水培条件下毛竹幼苗的氮响应研究

Growth Response of Phyllostachys edulis Seedlings to Different Nitrogen Concentrations under Hydroponic Conditions

为进一步了解毛竹幼苗的不同氮响应特征,采用室内可控水培方式,研究毛竹幼苗对不同氮浓度(0.1、8 mmol·L^-1)和形态(铵态氮NH 4^+、硝态氮NO 3^-)的响应。结果表明,铵态氮处理下的毛竹生物量和体内氮含量等优于等浓度的硝态氮处理,并且不同氮处理下毛竹幼苗各部分干重和氮含量由大到小趋势均为叶>根>茎和叶>茎>根。生物量和根冠比随着N处理浓度的增加而减少,但各部位N含量却随着N浓度的增加而显著增加。毛竹体内N含量与根系构型各指标的相关性分析结果表明,根长、根表面积和根体积是决定毛竹植株根系养分吸收能力的重要因素。但随着NH 4^+处理浓度的增加,根长、根表面积和根系体积均受到一定程度的抑制,并且低于NO 3^-处理幼苗根系构型各指标。因此,这些结果表明毛竹生长和N积累表现出铵氮偏好,但浓度过高时对植物生长又表现出抑制效应。

To further understand the nitrogen response characteristics of bamboo(Phyllostachys edulis)seedlings,indoor nutrient solution hydroponic method was used to study the responses of the seedlings to different nitrogen concentrations(0.1 mmol·L^-1,8 mmol·L^-1)and forms(NH 4^+-N,NO 3^--N).The results showed that under different nitrogen form treatments,the dry weight and nitrogen content of different parts of bamboo seedlings showed a tendency from large to small as leaf>root>stem&leaf>stem>root.Biomass and nitrogen content of ammonium-N treated seedlings were higher than those of nitrate-N treated seedlings with the same nitrogen concentrations.Biomass and root-shoot ratio decreased with the increase of N concentration,but N content of each part increased significantly with the increase of N concentration.With the increase of NH 4+concentration,the growths of root length,root surface area and root volume were inhibited,and the root architecture of NO 3^--N treated seedlings was better than that of NH 4^+-N treated ones.Correlation analysis between nitrogen content in roots and root architecture showed that root length,root surface area and root volume were important factors in determining the nutrient uptake capacity of roots in bamboo.These results indicated that bamboo growth and N accumulation showed ammonium nitrogen preference.However,when the concentration was too high,it showed an inhibitory effect on plant growth.The research results could provide a theoretical reference for the rational application of N fertilizer in bamboo seedlings.