低温驯化对西藏绵头雪莲愈伤组织抗冻性及抗氧化能力的影响

Effect of cold acclimation on freezing tolerance and antioxidant enzyme activities of callus of Tibet Saussurea laniceps Hand.-Mazz

【目的】研究高山植物对低温驯化的生理生化适应机制。【方法】以西藏绵头雪莲愈伤组织为材料,检测在变温[4℃/0℃(白天/夜晚,黑暗)]的低温驯化0、3、6、9、12 d过程中抗冻性、抗氧化酶和抗氧化物质含量的变化。【结果】经变温[4℃/0℃(白天/夜晚)]低温驯化后第9天西藏绵头雪莲抗冻性达到最高值,愈伤组织半致死温度(LT50)由常温培养-3.5℃降低到-12.0℃;经4℃/0℃低温驯化后,愈伤组织的可溶性蛋白质和脯氨酸含量以及抗氧化酶活性显著提高,至第9天达最大值,蛋白质比对照增加了89.1%、脯氨酸含量为驯化前的2.14倍,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)的活性分别比对照增加了48.04%、47.28%和73.18%,同时3种抗氧化酶的同工酶酶谱也验证了以上活性检测结果;低温驯化还提高了多酚含量,驯化至第12天时多酚含量为驯化前的3.91倍,此时多酚氧化酶(PPO)活性比驯化前增加了91.35%,与PPO同工酶的检测结果较为一致。【结论】低温驯化显著提高了高山植物绵头雪莲愈伤组织的抗寒力,在低温驯化过程中绵头雪莲发生了特有的适应低温环境的生理生化变化。

【Objective】This study aimed to elucidate the mechanisms of physiological and biochemical adaptations of alpine plants to cold acclimation.【Method】The callus of Tibet Saussurea laniceps Hand.-Mazz.was selected as the plant material to assess changes in antioxidant enzymes and antioxidants during the process of cold acclimation(4℃/0℃,day/night,dark,for 0,3,6,9,12 days,respectively).【Result】During the period of cold acclimation,freezing tolerance peaked on day 9,with the lethal temperature(LT50)from-3.5℃to-12.0℃.After 4℃/0℃cold acclimation,soluble protein,proline content and antioxidant enzyme activity increased significantly,reaching maximum levels on day 9,on which protein content increased by 89.1%,proline content was increased 2.14-fold,and superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD)activity increased by 48.04%,47.28%and 73.18%,respectively.Furthermore,these results were confirmed by three antioxidant enzyme isozyme zymograms.Cold acclimation increased the content of polyphenols,which were increased 3.91-fold compared with the control on day 12.The polyphenol oxidase(PPO)activity increased by 91.35%compared with the control,and these results were consistent with those for the isozyme.【Conclusion】The freezing tolerance of S.laniceps was significantly increased after cold acclimation,showing a unique adaptation mechanism to the low temperature environment.This study established a feasible experimental system that is valid and referenced for studying endangered plants.