施肥对盆栽香樟幼苗不同根序细根养分的影响

以盆栽的1年生香樟实生苗为研究对象,采用指数施肥的方式,测定1~5级细根的C、N、P、K含量,并探讨施肥对香樟幼苗细根养分浓度的影响。结果表明:(1)不同根序细根的全C浓度差异不显著,施肥对细根全C浓度影响不显著(P0.05);(2)在所有根序中,N、P浓度最高的是1级根,但其K浓度却最低;N、P含量最低的是5级根;(3)细根的N、P含量随着根序的增加呈显著的下降趋势(P0.05);(4)施N肥能显著增加1~2级细根的N含量,施P肥能显著增加1级根的P含量,N+P肥较之P肥更能提高1级根对P的吸收;(5)C∶N∶P受根序的影响非常明显,1级根平均为366∶16∶1,5级根则为807∶12∶1,而且C∶N∶P随着根序增加而显著升高,但N∶P无显著影响;(6)虽然施肥对细根C含量无影响,但施N肥或N+P肥对1~2级细根中N的含量有显著性增加。综合分析可知,处理9对香樟苗期养分浓度指标影响最为显著,即施肥量为氮素4g·株-1、磷素4g·株-1、钾素2g·株-1时,对香樟幼苗细根的生长发育有较好地促进作用。研究结果可为香樟的速生丰产及资源的高效利用提供理论依据。

Effects of fertilization on nutrient concentrations of different root orders' fine roots in Cinnamomum camphora seedings

Setting one-yearold potted Cinnmomum camphora seedlings as the research object, using exponential fertilization method, we detected the first to the fifth order fine roots C, N and P contents, in order to explore the effects of fertilization on C. camphora seedlings, and to provide a theoretical basis for C. camphor fast growing and efficient use of resources in nurturing process. The results were as follows:(1)C concentrations of the differences orders'' fine root were not significant, with the rise of the root order, while C content overall upward trend. Fertilization had no significant effect on the C concentration of fine root(P>0.05);(2)N and P concentrations of first order roots were the maximum, while fifth order roots were the minimum, with the rise of root orders. N and P concentrations significantly decreased(P<0.05);(3)N significantly increased the N content level of the first to the second fine roots, P fertilizer significantly increased the P content of a root, mix of nitrogen and phosphorus fertilizer could improve the root uptake of P;(4)C:N:P had a significant difference in different root orders roots;(5)The first order roots'' mean C:N:P was 366:16:1, the fifth order root 807:12:1, with increased root order, C ratio of three kinds of elements increased significantly, while the N:P changed little;(6)Fertilization did not change the proportion of C; however, N fertilizer or mix of nitrogen and phosphorus fertilizer significantly increased the N proportion of the first to second order roots. In conclusion: The treatment 9 pairs of C. camphor on seedling stage indicators impact most significantly. A fertilizer with the nitrogen 4 g·plant^-1, the phosphorus 4 g·plant^-1 and the potassium 2 g·plant^-1, would have significant promote growing for growing and development of fine roots in C. camphor seedlings.