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 ...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.展开更多
Although extensive investigations of biogenic and geological calcium phosphate crystallization/dissolution and their phase transformations have been performed,the mechanisms of crystallization and dissolution of spari...Although extensive investigations of biogenic and geological calcium phosphate crystallization/dissolution and their phase transformations have been performed,the mechanisms of crystallization and dissolution of sparingly soluble calcium phosphates in geological settings have not been completely determined at the near-molecular level.In particular,an understanding of the physical-chemical processes at the earliest nucleation stage and the subsequent crystal surface dynamics in soil solutions is lacking.This review focuses on the earliest events in homo/heterogeneous nucleation from an initial supersaturated solution phase,the subsequent growth of calcium phosphate phases,and the relevant influences of the presence of additional inorganic and organic molecules in both geological and biological settings.These studies have implications for the understanding of the complex processes of calcium phosphate transformations in soils,and provide possible physical-chemical mechanisms for the biogeochemical behavior of phosphorus at the near-molecular level.展开更多
基金supported by the National Basic Research Program of China (Grant No. 2011CB100301)
文摘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.
基金supported by the National Natural Science Foundation of China (41071208)a start-up grant from the Huazhong Agricultural University (52204-09008)
文摘Although extensive investigations of biogenic and geological calcium phosphate crystallization/dissolution and their phase transformations have been performed,the mechanisms of crystallization and dissolution of sparingly soluble calcium phosphates in geological settings have not been completely determined at the near-molecular level.In particular,an understanding of the physical-chemical processes at the earliest nucleation stage and the subsequent crystal surface dynamics in soil solutions is lacking.This review focuses on the earliest events in homo/heterogeneous nucleation from an initial supersaturated solution phase,the subsequent growth of calcium phosphate phases,and the relevant influences of the presence of additional inorganic and organic molecules in both geological and biological settings.These studies have implications for the understanding of the complex processes of calcium phosphate transformations in soils,and provide possible physical-chemical mechanisms for the biogeochemical behavior of phosphorus at the near-molecular level.
