摘要:土壤氮素和土壤含水量是森林生态系统中限制植物生长的重要因子。为探讨常绿阔叶树种对模拟氮沉降增加和降水减少的响应，以同质园中自然生长的壳斗科（Fagaceae）丝栗栲（Castanopsis fargesii）、大叶青冈（Cyclobalanopsis jensenniana）和麻栎（Quercus acutissima）五年生幼树为对象，比较了对照（CK）、施氮（+N，施氮60 kg hm^-2 a^-1）、减水（-W，减少自然降水的50%）以及施氮和减水（+N-W，施氮60 kg hm^-2 a^-1和减少自然降水的50%）对总生物量、各器官生物量及其生物量分配的影响。研究表明：（1）施氮显著增加了三种幼树的总生物量及各器官生物量（P < 0.05）。（2）减水未引起三种幼树的总生物量及各器官生物量的显著下降（P > 0.05）。（3）除麻栎树叶生物量、树枝生物量外，施氮和减水交互作用对三种幼树总生物量及各器官生物量没有明显影响（P > 0.05）。（4）施氮显著提高了丝栗栲幼树的干重比、大叶青冈幼树的干重比和枝重比（P < 0.05），降低了大叶青冈的叶重比和根重比（P < 0.05）。（5）减水导致丝栗栲幼树和麻栎幼树的根重比、麻栎幼树的根冠比显著增加（P < 0.05），引起丝栗栲幼树的枝重比、麻栎幼树的叶重比、枝重比和干重比显著降低（P < 0.05）。（6）施氮和减水交互作用显著提高了丝栗栲幼树的根重比（P < 0.05），降低了麻栎幼树的干重比（P < 0.05）。



Abstract:Soil nitrogen and moisture content are important factors that limit plant growth in forest ecosystems. In order to investigate the response of evergreen broadleaf tree species to increased nitrogen deposition and decreased precipitation, we conducted a common garden experiment in Fenyi county, Jiangxi Province. Five-year-old saplings of Castanopsis fargesii, Cyclobalanopsis jensenniana, and Quercus acutissima were subjected to control, nitrogen application (+N, 60 kg hm^-2 a^-1 nitrogen addition), rainfall exclusion (-W, natural rainfall reduced by 50%), and their interaction (+N-W, 60 kg hm^-2 a^-1 nitrogen addition together with natural rainfall reduced by 50%) respectively, and their total biomass, biomass of organs, and biomass allocation were analysed. The results showed that:(1) Nitrogen application increased the total biomass, the biomass of organs, and biomass allocation of the saplings of three species significantly compared to the control (P < 0.05). (2) Rainfall exclusion reduced the total biomass, the biomass of organs and biomass allocation non-significantly (P > 0.05). (3) Except for leaf and branch biomass of Q. acutissima, the interaction of nitrogen application and rainfall exclusion had no obvious effect on the total biomass, the biomass of organs, or biomass allocation of the the saplings of three species compared with the control (P > 0.05). (4) Nitrogen application increased the trunk weight ratio of C. fargesii, trunk weight ratio and branch weight ratio of C. jensenniana(P < 0.05), reduced the leaf weight ratio and root weight ratio of C. jensenniana (P < 0.05). (5) Rainfall exclusion increased the root weight ratio of C. fargesii and Q. acutissima, root-shoot ratio of Q. acutissima(P < 0.05), reduced the branch weight ratio of C. fargesii, leaf weight ratio, branch weight ratio and trunk weight ratio of Quercus acutissima(P < 0.05).(6)The interaction of nitrogen application and rainfall exclusion increased the root weight ratio of C. fargesii (P < 0.05), reduced the trunk weight ratio of Quercus acutissima(P < 0.05).





PDF全文下载地址:

https://www.ecologica.cn/stxb/article/pdf/stxb201805291178