RNA-seq analysis reveals key genes associated with seed germination of Fritillaria taipaiensis P.Y.Li by cold stratification.

Seed dormancy is an adaptive strategy for environmental evolution. However, the molecular mechanism of the breaking of seed dormancy at cold temperatures is still unclear, and the genetic regulation of germination initiated by exposure to cold temperature requires further investigation. In the initial phase of the current study, the seed coat characteristics and embryo development of Fritillaria taipaiensis P.Y.Li at different temperatures (0°C, 4°C, 10°C & 25°C) was recorded. The results obtained demonstrated that embryo elongation and the dormancy-breaking was most significantly affected at 4°C. Subsequently, transcriptome analyses of seeds in different states of dormancy, at two stratification temperatures (4°C and 25°C) was performed, combined with weighted gene coexpression network analysis (WGCNA) and metabolomics, to explore the transcriptional regulation of seed germination in F. taipaiensis at the two selected stratification temperatures. The results showed that stratification at the colder temperature (4°C) induced an up-regulation of gene expression involved in gibberellic acid (GA) and auxin biosynthesis and the down-regulation of genes related to the abscisic acid (ABA) biosynthetic pathway. Thereby promoting embryo development and the stimulation of seed germination. Collectively, these data constitute a significant advance in our understanding of the role of cold temperatures in the regulation of seed germination in F. taipaiensis and also provide valuable transcriptomic data for seed dormancy for other non-model plant species.

[Study on preferred food of adult Mylabris phalerata in different geographical populations].

With the deterioration of environment, and the excessive collection of wild resources, the wild populations of Myla- bris phalerata Pallas are less and less, almost extincted in many traditional distribution areas. It is necessary to breed M. phalerata artificially for sustainable utilization. Food preference of adult M. phalerata is the key to its provenance screening and domestication in the artificial breeding. In this paper, the food preference of 3 geographical populations of M. phalerata was studied. The results showed that the food preferences of adult M. phalerata in different geographical populations were different. The adult M. phalerata in Wuming preferred cucumber flowers, gourd flowers and melon flowers. The adult M. phalerata in Tianlin preferred cowpea flowers. And the adult M. phalerata in Guangzhou preferred cowpea flowers and gourd flowers. Gourd flowers were the most attractive food for the adult M. phalerata of 3 geographical populations of M. phalerata.

[Study on the net photosynthesis rate of Coptis chinensis from different types and production places].

OBJECTIVE: Evaluate the photosynthesis characteristics of Coptis chinensis and provide theoretical basis for the optimization of Coptis chinensis germplasm resources and variety. METHODS: The daily variation of the net photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 density in leaf blade were determined by Photosynthesis analyzer, and the net photosynthesis rate of Coptis chinensis from different plant ages, types and production places was compared. RESULTS: The light saturation point in Coptis chinensis was about 500 micromol/m2 x s, light compensation point was about 12.04 micromol/(m2 x s), apparent quantum yield was 0.011. When the temperature was above 33 degrees C, the transpiration rate increased but the net photosynthesis rate decreased. There was no significant difference (P > 0.05) among the net photosynthesis rate of Coptis chinensis from different plant ages. The net photosynthesis rate of the type DA-YE and ZHI-HUA was significantly higher than that of other types (P < 0.05); The net photosynthesis rates of specimens from Fubao mountain in Lichuan county of Hubei and Fengmu village in Shizhu county of Chongqing were significantly higher than that of others. CONCLUSIONS: The net photosynthesis rate of Coptis chinensis decreased under hight temperation and hight light. Different germplasm resources of Coptis chinensis, the net photosynthetic rate had certain differences.

[Effect of different soil water treatments on physiological characteristics and yield of Artemisia annua].

OBJECTIVE: To study the effect of water content in soil on physiological characters and yield of Artemisia annua. METHOD: The pot experiment was applied and activity of protective enzyme, biomass and artemisinin accumulation were measured under different water treatments. RESULT AND CONCLUSION: The results showed that contents of osmotic adjustable substances, activity of protective enzyme, biomass and artemisinin accumulation were greatly affected by water content in the soil. Under water stress the water content in leave decreased, relative plasmalemma permeability increased, proline quickly accumulated to promote water retaining capability of cell, POD, CAT and SOD cooperated to reduce lipid peroxidation and reduced cell damage, and biomass decreased. At the seedling stage, the content of artemisinin and yield reached the maximal when the water content in soil was between 50%-55%. At the beginning of the branching stage, the content of artemisinin was the highest at the water content of 50%-55%, while the yield reached the maximal at the water content of 70%-75%. At the end of branching stage, the content of artemisinin was the highest at the water content of 40%-45%, while the yield reached the maximal at the water content of 60%-65%. In conclusion, the optimum water content in soil was between 50%-55% at the seedling stage, at the branching stage, higher water content was beneficial for the higher yield.

[Study on genetic diversity of Codonopsis tangshen by SRAP and ISSR markers].

OBJECTIVE: To study the genetic diversity of Codonopsis tangshen. METHOD: Eighteen germplasmic resources of C. tangshen were analyzed by SRAP and ISSR molecular markers. The systematic diagram of genetic relationship was made by TREECONW software and clustered by UPGMA method. RESULT: Twenty-nine SRAP primer combination amplified 329 bands with 266 (80.85%) polymorphic and 21 ISSR primers amplified 223 bands with 166 (74.44%) polymorphic. The average genetic similarity coefficient was 0.7121 (by SRAPs) and 0.7781 (by ISSRs). Both SRAP and ISSR analyses revealed a high level of genetic diversity in C. tangshen. By cluster analysis, the geographical distribution was not distinctive. The significant positive correlation between SRAPs and ISSRs was observed (r=0.802, P<0.01), although the dendrograms based on SRAP and ISSR markers were not all the same. CONCLUSION: Different germplasms diversity of C. tangshen is high and SRAP and ISSR can be used in genetic diversity study of C. tangshen.

[Study on seed germination testing standardization of Codonopsis tangshen].

OBJECTIVE: To study the influence of different factors (temperature, light and germinating beds) on seed germination of Codonopsis tangshen. METHOD: The general germination method was applied. RESULT AND CONCLUSION: The optimum seed germination conditions of C. tangshen were as follows: temperature 25 degrees C, light, germinating-beds top of paper (TP) or between of paper (BP). The first seedling--counting time was the 10th day after beginning the test; the final time was the 18th day. The test also showed that gibberellin notably increased the seed germination rate of C. tangshen.