潮滩红树植物抗低温适应的生态学研究

采用电导法定量测定了中国东南沿海红树植物叶片的抗寒力变化。结果表明；(1)海南琼山东寨港主要红树种类冬季抗寒力(半致死温度)介于-2.3～-6.8℃之间，其中红树科植物抗寒力较强，多数种类属于低温敏感性相对较弱的L类型；海桑科和楝科红树种类抗寒力较弱，属于低温敏感性较强的H类型。(2)随纬度升高(个别地点除外)，秋茄(Kandelia candel)、桐花树(Aegiceras corniculatum)和红海榄(Rhizophors，stylosa)抗寒力增强，呈现种群分化趋势。(3)同一地点，秋茄和桐花树抗寒力有明显季节变化：夏季最低，秋冬两季高于春季。(4)同一群落内，生长于中潮区滩面的秋茄抗寒力强于高潮区，但桐花树抗寒力在各个滩面相差木大。(5)秋茄和桐花树树冠上不同部位叶片的抗寒力不同，由表及里，由上至下，呈降低趋势。红树叶片抗寒力的种群分化、季节变化和部位差异是其趋异适应的结果，有益于红树植物的生存和繁育。

ECOLOGICAL STUDIES ON THE RESISTANCE AND ADAPTATION TO COLD OF SOME TIDAL MANGROVE SPECIES IN CHINA

Leaf cold resistance abilities of mangrove species along the eastsouthern coast of China had been measured by conductivity method. The results show: (1)The cold resistance abilities (LT50) of 16 mangrove species at Dongzhai Estuary,Qiongshan. Hainan province were from -2.3 ℃ to -6.8℃. The species from Rhizophoraceae had higher cold resistance abilities than that from Sonneratiaceae and Meliaceae, so most of them could be classified into low cold sensitivity type (L type) ,and the late ones into high cold sensitivity type (H type). (2)As the latitude increased, the cold resistance abilities of Kandelia candel and Aegiceras corniculatum also increased, and reflected the trend of population differentiation(except one location). (3) At the same location, Kandelia candel and Aegiceras corniculatum had the lowest cold resistance abilities in summer, and higher cold resistance abilities in autumn and winter than those in spring. (4) Among the same mangrove community, Kandelia candel plants growing in the middle tidal zone had higher cold resistance ability than those in the high tidal zone, but no this difference was found in Aegiceras corniculatum. (5) Kandelia candel and Aegiceras corniculatum leaves had different cold resistance abilities according to their locations on the community crown. The cold resistance ability of leaves decreased from upper surface to lower layer, and from surface to inner part. The population differentiation ,season changes ,and leaf location variation of mangrove cold resistance abilities were due to the ecological adaptation to various habitats which were beneficial for the survival and regeneration of mangroves.