为了阐明氮肥减量配施生物炭对闽楠幼苗生长和光合特性的影响,通过盆栽试验,设置空白对照(CK)、常规施氮(F1)、减氮20%配施生物炭(F2B1)和减氮40%配施生物炭(F3B2)4个处理。结果表明:与CK相比,经F2B1和F3B2处理6个月后,闽楠幼苗的株高分别提高了11.5%和19.5%,地径分别提高了7.5%和9.1%。F1、F2B1、F3B2处理闽楠幼苗的叶片总长分别比CK多10.1%、26.1%、24.9%。叶片总面积的变化也呈现相同的趋势,3种施肥处理都显著高于CK,但不同处理间的叶片形状系数无显著差异。光合生理参数的结果表明,与CK相比,F2B1和F3B2处理对闽楠幼苗的净光合速率(P_n)、蒸腾速率(T_r)和气孔导度(G_s)均有明显提高,但对水分利用效率无显著影响。闽楠幼苗的株高、地径与大部分叶片特征参数和光合参数之间均为正相关。F2B1和F3B2处理均可促进闽楠幼苗生长和光合作用,其中F3B2处理对株高、净光合速率和气孔导度的提升作用最佳,研究结果可为制定闽楠幼苗氮肥和生物炭的最优配施比例提供参考。

In order to clarify the effects of biochar application and nitrogen reduction on the growth and photosynthetic characteristics of Phoebe bournei seedlings,four treatments were set up in a pot experiment,such as blank control(CK),conventional nitrogen application(F1),biochar application with 20% nitrogen reduction(F2B1)and biochar application with 40% nitrogen reduction(F3B2).After six months of treatment with F2B1 and F3B2,compared with CK,the results demonstrated that the plant height increased by 11.5% and 19.5%,respectively,and the ground diameter increased by 7.5% and 9.1%,respectively.The total leaf length of F1,F2B1 and F3B2 treatments was 10.1%,26.1% and 24.9% longer than that of CK,respectively.The same trend was observed for total leaf area,which was significantly higher than CK for all three fertilization treatments.However,there was no significant difference between the leaf shape coefficients.The results of photosynthetic physiological parameters revealed that the net photosynthetic rate(P_n),transpiration rate(T_r),and stomatal conductance(G_s) were markedly enhanced in F2B1 and F3B2 treatments compared to CK.There was no significant effect on water use efficiency.There was a significant positive association between plant height,ground diameter,and leaf net photosynthetic rate.Both F2B1 and F3B2 treatments could promote plant growth and photosynthesis.Among them the F3B2 treatment had better effects on plant height,net photosynthetic rate,and stomatal conductance.This study could serve as a framework for determining the ideal ratio of nitrogen fertilizer and biochar application when cultivating P.bournei seedlings.