供氮形态对低磷胁迫下红锥幼苗生长生理的影响

Effects of Nitrogen Forms on Growth Physiology of Castanopsis HystrixSeedlings under Low Phosphorus Stress

本试验以红锥苗木为试验材料,采用水培法探究低磷胁迫下供氮形态对红锥幼苗生长生理方面的影响。结果表明:在13.6 mg·L^(-1) KH_(2)PO_4低磷胁迫下,供氮量为210 mg·L^(-1),施用不同配比硝铵态氮,各处理间苗木生长生理指标差异显著。其中,以3∶2硝铵态氮比处理下苗木高度、地径、根长、根条数、叶面积生长表现最佳,根冠比最小,叶片中氮、磷、叶绿素、可溶性糖、淀粉含量最高,净光合速率最大。与对照相比(NO~-_3∶NH~+_4=25∶1),混合态氮施氮效果明显提升,而单纯硝态氮或铵态氮施氮效果明显下降,且供试5种施氮处理中,以纯铵态氮幼苗生长生理表现最差。研究结果表明,3∶2硝铵态氮比的施氮肥效最高,能显著改善低磷胁迫下红锥幼苗受到的胁迫伤害。

In this experiment,the effects of nitrogen forms on the growth and physiology of Castanopsis hystrix seedlings under low phosphorus stress were studied by hydroponics.The results showed that under the low phosphorus stress of 13.6 mg·L-1 KH 2 PO 4,the nitrogen supply was 210 mg·L-1,and different ratios of ammonium nitrate nitrogen were applied.There were significant differences in seedling growth physiological indexes among treatments.Among them,the seedling height,ground diameter,root length,root number and leaf area under the treatment of 3∶2 ammonium nitrate nitrogen ratio showed the best growth performance,the ratio of root biomass to shoot biomass was the smallest,the content of nitrogen,phosphorus,chlorophyll,soluble sugar and starch in leaves was the highest,and the net photosynthetic rate was the highest.Compared with the control(NO-3∶NH+4=25∶1),the effect of mixed nitrogen application was significantly improved,while the effect of single nitrate or ammonium nitrogen application was significantly decreased.Among the five nitrogen application treatments,the growth and physiological performance of pure ammonium nitrogen seedlings was the worst.The results showed that the nitrogen fertilizer efficiency of 3∶2 was the highest,which could significantly improve the damage of C.hystrix seedlings under low phosphorus stress.