磷胁迫对不同种源枫香生长及氮、磷吸收利用率的影响

基于枫香(Liquidambar formosana)作为先锋树种的生态价值及南方红壤缺磷的现状，采用裂区设计，以不同磷水平模拟磷胁迫砂培处理枫香三叶期幼苗，研究7个种源枫香对磷水平的响应差异.结果表明：不同种源枫香间耐磷胁迫差异显著.随磷胁迫的加剧，各种源的生物量和氮、磷吸收量减少，而利用率增加.高磷处理条件下，南昌和宜兴种源枫香生物量和氮、磷吸收量较高，利用率较低，南丹种源枫香的氮、磷利用率较高，吸收量较低；低磷处理时，南昌和南丹种源枫香的磷吸收量、利用率和生物量均较高.说明高磷时，枫香高生物量种源呈高效吸收；而低磷时，则呈高效吸收和高效利用的特点.南昌种源是优良的耐磷胁迫种源，南丹种源次之；磷不是枫香的限制性养分因子.叶片Δ（N/P）、磷效率和生物量可作为确定枫香耐磷胁迫的指标.

Effects of phosphorus stress on the growth and nitrogen and phosphorus absorption of different Formosan sweet gum provenances.

Aiming at the ecological value of Formosan sweet gum (Liquidambar formosana) as a pioneer species and the status of red soil phosphorus (P) deficiency, a sand culture experiment of split design was conducted to study the responses of three-leaf stage seedlings of seven Formosan sweet gum provenances from Yixing of Jiangsu, Jingxian of Anhui, Yongkang of Zhejiang, Nanchang of Jiangxi, Shaowu of Fujian, Yanping of Fujian, and Nandan of Guangxi to four levels of P (P0, P1/2, P1, P2). With increasing P stress, the biomass and the N and P absorption of test provenances decreased, whereas the utilization efficiency increased. In higher P treatments, the provenances from Nanchang and Yixing had higher biomass and higher N and P absorption but lower utilization efficiency, while the provenance from Nandan had lower N and P absorption but higher utilization efficiency. In lower P treatments, the biomass and the P absorption and utilization efficiency of the provenances from Nanchang and Nandan were all higher. All the results illustrated that the provenances with high biomass had high P absorption at high P level, and had both high P absorption and high utilization efficiency at low P level. The provenance from Nanchang could be considered to be an excellent P stress-resistant provenance, followed by that from Nandan. Phosphorus was not a limiting nutritional factor of Formosan sweet gum, biomass, leaf Δ(N/P) ratio and P efficiency could be used as the indicators of P stress-tolerance of Formosan sweet gum provenances.