Effect Of P Sources And Culture Conditions With Two P Efficiency Wheat Genotypes On Characteristics Of Roots And Rhizosphere

Experiments were carried out to explore avilable methods to utilize sparingly soluble inorganicphosphorus and organic phosphorus. Xiaoyan54（P-efficient） and Jing411（P-inefficient） were selectedin the experiment. The two representative genotype wheats which have applied widely were screened byChinese Academy of Sciences. Three experiments: sand culture, liquid culture and soil culture wereused to study the root biomass, P content, root morphology, root-acidification ability and so on. The aimis to explore the effect of different P sources and culture conditions on characteristics of roots andrhizosphere of two P efficiency wheat genotypes. The main results of the research are showed asfollows:（1） Characteristics of roots and rhizosphere of two P efficiency wheat genotypes are affected bydifferent P sources. When FePO₄was applied, aboveground biomass of these two kinds of wheats waslower than the non-phosphorus treatment and P-efficient wheat Xiaoyan54expressed responsesincluding elongation of root length and reduction of rhizosphere pH, protons flow, root biomass androot-cap ratio compared with P-inefficient Jing411. Xiaoyan54could accumulate more P than Jing411under the treatment of Na-Phytate （Na-Phytate） through extending root length, increasing root tipnumbers and acid phosphatase secretion of per weigh root.The two genotypes of wheat had higher P efficiency at seedling stage （40days） under Na-Phytatetreatments than FePO₄. There was no significant advantage of biomass and P accumulation between thecombined application of Na-Phytate with FePO₄and the single application of Na-Phytate. Shoot andtotal P content of wheats will increase followed the high percentage of Na-Phytate.（2） Characteristics of roots and rhizosphere of two P efficiency wheat genotypes are affected bydifferent P levels. On alluvial soil, P applied can increase P content and total biomass of Jing411, butXiaoyan54attend its highest shoot and total biomass under25mg P·kg-1soil treatment, secondly the50mg P·kg-1soil treatment.Under no P and25mg P·kg-1soil treatment, the biomass and P content of Xiaoyan54was higherthan Jing411. On alluvial soil, the pH value of two kinds of wheats had no significant difference, exceptthat the pH value of Xiaoyan54under no P applied was lower than Jing411at inner compartment soil.Acid phosphatase of Xiaoyan54was significantly lower than Jing411at any P treatments.The content of different forms of inorganic phosphorus on alluvial soil was: Ca10-P＞Ca8-P＞Al-P＞Ca2-P＞Fe-P. The two wheats mainly used Ca2-P, Fe-P and Ca8-P of rhizosphere, and Ca10-Pand Al-P was rarely used. Organic phosphorus content was: moderate labile organic P＞high stableorganic P＞moderately stable organic phosphorus＞active organic phosphorus. Xiaoyan54and Jing411have no significant difference under the five forms of inorganic phosphorus, so does the active organicphosphorus, moderately stable organic phosphorus and high stable organic P. The uptake of moderatelabile organic P of Xiaoyan54under no P applied was higher than Jing411, which is opposite to50mgP·kg-1soil treatment. （3） Characteristics of roots and rhizosphere of two P efficiency wheat genotypes are affected bydifferent culture conditions. Among the three culture conditions, the two wheats showed the mostobvious physiological characteristics under the treatments of liquid culture, and pH value of two wheatsin no P treatments were: liquid culture＜sand culture＜soil culture, which were opposite to acidphosphatase. To root morphology, liquid culture has smaller resistance and can better observe the builtof root. Liquid culture is a good environment for mechanism research in the rhizosphere.The two wheats had difference under various culture conditions. P stress made the biomass and Pcontent attended significant differences under liquid culture and soil culture of two wheats. The acidphosphatase secretion of per weigh, root length, root surface area, root volume and root tip numbersunder liquid culture of two wheats attended significant difference.