短期夜间低温胁迫对秋茄幼苗碳氮代谢及其相关酶活性的影响  

Effects of short-term dark chilling on leaves carbon and nitrogen metabolism and involved activities of enzymes in mangrove Kandelia obovata seedling

作　　者：郑春芳[1] 刘伟成[1] 陈少波[1] 仇建标[1] 黄丽[1] 彭欣[1] 黄晓林[1] 王宁[1] 

机构地区：[1]浙江省海洋水产养殖研究所,浙江省近岸水域生物资源开发与保护重点实验室,温州海洋研究院,温州325005

出　　处：《生态学报》2013年第21期6853-6862,共10页Acta Ecologica Sinica

基　　金：国家海洋公益性行业科研专项经费项目(201005012;200805072);浙江省自然科学基金资助项目(LQ13C030002);浙江省近岸水域生物资源开发与保护重点实验室开放资助项目(2010F30003);浙江省科技厅创新团队建设与人才培养资助项目(2011F20032);浙江省海洋与渔业资助项目(高纬度红树林生态恢复关键技术应用示范);温州市科技计划资助项目(S20110007)

摘　　要：-2℃夜间低温处理秋茄幼苗12 h后,白天温度升高到5℃再低温处理4 h,研究了低温16 h处理对秋茄幼苗叶片光合特性、色素含量、抗氧化系统、细胞膜透性以及碳氮代谢相关酶活性的影响。结果表明:(1)低温16 h内,秋茄的净光合速率、气孔导度、气孔限制值均显著降低,而胞间CO2浓度显著增加。(2)低温低于8 h,叶片叶绿素含量、类胡萝卜素含量以及Chl a/Chl b比值均未产生显著变化,而Car/Chl比值显著增加。低温12、16 h,其叶片光合色素均下降,尤其白天下降幅度更大。(3)低温16 h内叶片可溶性总糖一直增加,而蔗糖含量、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)活性均在低温12 h后下降。(4)低温16 h内叶片可溶性蛋白、游离氨基酸含量以及羧肽酶活性均增加,而低温8 h时叶片内肽酶活性就开始下降。(5)低温16 h内叶片相对电导率、MDA均增加,而叶片POD活性均下降,尤其夜间下降更明显。另外,低温4、16 h能显著降低叶片SOD活性。以上说明,低温16 h时秋茄叶片光合作用的下降主要是因为非气孔导度限制引起,这主要与光合色素下降、抗氧化酶活性降低有关。此外,短期夜间低温通过影响SS、SPS、内肽酶以及羧肽酶活性,从而抑制了秋茄自身的碳氮代谢调控能力。The frequency, duration and intensity of extreme cold events have been hypothesized to explain the current latitudinal limits of mangrove distribution. At present, Kandelia obovata is the major mangrove species for forestation on the southeast coast of China, whose northern distribution boundary transplanted is in Yueqing county （28°25＇N）. Therefore, the incidence of extreme cold events is likely to be a factor limiting mangrove survival ratio. Kandelia obovata seedling grown in a controlled-environment chamber equipped were exposed to two different night temperature regimes： （low temperature treatment）-2℃ and （control） 20℃ for 12 h. During the day, temperature were maintained in both treatments at a minimum of 5 ℃ and a maximum of 25 ℃ for 4 h. Our objective was to investigate the possible physiological mechanisms of Kandelia obovata in responses to the short-term chilling 16 hours. Kandelia obovata seedling were cultivated in the illuminating incubator to study the effects of short-term dark chilling on photosynthetic characteristic, photosynthetic pigment contents, antioxidation system, cell membrane permeability and involved activities of enzymes in carbon and nitrogen metabolism. The results obtained are as follows： （1） The leaf net photosynthetic rate （Pn）, stomatal conductance （Gs） and stomatatal limitation （Ls） of Kandelia obovata were significantly decreased at low temperature 16 h, while leaf intercellular CO2 concentration was increased. （2）The contents of chlorophyll, carotenoids, and Chl a/Chl b ratio in leaf had no significantly changes at low temperature less than 8 h, whereas leaf Car/Chl ratio was significantly improved. In addition, photosynthetic pigment contents were decreased at low temperature between 12 h and 16 h. （3） The leaf total soluble sugars was increased during low temperature 16 h, while sucrose content, sucrose synthase （SS） and sucrose phosphate synthase （SPS） activities were decreased after low temperature 12 h. （4）

关 键 词：秋茄 短期夜间低温 光合作用 蔗糖代谢相关酶 蛋白水解酶 

分 类 号：S641.1[农业科学—蔬菜学]