常绿阔叶树种栲树开花物候动态及花的空间配置

 基于定株观测和随机枝取样法，对浙江天童常绿阔叶林内栲树（Castanopsis fargesii）的开花物候动态及其雌花、雄花的空间配置进行了研究。结果表明：在栲树的生殖枝上，并非所有的芽都分化、萌发生成花序，栲树花芽的分化和发育集中在一级生殖枝上。生殖枝上花芽的分化与该枝的空间位置密切相关。栲树花期明显晚于春季的展叶期，与叶片生长时间重叠。盛花期集中于5月下旬，约持续8 d左右，属于同步发生的花期。栲树雄花序的数量明显高于雌花序，雄花序约占花序总数的77.88%，雌花序仅占22.12%。大量雄花和花粉的存在是保证雌花接受花粉和完成受精的基础。花序在植冠层中的空间配置明显不同：在同一植冠内，向阳面和背阴面生殖枝上芽萌发成花序的比率存在明显差异(p<0.01)，阳面生殖枝上顶芽萌发成花序的比率高于阴面生殖枝的比率，并且，阳面的每个生殖枝上平均花序数和雄花数量均高于阴面生殖枝，花序的分化和发育与枝系的生长发育状况有密切关系。

FLOWERING PHENOLOGY AND FLORAL DISTRIBUTION OF CASTANOPSIS FARGESII IN TIANTONG, ZHEJIANG PROVINCE

Forested areas of eastern China are predominatly evergreen broad_leaved forests which are typically zonal or climatic climax vegetation in subtropical areas, dominated by Castanopsis fargesii Franch.(Fagaceae)，a shade-tolerant and long-lived species. The observation and study of its reproductive characteristics in the field still remain poorly understood. Based on the methods of Randomized Branch Sampling and observation of labeled individuals, the flowering phenology, flower number and spatial distribution of Castanopsis fargesii Franch. from the Schimeto-Castanopsietum fargesii Association in the Tiantong National Forest Park (TNFP) were studied in this paper. The results showed that the floral bud flushing and inflorescence elongation of C. fargesii emerged at end of April and the trees flowered after leaf emergence. The onset of mass flowering occurred at late May, and its duration within population could last more or less eight days, while the flowering time among individuals experienced less difference. The refore C. fargesiidisplays synchronous flowering. Given the lower precipit ation and gradually increasing temperature during April_May, synchronous flowering and therefore pollination in C. fargesii is a beneficial adaptation. Floral buds commonly located at the first-order branch, which made up 91.92% of all the reproductive branch, nearly 7.07% and 1.01% at the second and the third branch, respectively. There was an apparent difference between the floral bud initiation at the toward-sun reproductive branch and the toward_shade ones within a crown (p<0.01) and the floral bud initiation were 78%±5.7% and 67%±5.7% respectively. Within a crown, there were about 4.89±1.82 panicles per reproductive branch at sun-side and 3.08 ±2.08 at shade-side.The number of male inflorescence of C. fargesii is more than that of the female and male inflorescence occupied 77.9% of the total and female inflorescence 22.1% respectively. There were 67.9±16.7 staminate at one male inflorescence and 26.1 ±5.08 pistillate at one female inflorescence. Furthermore, the flower numbers were male biased during spring censuses and the ratio of staminate to pistillate was about 9.2∶ 1.Mass staminate could produce higher pollen concentration during synchronous period 2.and should increase the pollination efficiency. Therefore flowering in spring exerted 3.great influence on the reproductive output ofC. fargesii.