研究了10个品种紫花苜蓿（Medicago sativa）在宁夏中部半干旱区3种灌溉条件下叶片△13C、整株△13C及叶片可溶性糖△13C与各组分碳含量及光合气体交换参数的关系.结果表明：水分处理显著影响不同茬次各组分碳同位素分辨率（△13C），且叶片可溶性糖△13C在不同水分处理条件下的差异显著性大于叶片△13C及整株△13C.第1茬和第2茬叶片△13C及可溶性糖△13C与碳含量呈显著负相关.在第2茬，叶片及可溶性糖△13C与蒸腾速率、气孔导度显著正相关、与叶片温度及瞬间水分利用效率（WUE）呈显著负相关.第1茬叶片可溶性糖△13C、第3茬叶片△13C与Ci/Ca（胞间CO2浓度/空气中CO2浓度）呈显著正相关.以上结果说明苜蓿叶片△13C、可溶性糖△13C以及整株△13C较好地反映了植株水分状况，尤其是叶片可溶性糖△13C与光合产物的合成与转运有密切的关系，在苜蓿高WUE品种筛选中有较好的应用价值.%Relationship of carbon isotope discrimination (Δ13C) with carbon content in leaf, whole plant and leaf soluble sugar and leaf gas exchange parameters of Medicago sativa grown under three irrigation conditions in Ningxia Central Semi-arid region were studied. The results showed that water treatment significantly affected different fractionsΔ13C for Medicago sativa in three cuttings, with leaf soluble sugarΔ13C being higher than leaf and whole plantΔ13C. There were significant and negative correlations betweenΔ13C and carbon content in leaf and leaf soluble sugar before first and second cuttings. In second cutting, leafΔ13C and leaf soluble sugarΔ13C significantly and positively correlated with transpiration speed and stomatal conductance, and negatively with leaf temperature and leaf intrinsic water use efficiency (WUE) in second cutting. There were significant and positive correlations between Ci/Ca (the ratio of internal leaf CO2 concentration to ambient CO2 concentration) and leaf soluble sugarΔ13C in the first cutting, and leafΔ13C in the third cutting. The result indicated that leaf Δ13C and soluble sugar Δ13C of Medicago sativa reflected plant water status. Leaf soluble sugar Δ13C was closely related with the assimilation and partitioning of photosynthetic product, which have potential value in selection for high WUE Medicago sativa variety in the breeding project.
展开▼
