Leaf-color modification can affect canopy photosynthesis,with potential effects on rice yield and yield components.Modulating source-sink relationships through crop management is often used to improve crop productivit...Leaf-color modification can affect canopy photosynthesis,with potential effects on rice yield and yield components.Modulating source-sink relationships through crop management is often used to improve crop productivity.This study investigated whether and how modifying leaf color alters source-sink relationships and whether current crop cultivation practices remain applicable for leaf-color modified genotypes.Periodically collected data of total biomass and nitrogen(N)accumulation in rice genotypes of four genetic backgrounds and their leaf-color modified variants(greener or yellower)were analyzed,using a recently established modelling method to quantify the source-sink(im)balance during grain filling.Among all leaf-color variants,only one yellower-leaf variant showed a higher source capacity than its normal genotype.This was associated with greater post-flowering N-uptake that prolonged the functional leaf-N duration,and this greater post-flowering N-uptake was possible because of reduced pre-flowering N-uptake.A density experiment showed that current management practices(insufficient planting density accompanied by abundant N application)are unsuitable for the yellower-leaf genotype,ultimately limiting its yield potential.Leaf-color modification affects source-sink relationships by regulating the N trade-off between pre-and post-flowering uptake,as well as N translocation between source and sink organs.To best exploit leaf-color modification for improving crop productivity,adjustments of crop management practices are required.展开更多
Drought tolerance is governed by constitutive and acquired traits.Combining them has relevance for sustaining crop productivity under drought.Mild levels of stress induce specific mechanisms that protect metabolism wh...Drought tolerance is governed by constitutive and acquired traits.Combining them has relevance for sustaining crop productivity under drought.Mild levels of stress induce specific mechanisms that protect metabolism when stress becomes severe.Here,we report a comparative assessment of“acquired drought tolerance(ADT)”traits in two rice cultivars,IR64(drought susceptible)and Apo(tolerant),and a drought-tolerant wheat cultivar,Weebill.Young seedlings were exposed to progressive concentrations of methyl viologen(MV),a stress inducer,before transferring to a severe concentration.“Induced”seedlings showed higher tolerance and recovery growth than seedlings exposed directly to severe stress.A novel phenomic platform with an automated irrigation system was used for precisely imposing soil moisture stress to capture ADT traits during the vegetative stage.Gradual progression of drought was achieved through a software-controlled automated irrigation facility.This facility allowed the maintenance of the same level of soil moisture irrespective of differences in transpiration,and hence,this platform provided the most appropriate method to assess ADT traits.Total biomass decreased more in IR64 than in Apo.The wheat cultivar showed lower levels of damage and higher recovery growth even compared to Apo.Expression of ROS-scavenging enzymes and drought-responsive genes was significantly higher in Apo than in IR64,but differences were only marginal between Apo and Weebill.The wheat cultivar showed significantly higher stomatal conductance,carbon gain,and biomass than the rice cultivars,under drought.These differences in ADT traits between cultivars as well as between species can be utilised for improving drought tolerance in crop plants.展开更多
文摘Leaf-color modification can affect canopy photosynthesis,with potential effects on rice yield and yield components.Modulating source-sink relationships through crop management is often used to improve crop productivity.This study investigated whether and how modifying leaf color alters source-sink relationships and whether current crop cultivation practices remain applicable for leaf-color modified genotypes.Periodically collected data of total biomass and nitrogen(N)accumulation in rice genotypes of four genetic backgrounds and their leaf-color modified variants(greener or yellower)were analyzed,using a recently established modelling method to quantify the source-sink(im)balance during grain filling.Among all leaf-color variants,only one yellower-leaf variant showed a higher source capacity than its normal genotype.This was associated with greater post-flowering N-uptake that prolonged the functional leaf-N duration,and this greater post-flowering N-uptake was possible because of reduced pre-flowering N-uptake.A density experiment showed that current management practices(insufficient planting density accompanied by abundant N application)are unsuitable for the yellower-leaf genotype,ultimately limiting its yield potential.Leaf-color modification affects source-sink relationships by regulating the N trade-off between pre-and post-flowering uptake,as well as N translocation between source and sink organs.To best exploit leaf-color modification for improving crop productivity,adjustments of crop management practices are required.
文摘Drought tolerance is governed by constitutive and acquired traits.Combining them has relevance for sustaining crop productivity under drought.Mild levels of stress induce specific mechanisms that protect metabolism when stress becomes severe.Here,we report a comparative assessment of“acquired drought tolerance(ADT)”traits in two rice cultivars,IR64(drought susceptible)and Apo(tolerant),and a drought-tolerant wheat cultivar,Weebill.Young seedlings were exposed to progressive concentrations of methyl viologen(MV),a stress inducer,before transferring to a severe concentration.“Induced”seedlings showed higher tolerance and recovery growth than seedlings exposed directly to severe stress.A novel phenomic platform with an automated irrigation system was used for precisely imposing soil moisture stress to capture ADT traits during the vegetative stage.Gradual progression of drought was achieved through a software-controlled automated irrigation facility.This facility allowed the maintenance of the same level of soil moisture irrespective of differences in transpiration,and hence,this platform provided the most appropriate method to assess ADT traits.Total biomass decreased more in IR64 than in Apo.The wheat cultivar showed lower levels of damage and higher recovery growth even compared to Apo.Expression of ROS-scavenging enzymes and drought-responsive genes was significantly higher in Apo than in IR64,but differences were only marginal between Apo and Weebill.The wheat cultivar showed significantly higher stomatal conductance,carbon gain,and biomass than the rice cultivars,under drought.These differences in ADT traits between cultivars as well as between species can be utilised for improving drought tolerance in crop plants.
