Dwarf Reasons of Mangrove Plant Kandelia obovata in Shancheng Bay,Fujian

明确了低温和淹水对分布在福建沙埕湾(27°17′N,120°18′E)的红树植物秋茄(Kandelia obovata)生长的直接作用方式,探讨了纬度较高地区秋茄矮化的原因,以期在全球气候变暖影响下,为中国纬度较高地区红树林人工造林提供理论指导。通过调查福建省福鼎市沙埕湾高潮淹水线上下秋茄末端小枝生长状况、不同相对高程秋茄高度以及淹水线上下温度的实时监测,研究低温和淹水对纬度较高地区秋茄生长的影响。结果表明,低温对该地区秋茄淹水线以上部分影响显著,主要表现在枝条和叶片受低温胁迫严重,生长缓慢,顶端顶芽大量枯死;相对高程与秋茄的高度显著负相关;淹水降低了秋茄叶片的光合能力。淹水降低了低温对沙埕湾秋茄生长的胁迫程度,且对秋茄向上生长有一定的促进作用,但是在低温和强潮差的影响下,在纬度较高地区很难营造出高大繁茂的秋茄林。This study explicated the ways that how low temperature and water flooding had directly influenced the growth of mangrove plant Kandelia obovata distributed in Shacheng Bay(27°17′N,120°18′E), Fujian province where latitude is higher than 25°N and discussed the dwarf reasons of mangrove plants in higher latitude.Under the influence of global warming, it can provide the theoretical guidance for mangrove afforestation in higher-latitude areas in China. Through the survey of the growth status of the shoots of Kandelia obovata and the real-time monitoring of temperature under and above the flooded waterline and the tree height at different relative elevation for Kandelia obovata in Shacheng Bay, how low temperature and flooding influenced the growth of Kandelia obovata was studied. The results showed that low temperature had significant effects on Kandelia obovata growth, especially the part above the flooded waterline, mainly displayed in the branches and leaves of Kandelia obovata were strongly subjected to the low temperature stress, growing slowly, the bud withering at the top of crown; there was significant negative correlation between the Kandelia obovata height and the relative elevation; flooding reduced the photosynthetic capacity of Kandelia obovata leaves. To a certain extent, flooding could reduce the low temperature stress impact on the growth of Kandelia obovata and promote the upward growth of Kandelia obovata in higher-latitude area. But under the influence of low temperature and strong tidal range, a tall Kandelia obovata forest could not be built in higher-latitude regions.国家重点研发计划项目课题(2016YFC0502904);; 广西科学院基本科研业务费项目(13YJ25HS04和12YJ25HS15)资