遮光和施肥对桢楠苗期生长和氮素积累的影响

Effects of shading and fertilization on growth and nitrogen accumulation of Phoebe zhennan seedlings

【目的】探索遮光和施肥对桢楠Phoebe zhennan苗期生长和氮素积累的影响,可为其苗期生长调控提供科学依据。【方法】采用二裂式裂区试验设计,设置全光(A1,遮光率0%)、1层遮光(A2,遮光率54.5%)、2层遮光(A3,遮光率85.3%)等3个遮光水平和不施肥(B1)、中度施肥(B2,施复合肥3.3 g·株^−1)、大量施肥(B3,施复合肥6.7 g·株^−1)等3个施肥水平,分析遮光、施肥及两者交互作用对1年生桢楠生长、生物量积累和氮素积累的影响。【结果】遮光、施肥和两者交互作用显著影响了桢楠的生长和氮素积累(P<0.05),其中A2B2处理下桢楠的苗高、地径和总生物量比其他处理平均高77.2%、30.3%和62.1%。同样氮素积累量在A2B2处理下达最大值,比其他处理平均高68.3%。然而,桢楠苗氮质量分数在A3B3处理下达最大,且显著高于其他处理(P<0.05)。【结论】中等强度的遮光和施肥可提高桢楠幼苗氮素的积累,促进光合作用,提高生长和生物量积累,但过度的遮光和施肥则会在一定程度上抑制其生长。

[Objective]This study aims to reveal the effects of shading and fertilization on growth and nitrogen accumulation of Phoebe zhennan seedlings to provide scientific basis for the growth control of this plant.[Method]The two-split-plot test design was used to analyze the effects of shading,fertilization,and interaction of shading and fertilization on the growth,biomass accumulation and nitrogen accumulation of the 1-year-old P.zhennan seedlings.The main plot contained three different shading levels:natural light(A1,0%of shading rate),one-layer shading(A2,54.5%of shading rate),and two-layer shading(A3,85.3%of shading rate).Each main plot contained three different sub-plots with three different fertilization levels:no fertilization(B1),mild fertilization(B2,3.3 g compound fertilizer per plant),and moderate fertilization(B3,6.7 g compound fertilizer per plant).A total of 9 treatments were included in this study.[Result]The growth and nitrogen accumulation were significantly influenced by shading,fertilization,and their interaction(P<0.05).The seedling height,basal diameter,and biomass accumulation under A2B2 treatment were 77.2%,30.3%and 62.1%higher than those under other treatments,respectively.Furthermore,the nitrogen accumulation reached the maximum under A2B2 treatment,68.3%higher than that of other treatments.However,the nitrogen content was highest under A3B3 treatment,and was significantly higher than that under other treatments(P<0.05).[Conclusion]Moderate shading and fertilization can increase the nitrogen accumulation,and promote the photosynthesis,growth and biomass accumulation of P.zhennan,but excessive shading and fertilization can inhibit its growth to some extent.