Influences of seed molybdenum and molybdenum application on nitrate reductase activity,shoot dry matter,and grain yields of winter wheat cultivars

The influences of seed molybdenum (Mo) and application of Mo on nitrate reductase activity(NRA) in seedling stage, shoot dry matter in stem elongation stage, and grain yields in harvesting stage were compared among 35 winter wheat cultivars grown on acid yellow brown earths. Seedling NRA was significantly and positively correlated with seed Mo content regardless of further molybdenum application. The correlation of both shoot dry matter in stem elongation stage and grain yields to seed Mo content were also significant in a much less degree under Mo deficiency, but not after molybdenum application. Molybdenum application significantly increased seedling NRA, shoot dry matter in stem elongation stage and grain yields for most cultivars. There were no obvious relationships between molybdenum efficiency ratios and seed molybdenum content. These showed that seed Mo was very important for plant growth, but it was not sufficient to complete the whole life of plant. Therefore, Mo must be applied in order to get satisfactory grain yields from most cultivars. However, a high Mo efficiency genotype (97003) was promising to adapt to Mo deficient soils without added Mo.