摘要
Abstract
Soil salinization reduces plant uptake of manganese,seriously affecting the growth and yield of crops.However,it is unclear if exogenously supplied manganese sulfate can improve crop growth under soda solonetz conditions.In this experiment,two Mn supplementation treatments,manganese sulfate seed soaking and fertilization,were applied to cultivated Indian barnyard grass(Echinochloa frumentacea),to investigate the physiological response to manganese sulfate of crop seedlings at V5 growth stage under saline-alkali stress.It was found that saline-alkaline stress significantly reduced the chlorophyll content and decreased the optimal/maximal quantum yield of PSⅡ(Fv/Fm)of Indian barnyard grass seedlings.This inhibition affected the performance of chlorophyll fluorescence parameters in the light response curve and led to a significant decrease in photosynthetic efficiency.Additionally the activities of key enzymes involved in nitrogen assimilation,such as nitrate reductase and glutathione synthetase decreased while the nitrate nitrogen content increased,ultimately this imbalance disrupted the carbon and nitrogen metabolism balance,inhibiting shoot growth.More dry matter was allocated to the roots,resulting in a significant increase in the root∶shoot.For saline-alkali-inhibited seedlings,application of manganese sulfate fertilizer or seed dipping treatment,promoted the development of the root system,enhancing nitrogen absorption ability,and increasing the activity of key enzymes involved in nitrogen metabolism.This led to effective accumulation of free amino acids and enhanced overall nitrogen assimilation efficiency in the plant.Additionally,manganese supplementation promoted the accumulation of chlorophyll and carotenoids,increased the Fv/Fm,and improved energy transfer within the photosystem.Consequently,the photosynthetic capacity of crop seedlings under salinity stress was significantly increased,resulting in improved crop growth.Comparing the seed soaking and fertilization treatments,fertilization was more effective in reducing the damage caused by saline-alkali stress and in balancing the overall carbon and nitrogen metabolism of the crop.关键词
栽培稗/苏打盐碱土/硫酸锰/光合作用/氮同化Key words
cultivated Indian barnyard grass/soda saline-alkali soil/manganese sulfate/photosynthesis/nitrogen assimilation
