Study On The Difference Of Phosphorus Utilization Efficiency In Wheat Cultivars

The study on the difference of phosphorus(P)utilization efficiency of wheat varieties and the characteristics of P absorption,transport and utilization of wheat varieties with different P efficiency can provide a theoretical basis for the rational application of P fertilizer,the improvement of P utilization rate and the cultivation of P efficient wheat.Based on the 31-year positioning experiment of the “National Long-term Monitoring Station for Fluvial Soil Fertility and Fertilizer Benefits”,fertilization treatments including NK and NPK were selected to conduct the equation of P efficiency evaluation screening P high-efficiency wheat cultivars using the principal component analysis(PCA),further analyzing the P absorption,transport and utilization in major growing stage of wheat with different P efficiency.The main conclusions are as follows:1.There were differences in P efficiency indexes between wheat cultivars,in which the coefficient of variation ranged from 3.26% to 38.77% and from 2.72% to37.69% under NK and NPK treatment,respectively.The PCA indicated three principal components were extracted,and the cumulative contribution rate was88.44% and 90.04% under NK and NPK treatment,which basically contained all the information of P efficiency.Further cluster analysis divided the 27 wheats cultivars into three type: P high-efficiency including Xuke 168 and Luomai 34;P medium-efficiency including Zhengmai 113,Yangao 21,Zhongmai 895 and Zhengpinmai 8;P low-efficiency including Zhoumai 28,Zhoumai 22,Bainong 4199,Zhongyu 1220,Zhongyu 1211,Xinong 511,Zhoumai 32,Yangao 58,Luomai 29,Luomai 26,Cunmai 8,Xinmai 29,Lankao 198,Zhengmai 379,Luomai 31,Zhoumai27,Zhoumai 30,Xinong 979,Fengdecunmai 5,Luomai 18,and Xinmai 30.2.Through the study of rhizosphere soil characteristics of wheat with different P efficiency in key growth stages: the soil p H,phosphatase activity(AP),and available P content of the two P levels were low P was lower than normal P.The soil p H and available P content of the two types of wheat showed rhizosphere was lower than non-rhizosphere,while AP was the opposite.In the same treatment,Xuke168 rhizosphere soil p H and available P content were lower than Lankao 198,while rhizosphere AP showed the opposite.Through the research of root growth characteristics of wheat with different P efficiency in key growth period,it was found that the root growth characteristics of wheat were as follows: in the same treatment,the root dry quality,root length,root surface area,root volume,of the same treatment generally showed that Xuke168 was greater than Lankao198.Low P treatment,the root average diameter of Xuke 168 was smaller than that of Lankao 198.Except for the overwintering stage,the root average diameter of was Xuke168 higher than that of Lankao198 under normal P treatment.In the same treatment,the root-shoot ratio、root activity of Xuke 168 was higher than that of Lankao 198.At booting stage,the root activity difference between the two cultivars was the biggest,Xuke168 was 1.36 times and 1.34 times that of Lankao 198 under NK and NPK treatment.3.Through the analysis of P transportation characteristics of wheat with different P efficiency in key growth stage,it was found that: the P content and the proportion of P in organs of wheat plants with different P efficiency were different.Under the same treatment,pre-anthesis P transport and the contribution rate of post-anthesis P uptake to grain P of Xuke168 was significantly higher than that of Lankao 198,and the contribution rate of pre-anthesis P transport to grain P of Xuke168 was lower than that of Lankao198.Through the analysis of P utilization characteristics of wheat with different P efficiency in key growth stage,it was found that: the P utilization rate of Xuke 168 was 13.42% higher than that of Lankao 198.To sum up,phosphorus-efficient wheat Xuke168 has strong rhizosphere acidification ability and high rhizosphere phosphatase activity to promote the absorption of phosphorus by roots.At the same time,high P efficiency wheat can widely absorb P in the surrounding environment due to its long root length,large root surface area and root volume.It also promoted the transportation of P and P to plant roots.Low P efficiency cultivar Lankao 198 has insufficient absorption capacity due to low root biomass in the early stage of growth and unbalanced root-to-shoot ratio in the later stage of growth.Although the P transport rate before anthesis has a high contribution to the grain P,the poor P absorption capacity is difficult to meet the growth.The nutrient requirement in the later stage and the lower root vigor in the later stage of growth are not conducive to the transportation of plant P to the grain,and the P utilization rate is low.