中国红树林最北缘引种区不同季节和树龄秋茄生理特征比较

Comparison of Physiological Characteristics of Different Aged Transplanted Kandelia obovata Trees in Summer and Winter in the Northest Transplanted Area of China

以中国红树林引种最北缘的乐清湾西门岛海域为研究地点,研究了夏季、冬季5年生、9年生、54年生秋茄植株的光合色素、抗氧化系统、蛋白水解酶等相关指标的变化。结果表明:(1)夏季秋茄叶绿素含量高于冬季,而丙二醛(MDA)、可溶性总糖、可溶性蛋白质、游离氨基酸含量、叶绿素a/叶绿素b(Chla/Chlb)值以及内肽酶、羧肽酶活性均低于冬季;(2)不同树龄秋茄可溶性总糖、可溶性蛋白、游离氨基酸含量及内肽酶、羧肽酶活性在夏季、冬季均随树龄增加而减少;(3)在夏季,叶绿素含量5年生、9年生显著高于54年生秋茄,而叶片超氧化物歧化酶(SOD)活性和MDA含量均随树龄增加而增加,过氧化物酶(POD)随树龄增加而减少;(4)在冬季,叶绿素、MDA含量随树龄增加而减少,而Chla/Chlb值和POD活性均随树龄增加而增加,此外,秋茄叶片SOD活性随树龄增加呈先降后升的趋势。综合以上分析,在夏季5年生、9年生秋茄生长旺盛,而54年生秋茄代谢稳定;在冬季5年生、9年生秋茄的生理反应对低温较54年生秋茄敏感,但通过自身的代谢有效调节,仍能正常越冬。

Ximen island of Yueqing bay,the northernmost boundary of artificially planted mangrove in China,was chosen as a study site.Changes of photosynthetic pigment content,the antioxidation system,proteinases of different aged Kandelia obovata（aged 5,9 and 54 years old） in summer and winter were studied.The results obtained were as follows.（1） Low temperature in winter reduced the leaf chlorophyll content,but increased leaf chlorophyll a to chlorophyll b（chl a/b） ratio,contents of malondialdehyde（MDA）,soluble sugar,soluble protein and free amino acid,and enhanced activities of endopeptidase and carboxypeptidase in leaf.（2） The contents of the soluble sugar,soluble protein and free amino acid,and the activities of endopeptidase,carboxypeptidase in leaf were decreased with increasing age in summer and winter.（3） In summer,the content of the chlorophyll of the Kandelia obovata aged 5,9 years old was more higher than the Kandelia obovata aged 54 years old. The super oxygen dehydrogenises（SOD） activity and malondialdehyde（MDA） content were increased with increasing age. However,the peroxidase（POD） activity was decreased with increasing age.（4） In winter,the contents of leaf chlorophyll and MDA were decreased with increased age,while of the POD activity and Chla/Chlb ratio in leaf were increased with increasing age.Also,the SOD activity in leaf decreased and then increased with increasing age.In short,Kandelia obovata with 5 years old and 9 years old could vigorously grow,while 54 years old mangrove keep metabolism stability in summer.In winter,the physiological response of 5-year and 9-year old Kandelia obovata to low temperature was more sensitive than that of 54 years old,but 5-year and 9-year old trees could survive safely the winter through adjusting their carbon and nitrogen metabolism.