外源钙及其抑制剂对蝴蝶兰幼苗耐热性的影响

为探讨Ca²⁺信号参与调节蝴蝶兰耐热性形成的生理机制,采用适宜浓度的外源Ca²⁺（CaCl₂）、胞外Ca²⁺螯合剂（EGTA）和质膜Ca²⁺通道抑制剂（LaCl₃）溶液喷施蝴蝶兰幼苗植株,以喷施蒸馏水为对照,测定高温胁迫下蝴蝶兰幼苗植株的抗氧化酶活性、丙二醛、渗透调节物质和光合色素含量的变化。结果表明,与对照相比,CaCl₂处理能显著增强超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性,增加脯氨酸、可溶性蛋白、可溶性糖、叶绿素和类胡萝卜素含量,显著降低丙二醛含量,减轻了蝴蝶兰幼苗的高温伤害,而LaCl₃和EGTA处理不同程度地降低SOD、POD和CAT活性,降低脯氨酸、可溶性蛋白、可溶性糖、叶绿素和类胡萝卜素含量,显著增加丙二醛含量,使蝴蝶兰幼苗受害加重。由此认为,Ca²⁺信号可通过参与抗氧化酶活性、脯氨酸和光合色素的代谢过程来调控蝴蝶兰幼苗耐热性的形成。

Effect of Exogenous Calcium and Calcium Inhibitors on the Heat Tolerance in Phalaenopsis Seedlings

The objective of the study is to explore the underlying physiological mechanism of Ca²⁺signal participating in the enhancement of Phalaenopsis heat tolerance.The seedlings of Phalaenopsis were sprayed appropriate concentration of exogenous calcium(Ca²⁺),extracellular Ca²⁺chelator(EGTA)and plasma membrane Ca²⁺channel inhibitor(LaCl3)respectively,taking distilled water as the control.The effects of antioxidant enzyme activity,malondialdehyde(MDA),osmotic regulators and photosynthetic pigment contents in Phalaenopsis leaves under high temperature stress were investigated.The results showed that SOD,POD and CAT activities,proline,soluble sugar,soluble protein,total chlorophyll and carotenoids contents were significantly increased and MDA content was significantly reduced in the CaCl2 treatment group,stress damages in Phalaenopsis seedlings caused by high temperature were alleviated.while the activities of three antioxidant enzymes and contents of three osmoregulation substances and contents of two photosynthetic pigments mentioned above were decreased to different extents and MDA content was significantly improved in LaCl3 and EGTA treatments group compared with the control group,thereby aggravating the damage of high temperature stress in Phalaenopsis seedlings.The study showed that Ca²⁺signaling could improve the resistance of Phalaenopsis seedlings to high temperature stress by participating in antioxidant enzyme activity,proline and photosynthetic pigment metabolism processes.