氮素供应对欧洲云杉根系生长发育效应分析

研究氮素供应对欧洲云杉Picea abies (L) Karst]无性系根系生长发育的施肥效应，进而为该树种苗木根系发育的施肥调控提供依据。以欧洲云杉优良无性系pab081140 3年生苗木为试材，对不同氮素供应剂量下盆栽植株的根系生长发育指标进行测定分析。结果表明：与对照相比，测试剂量N-6（含氮量为46%的尿素6 g/株）、N-9（含氮量为46%的尿素9 g/株）、N-12（含氮量为46%的尿素12 g/株）均促进了根长、根表面积、根平均直径与根体积的生长，同时提高了根系生物量、植株总生物量和根系含氮量及植株总含氮量的水平，根系生物量占植株总量的比值和根冠生物量比值随之提高，但不同剂量的施肥效应存在差异；其中，N-9剂量处理下的欧洲云杉根系形态指标均是对照的1.3倍以上（1.38~1.89倍），而根系生物量、植物总生物量、根冠生物量的比值也显著高于对照(P<0.05)；此外，根含氮量与植株总含氮量分别比对照提高了73.2%和80.9%。由此可知，N-9剂量对欧洲云杉pab081140无性系根系生长发育的促进效果最为明显。

Analysis of the Effect of Nitrogen Supply on Root Growth and Development of Picea abies

The present study aims to reveal the implication effect of nitrogen on root growth and development of Picea abies, therefore to provide a basis for the regulation of root development with fertilizer. Three-year-old plantlets of Picea abies were employed and tested regarding their growth and development indexes of roots under different doses supply condition of nitrogen in pots. The obtained results indicated that all the tested doses of nitrogen, including N-6 (6 g urea containing 46% nitrogen for each plantlet), N-9 (9 g urea containing 46% nitrogen for each plantlet) and N-12 (12 g urea containing 46% nitrogen for each plantlet), consistently had a positive effect on roots in length, surface area, average diameter and volume, when compared to the control. The biomass and nitrogen content of roots and plantlets, the ratio of total root biomass of plants and the root-crown ratio in biomass also increased under the treatment of nitrogen. However, the regulated effect of nitrogen seemed to be different in dosage. The positive effect from N-9 appeared to be the most impressive (P<0.05) in that this dosage had a significant change of root morphology over 1.3 fold (1.38-1.89 fold) of the control, while the biomass of roots and plantlets, and the root-crown biomass ratio of plants were found to be also higher than that of the control at a significant level (P<0.05); moreover, the nitrogen content of roots and plantlets presented a 73.2% and 80.9% gains, respectively.