独脚金内酯对低氮处理下大豆幼苗生长及产量的影响OA

To investigate the regulatory of influence exogenous strigolactones(SL)spraying on the growth of soybean seedlings under low-nitrogen conditions,two soybean varieties Dongnong 52(a low-nitrogen tolerant variety)and Heinong 62(a low-nitrogen sensitive variety)were used as experimental materials.A pot sand culture method was adopted,and the nitrogen content in the nutrient solution was controlled to simulate a low-nitrogen environment,so as to study the mitigating influence of exogenous strigolactones on soybean seedlings under low-nitrogen treatment.The results showed that,compared with the normal nitrogen treatment,the low-nitrogen treatment led to an 8.34％-30.51％decrease in plant height,a 12.15％-18.40％reduction in stem diameter,and a 19.20％-50.85％decline in leaf area of soybean seedlings.Additionally,the leaves of the plants turned yellow overall,and their growth vigor was significantly weakened.In terms of physiological metabolism,the low-nitrogen treatment reduced the activities of key nitrogen-metabolizing enzymes such as nitrate reductase and glutamine synthetase.Compared with the normal treatment,the activities of these two enzymes decreased by 13.56％-27.76％and5.03％-11.40％,respectively.This reduction further caused a decrease in leaf chlorophyll content,which was 11.31％-27.97％lower than that under the normal treatment.Moreover,under low-nitrogen conditions,the contents of nitrate nitrogen and ammonium nitrogen in soybean seedlings decreased by 3.83％-23.29％and 6.99％-12.00％,respectively,compared with the normal treatment.Ultimately,these changes affected yield formation and reduced soybean yield.However,the experiment indicated that spraying strigolactones at the V3 stage could significantly alleviate the inhibitory effects of low-nitrogen treatment on soybean seedlings at both morphological and physiological levels.For the soybean seedlings treated with SL spraying under low-nitrogen conditions,their morphological indicators were improved:plant height,stem diameter,and leaf area increased by 6.10％-21.59％,5.11％-18.04％,and 12.59％-31.79％,respectively,compared with those under low-nitrogen treatment alone,and the growth status of the plants improved significantly.In terms of physiological metabolism,the activities of enzymes such as nitrate reductase and glutamine synthetase in soybean seedlings treated with SL spraying under low-nitrogen conditions were enhanced,increasing by12.14％-27.52％and3.75％-9.82％,respectively,compared with the low-nitrogen treatment alone.This enhancement promoted the absorption and assimilation of nitrogen,leading to a significant increase in leaf chlorophyll content of soybean,which was 21.45％-73.25％higher than that under low-nitrogen treatment alone.At the same time,SL spraying also significantly increased the contents of inorganic nitrogen and carbohydrates in soybean seedlings,promoted substance accumulation,and laid a material foundation for subsequent yield formation.The results showed that low-nitrogen treatment had a significant inhibitory influence on the growth of soybean seedlings,while spraying strigolactones at the V3 stage could effectively alleviate the adverse influence of low-nitrogen treatment on soybean seedling growth through multiple pathways,such as regulating key indicators of nitrogen metabolism,promoting dry matter accumulation,and enhancing photosynthesis.