高温胁迫对黑麦草生长及生理代谢的影响

以两个耐热性差异较大的多年生黑麦草品种首相(Premier,耐热性强)和顶峰(Pinnacle,耐热性弱)为试验材料,分析了人工模拟昼夜温度为适温(25 ℃/20 ℃)和高温(35 ℃/30 ℃)两种温度条件下,高温胁迫对黑麦草生长、叶片细胞膜稳定性、叶绿素含量、光合作用、内源激素(ABA、IAA,GA₃和ZR)以及碳水化合物(可溶性糖、淀粉、果聚糖)代谢的影响。结果表明,高温胁迫条件下黑麦草生长减缓,叶片电导率升高,叶绿素含量和光合作用显著下降,内源激素脱落酸(ABA)含量升高,而生长素(IAA)、赤霉素(GA₃)和细胞分裂素(ZR)含量均下降,但是在耐热性强的品种中的变化程度均小于耐热性弱的品种;高温胁迫下碳水化合物中的可溶性糖含量随处理时间的延长呈先升高随后下降的趋势,淀粉含量在两个品种中均呈不同程度的下降,果聚糖含量在耐热性强的品种中升高,在耐热性弱的品种中先升高随后下降。高温胁迫下黑麦草叶片中积累或维持较高的内源激素(ABA、GA₃、IAA、ZR)和碳水化合物(可溶性糖和果聚糖)可能是耐热性较强的主要原因,这些内源激素或碳水化合物的积累或维持有助于黑麦草细胞内渗透平衡和细胞膜稳定性,保护光合器官免受损害以维持光合能力,延缓因高温和呼吸增强导致的叶片的枯黄衰老,从而提高了黑麦草的耐高温能力。

Effect of temperature stress on growth and metabolism in perennial ryegrass

In order to investigate the effects of high temperatures on growth,leaf membrane stability,chloro-phyll content,photosynthesis,endogenous hormones and carbohydrate metabolism,two perennial ryegrass (Lolium perenne )cultivars with contrasting heat tolerance,‘Premier’(tolerant)and ‘Pinnacle’(sensitive) were selected and treated under optimum (25 ℃/20 ℃)and high (35 ℃/30 ℃)temperatures in growth cham-bers for 21 days.The results demonstrated that leaf electrolyte leakage and abscisic acid (ABA)content in-creased while plant growth,chlorophyll content,photosynthesis and endogenous hormones auxin (IAA),gib-berellin (GA3 )and cytokinin (ZR)decreased under high temperature,more so in Pinnacle than in Premier. Soluble sugars and fructans increased and subsequently decreased with prolonged temperature treatment,while starch content decreased in both cultivars under high temperature,but Premier maintained relatively high starch content compared to Pinnacle.Accumulating or maintaining high phytohormones levels,including ABA,GA3 ,IAA and ZR,and carbohydrates including soluble sugars and fructans associated with cellular os-motic homeostasis and membrane stability,delayed leaf senescence,protecting photosynthetic apparatus from heat damage and maintaining photosynthetic capacity may all contribute to heat tolerance in perennial ryegrass.