氮素对NaCl胁迫下甜高粱种子萌发及芽苗生长与生理的影响

Effects of nitrogen on sweet sorghum seed germination, seedling growth and physiological traits under NaCl stress

为了研究NaCl胁迫下氮肥对甜高粱种子萌发及芽苗生长和生理特性的影响,探索提高甜高粱耐盐能力的措施,室内设置不同盐分浓度、不同氮源及浓度条件下甜高粱萌芽试验。结果表明:NaCl胁迫和不同氮源对甜高粱发芽和芽苗生长的影响各有不同。NaCl浓度对甜高粱种子萌发有显著影响,在甜高粱芽苗生长阶段,通过提高保护酶活性和渗透调节物质而增强耐盐伤害能力是有限的。100 mmol.L 1NaCl胁迫下,根系POD活性最低,而叶片MDA积累量、可溶性糖含量、POD活性最高,受盐害程度最大。没有盐胁迫情况下增加不同氮源及氮量对甜高粱根叶生理特性的影响差异显著,当氮浓度在20 mmol.L 1时,细胞受伤害程度最低,生长最好。不同形态氮源对甜高粱发芽和幼苗生长的影响差异明显,NH4Cl的促进效果优于KNO3。在100mmol.L 1的NaCl胁迫下,施加铵态氮或硝态氮源均可以增强甜高粱芽苗期的POD活性,减少MDA积累,从而缓解盐胁迫带来的伤害。研究表明采取适当的氮肥调控措施可以提高甜高粱的耐盐能力。

The effects of nitrogen application on germination,seedling growth and physiological traits of sweet sorghum [Sorghum bicolor（L.） Moench] were investigated under NaCl stress.The aim of the study was to enhance salt-tolerance of sweet sorghum through laboratory germination experiments at different salt and nitrogen（N） concentrations using two N sources.The results showed that either salt or N significantly influenced seed germination and seedling growth of sweet sorghum.Under NaCl stress,sweet sorghum salt uptake increased via improved enzyme activities and osmoregulation during seed germination and bud seedling growth stages.Under NaCl stress,there was a little ability for sweet sorghum to resist salt by improving enzyme activity and osmoregulation substance during seed germination and seedling growth stage.Lowest root POD activity,highest leaf MDA accumulation,leaf soluble sugar and leaf POD under 100 mmol.L 1NaCl stress indicated the greatest salt damage to sweet sorghum.N treatments without NaCl markedly affected seed germination and seedling growth of sweet sorghum.Sweet sorghum seedling grew best under 20 mmol（N）.L 1 due to lessening cell damage by NaCl.NH4Cl improved more than KNO3in seed germination and seedling growth of sweet sorghum.Under 100 mmol.L 1 NaCl stress,supplementation with either form of the two N sources（NH4＋and NO3） ameliorated adverse salt stress effects on seedling growth and examined physiological traits.This was possible by improving POD activity and reducing MDA accumulation.It was evident that an appropriate nitrogen fertilizer application improved the salt tolerability of sweet sorghum.