Effects Of Phosphorus On Soybean Cultivars With Different Phosphorus Efficiency

In this experiment,4 soybean cultivars[Glycine max(L.)Merr.]with high phosphorus efficiencies and 2 soybean cultivars with low phosphorus efficiency were used as materials to compare the effect of P on physiological traits and biochemical traits of soybean cultivars with different phosphorus efficiencies.The mechanism of high-yield in high phosphorus efficiency soybean cultivars was analyzed on photo-physiology,stress-resistance physiology and the absorption characteristic of major nutrition element,in order to offer theoretical basis for phosphorus efficiency soybean breeding and high yield cultivation.The main results were as follows:1 Effect of P on the photo-physiology and protective enzymes of soybean cultivars with different phosphorus efficiency.The high phosphorus efficiency soybean cultivars had relative higher chlorophyll content, net photosynthetic rate and stomatal conductance in the whole growth stages.And P had a little effect on chlorophyll content,net photosynthetic rate and stomatal conductance in later growth stage.The decreasing ranges of these traits were small.The low phosphorus efficiency soybean showed a higher photosynthetic rate only under the high phosphorus treatment.Under different phosphorus treatments,the diurnal variation of photosynthesis of these two types of soybean cultivars showed no "noontime snooze" during flowering stage.And the high phosphorus efficiency soybean cultivars showed higher net photosynthetic rate under low phosphorus treatment.The high phosphorus efficiency soybean cultivars had high net photosynthetic rate in a.m.during podding stage and grain-filling stage.The leaves of high phosphorus efficiency soybean cultivars had high soluble protein content during the whole growth stages,and decreased slowly in the later growth stages. Compared with low phosphorus treatment,the soluble protein content in the leaves of high phosphorus efficiency soybean cultivars showed a downward trend in the flowering stage and showed an upward trend in seed-filling stage under moderate phosphorus and high phosphorus.Under moderate and high phosphorus treatments,the soluble protein content in the leaves of low phosphorus efficienc soybean cultivars was lower than that undre low phosphorus treatments.The soluble sugar contents of soybean cultivars with high phosphorus efficiency were lower than that of soybean cultivars with low phosphorus efficiency in the seed-filling stage under different phosphorus treatments.Under moderate and high phosphorus treatments,the soluble sugar contents in the leaves of soybean cultivars with high phosphorus efficiency decreased a little,while that of soybean cultivars with low phosphorus efficiency increased a little in the later growth stage.Under low phosphorus treatment,the activities of SOD of soybean cultivars with high phosphorus efficiency were lower than that of soybean cultivars with low phosphorus efficiency in the whole growth stage.The activities of POD and CAT in the high phosphorus efficiency cultivars were higher than that of low phosphorus efficiency cultivars in reproductive growth stage,and decreased slowly in later growth stage.Under low phosphorus treatment,the MAD contents of high phosphorus cultivars were lower than that of low phosphorus cultivars significantly.2 Effect of P on the content of nitrogen,phosphorus and potassium in every soybean organ in soybean cultivars with different phosphorus efficiency.Under low phosphorus treatment,the contents of nitrogen in the stem and in the whole plant of soybean cultivars with high phosphorus efficiency were higher than those of soybean cultivars with low phosphorus efficiency in the reproductive stage.The nitrogen content in leaf was higher in the whole growth stages except podding stage.In grain-filling stage,the nitrogen content in pod shell were significantly higher than that of low phosphorus efficiency cultivars.The difference between these two soybean types was small under moderate and high phosphorus treatments.The phosphorus treatment had small effects on the nitrogen contents in the stem of high phosphorus efficiency cultivars.The phosphorus treatment had big effect on the nitrogen content in the stem of low phosphorus efficiency cultivars.Compared with low phosphorus treatment,the nitrogen content in the leaf and in the whole plant increased significantly in the podding stage under moderate phosphorus treatment.The nitrogen content in the leaf of low phosphorus cultivars increased in the later growth stage. The nitrogen content of the whole plant increased significantly in podding stage and initial maturity stage.Compared with low phosphorus treatment,the nitrogen content in the leaf and in the whole plant showed no significant change during the whole growth stages under high phosphorus treatment.The nitrogen content in the leaf of low phosphorus efficiency cultivars increased significantly in podding stage and later podding stage.The nitrogen content of the whole plant increased significantly in the later growth stage.Under low phosphorus treatment,the phosphorus contents in the stem,leaf and in the whole plant of high phosphorus efficiency cultivars were higher than that of low phosphorus efficiency cultivars in the reproductive stage.The phosphorus content in pod shell was significantly lower than that of low phosphorus efficiency cultivars in seed-filling stage.This difference became small under moderate and high phosphorus treatment.Compared with low phosphorus treatment,the phosphorus content in the stem,leaf and in the whole plant of soybean cultivars with high phosphorus efficiency increased in the reproductive stage.But the increasing ranges of low phosphorus efficiency cultivars were small.Under moderate phosphorus treatment,the phosphorus content in the seed of high phosphorus efficiency cultivars increased in maturity stage.Under high phosphorus treatment,the phosphorus content in the seed of high phosphorus efficiency cultivars increased significantly than that of under low phosphorus treatment in the maturity stage.The phosphorus content in the seed of low phosphorus efficiency cultivars increased significantly in grain-filling stage and maturity stage.Under low phosphorus treatment,the potassium contents in the stem and in the whole plant of soybean cultivars with high phosphorus efficiency were higher than those of soybean cultivars with low phosphorus efficiency.The potassium contents in pod wall were significantly higher than those of low phosphorus efficiency cultivars in the initial maturity stage.Compared with low phosphorus treatment,the potassium contents in stem,pod wall and seed of low phosphorus efficiency cultivars increased in every growth stage.And the increasing ranges were large.The phosphorus treatment had relatively small effect on the potassium contents in stem,pod shell,grain and whole plant.3 Effect of P on the accumulations of nitrogen,phosphorus and potassium in soybean cultivars with different phosphorus efficiencies.Under low phosphorus treatment,the nitrogen accumulation and phosporus accumulation in the stem of high phosphorus efficiency cultivars were higher than those of low phosphorus efficiency cultivars.The potassium accumulation was higher than those of low phosphorus efficiency cultivars during branching stage to initial maturity stage.Under moderate and high phosphorus treatments,the differences become small between soybean cultivars with different phosphorus efficiencies.Compared with low phosphorus treatment,the nitrogen accumulation and phosphorus accumulation in the stem of high phosphorus efficiency cultivars and the nitrogen,phosphorus and potassium accumulation in the stem of low phosphorus efficiency cultivars were relatively high during the whole growth stages,but the increasing ranges of low phosphorus efficiency were large.The potassium accumulation in stem was relatively higher during the whole growth stages except initial maturity stage.Under low phosphorus treatment,the nitrogen and phosphorus accumulation in the leaf of soybean cultivars with high phosphorus efficiency were higher than those of soybean cultivars with low phosphorus efficiency in every growth stage.The potassium accumulation in the leaf was higher than that of low phosphorus efficiency cultivars in every growth stage except podding stage.Under moderate treatment,the nitrogen accumulation in leaf of high phosphorus efficiency cultivars was higher than that of low phosphorus efficiency cultivars. The phosphorus and potassium accumulation in the leaf were significantly higher than those of low phosphorus efficiency cultivars in flowering stage.Under high phosphorus treatment, the nitrogen accumulation in the leaf was higher than that of low phosphorus efficiency cultivars in the seed-filling stage and maturity stage.The accumulation of phosphorus was higher than that of low phosphorus efficiency cultivars in seed-filling stage and initial maturity stage.The difference of potassium accumulation in the leaf was small between these two soybean types.Compared with low phosphorus treatment,the nitrogen accumulation in the leaf of these two types of soybean increased under the moderate and high phosphorus treatments.And the increasing ranges of low phosphorus efficiency cultivars were large.And the potassium accumulation in the leaf of cultivar with tow phosphorus efficiency increased greatly in the whole growth stages.Under low phosphorus treatment,the nitrogen accumulation in the pod wall of high phosphorus efficiency cultivars was significantly higher than that of low phosphorus efficiency cultivars in the maturity stage.The accumulation of phosphorus in pod wall was higher from seed-filling stage to maturity stage.The potassium accumulation in the pod wall was significantly higher than that of low phosphorus efficiency cultivars in initial maturity stage and maturity stage.Compared with low phosphorus treatment,under the moderate and high phosphorus treatment,the nitrogen and phosphorus accumulation in the pod shell increased a little.The potassium accumulation showed no change.The nitrogen,phosphorus and potassiu accumulation in the pod shell of low phosphorus efficiency cultivars increased greatly in the seed-filling stage and maturity stage.The nitrogen and phosphorus accumulation in the grain of high phosphorus efficiency cultivars were higher than that of low phosphorus efficiency cultivars in the initial maturity stage and maturity stage.Compared with low phosphorus treatment,under moderate and high phosphorus treatment,the nitrogen,phosphorus and potassium accumulation increased in these two soybean types.The increasing range of low phosphorus efficiency cultivars was great.Under low phosphorus treatment,the nitrogen,phosphorus and potassium accumulation in the whole plant of high phosphorus efficiency cultivars were higher than those of low phosphorus efficiency cultivars during every growth stage.Compared with low phosphorus treatment,under moderate and high phosphorus treatment,the nitrogen,phosphorus and potassium accumulation in the whole plant of soybean cultivars with high phosphorus efficiency were increased.And the increasing range of low phosphorus efficiency cultivars was great.4 Effect of P on the dry matter aceumulationof soybean cultivars with different phosphorus efficiency.Under low phosphorus treatment,the cultivars with high phosphorus efficiency had high biomass and dry material production.And the biomasses of high phosphorus efficiency cultivars were higher than that of low phosphorus efficiency cultivars.Compared with low phosphorus treatment,under moderate and high phosphorus treatment,the biomass of both types of soybean increased.And the increasing range of low phosphorus efficiency cultivars was larger.The high phosphorus efficiency cultivars still had relatively high population-growth parameter under low phosphorus treatment,which ensured the high biomass of high phosphorus efficiency cultivars both on the level and on the single plant level. And this is the basis for the high biomass under low phosphorus treatment.Compared with low phosphorus efficiency cultivars,the high phosphorus efficiency cultivars had lower first pod height,and more branch number,pod number per plant, seed-stem ratio,economic coefficient,100-seed weight and seed weight per plant.All of these made the high yield of soybean cultivars with high phosphorus efficiency even under low phosphorus treatment.