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应用生态学报 ›› 2016, Vol. 27 ›› Issue (6): 1870-1876.doi: 10.13287/j.1001-9332.201606.001

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沙柳丛生枝代谢指数的龄级效应

陈国鹏1,2, 赵文智1,3*   

  1. 1甘肃农业大学林学院, 兰州 730070;
    2甘肃省白龙江林业管理局林业科学研究所, 兰州 730070;
    3中国科学院寒区旱区环境与工程研究所中国生态系统研究网络临泽内陆河流域研究站/中国科学院内陆河流域生态水文重点实验室, 兰州 730000
  • 收稿日期:2015-11-03 发布日期:2016-06-18
  • 通讯作者: zhaowzh@lab.ac.cn
  • 作者简介:陈国鹏,男,1986年生,博士研究生. 主要从事生态系统碳水循环过程研究. E-mail: chgp1986@gmail.com
  • 基金资助:
    本文由国家基础研究发展计划项目(2013CB429903)、甘肃省青年科技基金计划项目(145RJYK278)和陇原青年创新人才扶持计划项目资助

Effects of age classes on metabolic exponents of Salix psammophila branches.

CHEN Guo-peng1,2, ZHAO Wen-zhi1,3*   

  1. 1College of Forestry, Gansu Agricultural University, Lanzhou 730070, China;
    2Institute of Forestry Sciences, Bailongjiang Forestry Management Bureau of Gansu Province, Lanzhou 730070, China;
    3Linze Inland River Basin Research Station/Key Laboratory Inland River Ecohydrology, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2015-11-03 Published:2016-06-18

摘要: 新陈代谢速率是植物最基本的生物学速率,与地表植被的水碳代谢过程密切相关.表征代谢速率及其替代指标(如叶生物量等)与个体大小间相关生长关系的代谢指数是生态学研究的一个热点,WBE模型论证的3/4恒定代谢指数最为经典,但也饱受争议.本研究以毛乌素沙地南缘沙柳为对象,检验了WBE模型的可用性,揭示代谢指数随丛生枝生长发育的变化规律.结果表明: 基于叶生物量和茎叶生物量估计的沙柳丛生枝代谢指数α为0.97,显著大于WBE模型的恒定指数3/4;分支半径指数1/a和分支长度指数1/b分别为2.67和3.83,均显著大于理论值2.0和3.0.分龄级估计的丛生枝分支半径指数和分支长度指数分别为2.64~3.24和2.86~4.30,各龄级代谢指数的估计值和计算值分别为1.01~1.29和0.94~1.13,龄级差异均不显著.斜率异质性检验表明,不同龄级的丛生枝共有代谢指数估计值1.08和计算值1.00、分支半径指数2.84和分支长度指数3.35,均显著大于理论值.在各龄级丛生枝共有代谢指数1.08下,代谢常数在y轴上的负向漂移幅度随龄级增加而显著增大.尽管枝龄未引起沙柳丛生枝代谢指数的显著变化,但在给定大小的枝条上,大龄枝较低龄枝的代谢活性下降明显.

Abstract: Metabolisms are fundamental processes of organisms. They are related to carbon and water cycling of a plant. The relationship between the metabolic rate and the body size of an organism has been a hot spot in ecological research. The typical WBE model with 3/4 power has been controversial. This study tested the applicability of WBE model and examined the change of metabolic exponents with the age class at branch scale in a typical plant, Salix psammophila in the southern edge of the Mu Us desert. The results showed that the estimated metabolic exponent based on the leaf biomass and total biomass was 0.97 for all branches of the S. psammophila. This was significantly greater than the constant power of 3/4 proposed by the WBE model. The branching radius exponent and branching length exponent were 2.67 and 3.83, respectively, being significantly greater than the constant values of 2.0 and 3.0, respectively. The ranges of branching radius exponents and branching length exponents among the age classes were 2.64-3.24 and 2.86-4.30, respectively. Meanwhile, the estimated values and calculated values of metabolic exponents ranged from 1.01-1.29 and 0.94-1.13, respectively. The values of all above were statistically indistinguishable among the six age classes. The common slopes among the six age classes for estimated values and calculated values of metabolic exponents, branching radius exponents and branching length exponents were 1.08, 1.00, 2.84 and 3.35, respectively. These values were significantly greater than the constant values. The changes of the intercept at the y-axis shifted negatively at the common slope of estimated metabolic exponents with significant elevation shift between groups, and the higher age class branches had the greater shift. These indicated that the age classes did not change the metabolic exponents, but changed the metabolic constant significantly. The older branches had lower metabolic activity than the younger branches.