Abstract: [Objective]Salinity is one of the major abiotic stresses affecting plant productivity.[Method]The enflunce of different ratio of ammomium and nitrate on cotton seedling growth and development as well as seedlings N nutrition character were investigated under three leveles of NaCl stress,namely 0,100,200 mM. Experiment was carried out in hydroponic culture condition in greenhouse.[Result]The results show that dry weight of cotton seedling,leaf,stem and root as well significantly increased under ammomium/nitrate ratio of NNH_4~+/NO_3~y=50/50 and 75/25 (P＜0.05). Compared with the N application ratio of NH_4~+/NO_3~=0/100 treatment,cotton seedling totoal biomass dry weight enhanced by 47.4; and 44.0; at the N ratio of NH_4~+/NO_3~=75/25 under 0mM and 100mM NaCl levels respectively. The amount of N uptake by cotton seedling is greatly higher in the treatment of ammomium and nitrate supply ratio of 50/50 and 75/25 than ammonium or nitrate supply sololy. Leaf expand rate and stem extend rate of cotton were significantly increased in ammomium and nitrate supply ratio of 50/50 and 75/25.NaCl stress has obvious inhibition effect on cotton seedling growth and sharply decrease cotton dry weight and the amount of N accumulation and leaf chlorophyl content as well,[Conclusion]while the inhibitation effece caused by salt stress could be obviously alleviated under ammomium/nitrate supply ratio of 50/50 and 75/25.

摘要： [目的]通过氮素营养调控克服盐分胁迫,促进棉花苗期生长发育.[方法]在控制条件下采用水培的方法,研究了NaCl胁迫下不同铵硝配比对棉花苗期生长发育的影响.[结果]在0、100、200 mM 3个NaCl浓度条件下,棉苗叶片、茎秆和根系的干物质生物量均表现为铵硝混合营养处理(NH_4~+/NO_3~为50/50和75/25)显著高于纯铵或纯硝营养(P＜0.05),0和100 mM NaCl浓度下,NH_4~+/NO_3~-为75/25处理棉花干物质量分别较NH_4~+/NO_3~为0/100处理高47.4;和44.0;;在同一盐分水平条件下,铵硝混合营养棉株吸氮量明显高于纯铵或纯硝营养处理,并可显著提高棉花叶片叶绿素含量;棉花吸氮量随着盐分浓度的增加而显著下降(P＜0.05),铵硝混合营养可明显减轻盐分胁迫对棉苗氮素吸收的抑制作用;在同一盐分浓度下,铵硝混合营养处理的棉苗叶片展出速率和茎秆伸长速率均高于纯铵或纯硝营养处理,棉苗叶片的展出速率随NaCl浓度的增加而降低,通过铵硝混合营养可减轻盐分对幼苗生长的抑制作用.[结论]铵硝混合营养(NH_4~+/NO_3~为75/25和75/25)可以显著提高棉花苗期的氮素营养,改善盐分胁迫对棉花的抑制作用,促进棉花早期的生长发育.