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以盆栽平邑甜茶(Malus hupenhensis)为实验材料,研究等氮(N)量分次追施N肥(一次、二次和三次)对平邑甜茶叶片衰老及15N-尿素吸收、利用的影响。采用15N示踪技术,研究不同施肥处理下植株的生长、酶活性和15N吸收利用等参数。研究结果表明:植株的株高、茎粗、叶面积和叶绿素含量(SPAD)在生长前期均以一次性追肥处理最高,三次追肥处理最低,且与一次追肥处理差异显著;在生长中期均以二次追肥处理最高,一次追肥处理最低;在生长后期均以三次追肥处理最高,一次追肥处理最低,且与三次追肥处理差异显著;叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性在生长前期均以一次追肥处理最高,三次追肥处理最低,且与一次追肥处理差异显著;在生长中期均以二次追肥处理最高,一次追肥处理最低;在生长后期均以三次追肥处理最高,一次追肥处理最低,且与三次追肥处理差异显著;生长后期植株各器官从肥料中吸收分配到的15N量对该器官全N量的贡献率差异显著,三次追肥处理显著高于一次和二次追肥处理;生长后期三次追肥处理植株的总N量、吸收的15N量及15N肥料利用率均为最大。三次追肥处理能提高叶片全N量,延缓生长后期叶片衰老,提高N肥利用率。
The potted Malus hupenhensis was used to study the effects of nitrogen (N) level topdressing N fertilizer (primary, secondary and tertiary) on senescence and 15N-urea absorption and utilization of Malus hupenhensis. The 15N tracing technique was used to study the growth, enzyme activity and 15N uptake and utilization of plants under different fertilization treatments. The results showed that the plant height, stem diameter, leaf area and chlorophyll content (SPAD) of the plants were highest at the early stage of growth, the lowest in the three top dressing treatments and significantly different from the top dressing treatments at the early stage of growth. The top dressing treatments were the top dressing and the top dressing treatments were the lowest. The top three top dressing treatments, the lowest top dressing treatments and the three top dressing treatments were all significant differences in the late growth stage. The contents of superoxide dismutase (SOD), peroxidase (POD) ), And CAT activity was the highest in the early stage of growth, the lowest in the three top dressing treatments, and the lowest in the top dressing treatments. The second top dressing treatment and the second top dressing treatment in the growth stage were the lowest. In the late growth period, the three top dressing treatments were the highest, the top dressing treatments were the lowest, and the three top dressing treatments had significant differences. The 15N contents of various organs assimilated from fertilizers in the late growth stage had significant differences in the contribution rate of all N to the organs. The treatment was significantly higher than the first and second topdressing treatments; the total N content, absorbed 15N and 15N fertilizer utilization rate of the three top dressing treatments in the late growth stage were Big. Three topdressing treatments could increase the total N content of leaves, delay the leaf senescence and increase the N use efficiency.