城市地被植物麦冬叶片氮磷化学计量比和养分再吸收效率

Leaf N∶P stoichiometry and nutrient resorption efficiency of Ophiopogon japonicus in Nanchang City

氮磷供应、叶片氮、磷含量及其化学计量比和再吸收效率可反映植物对土壤氮、磷养分状况及全球变化氮沉降的响应和适应机制。本研究以城市地被植物麦冬为研究对象,分析氮、磷添加后麦冬叶片的氮、磷含量、化学计量比及其再吸收效率的响应过程。结果表明,氮、磷养分的供应明显影响植物叶片氮、磷浓度及其化学计量比和再吸收效率。氮添加提高了叶片氮浓度、氮∶磷和氮再吸收效率,而降低了叶片磷浓度和磷再吸收效率(P<0.05);磷添加提高了叶片磷浓度和磷再吸收效率,降低叶片氮∶磷,而对叶片氮浓度和氮再吸收效率影响不显著(P<0.05)。氮、磷同添使叶片氮、磷浓度、化学计量比及其再吸收效率表现出不同程度的提高。叶片氮∶磷能反映土壤养分供应状况,并与植物氮、磷再吸收效率存在一定的相关性。与模拟氮沉降相比,麦冬对磷富集的响应过程更加敏感,调节能力更强,同时,也反映出其具有更强地净化磷富集的功能。氮、磷存在明显的生态耦合过程,南昌城市地被植物的养分管理必须兼顾氮、磷,但磷的重要性高于氮。

Relationships among nitrogen （N） and phosphorus （P） supply, leaf N and P concentration, N ： P stoichiometry, and nutrient resorption efficiency reflect plant responses and their adaptive mechanisms to soil N and P condition, and global change （N and P deposition）. This study analyses the influences of N and P additions on leaf N and P concentration, N ： P stoichiometry, and nutrient resorption efficiency of Ophiopogon japonicus Ker-Gawl. in Nanchang City. The results showed that leaf N and P concentration, N ： P stoichiometry, and nutrient resorption efficiency were influenced by N and P supply. N addition increased leaf N concentration, N ： P ratio and N resorption efficiency, and decreased leaf P concentration and P resorption efficiency （P〈0.05） P addition increased leaf P concentration and P resorption efficiency, decreased the N ： P ratio （P〈 0.05）, but had no evident influence on leaf N concentration and N resorption efficiency. N plus P addition gave some improved leaf N and P concentration, N ~ P ratio, and nutrient resorption efficiency. Leaf N ： P ratio could reflect the supply of soil nutrient elements, and was related to N and P resorption efficiency. Compared with simulated N deposition, O. japonicus showed a more sensitive response and weaker regulating ability to simulated P deposition; however it had a stronger ecological function of purifying P deposition. Ecological interactions between N and P on O. japonicus were evident, thus, both N and simultaneously although the role of P was more important than N during soil ground cover in Nanchang City. P nutrient needed to be studied nutrient management of urbanground cover in Nanchang City.