摘要
基于分维数理论,对荒漠草原5个不同生长年限(未平茬16年、25年、37年生及平茬后1年、5年生)中间锦鸡儿(Caragana intermedia)灌丛的枝系构型变化进行分析,并探讨其生态适应策略。中间锦鸡儿灌丛的冠幅、株高、基径等指标基本随生长年限的增加呈先增大后降低趋势,未平茬中间锦鸡儿灌丛的地上生物量随林龄的增加呈下降趋势,老林龄(37年生)灌丛以自我更新的方式来抵制衰老的态势;平茬后1年与5年生中间锦鸡儿灌丛的枝径比(ratio of branch diameter,RBD)较未平茬16、25、37年林龄灌丛大,平茬后灌丛枝条间的承载力增大;中间锦鸡儿灌丛的总体分枝率(overall bifurcation ratio,OBR)以及低级枝的逐步分枝率(stepwise bifurcation ratio,SBR1∶2)随林龄增大而减小,平茬后1年生灌丛的OBR及SBR1∶2较未平茬3种年限林龄的灌丛大,但平茬后5年生灌丛的OBR和SBR1∶2急剧降低;未平茬灌丛的树冠分维数(crown fractal dimensions,CFD)较低,均小于1,且随林龄增大,树冠分维数降低。平茬后的灌丛CFD值大于1,尤以平茬后5年生灌丛为最大。未平茬灌丛的分枝分维数(bifurcation fractal dimensions,BFD)随林龄增大而减小,平茬后1年生灌丛BFD值大于未平茬灌丛,平茬后5年生灌丛BFD值最小。在构件水平上,16、25、37年生中间锦鸡儿灌丛出现衰退型发育的趋势。16年生中间锦鸡儿灌丛的枝系空间格局最为复杂,其占据空间的能力以及利用空间资源的潜能较高。但随着灌丛林龄的增加,中间锦鸡儿的枝系构型趋于简化,对空间资源的利用潜能和生态适应能力下降。平茬有利于刺激灌丛空间格局的发展,使灌丛枝系构型复杂化,但平茬后生长5年的灌丛,其构型发展主要以各级分枝枝长为主,分枝数对其贡献不大。
Summary Caragana intermediais a bush-like plant,and its branching architectures are more complex.Fractal theory provides a new tool for the study of trees and their properties.The crown characteristics of trees can bequantified by fractal dimensions,and the architectures can be described accurately. The relationships between branching architectures and growth of C.intermedia were studied from the viewpoint of fractal theory,in order to study the branching architectures and adaptation strategies to the environment of C.intermediain desert steppe areas. Based on the theory of fractal dimension in forestry application,the changes of branching architectures and strategies of ecological adaptation of C.intermediaat different ages（growth for 16 a,25a,37 aof intact plants and growth for 1a,5aafter stumping）were studied in desert steppe areas. The indexes of crown size,height and basal diameter of C.intermediaincreased firstly and then decreased with the increasing ages.Aboveground biomass of intact C.intermedia at different ages decreased gradually with the increasing ages.Older shrubs（37a）resisted the situation of senescence by self renewing.The ratio of branch diameter（RBD）of C.intermedia shrubs which grew for one year after stumping was higher than those without stumping.The bearing capacity of shrub branches increased after stumping.The overall bifurcation ratio（OBR）and the lower-level stepwise bifurcation ratio（SBR1∶2）decreased with the increasing ages.The OBR and SBR1∶2of shrubs which grew for one year after stumping were higher than the shrubs without stumping,but OBR and SBR1∶2of shrubs which grew for 5years after stumping decreased dramatically.The crown fractal dimensions（CFD）of shrubs without stumping were lower than 1,and CFD decreased with the increasing ages.The CFD of shrubs after stumping were higher than 1,especially the shrubs which grew for five years after stumping were the highest.The bifurcation fractal dimensions（BFD）of shrubs without stumping decreased with the increasing ages.The BFD of shrubs which grew for one year after stumping were higher than those without stumping,and the BFD of shrubs which grew for five years after stumping were the lowest. At the module level,C.intermedia at the ages of 16 a,25a,37 apresented a tendency of declining development.The branching pattern of 16 ashrubs was the most complex,and the ability to occupy the space and the potential of using spatial resources were higher.But the branching architecture of C.intermedia became simplified and the utilization potential of spatial resources and ecological adaptability declined with the increasing ages.Stumping was beneficial to stimulating the development of shrubs＇ spatial patterns,and made branching architectures more complicated.The architectures development of shrubs which grew for 5years after stumping mainly depended on branch length of different branch orders,and the branch number contributed little to it.
出处
《浙江大学学报（农业与生命科学版）》
CAS
CSCD
北大核心
2015年第3期340-348,共9页
Journal of Zhejiang University:Agriculture and Life Sciences
基金
国家自然科学基金(31460161
31460123)
国家重点基础研究发展计划(973计划)前期专项项目(2012CB723206)
宁夏自然科学基金(NZ14006)
关键词
中间锦鸡儿
生物量
枝序
分维数
枝系构型
Caragana intermedia
biomass
branch order
fractal dimension
branching architecture
