外源NO缓解蝴蝶兰低温胁迫伤害的生理机制研究

Physiological Mechanism of Exogenous Nitric Oxide on Alleviating Low Temperature Stress of Phalaenopsis spp.

以蝴蝶兰品种‘台湾黄金’幼苗(苗龄15个月)为试验材料,通过叶面喷施200μmol·L-1的NO供体硝普钠(SNP),低温胁迫(昼/夜:12℃/7℃)处理5d和10d,分别测定叶片电解质渗漏率、丙二醛(MDA)含量、pH、渗透调节物质含量及几种保护酶活性,探讨外源NO缓解蝴蝶兰低温胁迫伤害的生理机制。结果表明:低温胁迫条件下,预施SNP处理可以有效抑制蝴蝶兰叶片电解质渗漏率、MDA含量和pH的上升,显著提高叶片可溶性糖、可溶性蛋白及脯氨酸(Pro)含量,显著延缓超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)等抗氧化酶活性的下降,增强多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)的活性。研究认为,外源NO供体SNP可以通过保护蝴蝶兰幼苗的细胞膜系统,增加渗透调节物质含量,提高保护酶活性来减轻低温胁迫对蝴蝶兰幼苗的伤害,提高其抗低温胁迫的能力。

Phalaenopsis‘Taiwan＇s Golden＇（seedling age 15months）were used as the study materials.Its leaves were sprayed with 200μmol·L^-1 SNP（NO donor）,and then plants were treated under 12 ℃/7 ℃（day/night）.The electrolyte leakage rate,MDA content,pH,osmotic adjustment substances contents and protective enzymes were determined on five days and ten days after cold treatment.The results showed that the SNP treatment could restrain the increase of pH,electrolyte leakage rate and MDA content effectively,increase the contents of soluble sugar,soluble protein and proline and delay the decrease of SOD,POD,CAT and APX activities significantly,enhance the activities of PPO and PAL.The above results indicated the SNP treatment could reduce the damage under low temperature,improve the ability of resistance to low temperature stress in Phalaenopsis plants through protecting the cell membrane system,increasing the osmotic adjustment substance contents and improving the activities of protective enzymes.