外源钙及其抑制剂对蝴蝶兰幼苗耐热性的影响

杨华庚 杨毅敏

摘  要：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。

关键词：蝴蝶兰;钙离子信号;耐热性;生理机制

Abstract： 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.

Keywords： Phalaenopsis; Ca2+ signal; heat tolerance; physiological mechanism

蝴蝶兰（Phalaenopsis ssp.）是具有较高观赏性和商业价值的热带附生兰花。其生长发育对高温敏感，易受高温的抑制和危害，不利于蝴蝶兰植株的正常生长发育。因此，应用外源Ca2+等生长调节物质提高蝴蝶兰耐热性对蝴蝶兰抗热性栽培具有重要的生产意义。Ca2+是植物体生长发育的必需营养元素，不仅可作为细胞壁的結构成分、生物膜的稳定剂和多种酶的活化剂影响植物的生长发育过程，而且还作为偶联胞外信号与胞内生理生化反应的第二信使，参与植物对高温等逆境的信号转导[1]。……