施肥对降香黄檀幼苗生长和光合的影响

以2年生降香黄檀(Dalbergia odorifera T.Chen)幼苗为研究对象,通过盆栽试验研究不同氮(N)、磷(P)、钾(K)配比下的施肥处理对苗木生长和光合的影响。结果表明:(1)施肥显著促进了降香黄檀幼苗的生长,苗高、地径、生物量均存在显著的差异(P0.01),随着施肥量的增加,地径、苗高、总生物量、茎生物量、叶生物量和根生物量的增大幅度均表现出增大的趋势,并在N3P3K1(氮、磷、钾质量分别为1.8、0.6、0.3g)配比下出现最大值(根和叶生物量除外),然后增幅均呈递减趋势;施肥后茎生物量在总生物量中所占比例显著增大,而叶生物量和根生物量在总生物量中所占比例均显著减小(P0.01);(2)施肥显著提高了降香黄檀幼苗的光合能力,随着肥量的增加,最大净光合速率(Pmax)增幅逐步增大,并在N3P3K1配比下达到最大值172.38 nmol·g-1·s-1,随后增幅呈递减趋势;Pmax、叶生物量和总生物量间均为正相关关系,光合能力的提高和叶生物量的增大是总生物量增大的原因。

Effect of Fertilization on Growth and Photosynthesis of Dalbergia odorifera Seedlings

A potted experiment with 2-year-old seedlings was conducted to study the growth (height, ground diameter, and bio-mass), biomass allocation, and leaf photosynthesis of Dalbergia odorifera under different N, P, K contents at four levels with orthogonal design .The results showed that:( 1) Fertilization had obvious promoting effect on the growth of D.odorifera seedlings, and the height, ground diameter, total biomass, stem biomass, leaf biomass and root biomass had significant differences and were increased with the increase of fertilizer amount before N 3P3K1 combination (N3:1.8 g, P3:0.6 g, K3:0.3 g) ( leaf biomass and root biomass excepted ); the proportion of stem biomass to total biomass was significantly and positively correlated with total biomass after fertilization , while the leaf biomass and root biomass showed opposite trends with total biomass (P<0.01);(2)The photosynthetic capacity of D.odorifera was significantly increased after fertilization and the light-saturated net photosynthetic rate (Pmax) increased with the increasing fertilizer amount and peaked at N 3P3K1 combination (172.38 nmol· g-1· s-1);total biomass was significantly and positively correlated with Pmax and leaf biomass. The enhanced photosynthetic capacity and increased leaf biomass contributed to the increase of the total biomass .