Based on a field water table drawdown manipulation platform of Naleqiao marsh on the Rueorgai Plateau, we lifted in situ soil block of 1 m×1 m by 20 cm for simulating water table decline, and analyzed the response of carbon, nitrogen, and phosphorus stoichiometry in the wetland species Carex muliensis from June to September 2020. The results showed that there was no significant difference in leaf C content during the whole growing season, while N and P content gra-dually decreased along the growing season. After the drawdown of water table, the C content in leaves during the growing season was not consistent. Water table drawdown increased leaf C content in the early and middle growth stages, but changed little in the peak growth stage. Water table drawdown significantly increased leaf N content, while significantly decreased leaf P content. C:N, C:P, and N:P for leaves all increased along the whole growing period. The relative growth rate of C. muliensis was positively correlated with leaf C:N, but negatively correlated with leaf C:P and N:P. Water table drawdown significantly decreased leaf C:N, while significantly increased leaf C:P and N:P, which significantly reduced the relative growth rate of C. muliensis. The decrease of foliar P content induced by water table drawdown was the main regulating factor for the decrease of single leaf weight and specific leaf weight.
2020年6—9月,以若尔盖高原纳勒乔沼泽水位下降模拟控制实验平台为依托,在若尔盖县纳勒乔沼泽原位切割1 m×1 m原状土块,原位抬升20 cm,原位模拟水位下降20 cm,研究湿地植物木里薹草碳氮磷化学计量特征对水位下降的响应。结果表明: 在整个生长季,木里薹草叶片C含量没有显著变化,N、P含量随着生长季的推移逐渐下降。水位下降后,叶片C含量在生长季的变化并不一致,在生长初期、中期水位下降导致C含量增加,生长旺期无显著变化;叶片N含量对水位下降的响应为显著升高,叶片P含量则显著降低。叶片C∶N、C∶P、N∶P在整个生长季内均表现为随季节变化而上升,木里薹草的相对生长速率与叶片C∶N呈显著正相关,与C∶P和N∶P呈显著负相关。水位下降后,叶片C∶N显著降低,C∶P和N∶P显著上升,导致木里薹草的相对生长速率显著降低。水位下降后,叶片P含量降低是木里薹草单叶质量和比叶重下降的主要调控因子。.
Keywords: Carex muliensis; Ruoergai Plateau; carbon, nitrogen and phosphorus stoichiometry; water table drawdown.