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近年来大气N沉降日趋严重,导致森林土壤有效N含量增加,N/P发生改变,将会影响低P胁迫下林木的生长发育和P效率.本文以马尾松家系为研究对象,设置模拟N沉降与同质低P(介质表层与深层均缺P)、异质低P(介质表层P丰富、深层缺P)耦合的盆栽试验,研究N沉降对马尾松生长性状以及P吸收和利用效率的影响.结果表明:同质低P下,模拟N沉降对马尾松生长性状和P效率影响较小,但存在显著的N×家系互作效应,家系40×44和71×20在N沉降后生物量增加,家系36×29和73×23生物量降低;异质低P下,模拟N沉降显著增加了马尾松苗高、生物量以及P吸收效率等,其原因是促进了根系生长和表层土壤中根系分布比例的增加.不同P环境下模拟N沉降对马尾松生长的影响,还与植株N/P有关.同质低P环境下,马尾松植株N/P为13.8,植株对N敏感性低,酸性磷酸酶活性增加,但未改善马尾松生长状况.在异质低P环境中,植株N/P为9.7,模拟N沉降显著增加了苗木生物量和P吸收效率,但未显著改变酸性磷酸酶活性.
In recent years, the atmospheric N deposition is more and more serious, resulting in an increase of available N and N / P in forest soils, which will affect the growth and P efficiency of trees under low P stress.In this paper, Pot experiments were carried out to investigate the effects of N deposition on the growth traits and P uptake and utilization efficiency of Pinus massoniana with pot experiments on the coupling of homozygous low P (medium surface and deep layer lacking P), heterogeneous low P (medium P rich and deep lack of P) The results showed that simulated N deposition had little effect on the growth traits and P efficiency of Pinus massoniana at homogenous low P, but there was a significant N × pedigree interaction effect. After 40 × 44 and 71 × 20 pedigrees, Increased the biomass of 36 × 29 and 73 × 23 pedigrees. Under heterogeneous low P, simulated N deposition significantly increased the seedling height, biomass and P absorption efficiency of Pinus massoniana, which was due to the promotion of root growth and root growth in surface soils And the increase of the distribution proportion.The effect of simulated N deposition on the growth of Pinus massoniana in different P environments was also related to plant N / P. Under the same low P condition, the N / P of Masson pine plant was 13.8, the sensitivity of plant to N was low, Acid phosphatase activity increased, but did not improve the growth of Pinus massoniana in heterogeneous low P Environment, plant N / P was 9.7. Simulated N deposition significantly increased seedling biomass and P uptake efficiency but did not significantly alter acid phosphatase activity.