高温胁迫下不同氮肥处理对凌志高羊茅耐热性的调控效果

Effects of different nitrogen fertilizers on the heat tolerance of Barlexas tall fescue under heat stress

通过盆栽试验,研究不同氮肥处理(NO3--N、NH4+-N、NH4NO3--N)对凌志高羊茅(Fes-tuca arundinacea cv. Barlexas)在高温38℃/30℃(昼/夜)胁迫下部分生理生化指标的调控效果。结果表明:(1)NH4+-N和NO3--N处理根冠比、叶片相对含水量、叶绿素含量都持续下降,NH4+-N处理下降幅度大于NO3--N处理;NH4NO3-N处理先升后降。同等胁迫水平下,NH4NO3-N处理高于NO3--N和NH4+-N处理;(2)3种氮肥处理使叶片可溶性蛋白含量下降,可溶性糖和脯氨酸含量上升。且同等胁迫水平下,NH4NO3-N处理可溶性蛋白,可溶性糖和脯氨酸含量均最高;(3)NH4+-N和NO3--N处理叶片过氧化氢和超氧阴离子含量上升,NO3--N处理的上升幅度小于NH4+-N处理;NH4NO3-N处理先下降后上升,且同等胁迫水平下低于NH4+-N和NO3--N处理;(4)NH4+-N和NO3--N处理叶片丙二醛(MDA)含量增加;NH4NO3-N处理在胁迫前两天略微下降随后上升,且同等胁迫水平下,MDA含量最低。试验分析显示,3种氮肥处理相比较NH4NO3-N处理对提高凌志高羊茅耐热性的调控效果最好。

Effects of different nitrogen fertilizers （NO3^- - N, NH4^＋ -N, N H4NO3^-N） on the physiological and biochemical indexes of Barlexas tall rescue under high temperature （38℃/30℃, day/night） were studied by pot experiment. The results indicated that （1） root/shoot ratio, relative water content, chlorophyll a,h content in leaf decreased constantly while treated by NO3^--N and NH4^＋-N. Meanwhile, these indices declined more significantly in NH4^＋ -N group than in NO3^- -N group. However, these indices in NH4NO^3-N group increased at beginning and then decreased. Under the same stress conditions, these indices were the highest in NH4NO^3-N group. （2） Soluble protein content in leaf of NO3^--N, NH4^＋-N and NH4NO3--N groups decreased constantly, meanwhile, the soluble sugar content and protein content increased constantly. Under the same stress conditions, the soluble protein content, soluble sugar content and protein content in NH4NO3--N group were the highest. （3） H2O2 content and O2^＋ - content in NO3^--N and NH4^＋ --N group increased constantly. However, these indices in NH4^＋ --N group showed higher increase than those of NO3^- --N group. Meanwhile, these indices in NH4NO3- N group decreased at the beginning and then increased. Under the same stress conditions, H2O2 content and O2^＋- content in NH4NO3^--N group were the highest. （4） MDA content in both NO3^- -N and NH4^＋ -N groups increased constantly. However, MDA content in NH4NO3-N group declined slightly in the first two days and then increased. Under the same stress conditions, MDA content in NH4^＋ -N group was significantly higher than those in NO3^- -N group, and it was the highest among three treatments. It could be concluded that NH4NO3-N was the best.