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    叶子奇, 邓如军, 王雨辰, 王健铭, 李景文, 张凡兵, 陈杰. 胡杨繁殖根系分枝特征及其与土壤因子的关联性[J]. 北京林业大学学报, 2018, 40(2): 31-39. DOI: 10.13332/j.1000-1522.20170426
    引用本文: 叶子奇, 邓如军, 王雨辰, 王健铭, 李景文, 张凡兵, 陈杰. 胡杨繁殖根系分枝特征及其与土壤因子的关联性[J]. 北京林业大学学报, 2018, 40(2): 31-39. DOI: 10.13332/j.1000-1522.20170426
    Ye Zi-qi, Deng Ru-jun, Wang Yu-chen, Wang Jian-ming, Li Jing-wen, Zhang Fan-bing, Chen Jie. Branching patterns of clonal root of Populus euphratica and its associations with soil factors[J]. Journal of Beijing Forestry University, 2018, 40(2): 31-39. DOI: 10.13332/j.1000-1522.20170426
    Citation: Ye Zi-qi, Deng Ru-jun, Wang Yu-chen, Wang Jian-ming, Li Jing-wen, Zhang Fan-bing, Chen Jie. Branching patterns of clonal root of Populus euphratica and its associations with soil factors[J]. Journal of Beijing Forestry University, 2018, 40(2): 31-39. DOI: 10.13332/j.1000-1522.20170426

    胡杨繁殖根系分枝特征及其与土壤因子的关联性

    Branching patterns of clonal root of Populus euphratica and its associations with soil factors

    • 摘要:
      目的胡杨根系克隆繁殖对胡杨林更新及其群落维持具有重要作用,而胡杨根克隆器官——繁殖根系的扩展分枝是实现克隆繁殖的重要生态过程。本文以明确胡杨繁殖根系分枝特征(节间长、分支强度、分支垂向和水平向夹度)在异质生境下的可塑性和主要分枝类型,探究胡杨繁殖根系特征与土壤因子的关系,找到影响胡杨繁殖根系变化的关键环境因子。
      方法采用典型抽样对16个样点的一段跨度10 m以上的繁殖根分枝以及对应的土壤因子进行挖掘和调查。运用相关性分析(CA)和主成分分析(PCA)方法分析繁殖根特征之间的相关性和分布规律。运用冗余分析(RDA)和方差分解探究根分枝特征与土壤因子的关联性。
      结果(1) CA和PCA结果显示,4个分枝特征之间的相关性较高(P<0.05),PCA第1轴解释了繁殖根特征变异的66.88%,基本代表了从占据型(分枝强、短、垂向角小、水平角大)到游击型(分枝弱、长、垂向角大、水平角小)两种极端分枝类型的变化。占据型分枝更多出现在林缘,而游击型分枝更多出现在靠近河道处。(2)RDA结果显示,垂向分枝夹角主要受土壤紧实度的正影响(R2=0.64,P<0.05),节间长度主要受紧实度的负向影响(R2=0.87,P<0.05)。土壤全碳和全氮主要对分枝强度和分枝水平夹角有正向作用,但土壤含砂量对它们具有负向作用。主轴分布深度主要受毛管水埋深影响(R2=0.62,P<0.05)。(3)方差分解结果显示,三类土壤特征共解释了胡杨分枝特征变异的68.3%,土壤物理特征(土壤质地、紧实度)的独立作用最大(R2=0.12,P<0.05),土壤水分(土壤含盐量、含水量)和养分特征(全N、C)的独立作用较小(R2=0.07,P<0.05;R2=0.03),但与土壤物理特征的共同作用较大(R2=0.23, P<0.05)。
      结论(1) 在异质性的河漫滩环境中,胡杨繁殖根系分枝在两种极端分枝类型——游击型和占据型分枝形成的连续谱之间变化。(2)土壤物理特征是影响胡杨繁殖根分枝的最关键因素,胡杨繁殖根系主要选择占据土壤质地良好,紧实度小的斑块。单纯水分或养分丰富的斑块不会引起胡杨繁殖根分枝明显变异,但是在土壤质地和紧实度良好的土壤斑块中,水分和养分的变化会对繁殖根分枝产生显著影响。(3)胡杨繁殖根的垂向分枝夹角具有明显的生态塑性,是胡杨克隆器官的重要适应特征。

       

      Abstract:
      ObjectiveThe clonal growth of Populus euphratica plays an important role to the recruitment and persistence of the population in arid-climate region, and the change in branching pattern of clonal roots is a key process for P. euphratica to achieve the clonal growth in heterogeneous environment. This paper attempts to clarify the branching pattern of clonal root system of P. euphratica in heterogeneous riparian habitat, to estimate the correlations between branching traits of clonal roots including internal length (IL), branching intensity (BI), vertical-and horizontal-branching angle (VBA and HBA), and soil factors, and then to find the key factors driving changes of the branching pattern.
      MethodWe investigated 16 clonal root branches over 10 m by manual digging and collected below-ground environmental factors correspondingly in a natural floodplain of Ejin Oasis, Inner Mongolia of northern China. Correlation and ordination of the branching traits of clonal root were analyzed using correlation analysis (CA) and principal component analysis (PCA). Redundancy analysis (RDA) and variation partitioning (VP) were applied to explore the relationship between root branching traits and soil factors.
      Result(1) The results of CA and PCA showed that there was a high correlation between the four branching traits (P < 0.05), and the first axis, reflecting 66.88% variation of the branching traits, can represent the changes from guerrilla-branching type (with sparser and longer branches, smaller branching angle in vertical and horizontal) to occupation-branching type (with denser and shorter branches, steeper branching angle in vertical and wider branching angle in horizontal). The former more occur on the edge of the river, and the later more on the edge of the forest. (2) The results of RDA revealed that VBA was mainly affected by soil compactness positively (R2=0.64, P < 0.05), and IL was mainly affected by it negatively (R2=0.87, P < 0.05). Soil total carbon and total nitrogen had a major positive influence on BI and HBA, but soil sandy content had a negative effects on them. The depth of branching points of clonal root was positively controlled by capillary water depth (R2=0.62, P < 0.05). (3) VP results showed that the three set of soil variables including soil nutrient-related, water-related and physical factors explained a total of 68.3% of the variance of P. euphratica branching traits. The independent effects of soil physical factors (soil texture, compactness) were the highest (R2=0.12, P < 0.05). Nutrient- and water-related factors had relative smaller independent effects (R2=0.07, P < 0.05; R2=0.03, respectively), but they had a greatest together influences with soil physical factors to variance of the branching traits (R2=0.23, P < 0.05).
      Conclusion(1) Guerrilla-branching type and occupation-branching type are two main branching pattern of clonal roots for P. euphratica to vegetative propagate in heterogeneous floodplain of arid region. (2) Soil physical factor is the most important factor to drive changes in branching pattern of the clonal roots. P. euphratica tends to develop an occupation-branching clonal roots in soil patches with less sandy and smaller compactness to establish its ramets. (3) The vertical branching angle of clonal roots of P. euphratica expresses a significant ecological plasticity, it may be an important adaptive trait of clonal roots for woody plant that should be paid attention in the future researches of clonal plant.

       

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