Genotypic variation in phosphorus acquisition from sparingly soluble P sources is related to root morphology and root exudates in Brassica napus  

作　　者：ZHANG HaiWei HUANG Yu YE XiangSheng XU FangSen 

机构地区：[1]National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China [2]Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China

出　　处：《Science China(Life Sciences)》2011年第12期1134-1142,共9页中国科学（生命科学英文版）

基　　金：supported by the National Basic Research Program of China (Grant No. 2011CB100301)

摘　　要：Genotypic variations in the adaptive response to low-phosphorus （P） stress and P-uptake efficiency have been widely reported in many crops. We conducted a pot experiment to evaluate the P-acquisition ability of two rapeseed （Brassica napus） geno- types supplied with two sparingly soluble sources of P, A1-P and Fe-P. Then, the root morphology, proton concentrations, and carboxylate content were investigated in a solution experiment to examine the genotypic difference in P-acquisition efficiency. Both genotypes produced greater biomass and accumulated more P when supplied with A1-P than when supplied with Fe-P. The P-efficient genotype 102 showed a significantly greater ability to deplete sparingly soluble P from the rhizosphere soil be- cause of its greater biomass and higher P uptake compared with those of the P-inefficient genotype 105. In the solution exper- iment, the P-efficient genotype under low-P conditions developed dominant root morphological traits, and it showed more in- tensive rhizosphere acidification because of greater H＋ effiux, higher H＋-ATPase activity, and greater exudation of carbox- ylates than the P-inefficient genotype. Thus, a combination of morphological and physiological mechanisms contributed to the genotypic variation in the utilization of different sparingly soluble P sources in B. napus.Genotypic variations in the adaptive response to low-phosphorus(P) stress and P-uptake efficiency have been widely reported in many crops.We conducted a pot experiment to evaluate the P-acquisition ability of two rapeseed(Brassica napus) genotypes supplied with two sparingly soluble sources of P,Al-P and Fe-P.Then,the root morphology,proton concentrations,and carboxylate content were investigated in a solution experiment to examine the genotypic difference in P-acquisition efficiency.Both genotypes produced greater biomass and accumulated more P when supplied with Al-P than when supplied with Fe-P.The P-efficient genotype 102 showed a significantly greater ability to deplete sparingly soluble P from the rhizosphere soil because of its greater biomass and higher P uptake compared with those of the P-inefficient genotype 105.In the solution experiment,the P-efficient genotype under low-P conditions developed dominant root morphological traits,and it showed more intensive rhizosphere acidification because of greater H+ efflux,higher H+-ATPase activity,and greater exudation of carboxylates than the P-inefficient genotype.Thus,a combination of morphological and physiological mechanisms contributed to the genotypic variation in the utilization of different sparingly soluble P sources in B.napus.

关 键 词：Brassica napus sparingly soluble P genotypic variation root morphology H＋ and carboxylate exudation 

分 类 号：S513[农业科学—作物学] S565.4