摘要
在黑龙江省穆棱东北红豆杉自然保护区,路线踏查到271株天然东北红豆杉,选择其中具有生殖活力(开花)的29雄株和30雌株作为样株,采用标准枝法对孢子叶球和结实状况及其与生态因子关系进行研究。结果表明:现实东北红豆杉天然种群中,♀♂性比为1∶2;天然东北红豆杉有性生殖持续时间长,雄株胸径在1.5～92cm,雌株胸径在9.5～68.1cm保持生殖状态,雄株较雌株早约20年进入花期;天然东北红豆杉小孢子叶球数量平均为大孢子叶球数量的3倍,大孢子叶球转化为果实的数量不足1/10,孢子叶球数量、结实数量与样株的胸径、冠幅、树高显著相关,与其他立地因子相关不显著;孢子叶球数量在冠层间的分布呈现由上至下的递减规律,而结实数量在冠层间沿中、上、下递减,结实率沿冠层自上而下递增;孢子叶球与结实数量在树冠不同朝向上也呈现出一定的特点,但总体上差异不显著。天然东北红豆杉的上述生殖特征的形成,既是物种本身与环境相适应的结果,也有动物和人类活动的影响。
In the Taxus cuspidata nature reserve of Muling County in southeastern Heilongjiang Province, we selected 29 males and 30 females from a population of 271 natural T. cuspidata trees found by a route-checking survey to investigate the population fecundity. The strobilus development and the fruiting status, and their relationships with various ecological factors were examined by using the method of standard branches. The results showed that the sex ratio of trees was 1 m 2 f, and the natural T. cuspidata tree was able to sexually reproduce for many years. Male trees had fecundity when the diameter at breast height （DBH） ranged from 1.5 cm to 92 cm, while female trees had fecundity when the DBH from 9.5 cm to 68.1 cm. Male trees typically flowered at the age about 20 years earlier than female trees. The numbers of microstrobili were 3 times more than that of megastrobili, and only 1/10 megastrobili developed into seed. The numbers of strobili and seed were correlated with DBH, crown diameter and height of trees; however, no significant correlations were observed with other site factors. Numbers of strobili decreased from the upper to lower canopy layers, while the quantity of seed decreased from the middle, upper to lower canopy layers. Seed-setting rate increased from the upper to lower canopy layers. Numbers of strobili and seeds in different directions of the canopy were not uniform, but the differences weren＇t significant. These reproductive characteristics of natural T. cuspidata reflected long-term adaptations to the environment, including the activities of wildlife and humankind.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2009年第5期80-86,共7页
Scientia Silvae Sinicae
基金
"十一五"国家科技支撑计划重点项目"自然保护区建设关键技术研究与示范"(2008BADB0B04)
国家自然科学基金面上项目(30870464)
黑龙江省博士后启动基金项目
