水分和氮磷水平对小麦碳同位素分辨率和水分利用效率的影响

 依据盆栽试验数据，利用植物稳定性碳同位素分辨率的理论模型，研究了水分和氮磷营养对小麦叶片碳同位素分辨率(Carbon-isotope discrimination △)的影响。结果表明：水分差异引起碳同位素分辨率较大变异，碳同位素分辨率随土壤相对含水量(Soil relative water content)的提高而提高，在土壤相对含水量为60％～70％条件下碳同位素分辨率最高。缺水时磷水平提高，碳同位素分辨率提高。水分利用效率(Water use efficiency)与碳同位素分辨率关系受土壤水分和养分水平的影响。缺水条件下水分利用效率与碳同位素分辨率之间为负相关，充分供水下为正相关；在低氮水平下的关系不明显，施氮150kg·hm-2时相关性显著。

THE EFFECTS OF SOIL MOISTURE AND NITROGEN AND PHOSPHORUS ADDITION ON CARBON ISOTOPE DISCRIMINATION AND WATER USE EFFICIENCY IN WHEAT

Data obtained from pot experiments was analyzed using a theoretical model of carbon isotope discrimination (△) for the effects of soil moisture and nitrogen phosphorus nutrient on carbon isotope discrimination. The results showed that △ increased with increasing soil relative water content (SRWC),with the highest △ values found between 60% and 70% SRWC. △ also increased with increasing phosphorus levels under conditions of water deficit. Correlation between water use efficiency (WUE) and △ could be dependent on the status of soil moisture and nutrient availability. Stable △ was negatively associated with WUE under water stress, and positively associated with WUE under optimum soil moisture. However, there was no correlation between △ and WUE under nitrogen deficit and correlations were significant when nitrogen was applied at 150 kg·hm-2.