古尔班通古特沙漠4种短命植物生物量与化学计量特征

Biomass and Stoichiometric Characteristics of Four Species of Ephemeral Plant in the Guerbantongut Desert

为了深入了解古尔班通古特沙漠植物在极端环境下养分循环及限制状况,以琉苞菊(Hyalea pulchella)、假狼紫草(Nonea caspica)、尖喙牻牛儿苗(Erodium oxyrrhynchum)和飘带果(Lactuca undulata)为研究对象,分析了4种短命植物的生物量与化学计量特征变化以及二者之间的相关性。结果表明,(1)4种荒漠植物生物量分配在整个生长周期内呈一致增长规律,而根冠比(R/S)均呈下降趋势;生物量累计速率在各生长期不尽相同,但4种植物随生活史的完成最终分配比例趋同。(2)4种植物的C元素在整个生长周期内居高不下,N、P元素在植物体内总体呈下降趋势。对计量比分析发现,C∶N与C∶P间呈正相关关系,且二者都与N∶P呈负相关关系,但N∶P则相比旱生植物的平均值低。(3)生物量与化学计量比的综合排序显示:第1轴、第2轴的解释程度分别为58.89%和19.43%,可累计解释其总信息量的78.32%,表明可信度较高,但整体指标间的相关性较弱,说明4种荒漠短命植物生长过程中的化学计量比并未对生物量分配起决定作用,可能是由于干旱环境下植物的不同生存策略所引起的结果,或生物量分配的主要占比因素可能是植物自身遗传所决定的。

The study on the biomass allocation and stoichiometric ratio of desert plants in different growth periods can help todeeply understand nutrient cycling and limiting conditions of Guerbantongut Desert plants in extreme environment. In this study, four ephemeral plants, Hyalea pulchella(Ledeb.) C. Koch, Nonea caspica(Willd.) G. Don., Erodium oxyrrhynchum M.B. and Lactuca undulata Ledeb. were selected. The results showed that:(1) the biomass distribution of the four desert plants showed a consistent growth law during the whole growth cycle, while root-shoot ratio(R/S) showed a decreasing trend. However, the biomass accumulation rate was not the same in each growing period, but the final distribution ratio of the four plants converged with the completion of life cycle.(2) The C elements of the four plants remained high throughout the growth cycle, and the N and P elements in the plants showed an overall downward trend. As for the metrology ratio analysis, there is a positive correlation between C∶N and C∶P, but both are negatively correlated with N∶P, while the results of N∶P study are lower than the average of all xerophytes.(3) Comprehensive ranking of biomass and stoichiometric ratio showed that the degree of explanation of the first and second axes was 58.89% and 19.43% respectively, and 78.32% of the total information could be explained cumulatively, indicating a high credibility, but with weak correlation between overall index. The results illustrates that the four desert ephemeral plants grow in the process of stoichiometric ratio did not decide on the biomass allocation. Plants may be due to the drought environment caused by the different survival strategy results or biomass allocation of the main factors of plants could be decided by their own genetics.