高温胁迫下NO对铁线莲光合特性和活性氧代谢的影响

Effects of NO on Photosynthetic Characteristics and Active Oxygen Metabolism of Clematis under High Temperature Stress

一氧化氮(nitric oxide,NO)作为一种新的植物生长调节剂,对植物胁迫应答具有积极的作用。本研究以铁线莲‘钻石’品种幼苗为材料,对其施加不同浓度(0,0.1,0.4,0.8,1.2 mmol/L)的外源NO供体硝普钠(SNP)并进行高温胁迫处理,分析质膜透性、活性氧代谢、光合特性等变化。结果表明,高温胁迫下外源NO处理可以显著降低铁线莲幼苗叶片相对电导率和MDA含量(P<0.05),减少H2O2和O2-的积累;同时外源NO处理可以增强抗氧化酶(SOD,CAT,POD)的活性,提高Fv/Fm、ETR、ΦPSⅡ、NPQ(P<0.05),维持较高的PSⅡ光化学活性,由此提高铁线莲耐高温能力,其中0.4 mmol/L NO处理效果最明显。上述结果表明,外源NO处理缓解高温对铁线莲的伤害可能与抗氧化酶活性和光合特性的提高有关。

Nitric oxide(NO)as a new plant growth regulator has a positive role in plant stress response.In this study clematis cultivar'Diamonds'as the experimental materials was treated with different concentrations of NO(0,0.1,0.4,0.8,1.2 mmol/L)under high temperature stress to determine the membrane permeability,activate oxygen metabolism and photosynthetic characteristics.Exogenous NO treatment could significantly reduce the relative electrical conductivity and MDA content of clematis seedlings under high temperature stress(P0.05)and re-duce the accumulation of H_2O_2and O_2~-.Meantime,exogenous NO treatment also increased the activities of antioxidant enzymes(SOD,CAT,POD),F_v/F_m,ETR,Φ_(PSⅡ)and NPQ to enhance the tolerance to high temperature.Among them the 0.4 mmol/L NO treatment is the most notable.All above results demonstrated that the application of exogenous NO could alleviate the damage caused by high temperature stress in clematis seedlings.Above results indicated that it might also be related to the enhancement of antioxidant activity and photosynthetic characteristics.