Effects Of Low Light Environment On Seed Vigor Of Sichuan Wheat And Its Physiological Mechanism

Agricultural production supports the development of the national economy,among which high-vigorous seeds are the basis for increasing and stabilizing crop yields and the guarantee for stable and orderly agricultural production.At present,basic research on the effect of low-light environment on seed vigor is still in its infancy,and there is a lack of corresponding accumulation.In this paper,Chuan mai 39,Mian mai 51,Chang mai 34 and Shu mai 482 were used as materials,and the low-light environment was simulated by shading after flowering and shading before flowering.To study the effect of low light environment on quality traits and seed vigor of Sichuan wheat,and analyze the effect of low light environment on the main traits related to seed vigor.Below are key research findings:1.Low light environment reduced the vigor level of wheat seeds,and the effect of shading after flowering was more obvious.Under the condition of shading after anthesis except for the germination rate of artificial accelerated aging of Shu mai 482(2019)and the control,there was no significant difference,and the germination rate of artificial accelerated aging seeds of the four wheat varieties in each year was significantly lower than that of the corresponding control.Under shading conditions before flowering,except for the aging germination rate of Shu mai 482(2020)which was significantly lower than that of the control,the artificial accelerated aging seed germination rate of the four wheat varieties in each year had no significant difference from the corresponding control.2.Shading after anthesis reduced the thousand-grain weight,length and width of wheat seeds,and the effects of shading on grain width,thousand-grain weight and length were weakened in turn.The effects of low light before anthesis on thousand-grain weight,length and width of wheat seeds had no obvious rules.3.Low light environment increased the ABA/GA3 of wheat seeds,and the effect of shading after flowering was more obvious.Under shading conditions after anthesis,except for Shu mai 482(2019)whose ABA/GA3 was significantly lower than the control,the ABA/GA3 ratios of the four wheat varieties in each year were significantly higher than the corresponding control.Under shading conditions before anthesis,except Changmai 34(2019)ABA/GA3 was significantly lower than the control,Chuan mai 39(2020,2022),Mian mai 51(2019),Chang mai 34(2022)ABA/GA3 had no significant difference compared with the control The ABA/GA3 of the four wheat varieties in each year was significantly higher than that of the corresponding control.4.Low light environment promoted the accumulation of protein in wheat seeds,and the effect of shading after flowering was more obvious.Under shading conditions after anthesis,except that the protein content of Chuan mai 39(2020)and Mian mai 51(2019)had no significant difference from the corresponding control,the protein content of the four wheat varieties in each year was significantly higher than that of the corresponding control.Under shading conditions before anthesis,except for Chuan mai 39(2022),Mian mai 51(2019,2020),Shu mai 482(2019,2020)which were significantly higher than the corresponding control,the protein content of the four wheat varieties in each year had no significant difference compared with the control.difference.5.Low light environment promoted the accumulation of wheat protein,and protein accumulation was more sensitive to shading after anthesis.Under shading conditions after anthesis,except that the protein content of Chuan mai 39(2020)and Mian mai 51(2019)had no significant difference from the control,the protein content of the four wheat varieties in each year was significantly higher than that of the corresponding control.Under shading conditions before anthesis,except for Chuan mai 39(2022),Mian mai 51(2019,2020),Shu mai 482(2019,2020)which were significantly higher than the control,the protein content of the four wheat varieties in each year had no significant difference from the control.6.Low light environment reduced the content of raffinose and sucrose in wheat seed mature stage,and the shading effect was more obvious after flowering.Under shading conditions after and before anthesis,the raffinose and sucrose contents of the four wheat varieties decreased to varying degrees at each stage.7.Low light environment reduced the expression of Ta AGPase L1,Ta AGPase L2,Ta AGPase S1,Ta AGPase S2,Ta SSS,and Ta GBSSI genes related to starch synthesis during wheat flowering and maturation,promoted the expression of abscisic acid synthase gene Ta NCED1,and decreased the expression of abscisic acid catabolic enzyme gene Ta CYP707A2,Among them,the effect of shading after flowering is also more obvious.The physiological pathways for reducing the vigor level of wheat seeds in Sichuan mainly include the following two aspects.(1)Low light environment promotes the accumulation of abscisic acid in wheat seeds,reduces the accumulation of gibberellins,and leads to the imbalance of ABA/GA3 ratio in wheat seeds.(2)Low light environment reduced the accumulation of amylose and amylopectin during the growth and development of wheat,resulting in insufficient accumulation of seed nutrients.