The variation in nitrogen (N) uptake by rice has been widely studied but differences in rice root morphology that may contribute to this variation are not completely understood. Field and greenhouse experiments were c...The variation in nitrogen (N) uptake by rice has been widely studied but differences in rice root morphology that may contribute to this variation are not completely understood. Field and greenhouse experiments were carried out to study N accumulation, root dry weights, total root lengths, root surface areas, and root bleeding rates of two rice cultivars, Elio with low N-use efficiency and Nanguang with high N-use efficiency. Low (1 mmol N L-1) and high (5 mmol N L-1) N applications were established in the greenhouse experiment, and the N rates were 0, 120, and 240 kg ha-1 in the field experiments at Jiangning and Jiangpu farms, Nanjing, China. The results showed that the N accumulation, root dry weight, total root length, and root surface area increased with an increase in N application. At the heading stage, N accumulation in the shoots and roots of Nanguang was greater than that of Elio in the field experiments and that of Elio at 5 mmol N L-1 in the greenhouse experiment. After the heading stage, N accumulation was higher for Nanguang at both 1 and 5 mmol N L-1 in the greenhouse experiment. The total root length and root surface area were significantly different between the two cultivars. Over the range of the fertilizer application rates, the root lengths of Nanguang at Jiangning Farm were 49%-61% greater at booting and 26%-39% greater at heading than those of Elio, and at Jiangpu Farm they were 22%-42% and 26%-38% greater, respectively. Nanguang had a greater root bleeding rate than Elio. It was concluded that the N-use efficiency of the two rice cultivars studied depended to a great extent on the root morphological parameters and root physiological characteristics at different growth stages.展开更多
Limited information is available for soybean root traits and their plasticity under drought stress. To date, no studies have focused on examining diverse soybean germ- plasm for regulation of shoot and root response u...Limited information is available for soybean root traits and their plasticity under drought stress. To date, no studies have focused on examining diverse soybean germ- plasm for regulation of shoot and root response under water limited conditions across varying soil types. In this study, 17 genetically diverse soybean germplasm lines were selected to study root response to water limited conditions in clay （trial 1） and sandy soil （trial 2） in two target environments. Physiological data on shoot traits was measured at multiple crop stages ranging from early vegetative to pod filling. The phenotypic root traits, and biomass accumulation data are collected at pod filling stage. In trial 1, the number of lateral roots and forks were positively correlated with plot yield under water limitation and in trial 2, lateral root thickness was positively correlated with the hill plot yield. Plant Introduction （PI） 578477A and 088444 were found to have higher later root number and forks in clay soil with higher yield under water limitation, in sandy soil, P1458o2o was found to have a thicker lateral root system and higher yield under water limitation. The genotypes identified in this study could be used to enhance drought tolerance of elite soybean cultivars through improved root traits specific to target environments.展开更多
基金Supported by the National Key Basic Research Program (973 Program) of China (No.2007CB109304)the NationalNatural Science Foundation of China (Nos.30771290 and 30671234)
文摘The variation in nitrogen (N) uptake by rice has been widely studied but differences in rice root morphology that may contribute to this variation are not completely understood. Field and greenhouse experiments were carried out to study N accumulation, root dry weights, total root lengths, root surface areas, and root bleeding rates of two rice cultivars, Elio with low N-use efficiency and Nanguang with high N-use efficiency. Low (1 mmol N L-1) and high (5 mmol N L-1) N applications were established in the greenhouse experiment, and the N rates were 0, 120, and 240 kg ha-1 in the field experiments at Jiangning and Jiangpu farms, Nanjing, China. The results showed that the N accumulation, root dry weight, total root length, and root surface area increased with an increase in N application. At the heading stage, N accumulation in the shoots and roots of Nanguang was greater than that of Elio in the field experiments and that of Elio at 5 mmol N L-1 in the greenhouse experiment. After the heading stage, N accumulation was higher for Nanguang at both 1 and 5 mmol N L-1 in the greenhouse experiment. The total root length and root surface area were significantly different between the two cultivars. Over the range of the fertilizer application rates, the root lengths of Nanguang at Jiangning Farm were 49%-61% greater at booting and 26%-39% greater at heading than those of Elio, and at Jiangpu Farm they were 22%-42% and 26%-38% greater, respectively. Nanguang had a greater root bleeding rate than Elio. It was concluded that the N-use efficiency of the two rice cultivars studied depended to a great extent on the root morphological parameters and root physiological characteristics at different growth stages.
基金funding support from Missouri Soybean Merchandising Council-Project 220
文摘Limited information is available for soybean root traits and their plasticity under drought stress. To date, no studies have focused on examining diverse soybean germ- plasm for regulation of shoot and root response under water limited conditions across varying soil types. In this study, 17 genetically diverse soybean germplasm lines were selected to study root response to water limited conditions in clay （trial 1） and sandy soil （trial 2） in two target environments. Physiological data on shoot traits was measured at multiple crop stages ranging from early vegetative to pod filling. The phenotypic root traits, and biomass accumulation data are collected at pod filling stage. In trial 1, the number of lateral roots and forks were positively correlated with plot yield under water limitation and in trial 2, lateral root thickness was positively correlated with the hill plot yield. Plant Introduction （PI） 578477A and 088444 were found to have higher later root number and forks in clay soil with higher yield under water limitation, in sandy soil, P1458o2o was found to have a thicker lateral root system and higher yield under water limitation. The genotypes identified in this study could be used to enhance drought tolerance of elite soybean cultivars through improved root traits specific to target environments.
