供磷水平对米老排苗木生长及养分状况的影响

为探讨供磷(P)对米老排(Mytilaria laosensis)生长和养分状况的影响,采用土培的方法,研究了不同供磷水平下米老排苗木的生长、养分含量、养分累积量和P吸收效率。结果表明,随着供P水平的提高,米老排苗木的苗高、生物量和养分累积量均呈先上升后下降的趋势;地径呈先增加后稳定的趋势;叶片和全株中的养分含量变化一致,氮(N)含量变化不明显,钾(K)含量呈先降低后升高的趋势,而P含量明显提高;P吸收效率呈现降低-升高-降低的趋势。在单株供P为30 mg时,米老排苗木的叶生物量、根生物量、叶片中N累积量及P吸收效率最大。当供P水平达到45 mg时,米老排苗木的苗高、茎生物量、总生物量、叶片中的P、K累积量和全株中的N、P、K累积量均达到最大值。而供P水平达60 mg时,米老排苗木苗高、生物量、养分累积量和P吸收效率均明显下降。这说明适合米老排苗木生长的供P水平为每株30~45 mg。

Effects of Supplying Phosphorus on Growth and Nutrient Status of Mytilaria laosensis Seedlings

In order to understand the effect of supplying phosphorus (P) on growth and nutrient status of Mytilaria laosensis, its growth character, nutrient content and accumulation, and uptake efficiency of P were studied treated with different P levels under soil culture. The results showed that with the supplying P increment, the plant height, biomass, and nutrient accumulation increased initially and then decreased, and the base diameter rose firstly and then kept stable. As supplying P levels increased, the changes in nutrient content of leaves and whole plant were not different, nitrogen (N) content had no obvious change, the content of potassium (K) decreased firstly and then increased, while the P content obviously enhanced, the uptake efficiency of P showed the trend of drop-rise-drop. Supplied with 30 mg P per plant, the biomass of leaves and root, the N accumulation in leaves and uptake efficiency of P were the highest. The plant height, biomass of stem, total biomass, K and P accumulation in leaves, N, P and K accumulation in the plant reached peak supplied 45 mg P per plant. As supplied 60 mg P per plant, the plant height, biomass, nutrient accumulation and uptake efficiency of P declined significantly. Therefore, the optimum supplying P level for plant growth of M. laosensis seedlings was 30-45 mg per plant, and beyond that, some obvious inhibitory effects would occur.