The unreasonable nitrogen(N)supply and low productivity are the main factors restricting the sustainable development of processing tomatoes.In addition,the mechanism by which the N application strategy affects root gr...The unreasonable nitrogen(N)supply and low productivity are the main factors restricting the sustainable development of processing tomatoes.In addition,the mechanism by which the N application strategy affects root growth and nitrate distributions in processing tomatoes remains unclear.In this study,we applied four N application levels to a field(including 0(N0),200(N200),300(N300),and 400(N400)kg/hm^(2))based on the critical N absorption ratio at each growth stage(planting stage to flowering stage:22%;fruit setting stage:24%;red ripening stage:45%;and maturity stage:9%).The results indicated that N300 treatment significantly improved the aboveground dry matter(DM),yield,N uptake,and nitrogen use efficiency(NUE),while N400 treatment increased nitrate nitrogen(NO_(3)^(-)-N)residue in the 20–60 cm soil layer.Temporal variations of total root dry weight(TRDW)and total root length(TRL)showed a single-peak curve.Overall,N300 treatment improved the secondary root parameter of TRDW,while N400 treatment improved the secondary root parameter of TRL.The grey correlation coefficients indicated that root dry weight density(RDWD)in the surface soil(0–20 cm)had the strongest relationship with yield,whereas root length density(RLD)in the middle soil(20–40 cm)had a strong relationship with yield.The path model indicated that N uptake is a crucial factor affecting aboveground DM,TRDW,and yield.The above results indicate that N application levels based on critical N absorption improve the production of processing tomatoes by regulating N uptake and root distribution.Furthermore,the results of this study provide a theoretical basis for precise N management.展开更多
Hybrid indica rice （Oryza sativa L.） cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle, and high yield potential. However, no attentio...Hybrid indica rice （Oryza sativa L.） cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle, and high yield potential. However, no attention has been given to its root growth dynamic responses to rising atmospheric CO2 concentration （[CO2]） in conjunction with nitrogen （N） availability. Free air COz enrichment （FACE） and N have significant effects on rice root growth. In this experiment, a hybrid cultivar Shanyou 63 （Oryza sativa L.） was used to study the effects of FACE and N levels on roots growth of rice. The results showed a significant increase in both adventitious root volume （ARV） and adventitious root dry weight （ARD） under the FACE treatment. The application of nitrogen also increased ARV and ARD, but the increase was smaller than that under FACE treatment. On the basis of the FACE experiment, numerical models for rice adventitious root volume and dry weight were built with the time as the driving factor. The models illustrated the dynamic development of rice adventitious root volume and dry weight after transplanting, regulated either by the influence factor of atmospheric [CO2] or by N application. The models were successfully used to predict ARV and ARD under FACE treatment in a different year with the predicted data being closely related to the actual experimental data. The model had guiding significance to growth regulation of rice root under the condition of atmospheric [CO2] rising in the future.展开更多
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
The efficient use of water by modern irrigation systems is becoming increasingly important in arid and semi-arid regions with limited water resources. Field experiments were conducted during 2008-2010 to study the eff...The efficient use of water by modern irrigation systems is becoming increasingly important in arid and semi-arid regions with limited water resources. Field experiments were conducted during 2008-2010 to study the effect of drip fertigation with water soluble fertilizer on root growth of maize under maize based intercropping system. The experiment was laid out in strip plot design with three replications. The treatment consists of nine fertigation levels in main plots and four inter crops in sub plots. Root spread and root dry mass were increased under drip fertigation practices while rooting depth was more under surface irrigation. Drip fertigation with water soluble fertilizer improved the root system by inducing new secondary roots which are succulent and actively involved in physiological responses. Drip fertigation has pronounced effect on the root architecture especially in the production of highly fibrous root system.展开更多
Common bean (Phaseolus vulgaris L.) is an important legume in the tropics, with production limited by low availability of soil phosphorus (P). An experiment was conducted in the glasshouse to evaluate P use efficiency...Common bean (Phaseolus vulgaris L.) is an important legume in the tropics, with production limited by low availability of soil phosphorus (P). An experiment was conducted in the glasshouse to evaluate P use efficiency of eight dry bean genotypes (G122, Montcalm, Taylor Horticulture, Cardinal, Bukoba, Kijivu, Rojo and CAL 143) of Andean origin. The treatments included: no P (0 kg P ha-1), normal P (50 kg P ha-1), and high P (100 kg P ha-1). There was variation for the measured traits shoot biomass (g), shoot P (mg kg-1), root P (mg kg-1), seed P (mg kg-1) and seed yield (g) among genotypes and P treatments. Biomass and all P concentrations increased with increasing P level and the genotypes Kijivu, Bukoba, Montcalm and Taylor Horticulture had higher P concentrations than Rojo, G122, Cardinal and CAL 143 across treatments. Genotype × treatment interactions were observed for shoot biomass. For the no P treatment, shoot and root biomass were positively correlated with PUE (phosphorus use efficiency). PUE had higher values and varied more among genotypes in the no P treatment compared to the normal P and high P treatments. The results suggest that seed yield in dry bean can be improved by selecting for genotypes with higher PUE under limiting P. The genotypes Bukoba, Kijivu and Montcalm with the highest values for PUE under no P treatment may be exhibiting some level of tolerance to low soil phosphorus. Higher shoot weight may provide simple criteria for selecting genotypes with greater yield and PUE (phosphorus use efficiency) under limiting P conditions. Therefore, a genotype is desired that can efficiently uptake and utilize available P under limited availability of this nutrient.展开更多
Under the conditions of drought and waterlogging,the dynamic of root dry weight and its distribution were studied with the method of root cutting collection in shajiang black soil. The result showed that root dry weig...Under the conditions of drought and waterlogging,the dynamic of root dry weight and its distribution were studied with the method of root cutting collection in shajiang black soil. The result showed that root dry weight and its distribution were largely affected by drought and waterlogging,especially the later. During a drought,root dry weight of maize per plant was higher, and the time of root dry weight increase and decrease were earlier, the speed of roots spreading into deep soil were quicker and many roots were distributed in deeper soil layer. While during a waterlogging, the result was contrary to the above.展开更多
基金supported by the National Natural Science Foundation of China (42077011).
文摘The unreasonable nitrogen(N)supply and low productivity are the main factors restricting the sustainable development of processing tomatoes.In addition,the mechanism by which the N application strategy affects root growth and nitrate distributions in processing tomatoes remains unclear.In this study,we applied four N application levels to a field(including 0(N0),200(N200),300(N300),and 400(N400)kg/hm^(2))based on the critical N absorption ratio at each growth stage(planting stage to flowering stage:22%;fruit setting stage:24%;red ripening stage:45%;and maturity stage:9%).The results indicated that N300 treatment significantly improved the aboveground dry matter(DM),yield,N uptake,and nitrogen use efficiency(NUE),while N400 treatment increased nitrate nitrogen(NO_(3)^(-)-N)residue in the 20–60 cm soil layer.Temporal variations of total root dry weight(TRDW)and total root length(TRL)showed a single-peak curve.Overall,N300 treatment improved the secondary root parameter of TRDW,while N400 treatment improved the secondary root parameter of TRL.The grey correlation coefficients indicated that root dry weight density(RDWD)in the surface soil(0–20 cm)had the strongest relationship with yield,whereas root length density(RLD)in the middle soil(20–40 cm)had a strong relationship with yield.The path model indicated that N uptake is a crucial factor affecting aboveground DM,TRDW,and yield.The above results indicate that N application levels based on critical N absorption improve the production of processing tomatoes by regulating N uptake and root distribution.Furthermore,the results of this study provide a theoretical basis for precise N management.
基金funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,Chinathe Key Direction Research of Knowledge Innovation in Chinese Academy of Science (KZCX3-SW-440)
文摘Hybrid indica rice （Oryza sativa L.） cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle, and high yield potential. However, no attention has been given to its root growth dynamic responses to rising atmospheric CO2 concentration （[CO2]） in conjunction with nitrogen （N） availability. Free air COz enrichment （FACE） and N have significant effects on rice root growth. In this experiment, a hybrid cultivar Shanyou 63 （Oryza sativa L.） was used to study the effects of FACE and N levels on roots growth of rice. The results showed a significant increase in both adventitious root volume （ARV） and adventitious root dry weight （ARD） under the FACE treatment. The application of nitrogen also increased ARV and ARD, but the increase was smaller than that under FACE treatment. On the basis of the FACE experiment, numerical models for rice adventitious root volume and dry weight were built with the time as the driving factor. The models illustrated the dynamic development of rice adventitious root volume and dry weight after transplanting, regulated either by the influence factor of atmospheric [CO2] or by N application. The models were successfully used to predict ARV and ARD under FACE treatment in a different year with the predicted data being closely related to the actual experimental data. The model had guiding significance to growth regulation of rice root under the condition of atmospheric [CO2] rising in the future.
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.
文摘The efficient use of water by modern irrigation systems is becoming increasingly important in arid and semi-arid regions with limited water resources. Field experiments were conducted during 2008-2010 to study the effect of drip fertigation with water soluble fertilizer on root growth of maize under maize based intercropping system. The experiment was laid out in strip plot design with three replications. The treatment consists of nine fertigation levels in main plots and four inter crops in sub plots. Root spread and root dry mass were increased under drip fertigation practices while rooting depth was more under surface irrigation. Drip fertigation with water soluble fertilizer improved the root system by inducing new secondary roots which are succulent and actively involved in physiological responses. Drip fertigation has pronounced effect on the root architecture especially in the production of highly fibrous root system.
文摘Common bean (Phaseolus vulgaris L.) is an important legume in the tropics, with production limited by low availability of soil phosphorus (P). An experiment was conducted in the glasshouse to evaluate P use efficiency of eight dry bean genotypes (G122, Montcalm, Taylor Horticulture, Cardinal, Bukoba, Kijivu, Rojo and CAL 143) of Andean origin. The treatments included: no P (0 kg P ha-1), normal P (50 kg P ha-1), and high P (100 kg P ha-1). There was variation for the measured traits shoot biomass (g), shoot P (mg kg-1), root P (mg kg-1), seed P (mg kg-1) and seed yield (g) among genotypes and P treatments. Biomass and all P concentrations increased with increasing P level and the genotypes Kijivu, Bukoba, Montcalm and Taylor Horticulture had higher P concentrations than Rojo, G122, Cardinal and CAL 143 across treatments. Genotype × treatment interactions were observed for shoot biomass. For the no P treatment, shoot and root biomass were positively correlated with PUE (phosphorus use efficiency). PUE had higher values and varied more among genotypes in the no P treatment compared to the normal P and high P treatments. The results suggest that seed yield in dry bean can be improved by selecting for genotypes with higher PUE under limiting P. The genotypes Bukoba, Kijivu and Montcalm with the highest values for PUE under no P treatment may be exhibiting some level of tolerance to low soil phosphorus. Higher shoot weight may provide simple criteria for selecting genotypes with greater yield and PUE (phosphorus use efficiency) under limiting P conditions. Therefore, a genotype is desired that can efficiently uptake and utilize available P under limited availability of this nutrient.
文摘Under the conditions of drought and waterlogging,the dynamic of root dry weight and its distribution were studied with the method of root cutting collection in shajiang black soil. The result showed that root dry weight and its distribution were largely affected by drought and waterlogging,especially the later. During a drought,root dry weight of maize per plant was higher, and the time of root dry weight increase and decrease were earlier, the speed of roots spreading into deep soil were quicker and many roots were distributed in deeper soil layer. While during a waterlogging, the result was contrary to the above.
