Phosphorus Contents in Different Organs of CTW and WTW Genotypes and Their Remobilization during Grain Filling

Previous studies indicated that there were differences of the canopy temperature of among different wheat genotypes after anthesis.There were many reports about the physiological,anatomic and ecological characteristics of different genotypes wheat with lower and higher canopy temperature,but little about their phosphorus nutrition.The objective of this study was to probe the P concentration of different organs of genotypes with lower canopy temperature and higher canopy temperature.Field experiments were conducted from 2002 to 2004 at the Agricultural Experimental Station of Northwest AF University,Yangling,Shaanxi Province,China.It is a sub-humid area incident to drought.The genotypes(Xiaoyan 6 and Shaan 229) have lower canopy temperature,and named cold type wheat(CTW).NR9405 and 9430 had higher canopy temperatures,o they weree belonged to warm type wheat(WTW).Each genotype received four fertilizer treatments,CK(no fertilizer),P fertilization(176.25 kg hm2 P2O5),N fertilization(237.0 kg hm2 N)a,nd NP fertilization(176.25 kg hm2 P2O5 plus 237.0 kg hm2 N).The experiments were laid out in a split-plot design with fertilization as main plots and genotypes as subplots.The treatments(variety × fertilizer) were factorial arranged in a 4×4 randomized complete block design.Each treatment was replicated three times.The area of each plot was 2.1 m2.The soil is classified as Eum-Orthic Anthrosol,equivalent to an Udic Haplustalf in the USDA system.The results indicated that the P concentration in ears of CTW were higher 23.28%,35.63%,4.25% and 2.04% than that of WTW in the CK,P,N and NP treatments respectively at anthesis.But the P concentrations in stem of CTW were lower 23.98%,10.30%,20.00% and 17.58% than that of WTW at anthesis.The P concentrations in grain of CTW were the higher 5.09%,4.47%,-2.74% and 18.18% than those of WTW in the CK,P,N and NP treatments respectively at maturity,but the P concentrations in other organs of CTW were lower than the WTW.So the CTW genotypes had higher capacity of P remobilise than WTW onesa,nd there were ones of higher P use efficiency.WTW were more sensitive to the N deficient.P fertilization could increase P concentration in the seed,but the N fertilization might have negative effects.