盐分差异分布下不同形态氮素对棉苗生长及主要营养元素吸收的影响

为探索氮素形态对盐碱地棉苗生长及养分吸收的影响,以鲁棉研28号为试验材料,利用嫁接建立的分根试验系统模拟盐分差异分布,研究了根区盐分差异分布和不同形态氮素(NH4+和NO3-)对棉苗生长和主要营养元素吸收的影响。结果表明:根区盐分差异分布和氮素形态对棉花营养元素吸收及幼苗生长存在互作效应;根区盐分差异分布较均匀分布增强了棉株对主要营养元素(N、P、K、Ca、Mg、Fe、Mn、Cu和Zn)的吸收、降低了Na+含量、提高了叶片净光合速率(17.1%)并增加了棉株生物积累量(18.5%);NO3--N较NH4+-N处理显著促进了棉苗主要营养元素(N、P、K、Mg、Fe、Mn)的吸收及生物量积累;根区盐分差异分布下,施用NO3--N较NH4+-N提高了棉苗主要营养元素的吸收及叶片光合速率(13.5%)、降低了各器官的Na+含量并促进了棉苗的生物量积累(7.2%)。研究结论是盐分差异分布下,施NO3--N较NH4+-N更有利于棉花主要营养元素的吸收及幼苗生长。

Effects of different nitrogen forms on seedling growth and main nutrient elements uptake under unequal salt distribution in cotton seedlings

It is well known that salinity levels are seldom uniform in saline fields.A new split-root system established through grafting was conducted to study the effects of nitrogen forms(NH+4 and NO-3) on nutrient elements uptake and plant growth under unequal salt distribution in a greenhouse.The results indicated that a significant interaction was detected between unequal salt distribution and nitrogen forms(NH+4 and NO-3) on nutrient uptake and seedlings growth.Compared with equal salt distribution,unequal salt distribution decreased Na+ concentration,and increased main nutrient elements(N,P,K,Ca,Mg,Fe,Mn,Cu,Zn) uptake,leaf photosynthesis(17.1%) and biomass accumulation(18.5%);the main nutrient elements(N,P,K,Mg,Fe,Mn) uptake and biomass in NO-3-N treatment were higher than that in NH+4-N treatment;Under unequal salt distribution,the main nutrient elements(N,P,K,Ca,Mg,Fe,Mn,Cu,Zn) uptake,leaf photosynthesis(13.5%) and biomass(7.2%) in NO-3-N were higher than that in NH+4-N treatment.It is concluded that NO-3-N is superior to NH+4-N in improvement of main nutrient elements uptake and plant growth under unequal salt distribution.