Nitrogen is essential for plant growth and development,with the ratio of ammonium(NH_(4)^(+))to nitrate(NO_(3)^(-))critically influencing physiological efficiency.This study investigated the effects of different NH_(4...Nitrogen is essential for plant growth and development,with the ratio of ammonium(NH_(4)^(+))to nitrate(NO_(3)^(-))critically influencing physiological efficiency.This study investigated the effects of different NH_(4)^(+)-N/NO_(3)^(-)-N mass ratios(0︰1,3︰7,1︰1,7︰3,1︰0)and a no-nitrogen control on Zanthoxylum planispinum var.dintanensis seedlings,using NH_(4)Cl and NaNO_(3) as nitrogen sources.Key results revealed that a 3︰7 NH_(4)^(+)︰NO_(3)^(-)ratio(T2)significantly enhanced stomatal conductance(G_(s)),amino acid content,root tip number,and the photochemical quenching parameters q_(P),q_(L),ETR,and F_(v)/F_(m).This treatment also maximized ground diameter increment,chlorophyll content,intercellular CO_(2)concentration(C_(i)),transpiration rate(T_(r)),ribulose-1,5-bisphosphate carboxylase(Rubisco)activity,nitrate reductase(NR)activity,and soluble protein content.Conversely,a 7︰3 ratio(T4)yielded the highest net photosynthetic rate(Pn)and fructose-1,6-bisphosphate aldolase(FBA)activity.Overall,the T4 treatment exhibited the second most effective promotion of Z.planispinum var.dintanensis seedling growth and development,after T2.In summary,mixed NH_(4)^(+)-N/NO_(3)^(-)-N nutrition markedly enhances seedling performance,with the 3︰7 ratio optimal for growth,photosynthesis,and nitrogen assimilation.Sole nitrogen sources,particularly pure NH_(4)^(+)-N,exert inhibitory effects.展开更多
文摘Nitrogen is essential for plant growth and development,with the ratio of ammonium(NH_(4)^(+))to nitrate(NO_(3)^(-))critically influencing physiological efficiency.This study investigated the effects of different NH_(4)^(+)-N/NO_(3)^(-)-N mass ratios(0︰1,3︰7,1︰1,7︰3,1︰0)and a no-nitrogen control on Zanthoxylum planispinum var.dintanensis seedlings,using NH_(4)Cl and NaNO_(3) as nitrogen sources.Key results revealed that a 3︰7 NH_(4)^(+)︰NO_(3)^(-)ratio(T2)significantly enhanced stomatal conductance(G_(s)),amino acid content,root tip number,and the photochemical quenching parameters q_(P),q_(L),ETR,and F_(v)/F_(m).This treatment also maximized ground diameter increment,chlorophyll content,intercellular CO_(2)concentration(C_(i)),transpiration rate(T_(r)),ribulose-1,5-bisphosphate carboxylase(Rubisco)activity,nitrate reductase(NR)activity,and soluble protein content.Conversely,a 7︰3 ratio(T4)yielded the highest net photosynthetic rate(Pn)and fructose-1,6-bisphosphate aldolase(FBA)activity.Overall,the T4 treatment exhibited the second most effective promotion of Z.planispinum var.dintanensis seedling growth and development,after T2.In summary,mixed NH_(4)^(+)-N/NO_(3)^(-)-N nutrition markedly enhances seedling performance,with the 3︰7 ratio optimal for growth,photosynthesis,and nitrogen assimilation.Sole nitrogen sources,particularly pure NH_(4)^(+)-N,exert inhibitory effects.
