秦岭冷杉球果与种子的形态变异

在秦岭冷杉的天然分布区 ,分别选取核心区和边缘区进行取样 ,比较球果和种子的形态变异。核心区为秦岭地区 ,边缘区选在湖北神农架地区。根据秦岭冷杉分布特征 ,核心区沿海拔高度连续采样 ,边缘区选择两个不同海拔高度的种群 ,分单株采样 ,测量了球果、种子、种鳞、种翅等器官的 15个形态指标。相关分析表明 ,秦岭冷杉球果和种子形态特征 (变化 )与海拔高度显著相关 ,说明海拔因素影响着球果和种子形态变异。比较发现 ,核心区 (即秦岭地区 )的秦岭冷杉球果和种子的绝大部分指标均值显著大于边缘区 (即神农架地区 ) ,说明秦岭冷杉在核心区的生殖生长好于边缘区。相同海拔条件下 ,秦岭冷杉球果和种子形态在地区间差异显著 ,约 85 %的变异来自地区内个体间和个体内 ,说明秦岭冷杉的球果和种子形态特征变化受遗传控制更显著。在边缘区还比较了不同种群间、人工林和天然林在球果和种子形态特征的差异。球果和种子形态在同一地区两个种群间、在人工林与天然林间都有显著差异 ,大部分人工林球果和种子指标均值和变异幅度大于天然林 ,表明通过人为经营可以改善秦岭冷杉的一些生殖性状

Morphological variation in cones and seeds in Abies chensiensis

The purposes of our study were: (1) to determine the relationships and variability between Abies chensiensis cones and seeds in different elevations and between the core and border regions, (2) to investigate variation between natural and managed forests, and (3) to determine the sources of variation to provide management suggestions.In this study, two sampling zones were selected from the core and border regions of Qin-Ling, China, where Abies chensiensis is naturally distributed. The core region is located in Qin-Ling Mountain and the border region in Shennongjia of Hubei Province. Morphological variations of cones and seeds collected from different altitudes and latitudes and between natural and managed forests were analyzed. We sampled twenty cones from 48 trees, 28 from Qinling Mountain and 20 from Shennongjia. Fifteen traits were measured for each cone and seed, including cone length, cone diameter, cone scale length, and bract length. Data were analyzed using SAS and SPSS. Our statistical analyses were composed of (1) correlation analyses for each trait among different elevations in Qinling Mountain, (2) calculation of means,standard deviation and coefficient of variation for each trait from natural and managed forests, (3) hierarchical analyses of variation with the same elevation in different regions, (4) variance analyses between two populations with different elevations in Shennongjia, and (5) variance analyses between natural and managed forests in Shennongjia. Results from correlation analyses suggested that morphological variation of cones and seeds was significantly correlated to elevation on Qinling Mountain, which indicated that elevation played an important role in morphological variation. Statistical differences were significant between regions with the same elevation and among trees within regions, as well as between natural and managed forests. The variance component analysis indicated that about 85 percent of the variation was attributable to differences between individual trees and within a tree, and the remaining 15 percent varied between regions,providing strong evidence of substantial genetic control over traits. The mean values of traits of cones and seeds from the core region were higher than that of in the border area, which indicated that Abies chensensis reproduced better in the core region. The analysis suggested that the mean and variation of traits of cones and seeds from managed forests were greater than that from the natural forests. It appears that traits of cones and seeds of Abies chensiensis could be improved by forestry practices in managed forests.