濒危植物七子花的开花与结实特性

Characteristics of Flowering and Fruiting of Heptacodium miconioides an Endangered Plant in Tiantai,Zhejiang Province

对濒危植物七子花(Heptacodium miconioides)的开花和结实特性进行了研究.结果显示:(1)生境的光照和土壤条件好有利于花枝多开花,而海拔低(或气温高)则有利于花序开多轮花,并使花期延长.(2)七子花的结实率不高(平均只有34.10%),主要原因是大多数早开的花没有获取资源的空间优势,结实率很低.(3)种子的大小也与花序类型及开花位置有关,其中Ⅰ型花序产生的最大,Ⅲ型花序上轮花产生的最小.(4)去基轮花可以提高花序的开花数量,但不能改善其结实状况。因此,提高七子花果期的生殖投资可能是解除其濒危状态的关键.

Three population of Heptacodium miconioides was researched of it＆：acute; s flowering and fruiting characteristics. The result as follow： the flower is effected by light, thickness of soil and temperature. With better light and thicker soil, the quantity of panicles and flowers on the flowering wood in population B was the largest with an average of 26.8 and 279, while 17.2 and 197 in population A, which is in located in the wdrst ecology environment when compared with the others. Also the influenced of temperature was observed, which is directly caused by the height. Population A, located in a place of lower height, so a higher temperature, has a larger proportion of panicle flowered with three whorls and a longer flowering phase than the others. With no space superiority to obtain the resources, most of the flowers bloomed early failed to develop into fruits, which caused a low fruit set rate of H. miconioides, 34.10% averaged in the three populations. The seed weight was also influenced by space superiority, which is present by panicle type and flower＇s position, the biggest was from the panicle flowered with only basal whorl, while the smallest was from the upper flowered with three whorls. When the basal whorl flowers removed, the flowers of panicles increased but the seed status remained or even decreased. All the results show that the crux factor made H. miconioides extinct was the resources limited, especially in the fruit developmeat period.