植物生态学报 ›› 2011, Vol. 35 ›› Issue (6): 641-652.DOI: 10.3724/SP.J.1258.2011.00641

• 研究论文 • 上一篇    下一篇

刈割、施肥和浇水对矮嵩草补偿生长的影响

张璐璐1, 周晓松1, 李英年2, 袁芙蓉1, 樊瑞俭1, 朱志红1*   

  1. 1陕西师范大学生命科学学院, 西安 710062;
    2中国科学院西北高原生物研究所, 西宁 810008
  • 收稿日期:2011-01-04 修回日期:2011-05-04 出版日期:2011-06-01 发布日期:2011-06-30
  • 通讯作者: 朱志红
  • 基金资助:

    高寒草甸放牧系统植物补偿性生长与群落物种多样性变化研究:放牧优化假说与中度扰动假说的验证;高寒草甸植物功能多样性对物种多样性与生态系统功能关系的影响

Effects of clipping, fertilizing and watering on compensatory growth of Kobresia humilis

ZHANG Lu-Lu1, ZHOU Xiao-Song1, LI Ying-Nian2, YUAN Fu-Rong1, FAN Rui-Jian1, ZHU Zhi-Hong1*   

  1. 1College of Life Sciences, Shaanxi Normal University, Xi’an 710062, China;

    2Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining810008, China
  • Received:2011-01-04 Revised:2011-05-04 Online:2011-06-01 Published:2011-06-30
  • Contact: ZHU Zhi-Hong

摘要:

通过对青海海北高寒矮嵩草(Kobresia humilis)草甸进行为期3年的野外控制试验, 研究了刈割(留茬1 cm、3 cm及不刈割)、施肥(2.5 g·m–2尿素+ 0.6 g·m–2磷酸二胺、不施肥)和浇水(20.1 kg·m–2、不浇水)处理对矮嵩草补偿生长(包括分株密度、株高和分株地上生物量)的影响, 及其比叶面积、叶片净光合速率和相对增长率的变化, 探讨矮嵩草补偿生长的机制。研究结果表明: 刈割后, 矮嵩草的补偿生长高度和比叶面积显著降低; 分株密度有增加的趋势, 但会随刈割强度的增加而下降; 株高和生物量的相对增长率随刈割强度的增加而呈上升趋势; 补偿地上生物量在重度刈割处理下最高。施肥能显著增加矮嵩草的补偿高度、分株密度、补偿地上生物量、株高相对增长率、生物量相对增长率、比叶面积和净光合速率; 与不浇水处理相比, 浇水处理对重度刈割处理下的分株地上生物量、密度相对增长率、比叶面积和净光合速率无影响, 而显著降低了中度刈割处理下的补偿高度和株高相对增长率, 提高了不刈割处理下的分株密度和重度刈割处理下的生物量相对增长率。刈割、施肥和浇水处理的交互作用也显示出刈割与施肥对矮嵩草补偿生长具有拮抗效应, 而刈割与浇水具有协同效应。上述结果说明,矮嵩草在刈割后可通过增加分株密度和相对增长率等途径来提高补偿能力, 弥补在生长高度上出现的低补偿, 而施肥可显著抵消刈割的不利影响, 提高矮嵩草的补偿能力。

Abstract:

Aims Kobresia humilis meadow is a disturbance-dependent (disclimax) community resulting from long-term and heavy grazing. Our objectives were to (a) examine how the compensatory growth of K. humilis (including ramet density, compensatory height and compensatory aboveground biomass per ramet) varies with different levels of clipping, fertilizing and watering and (b) examine changes in specific leaf area (SLA), lamina net photosynthetic rate (Pn) and relative growth rate (RGR) in order to reveal the compensatory mechanisms of the species.
Methods Our field experiment was carried out at the Haibei Research Station of the Chinese Academy of Sciences from 2007 to 2009. The experiment used a split-plot design with clipping treatment on the whole plot (stubbled 1 cm, 3 cm and unclipped) and both fertilizer (fertilized and unfertilized) and water (watered and unwatered) treatments in subplots. We analyzed effects of clipping, fertilizing and watering on the response variables by multivariate ANOVA. We used stepwise regression analysis to determine the contribution of SLA, Pn and RGR to compensatory growth and Pearson’s correlation to determine the correlation among ramet density, compensatory height and compensatory aboveground biomass.
Important findings Compensatory height and SLA were reduced after clipping; RGR of ramet height and aboveground biomass, ramet density and compensatory biomass were increased. Fertilizing can increase ramet density, compensatory height, compensatory biomass, RGR of ramet height and aboveground biomass, SLA and Pn. The effect of watering on compensatory height and RGR of ramet height under stubbled 1 cm clipping was not obvious, but reduced them under stubbled 3 cm clipping. The interactions of clipping, fertilizing and watering showed that the relation between clipping and fertilizing is “antagonistic” and the relation between clipping and watering is “cooperative”. Although K. humilis appeared under compensation in plant height, fertilizing could enhance the compensation ability and promote tolerance against defoliation at a certain level of clipping.