水杉原生种群核心种质资源的繁殖特性

水杉(Metasequoia glyptostroboides)原生种群天然更新困难, 为探究其原因是否与繁殖特性有关, 本文以其核心种质资源(40株个体)为对象, 通过对生境、母树个体和种子性状的调查, 并结合田间播种试验, 分析其繁殖特性。以方差分析检测不同母树个体间种子性状、发芽率和幼苗生长特征的差异; 采用相关性分析和多元线性回归模型分析个体性状对其种子、发芽率及幼苗生长的影响; 通过Logistic模型拟合, 分析幼苗生长的节律参数。结果显示: (1) 40株母树个体仅有7株产种, 产种率仅为17.50%, 且不同母树个体间产种量差异显著(P < 0.05)。(2)不同母树个体间的种子千粒重、种子发芽率、幼苗存活率和基径生长量均存在显著差异(P < 0.05)。(3) 7株母树个体种子的平均发芽率为19.73%, 幼苗平均存活率为73.42%, 不同母树之间差异显著(P < 0.05)。(4)母树个体的胸径与种子千粒重、种子发芽率呈显著负相关(P < 0.05), 种子发芽率与幼苗存活率呈极显著正相关(P < 0.001), 树高与幼苗存活率呈显著正相关(P < 0.05)、与幼苗基径呈极显著正相关(P < 0.001)。(5)母树树高对幼苗存活率有显著正效应(P < 0.05), 胸径对种子发芽率有显著负效应(P < 0.05)。(6)苗高、基径的生长符合“S”型生长曲线(R ² ≥ 0.928)。水杉原生种群产种量低, 种子发芽率低、幼苗存活率较低, 且不同母树之间差异显著可能是造成其天然更新困难的原因。

The reproductive characteristics of core germplasm in a native Metasequoia glyptostroboides population

In order to explore the reproductive characteristics of Metasequoia glyptostroboides, we explored a native population of original Metasequoia glyptostroboides. We investigated the core germplasm of 40 individuals of native Metasequoia glyptostroboides and collected data on habitats, parent trees and seed traits. We used field experiment to analyze reproductive characteristics. We detected differences in seed traits, germination rate and seedling growth characteristics among different parent trees using ANOVA. The effects of individual traits on seeds, germination rate and seedling growth were analyzed with correlation and linear regression models. The results showed that: (1) There were only 7 strains from 40 mother trees, the seed yield rate was 17.50%, and the difference in seed yield of 7 original mother trees was significant (P < 0.05). (2) There were significant differences in seed weight (1,000 grain), seed germination rate, seedling survival rate and base diameter growth among individuals of different parent trees (P < 0.05). (3) The average germination rate of seeds from seven mother trees was 19.73%, and the average survival rate of seedlings was 73.42% (inter-individual rates were also significantly different (P < 0.05). (4) Diameter at breast height (DBH) was negatively correlated with seed weight and germination rate (P < 0.05), while seed germination and seed weight (P < 0.05), seed germination and seedling survival (P < 0.001), and tree height and seedling survival (P < 0.05) were positively correlated. (5) The height of mother tree was positively correlated to seedling survival rate (P < 0.05), and DBH was negatively correlated to seed germination rate (P < 0.05); and (6) Seedling growth (height and base diameter) conforms with logistic growth (R ² ≥ 0.928).