不同浓度指数施肥对美丽异木棉等3个树种幼苗生长的影响

Effects of different concentrations of exponential fertilization on the growth of Chorisia speciosa and other two tree species seedlings

基于植物生长模型,考虑到植株体内养分含量的稳定性,本实验采用指数施肥法对美丽异木棉、红花荷和黄花风铃木3种华南地区常见园林树种幼苗进行N素指数施肥试验。结果表明,氮素指数施肥能给植物的生长、植物的根系和叶片带来显著的影响:(1)不同氮素处理间幼苗生长差异显著,其中美丽异木棉处理Ⅵ(5 000 mg)的苗高、地径及总干质量表现为最佳状态,红花荷与黄花风铃木的处理Ⅴ(4 000 mg)效果最好。3个树种幼苗各生长指标受N素影响的程度表现各不相同。(2)3个树种各处理间幼苗的根系变化有差异。美丽异木棉和红花荷幼苗根系的体积、表面积、投影面积均呈现出先上升后下降再上升的趋势。氮素对根系长度、根系的平均直径、根尖数、分叉数、交叉数的影响在3个树种上有不同的表现。(3)3个树种各处理间幼苗叶片的变化有显著差异。氮素对叶片的影响表现出相似的规律性变化,几乎所有幼苗的叶片长宽比随着氮素的施入,趋势基本保持稳定,而叶面积、叶片周长、穿孔数量等指标变化有差异。

Based on the growing model of plant, and considering the stability of nutrient content in the plant, an exponential fertilization trial was conducted to research the effects of different nitrogen levels of Chorisia speciosa, Rhodoleia championii Hook.f.＇ and Tabebuia chrysotricha. It was indicated that nitrogen exponential fertilization could bring a significant impact on seedling growth, root growth and leaf growth. （1） Effects of varied nitrogen exponential fertilization treatments on seedling growth of three species were quite different. The height＇ ground diameter and biomass of C. speciosa, fertilized by 5 000 mg/seedling, R. championii Hook.f.＇ fertilized by 4 000 mg/seedling and T. chrysotricha fertilized by 4 000 mg/seedling achieved the best effect. With the nitrogen intake, seedling growth indexes of different species had different performance. （2） Effects of varied nitrogen exponential fertilization treatments on root growth of three species were quite different. The volume and surface area, projection area of C. speciosa and R. championii Hook. f.＇ presented a trend that firstly rised followed by declining and a second rising. With the nitrogen intaken, the root length, average diameter of roots, number of roots, furcation, and crossing number of different tree seedling species had different performance. （3）Effects of varied nitrogen exponential fertilization treatments on leaf length/width ratio of three seedlings presented similar, with the increase in the amount of Nitrogen Fertilizer, the changing trend of leaf length/width ratio kept steady. But the changing trend of leaf area, leaf perimeter and perforation number performed different.