氮、磷对107杨苗木生物量的影响

Effects of Nitrogen and Phosphorus on Biomass Accumulation of Populus × euramericana cv. "74/76" Cuttings

采用二次饱和D-最优设计,对氮、磷配比下盆栽107杨(Populus×euramericana cv."74/76")幼苗叶片净光合速率、叶面积和生物量进行了研究。结果表明,施肥显著提高了苗木生物量,其中氮肥的作用最显著。生物量提高的主要原因是磷肥显著提高了叶片净光合速率(p=0.002),氮肥显著提高了苗木叶面积(p<0.0001);86%生物量积累是由单株光合产量(净光合速率×叶面积)变化造成的,其中,叶面积变化作用强度达到82%,而净光合速率对生物量积累的作用未达显著水平。结果表明,叶片净光合速率和叶面积的共同作用是影响氮、磷对107杨苗木生物量积累的重要原因。

A D-optimal regression design with quadratic saturation was applied to study the effects of nitrogen and phosphorus fertilization on growth of Populus×euramericana cv.＂74/76＂ cuttings in terms of leaf net photosynthetic rate,leaf area and biomass of cuttings.Results showed that the biomass of the cuttings obviously increased after nitrogen and phosphorus fertilization,and nitrogen had a more significant effect on biomass accumulation.The main reasons for biomass variation were that phosphorus addition markedly increased leaf net photosynthetic rate of P.×euramericana cv.＂74/76＂ cuttings（p0.01） and nitrogen addition remarkably increased the total leaf area（p0.000 1）.And 86% of the biomass variation was caused by photosynthetic yield（the product of leaf net photosynthetic rate multiplied by total leaf area per tree）.The total leaf area per tree contributed 82% of biomass accumulation,while the leaf net photosynthetic rate exhibited an unobvious effect on biomass accumulation.The coordinated function of leaf net photosynthetic rate and total leaf area is the basic reason for biomass variation of P.×euramericana cv.＂74/76＂ cuttings.