Key Techniques For Seedling Raising Of Sorbus Pohuashanensis

In this paper,Sorbus pohuashanensis was taken as the research object.The seed morphology and physiological characteristics of five provenances in the main distribution area were compared through provenance test,and the laws of different seed characteristics were revealed.Through seed germination test,the seed germination and seedling growth of Sorbus pohuashanensis under different hormone conditions were studied by single factor hormone germination method.The optimum reagent type and concentration for seed treatment were determined by comprehensive analysis of root growth.The effects of extreme temperature on the growth of Sorbus pohuashanensis were studied by chlorophyll fluorescence test.This study provided a basis for introduction and seedling propagation of Catalpa bungeana.The main results are as follows:(1)The average 1000-grain weight of seeds from various sources of Sorbus pohuashanensis is 2.32 g,and the seeds are partly dry-out.The characteristics of seeds from five provenances selected in the experiment are different.According to the changes of longitude and latitude,the seeds of Sorbus pohuashanensis grow larger and heavier from northeast to southwest.The plumpness of seeds of Sorbus pohuashanensis is affected by three factors: longitude and latitude,altitude and annual precipitation.Quantity,season and humidity factors affect seed vigor.(2)Pretreatment with 5% Na HCO3 reagent can promote seed germination of Sorbus pohuashanensis to some extent.The seed germination rate of Sorbus pohuashanensis treated with 1000mg/L CEPA at 10 ? under constant temperature was the highest,reaching 68.57%,which was significantly different from that of the control group.(3)CEPA soaking seeds at 3000mg/L for 24 hours not only can get higher germination rate,but also can promote seedling morphogenesis,which is the best method to relieve seed dormancy in this experiment.(4)With the deepening of high temperature and low temperature stress,PIABS values showed a significant decreasing trend,which indicated that different extreme temperature stress led to different degrees of reduction of PS II activity in seedlings of Sorbus pohuashanensis.PIABS could be used as an effective fluorescence parameter for response of seedlings of Sorbus pohuashanensis to extreme temperature stress.(5)Through comprehensive biomarker analysis,it was found that the IBR value of Sorbus pohuashanensis seedlings was the highest at 20-25?,which indicated that the light use efficiency of Sorbus pohuashanensis seedlings was the best at this temperature,and it was the suitable temperature for the growth of Sorbus pohuashanensis.