四种荒漠植物生物量分配对土壤因子的响应及异速生长分析

Response of four species of desert plant biomass distribution to soil factors and allometric growth analysis

关键词:  荒漠植物, 生物量分配, 主成分分析, 土壤因子, 异速生长

Key words:  desert plants, biomass allocation, principal component analysis, soil factors, allometric growth

摘要:

该研究以四种荒漠植物:盐地碱蓬(Suaeda salsa)、新疆绢蒿(Seriphidium kaschgaricum)、对节刺(Horaninowia ulicina)、骆驼刺(Alhagi sparsifolia)为对象,采用挖掘法获取完整的植株生物量,测定土壤理化性质,并通过四种荒漠植物生物量、生物量分配比对土壤因子的响应程度以及异速生长模型进行了对比分析。结果表明:(1)四种荒漠植物的生物量、生物量分配比重差异明显; 新疆绢蒿具有最大的地上、地下生物量,对节刺的生物量最小; 根冠比(R/S)大小排序依次是骆驼刺 > 对节刺、新疆绢蒿 > 盐地碱蓬(P<0.05)。(2)利用RDA分析土壤因子对R/S的影响,结果发现土壤因子对新疆绢蒿、盐地碱蓬、骆驼刺、对节刺的R/S解释程度分别是16.3%、24.8%、33.1%、35.4%,其中土壤全氮与对节刺的R/S呈正显著关系(P<0.05),土壤水分与盐地碱蓬的R/S呈极显著正相关(P<0.01)。(3)四种荒漠植物地上—地下间均具有极显著的相关生长关系(P<0.01); 新疆绢蒿地上—地下间为等速生长关系(α=1),而对节刺和骆驼刺则均为α=3/4的异速生长关系,盐地碱蓬属于非3/4幂指数的异速生长关系(α<1),四种荒漠植物间具有共同的异速生长指数(0.767)。以上结果说明艾比湖优势荒漠植物具有功能趋同性,其空间分配特征对土壤因子的响应存在物种特异性。

Abstract:

The river basin of Ebi Lake represents a typical ecosystem in arid land, a sensitive area for global change and a key protected area for biodiversity. The study of the relationship among biomass allocation of above-ground and below-ground plant, response mechanism of edaphic factor, and allometry helps understand the plants' survival and optimization strategies in terms of soil conditions and ecological functions. With excavation as the method that gave us adequate biomass information and the physical and chemical properties of the soil, four desert plants in the research area were analyzed: Suaeda salsa, Seriphidium kaschgaricum, Horaninowia ulicina, and Alhagi sparsifolia, among which the biomass, its allocation ratio in response to the edaphic factor, and allometric models were compared. The results were as follows:(1)There were significant differences in the biomass and its allocation ratios among the four plants, with Seriphidium kaschgaricum having the largest above-ground and below-ground biomass, while Horaninowia ulicina the smallest; The R/S(root-shoot ratio)showed Alhagi sparsifolia > Horaninowia ulicina and Seriphidium kaschgaricum > Suaeda salsa(P<0.05).(2)The effect of edaphic factor on R/S analyzed with RDA showed that the interpretability of edaphic factors towards R/S in terms of the four plants were 16.3%, 24.8%, 33.1% and 35.4%, respectively. Among them, the soil total nitrogen had a positive correlation with the R/S of Horaninowia ulicina (P<0.05), and the soil moisture a significantly positive correlation with the R/S of Suaeda salsa(P<0.01).(3)The four plants all had significant correlations with regards to AGB-BGB(P<0.01), where the AGB-BGB of Seriphidium kaschgaricum had a pattern of isometric scaling(α=1), while both Horaninowia ulicina and Alhagi sparsifolia showed an allometric scaling of α=3/4, and Suaeda salsa belonged to the allometric scaling of a non-3/4 power exponent(α<1). All the four plants shared a common allometric scaling index(0.767). The above results indicate that the desert plants in Ebi Lake have functional convergence, and the characteristics of their spatial distribution are species-specific in response to edaphic factors.