红树植物对不同海滩面高度的适应性研究

通过研究华南沿海珠江口深圳湾红树植物无瓣海桑、海桑和秋茄在不同海拔高度的滩面中的生长适应性,揭示红树植物对海水淹浸的适生特性.研究结果表明:(1)在一定的滩面高度范围内,红树植物无瓣海桑(滩面高度为-12～35.5 cm)、海桑(滩面高度为-1～24 cm)幼树的保存率和生长量随着滩面高度的降低(即海水淹浸程度的加强)而逐渐减低,秋茄(滩面高度为12～24 cm)的保存率和生长量则无明显差异.(2)随生长期的延长,各树种幼树的保存率逐渐减低.当生长期未超过1年时,幼树生长和成活极不稳定,保存率骤减;当生长期超过1年后,无瓣海桑和海桑保存率趋于相对稳定,秋茄保存率继续下降,极难长久保存和定居.(3)无瓣海桑能够忍耐海水淹浸的限度是滩面高度最低为10 cm,海桑是滩面高度最低为6.5 cm,秋茄是滩面高度至少在24 cm以上,在低于此海拔高度的滩面上各树种极难长期保存和定居.为了保证各树种正常生长发育,种植红树林要选择高于此滩面高度的泥滩区域.

Adaptability of several mangrove species on the mudflat with diverse altitudes

The adaptability of mangrove species Sonneratia apetala Buch.-Ham., Sonneratia caseolaris(L.) Engl., Kandelia candel Druce on the mudflat with diverse altitudes were studied in Shenzhen Bay, located at the mouth of Zhujiang River, south China, to discover their endurance to sea-water inundation. Results showed that: (1) At a certain range of mudflat altitudes, the survival rate and growth of mangrove species S. apetala Buch.-Ham. at altitudes of mudflat -12~35.5 cm, S. caseolaris(L.) Engl. -1~24 cm, turned to decrease following the descending of mudflat, namely, intensification of inundation, while the survival rate and growth amount of K. candel Druce at altitudes of mudflat - 12~24 cm, remained relatively unaffected by the variation of mudflat altitudes; (2)The survival rate of all the species studied became increasingly lower as the growth period became longer. The survival rate decreased greatly during the first year after being planted, showing the growth and survival was unstable at the early stage of development; after one year, the survival rate of S. apetala Buch.-Ham. and S. caseolaris(L.) Engl. tended to be steady, while that of K. candel Druce continued to decrease, difficult to exist in the long run. (3)The inundation limit that S. apetala Buch.-Ham. could stand was the mudflat altitude of 10 cm, and 6.5 cm for S. caseolaris(L.), and at least 24 cm for K. candel Druce. All species studied can hardly settle on mudflat below these altitude limits. To ensure them to grow and multiply normally, it is suggested to plant them on the mudflat above these altitude limits.