N-Exponential Fertilization Could Affect the Growth and Nitrogen Accumulation of Metasequoia glyptostroboides Seedling in a Greenhouse Environment

Metasequoia glyptostroboides(M.glyptostroboides)is a unique plant species related to relic flora in China.It plays a positive role in afforestation and its long-term protection with high paleoclimate research value.However,due to the nutrients-supply deficiency,it is a big challenge to cultivate the high-quality seedlings of M.glyptostroboides.In this study,a pot experiment in a greenhouse environment was carried out to identify the effect of N-exponential fertilization on the growth and nutrient distribution of M.glyptostroboides seedling.The M.glyptostroboides rooted seedlings with 12-month growth were chosen.Different N fertilizer levels with conventional fertilization(CF:5.0 g seedling^(−1)),exponential fertilization including EF1,EF2,EF3 and EF4 were determined.The relevant growth indexes were measured after 210-day growth.The results indicated that non-significant differences in seedlings’height and ground diameter were found among the above treatments(P>0.05);At the same time,N-exponential fertilization promoted the M.glyptostroboides’s biomass in different organs(P<0.05),with the maximum total biomass under EF3 treatment.The N accumulation in root and stem of the N-exponential fertilization treatments were increased in to some extent(P<0.05).The maximum N accumulation was also found under EF3 treatment.Therefore,steady-state nutrition and superior growth performance of M.glyptostroboides could be obtained by N-exponential fertilization of 5.0 g cutting^(−1).

生物多样性和环境因素对亚热带森林树木生物量和生物量生长的解耦影响

生物多样性与生态系统功能之间的关系已成为森林生态系统研究的核心问题。然而,在具有不同人类干扰历史的亚热带森林群落中,关于环境因子对生物多样性与生态系统功能关系影响的研究仍然较少。在本研究中,选择位于中国东部浙江省的34个亚热带森林样地,在考虑样方中的环境因子的基础上,利用线性模型,分析样地中木本植物多样性(物种、功能和谱系多样性)与样方内木本植物生物量或生物量变化量之间的关系。物种多样性和功能多样性,并非谱系多样性,与生物量和生物量的变化量之间存在显着相关性。生物量或生物量变化量与年平均温度和海拔高度之间存在显著的正相关关系。此外,在考虑环境因子和森林群落的演替阶段时,生物量变化量与功能多样性的关系显著强于生物量变化量与谱系多样性或物种多样性之间的关系。这些研究结果表明,生物多样性与生态系统功能之间的关系可能取决于生物多样性指数的选择和环境条件。