2021年12月9日 星期四
光照及地面覆盖物对水青树种子萌发和幼苗初期生长的影响
Effects of light and ground cover on seed germination and seedling initial growth of Tetracentron sinense
2015年 第24卷 第3期 页码[85-93]    下载全文[0.8MB]  
摘要

通过模拟野外自然环境,设置强光、中度光照和弱光(分别相当于自然光照强度的100%、50% 和10%)3 种光照条件以及无覆盖物、覆盖灌草丛及覆盖灌草丛和枯落物3 类苗床,研究了光照及地面覆盖物对水青树(Tetracentron sinense Oliv.)种子萌发率、幼苗存活率及初期生长状况的影响。结果显示:在不同光照条件下,水青树种子的萌发率均为在无覆盖物的苗床中最高、在覆盖灌草丛的苗床中最低,其中,中度光照条件下在无覆盖物的苗床中种子萌发率最高。各处理组1 月龄幼苗的存活率总体上高于2 月龄幼苗,且在不同的苗床中弱光条件下1 月龄幼苗存活率均最高;总体上,弱光条件下覆盖灌草丛的苗床最宜于水青树1 月龄幼苗存活。随光照强度减弱,在无覆盖物及覆盖灌草丛的苗床中幼苗的株高和主根长度均逐渐降低,而在覆盖灌草丛和枯落物的苗床中则呈波动趋势,但总体上各处理组幼苗的株高和主根长度无显著差异。随光照强度变化或苗床覆盖程度的变化,幼苗的侧根数,叶面积,根、茎和叶片的干质量以及总干质量均呈现不同的变化规律;强光条件下,在覆盖灌草丛的苗床中幼苗的根干质量均最大;中度光照条件下,在覆盖灌草丛的苗床中幼苗的侧根数、叶面积、叶片干质量及总干质量均最大;中度光照和弱光条件下在无覆盖物的苗床中幼苗的茎干质量最大。综合分析结果表明:水青树种子萌发需要一定的光照条件且地面的枯落物和灌草丛会阻碍其种子萌发,而其幼苗定居阶段则需要适度荫蔽且地面覆盖灌草丛有利于其幼苗存活,因此,林窗或林缘更适合于水青树的自然更新;此外,在水青树的就地保护过程中应根据其生活史的不同阶段采取不同的栽培措施。

Abstract

By means of simulating wild natural environment, three kinds of light conditions with strong,middle and weak lights ( being equivalent to 100%, 50% and 10% of natural light intensity, respectively) and three types of seedbeds with no cover, covering shrub-grass and covering shrub-grass and litter were set up. And effects of light and ground cover on seed germination rate, seedling survival rate and initial growth status of Tetracentron sinense Oliv. were investigated. The results show that under different light conditions, seed germination rate of T. sinense is the highest in no cover seedbed and the lowest in covering shrub-grass seedbed, in which, that is the highest in no cover seedbed under middle light condition. Survival rate of seedling with one month age in every treatment group is generally higher than that of seedling with two month age, and among different seedbeds, survival rate of seedling with one month age is the highest under weak light condition. In general, under weak light condition, covering shrub-grass seedbed is the most suitable for survive of T. sinense seedling with one month age. With decreasing of light intensity, height and main root length of seedling gradually decrease in no cover and covering shrub-grass seedbeds, while those appear the wavy trend in covering shrub-grass and litter seedbed, but there are no significant differences in height and main root length of seedling among different treatment groups. With changes of light intensity or seedbed cover degree, lateral root number,leaf area, dry weights of root, stem and leaf, and total dry weight of T. sinense seedling all appear different changing trends. Under strong light condition, root dry weight of seedling is the highest in covering shrub-grass seedbed; under middle light condition, lateral root number, leaf area, leaf dry weight and total dry weight of seedling are the highest in covering shrub-grass seedbed; and under middle light and weak light conditions, stem dry weight is the highest in no cover seedbed. Result of comprehensive analysis indicates that a certain degree of light is demanded for seed germination of T. sinense and litter and shrub-grass on ground would hinder its seed germination, while, at seedling establishment stage, the proper shading is demanded and cover shrub-grass on ground benefits seedling survive of T. sinense, therefore, forest gap or forest edge is more suitable for natural regeneration of T. sinense. Moreover, in situ conservation of T. sinense, different cultivation measures should be taken according to different stages of life history.

 

关键词水青树; 光照; 地面覆盖物; 种子萌发; 幼苗生长; 存活率
Key wordsTetracentron sinense Oliv.; light; ground cover; seed germination; seedling growth; survival rate
作者许宁a,b, 憨宏艳a,b, 甘小洪a,b
所在单位西华师范大学: a. 西南野生动植物资源保护教育部重点实验室, b. 生命科学学院, 四川南充637009
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基金项目国家自然科学基金资助项目(31370637); 四川省教育厅自然科学重点项目(12ZA169)