The Effects Of Growth And Carbon Assimilation Process Of Tomato Under Low Light Stress By Applying Exogenous Epibrassinolide

Tomato(Solanum lycopersicum L.),fruit nutrient rich,is one of the world's most popular vegetable cultivation.In western countries,China and Japan have a large glass greenhouse,plastic greenhouses and other protected cultivation.Because of the winter and spring seasonal low light weather,aging facilities covering material,resulting in breakage and greenhouse plants,often in low light conditions,seriously restricting the yield and quality of greenhouse crops.How to mitigate the effects of low light stress,in addition to breeding varieties resistant to low light,but also through the application of plant growth regulators to improve the resistance to low light.In this study,low-light-sensitive tomato 'Jiersi' were as the experimental materials,through cultivation substrate to explore the effects of tomato seedlings growth and photosynthetic carbon assimilation process by spray exogenous EBR under low light stress,providing a theoretical basis and practical experience for the future low light tolerance study.The main findings are as follows:1.The stem diameter,fresh and dry weight,leaf area,leaf angle,healthy seedling index of tomato were significantly improved under low light stress by applying exogenous brassinolides,and maintain the chlorophyll content and stability of ultrastructure,to.significantly enhance the photosynthetic activity of tomato seedlings,ease the restriction of tomato seedling growth under low light stress.2.Low light stress significantly reduce the content of soluble protein,and activities of ribulose 1,5-bisphosphate carboxylase/oxygenase(Rubisco),fructose-1,6-diphosphate aldolase enzyme(Ald),fructose-1,6-bisphosphate(FBPase)and Rubisco activating enzyme(RCA),hindering the normal Calvin cycle;Exogenous epibrassinolides significantly improve the activities of enzymes,accelerate the Calvin cycle operation,thus improve the low light tolerance of tomato seedlings.3.Low light stress significantly reduce the mRNA expression of transketolase(TK),ribulose-1,5-bisphosphate carboxylase/oxygenase(Rubisco),Rubisco activating enzyme(RCA),fructose-1,6-bisphosphate aldolase(Ald),fructose-1,6-phosphatase(FBPase),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),sedoheptulose-bisphosphatase(SBPase),ribulose 5-phosphate kinase(PRK).Exogenous epibrassinolide significantly upregulate the expression of these mRNA.Description exogenous brassinolide can promote carbon assimilation,increase the tolerance of tomato seedlings under low light stress by adjusting the tomato seedlings photosynthetic carbon assimilation gene expressions of key enzymes.