CO_2浓度与N素形态对白桦幼苗NO_3^--N代谢的影响

Interacting Effects of CO2 Concentrations and Nitrogen Forms on Nitrate Metabolism of Betula platyphylla

在CO2人工气候箱(Pervical,PGC-9/2)内,用水培的方法研究了CO2浓度和NO3--N/NH4+-N对白桦幼苗NO3--N代谢的影响。结果表明:白桦幼苗根系、叶片NR活性以及叶片NO3--N、可溶性蛋白含量均随NO3--N供应比例和CO2浓度的增加而有所增加。在NO3--N/NH4+-N≥50/50时,CO2浓度倍增显著提高了白桦幼苗根系和叶片NR活性。CO2浓度倍增显著提高了白桦幼苗叶片NO3--N含量,且促进程度随营养液NO3--N比例的增加而加大。除NO3--N/NH 4+-N为100/0外,CO2浓度倍增并未显著提高白桦幼苗叶片的可溶性蛋白含量。CO2浓度与N素形态的交互作用对白桦幼苗根系、叶片NR活性以及叶片NO3--N含量的影响显著。

Artificial climate-chamber experiments were conducted to determine the effects of NO-3-N/NH＋4-N ratio and elevated CO2 concentration on the nitrate metabolism of Betula platyphylla seedlings under hydroponic culture conditions.The results indicate that the NR activity of root and foliage,nitrate content and soluble protein increased with the increasing proportion of NO-3 in the nutrient solutions and CO2 concentration.Doubled CO2 concentration significantly promotes the NR activity of root and foliage when NO-3-N/NH＋4-N≥50/50.Nitrate content is benefit from CO2 enrichment as the proportion of NO-3-N in the nutrient solutions increases.Extra CO2 does not significantly increase soluble protein content except 100% NO3-N that substantially promotes the content.Interacting effects of CO2 concentrations and nitrogen forms on NR activity of root and foliage and nitrate content is significant.