光照强度和肥力变化对对垂穗披碱草生长的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 光照强度和肥力变化对垂穗披碱草生长的影响 DOI: 10.5846/stxb201211241667 作者: 作者单位: 河西学院农业与生物技术学院,兰州大学干旱与草地生态教育部重点实验室,兰州大学干旱与草地生态教育部重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 甘肃省科技计划资助项目（1304FKCG080）；河西学院校长基金（XZ2011-04） The effects of light intensity and fertilization on the growth of Elymus nutans Author: Affiliation: Biology Department of Hexi University,Key Laboratory of arid and grassland ecology of Ministry of Education,Lanzhou University,Key Laboratory of arid and grassland ecology of Ministry of Education,Lanzhou University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在野外条件下，采用析因设计，对光照和肥力变化影响下垂穗披碱草的生长参数进行测定，评估垂穗披碱草对异质环境的适应特性。光照分为高光照（100%光照强度）、中度光照（43.5%光照强度）与低光照（6.74%光照强度）；肥力分为施肥与不施肥。结果表明，垂穗披碱草在光照强度由高光照（100%）向中度光照（43.5%）变化情况下，地上生物量、分蘖数无变化，株高增大，光照强度减小到6.74%时，地上生物量、分蘖数、株高均减小。比叶面积（SLA）随光照强度的减弱而增加，相对生长率（RGR）随光照强度的减弱而减小，施肥对SLA和RGR无影响。根冠比在中度光照和低光照下各处理之间差异均不显著，高光照（100%）下增加肥力，根冠比增大。施肥时，叶分配随光照强度的减弱而增加，繁殖分配减小，不施肥时，叶分配与繁殖分配在高光照（100%）和中度光照（43.5%）下无差异，低光照（6.74%）下，叶分配增大，繁殖分配减小。施肥时茎分配在中度光照强度（43.5%）下最大，高光照强度（100%）下次之，低光照强度（6.74%）下最小，不施肥时，茎分配在高光照（100%）和中度光照（43.5%）下无差异，低光照（6.74%）下减小。研究表明：垂穗披碱草是一个光照耐受型物种，光照强度减小到全光照一半时仍可正常生长。在低光环境中，垂穗披碱草通过增加株高和大而薄的叶片，来适应环境，资源主要在叶分配、茎分配、繁殖分配之间进行了权衡。 Abstract:Elymus nutans Griseb. (Poaceae: Triticeae) is a tall (shoot height usually 60-120 cm) sparse bunchgrass with broad leaves that is native to the alpine meadows of the Qinghai-Tibetan plateau, China. The study was conducted in the Hezuo Sub-alpine Meadow Ecosystem Field Station of Lanzhou University. Field experiments based on a factorial design were used to measure the effects of illumination and fertilization on the growth parameters of E. nutans to assess the ability of E. nutans to adapt to heterogeneous environments. The experiment began in April, 2006 as part of mowing trials and included eighteen 1.3 m × 0.8 m plots with a total of six treatment combinations of light and fertilization, 80 of plants per plot, 30 that were marked. The plots were separated by 0.5 m. To simulate the effects of attenuated light beneath the canopy on plant growth, green shade nets that did not fundamentally change the spectral composition of sunlight were used in this trial to create three illumination conditions similar to those in the natural environment. The three light intensities were high (100% illumination), moderate (43.5%), and low (6.74%), and plots were either fertilized with diammonium hydrogen phosphate (50 g/m2) or left unfertilized. On 10th October, we harvested 15 individual plants (five marked individuals per plot) from each treatment. Harvested plants were dug up and washed. For each plant, the number of tillers (including withered ones) was recorded, and it was separated into leaves, stem (including leaf sheaths), inflorescences, and roots. Separated plant tissues were dried in an oven (80 ℃) for 48 h and then weighed. The results show that as illumination intensities decreased from high to moderate, the above-ground biomass and number of tillers of E. nutans did not change, while plant height increased. However, as the light intensity declined to 6.74%, the above-ground biomass, number of tillers, and plant height were all reduced. The specific leaf area increased as illumination intensity was attenuated, while the relative growth rate decreased, which suggested that fertilization had no effect on either specific leaf area or relative growth rate. The differences in root-to-shoot ratios at moderate and low illumination levels were not significant, while the root-to-shoot ratios increased with the application of fertilizer under high illumination. After fertilization, allocation to leaf biomass increased while allocation to reproductive structures decreased as the light intensity was attenuated. Without fertilization, there were no significant differences in biomass allocations to either leaves or inflorescences at high and moderate illumination levels, while allocations to leaves and to reproductive structures decreased at the low illumination level. After fertilization, the stem allocations were highest at the moderate illumination intensity, intermediate at the high illumination intensity, and lowest at the low illumination intensity. Without fertilization, there were no differences in the stem allocations at the high and moderate illumination levels, while the allocation to stem tissue decreased under low illumination. The results of this study show that E. nutans is an illumination-tolerate grass species that can grow normally even when the light intensity is reduced to half of full sun exposure. Elymus nutans adapts to low-illumination environments by increasing its height and by producing large thin leaves, and its resources are balanced through altered allocations to leaf biomass, stem tissue, and reproductive structures. 参考文献 相似文献 引证文献