The physiological and metabolic differences in maize under different nitrogen(N)levels are the basis of reasonable N management,which is vital in improving fertilizer utilization and reducing environmental pollution.I...The physiological and metabolic differences in maize under different nitrogen(N)levels are the basis of reasonable N management,which is vital in improving fertilizer utilization and reducing environmental pollution.In this paper,on the premise of defining the N fertilizer efficiency and yield under different long-term N fertilization treatments,the corresponding differential metabolites and their metabolic pathways were analyzed by untargeted metabolomics in maize.N stress,including deficiency and excess,affects the balance of carbon(C)metabolism and N metabolism by regulating C metabolites(sugar alcohols and tricarboxylic acid(TCA)cycle intermediates)and N metabolites(various amino acids and their derivatives).L-alanine,L-phenylalanine,L-histidine,and L-glutamine decreased under N deficiency,and L-valine,proline,and L-histidine increased under N excess.In addition to sugar alcohols and the above amino acids in C and N metabolism,differential secondary metabolites,flavonoids(e.g.,kaempferol,luteolin,rutin,and diosmetin),and hormones(e.g.,indoleacetic acid,trans-zeatin,and jasmonic acid)were initially considered as indicators for N stress diagnosis under this experimental conditions.This study also indicated that the leaf metabolic levels of N2(120 kg ha–1 N)and N3(180 kg ha–1 N)were similar,consistent with the differences in their physiological indexes and yields over 12 years.This study verified the feasibility of reducing N fertilization from 180 kg ha–1(locally recommended)to 120 kg ha–1 at the metabolic level,which provided a mechanistic basis for reducing N fertilization without reducing yield,further improving the N utilization rate and protecting the ecological environment.展开更多
Phosphorus(P)is a nonrenewable resource and a critical element for plant growth that plays an important role in improving crop yield.Excessive P fertilizer application is widespread in agricultural production,which no...Phosphorus(P)is a nonrenewable resource and a critical element for plant growth that plays an important role in improving crop yield.Excessive P fertilizer application is widespread in agricultural production,which not only wastes phosphate resources but also causes P accumulation and groundwater pollution.Here,we hypothesized that the apparent P balance of a crop system could be used as an indicator for identifying the critical P input in order to obtain a high yield with high phosphorus use efficiency(PUE).A 12-year field experiment with P fertilization rates of 0,45,90,135,180,and 225 kg P_(2)O_(5)ha^(-1)was conducted to determine the crop yield,PUE,and soil Olsen-P value response to P balance,and to optimize the P input.Annual yield stagnation occurred when the P fertilizer application exceeded a certain level,and high yield and PUE levels were achieved with annual P fertilizer application rates of 90-135 kg P_(2)O_(5)ha^(-1).A critical P balance range of 2.15-4.45 kg P ha^(-1)was recommended to achieve optimum yield with minimal environmental risk.The critical P input range estimated from the P balance was 95.7-101 kg P_(2)O_(5)ha^(-1),which improved relative yield(>90%)and PUE(90.0-94.9%).In addition,the P input-output balance helps in assessing future changes in Olsen-P values,which increased by 4.07 mg kg^(-1)of P for every 100 kg of P surplus.Overall,the P balance can be used as a critical indicator for P management in agriculture,providing a robust reference for limiting P excess and developing a more productive,efficient and environmentally friendly P fertilizer management strategy.展开更多
【目的】作物叶片颜色反映土壤养分的供应状况。研究作物叶片氮素相关的特征光谱信息与土壤无机氮含量的关系,以建立基于叶片光谱信息的土壤无机氮含量诊断模型,实现利用高光谱技术对作物和土壤进行实时监测。【方法】在两年(2017—2018...【目的】作物叶片颜色反映土壤养分的供应状况。研究作物叶片氮素相关的特征光谱信息与土壤无机氮含量的关系,以建立基于叶片光谱信息的土壤无机氮含量诊断模型,实现利用高光谱技术对作物和土壤进行实时监测。【方法】在两年(2017—2018)的玉米(郑单958)田间试验中,设置6个施氮水平,施氮量分别为0、60、120、180、240、300 kg/hm^2。在玉米的拔节期、大喇叭口期、开花吐丝期、灌浆期测定叶片高光谱反射率,对植株和土壤样品进行采集,分析土壤无机氮含量的变化,明确叶片光谱反射率与土壤无机氮含量的关系,利用光谱参数和偏最小二乘回归法(partial least squares regression,PLSR)建立诊断模型并进行模型精度的评价。【结果】施氮处理土壤无机氮含量显著高于不施氮处理,随着生育期的推移,土壤无机氮含量呈递减趋势,追肥可显著提高土壤无机氮含量。拔节期和开花吐丝期叶片光谱反射率与土壤无机氮含量在可见光波段呈负相关关系,在近红外波段呈正相关关系;大喇叭口期两者在可见光波段呈负相关关系,灌浆期两者无明显相关关系。在光谱参数模型中,4个生育期土壤无机氮含量预测的最佳光谱指数分别为RVI-2、RSI(534,726)、RSI(567,519)和RVI-2,其回归模型验证集的R^2分别为0.642、0.749、0.696、0.540。在PLSR预测模型中,利用PLSR建立的诊断模型验证集的R2分别为0.876、0.838、0.765、0.595,RPD(ratio of percent deviation)分别为2.140、2.077、2.002、1.369。【结论】基于叶片光谱反射率建立的PLSR估算模型,在玉米的拔节期、大喇叭口期、开花吐丝期均能很好地预测土壤无机氮含量。因此,利用叶片光谱特征诊断土壤无机氮含量具有一定的可行性。展开更多
Maize is one of the most important crops worldwide, but it suffers from salt stress when grown in saline-alkaline soil. There is therefore an urgent need to improve maize salt tolerance and crop yield. In this study, ...Maize is one of the most important crops worldwide, but it suffers from salt stress when grown in saline-alkaline soil. There is therefore an urgent need to improve maize salt tolerance and crop yield. In this study, the SsNHX1 gene of Suaeda salsa, which encodes a vacuolar membrane Na~+/H~+ antiporter, was transformed into the maize inbred line 18-599 by Agrobacterium-mediated transformation. Transgenic maize plants overexpressing the SsNHX1 gene showed less growth retardation when treated with an increasing NaCl gradient of up to 1%, indicating enhanced salt tolerance. The improved salt tolerance of transgenic plants was also demonstrated by a significantly elevated seed germination rate(79%) and a reduction in seminal root length inhibition. Moreover, transgenic plants under salt stress exhibited less physiological damage. SsNHX1-overexpressing transgenic maize accumulated more Na~+ and K~+ than wild-type(WT) plants particularly in the leaves, resulting in a higher ratio of K~+/Na~+ in the leaves under salt stress. This result revealed that the improved salt tolerance of SsNHX1-overexpressing transgenic maize plants was likely attributed to SsNHX1-mediated localization of Na~+ to vacuoles and subsequent maintenance of the cytosolic ionic balance. In addition, SsNHX1 overexpression also improved the drought tolerance of the transgenic maize plants, as rehydrated transgenic plants were restored to normal growth while WT plants did not grow normally after dehydration treatment. Therefore, based on our engineering approach, SsNHX1 represents a promising candidate gene for improving the salt and drought tolerance of maize and other crops.展开更多
基金support of the National Key R&D Program of China(2021YFD1700900).
文摘The physiological and metabolic differences in maize under different nitrogen(N)levels are the basis of reasonable N management,which is vital in improving fertilizer utilization and reducing environmental pollution.In this paper,on the premise of defining the N fertilizer efficiency and yield under different long-term N fertilization treatments,the corresponding differential metabolites and their metabolic pathways were analyzed by untargeted metabolomics in maize.N stress,including deficiency and excess,affects the balance of carbon(C)metabolism and N metabolism by regulating C metabolites(sugar alcohols and tricarboxylic acid(TCA)cycle intermediates)and N metabolites(various amino acids and their derivatives).L-alanine,L-phenylalanine,L-histidine,and L-glutamine decreased under N deficiency,and L-valine,proline,and L-histidine increased under N excess.In addition to sugar alcohols and the above amino acids in C and N metabolism,differential secondary metabolites,flavonoids(e.g.,kaempferol,luteolin,rutin,and diosmetin),and hormones(e.g.,indoleacetic acid,trans-zeatin,and jasmonic acid)were initially considered as indicators for N stress diagnosis under this experimental conditions.This study also indicated that the leaf metabolic levels of N2(120 kg ha–1 N)and N3(180 kg ha–1 N)were similar,consistent with the differences in their physiological indexes and yields over 12 years.This study verified the feasibility of reducing N fertilization from 180 kg ha–1(locally recommended)to 120 kg ha–1 at the metabolic level,which provided a mechanistic basis for reducing N fertilization without reducing yield,further improving the N utilization rate and protecting the ecological environment.
基金This study was funded by the National Key Research and Development Program of China(2021YFD1700900).
文摘Phosphorus(P)is a nonrenewable resource and a critical element for plant growth that plays an important role in improving crop yield.Excessive P fertilizer application is widespread in agricultural production,which not only wastes phosphate resources but also causes P accumulation and groundwater pollution.Here,we hypothesized that the apparent P balance of a crop system could be used as an indicator for identifying the critical P input in order to obtain a high yield with high phosphorus use efficiency(PUE).A 12-year field experiment with P fertilization rates of 0,45,90,135,180,and 225 kg P_(2)O_(5)ha^(-1)was conducted to determine the crop yield,PUE,and soil Olsen-P value response to P balance,and to optimize the P input.Annual yield stagnation occurred when the P fertilizer application exceeded a certain level,and high yield and PUE levels were achieved with annual P fertilizer application rates of 90-135 kg P_(2)O_(5)ha^(-1).A critical P balance range of 2.15-4.45 kg P ha^(-1)was recommended to achieve optimum yield with minimal environmental risk.The critical P input range estimated from the P balance was 95.7-101 kg P_(2)O_(5)ha^(-1),which improved relative yield(>90%)and PUE(90.0-94.9%).In addition,the P input-output balance helps in assessing future changes in Olsen-P values,which increased by 4.07 mg kg^(-1)of P for every 100 kg of P surplus.Overall,the P balance can be used as a critical indicator for P management in agriculture,providing a robust reference for limiting P excess and developing a more productive,efficient and environmentally friendly P fertilizer management strategy.
文摘【目的】作物叶片颜色反映土壤养分的供应状况。研究作物叶片氮素相关的特征光谱信息与土壤无机氮含量的关系,以建立基于叶片光谱信息的土壤无机氮含量诊断模型,实现利用高光谱技术对作物和土壤进行实时监测。【方法】在两年(2017—2018)的玉米(郑单958)田间试验中,设置6个施氮水平,施氮量分别为0、60、120、180、240、300 kg/hm^2。在玉米的拔节期、大喇叭口期、开花吐丝期、灌浆期测定叶片高光谱反射率,对植株和土壤样品进行采集,分析土壤无机氮含量的变化,明确叶片光谱反射率与土壤无机氮含量的关系,利用光谱参数和偏最小二乘回归法(partial least squares regression,PLSR)建立诊断模型并进行模型精度的评价。【结果】施氮处理土壤无机氮含量显著高于不施氮处理,随着生育期的推移,土壤无机氮含量呈递减趋势,追肥可显著提高土壤无机氮含量。拔节期和开花吐丝期叶片光谱反射率与土壤无机氮含量在可见光波段呈负相关关系,在近红外波段呈正相关关系;大喇叭口期两者在可见光波段呈负相关关系,灌浆期两者无明显相关关系。在光谱参数模型中,4个生育期土壤无机氮含量预测的最佳光谱指数分别为RVI-2、RSI(534,726)、RSI(567,519)和RVI-2,其回归模型验证集的R^2分别为0.642、0.749、0.696、0.540。在PLSR预测模型中,利用PLSR建立的诊断模型验证集的R2分别为0.876、0.838、0.765、0.595,RPD(ratio of percent deviation)分别为2.140、2.077、2.002、1.369。【结论】基于叶片光谱反射率建立的PLSR估算模型,在玉米的拔节期、大喇叭口期、开花吐丝期均能很好地预测土壤无机氮含量。因此,利用叶片光谱特征诊断土壤无机氮含量具有一定的可行性。
基金supported by the National Natural Science Foundation of China(31561143014,30800687,31071434,and 31522041)the Major Project of Education Department of Sichuan Province,China(15ZA0022)
文摘Maize is one of the most important crops worldwide, but it suffers from salt stress when grown in saline-alkaline soil. There is therefore an urgent need to improve maize salt tolerance and crop yield. In this study, the SsNHX1 gene of Suaeda salsa, which encodes a vacuolar membrane Na~+/H~+ antiporter, was transformed into the maize inbred line 18-599 by Agrobacterium-mediated transformation. Transgenic maize plants overexpressing the SsNHX1 gene showed less growth retardation when treated with an increasing NaCl gradient of up to 1%, indicating enhanced salt tolerance. The improved salt tolerance of transgenic plants was also demonstrated by a significantly elevated seed germination rate(79%) and a reduction in seminal root length inhibition. Moreover, transgenic plants under salt stress exhibited less physiological damage. SsNHX1-overexpressing transgenic maize accumulated more Na~+ and K~+ than wild-type(WT) plants particularly in the leaves, resulting in a higher ratio of K~+/Na~+ in the leaves under salt stress. This result revealed that the improved salt tolerance of SsNHX1-overexpressing transgenic maize plants was likely attributed to SsNHX1-mediated localization of Na~+ to vacuoles and subsequent maintenance of the cytosolic ionic balance. In addition, SsNHX1 overexpression also improved the drought tolerance of the transgenic maize plants, as rehydrated transgenic plants were restored to normal growth while WT plants did not grow normally after dehydration treatment. Therefore, based on our engineering approach, SsNHX1 represents a promising candidate gene for improving the salt and drought tolerance of maize and other crops.
