水分对敦煌阳关湿地芦苇叶片与土壤C、N、P生态化学计量特征的影响

土壤水分是影响干旱区植物养分吸收和利用策略的关键因子之一。研究不同水分梯度叶片与土壤生态化学计量特征,有助于揭示植物对环境变化的响应特征及生态适应性。通过野外调查与实验分析,对敦煌阳关不同水分梯度芦苇叶片与土壤碳(C)、氮(N)、磷(P)生态化学计量特征及其关系进行了研究。结果表明:(1)随土壤含水率升高,叶片C、N、P含量降低,叶片C/N、C/P、N/P升高。(2)随土壤含水率升高,土壤有机碳(OC)、总氮(TN)、总磷(TP)含量及土壤N/P升高,土壤C/N降低,土壤C/P先升后降。(3)低水分梯度叶片N、C/N与土壤N、C/N显著负相关(P<0.05),叶片C、P、C/P、N/P与土壤C、P、C/P、N/P无显著相关性(P>0.05);高、中水分梯度叶片C、N、P与土壤C、N、P化学计量特征相关性均不显著(P>0.05)。低水分梯度叶片受干旱胁迫和土壤养分制约,且能够保持较高的叶养分含量,体现了干旱区湿地植物异质生境下独特的养分调节机制。

Effects of soil moisture on Phragmites australis leaves and soil C, N and P ecological stoichiometric characteristics in Yangguanwetland, Dunhuang

Soil moisture is one of the key factors affecting the strategies of plant nutrient uptake and utilization in arid region. Studies on leaf and soil ecological stoichiometry characteristics under different soil moisture gradients are helpful to reveal the response and ecological adaptability of plants to environmental changes. Through field investigation and experimental analysis, reed leaves and soil C, N, P ecological stoichiometric characteristics under different soil moisture gradients and their relationships in the Yangguan wetland of Dunhuang were studied. The results showed that: (1) with the increase of soil moisture content, the contents of leaf C, N and P showed a decreasing trend, while leaf C/N, C/P, and N/P showed the opposite trend; (2) with the increase of soil moisture content, the content of soil organic carbon (OC),total nitrogen (TN), total phosphorus(TP), and N/P increased, soil C/N ratio decreased and soil C/P first increased and then decreased; (3)under the low soil moisture gradient, N and C/N of leaves were significantly negative correlated with soil N and C/N(P<0.05), and leaf C, P, C/P, N/P had no significant correlation with soil C, P, C/P, and N/P (P>0.05). There was no significant correlation between the soil and leaf stoichiometric characteristics under the high and medium soil moisture gradients (P>0.05). Leaves under low soil moisture gradient, which were restricted by drought stress and soil nutrients, could maintain higher leaf nutrient content, reflecting the unique nutrient regulation mechanism of wetland plants under heterogeneous habitats in arid areas.