亚低温下干旱胁迫对番茄幼苗叶片水分及活性氧代谢的影响
Effects of drought under sub-low temperature on water content and reactive oxygen metabolism of tomato leaves

【目的】探讨亚低温下干旱胁迫对番茄幼苗叶片水分状况以及活性氧代谢系统的影响，为日光温室冬春季水分的科学管理提供参考。【方法】以“金鹏1号”番茄为材料，利用植物气候箱，采用盆栽试验，以常温（昼/夜温度25 ℃/18 ℃）下正常水分（田间持水量的75%～85%）处理为对照，研究了常温下干旱胁迫（田间持水量的55%～65%，以下简称干旱胁迫）处理及亚低温（昼/夜温度15 ℃/8 ℃）下正常水分（以下简称亚低温）处理和干旱胁迫（以下简称亚低温干旱胁迫）处理的番茄幼苗叶片中水分含量、渗透调节物质、活性氧物质、抗氧化酶活性及AsA GSH循环物质的变化。【结果】亚低温处理下番茄叶片水分含量减少，亚低温干旱处理不会进一步加剧水分的减少，但影响番茄叶片水分的恢复。干旱胁迫下渗透调节物质以脯氨酸为主，亚低温胁迫下以可溶性糖为主，亚低温干旱胁迫下两者含量均最高。亚低温干旱胁迫比单一胁迫处理叶片MDA含量高、细胞膜相对透性大。不同处理的活性氧产生及清除机制不同，亚低温处理下活性氧积累主要为超氧阴离子，活性氧清除以SOD及CAT为主；干旱胁迫下则主要为过氧化氢，活性氧清除以SOD及POD为主；亚低温干旱胁迫下，活性氧积累最多，SOD和CAT活性最高。与对照相比，在亚低温干旱胁迫下，AsA-GSH循环中APX活性、GR活性、AsA含量和GSSG含量均最高。【结论】设施栽培番茄叶片对亚低温胁迫比干旱胁迫更敏感，科学灌水可减少亚低温对番茄幼苗造成的伤害。
【Objective】The relationship between water supply under low temperature and water status as well as ROS metabolism of tomato leaves was explored to provide theoretical basis for water management of greenhouse in winter.【Method】Tomato variety Jinpeng 1 was used for pot experiment in climatic chamber and changes in water content,osmotic substances,reactive oxygen,anti-oxidase activities and AsA-GSH recycle in leaves were studied.The treatments included normal temperature (day/night 25 ℃/18 ℃) and water (75%-85% of field capacity),normal temperature and drought (55%-65% of field capacity),sub-low temperature (day/night 15 ℃/8 ℃) and normal water,and sub-low temperature and drought.【Result】Water contents in leaves declined under chilling condition,and chilling and drought did not enhance moisture reduction but stopped the recovery of water contents.Pro was the main osmotic substance under drought,soluble sugar was the main one under chilling,and both of them were the highest under chilling and drought condition.Both MDA and relative permeability under simultaneous stress were greater than separate treatment of either chilling or drought.The generation and elimination mechanisms of ROS were different for different treatments.Under chilling condition,ROS was accumulated mainly by O2－·,and cleared by SOD and CAT.Under drought condition,ROS was accumulated mainly by H2O2,and cleared by SOD and POD.Under chilling and drought stress,ROS,SOD and CAT were the highest.APX,GR,AsA and GSSG were also the highest in AsA-GSH recycle compared to the control.【Conclusion】Tomato leaves were more sensitive to sub-low temperature,and the damage could be mitigated by reasonable irrigation