature, low temperature). The main research results were as follows:1. In our study, it was found that low temperature treatment had a significant effect on flowering initiation in Doritaenopsis hybrid plants. After the low temperature treatment for 4 weeks, the peduncles were initiated in some plants of the low temperature-treated group (LTG) (22/18°C), and after 8 weeks, some flower buds were formed. After 5 months, 100% of the plants were in flower. By contrast, the plants maintained vegetative growth and none of the plants had initiated an inflorescence in high temperature-treated group (HTG) (30/25°C) .2. Doritaenopsis‘Tinny Tender’suppression subtractive hybridization cDNA library was constructed using leaves of LTG(22℃/18℃, Tester)and HTG(30℃/25℃, Driver)with the purpose of enriching”temperature-sensitive”genes. The SSH cDNA library contained 2,373 positive clones (recombination rate is 95%), including 1,540 high quality ESTs. Blast search and analysis of the sequences showed that 17.7% unigenes were involved in metabolism, 9% unigenes participated in perception and response to stimuli; 7.65% involved in information pathways; 2.4% in transport ; and 1.71% in developmental processes; 1.1% in localization; Unigenes were obtained by GO function analysis which induced by”temperature-sensitive”phenomenon and related to flower formation, such as GIGANTEA (GI) gene, genes related ubiquitin pathogenesis, Zinc finger binding protein and sucrose synthase. The analysis information were collected in database. 3. To understand the molecular mechanism of flowering, the orchid GI gene, DhGI1, was isolated and characterized by using the rapid amplification of cDNA ends (RACE) PCR technique. Sequence analysis showed that the full-length cDNA is 4,022 bp with a major open reading frame of 3,483 bp, and the amino acid sequence showed high similarity to GI proteins in Zea mays, Oryza sativa, Arabidopsis and others.4. Semi-quantitative RT-PCR revealed that DhGI1 was expressed throughout development and can be detected in roots, stems, leaves, peduncles and flower buds. The expression level of DhGI1 was much higher when the plants were flowering at low temperature (22/18°C day/night) than other growth stages. Further analysis indicated that the accumulation of DhGI1 transcripts were significantly increased at low temperature, and concomitantly, initiation of the peduncle was observed. However, DhGI1 levels were low under high temperature (30/25°C) conditions, and the initiation of flower was inhibited.These results indicated that the expression of DhGI1 was regulated by low temperature and there may be a link through DhGI1 between inflorescence initiation and low temperature in the Doritaenopsis hybrid. Further investigation, that overexpression or knockout of DhGI1, would help to confirm the function of DhGI1 in transition from vegetative to reproductive growth at low temperature of Doritaenopsis, and elucidate the complicated mechanism of flowering in orchid plants. In industrial production, the application of DhGI1 through gene engineering would be another way for promoting inflorescence initiation, which would greatly reduced the production cost of Doritaenopsis hybrid or even other orchid plants.