Achieving a sustainable cropping system requires the efficient use of resources,particularly nitrogen(N).Nitrogen fertiliser is applied in most irrigated cotton fields to maximise yield potential,but plant fertiliser ...Achieving a sustainable cropping system requires the efficient use of resources,particularly nitrogen(N).Nitrogen fertiliser is applied in most irrigated cotton fields to maximise yield potential,but plant fertiliser recovery can be low.Identifying the crucial pathways of fertiliser remobilisation internally within cotton plants will lead to greater awareness of the plants’ability to match the N demands of the developing fruiting matter.This study investigated the fate of N fertiliser when applied to cotton at various dates,with the goal to improve N fertiliser recovery in a modern transgenic cotton cultivar.15N-labelled urea(10 atom%)was applied at multiple times and harvested at four key cotton growth stages(first square,early bolls,cut-out and maturity).Remobilised N was determined as the difference in the proportion of N fertiliser in individual plant components against the fertiliser utilised by the whole plant.The application of fertiliser N at first square resulted in 23%greater fertiliser N recovery at plant maturity compared to fertiliser N applied 100%pre-plant(P<0.001).The improvement was in-part due to higher N derived from the fertiliser(Ndff%)in the cotton seed(3%).Conversely,the Ndff%was higher in the stem(4%)and petioles(1%)when the fertiliser was applied pre-plant.In total,73%of plant N was remobilised to another plant organ,predominantly the seed(67%).Applying N fertiliser post-planting improved N recovery and lint yield compared to applying all fertiliser pre-plant.展开更多
Leaf senescence can impact crop production by either changing photosynthesis duration, or by modifying the nutrient remobiliza- tion efficiency and harvest index. The doubling of the grain yield in major cereals in th...Leaf senescence can impact crop production by either changing photosynthesis duration, or by modifying the nutrient remobiliza- tion efficiency and harvest index. The doubling of the grain yield in major cereals in the last 50 years was primarily achieved through the extension of photosynthesis duration and the increase in crop biomass partitioning, two things that are intrinsically coupled with leaf senescence. In this review, we consider the functionality of a leaf as a function of leaf age, and divide a leaf＇s life into three phases： the functionality increasing phase at the early growth stage, the full functionality phase, and the senescence and functionality decreasing phase. A genetic framework is proposed to describe gene actions at various checkpoints to regulate leaf development and senescence. Four categories of genes contribute to crop production： those which regulate （Ⅰ） the speed and transition of early leaf growth, （Ⅱ） photosynthesis rate, （Ⅲ） the onset and （Ⅳ） the progression of leaf senescence. Current advances in isolating and characterizing senescence regulatory genes are discussed in the leaf aging and crop production context. We argue that the breeding of crops with leaf senescence ideotypes should be an essential part of further crop genetic improvement.展开更多
基金funded by the Australian Government,Department of Agriculture,Fisheries and Forestry,and the Cotton Research and Development Corporation through the More Profit from Nitrogen project.
文摘Achieving a sustainable cropping system requires the efficient use of resources,particularly nitrogen(N).Nitrogen fertiliser is applied in most irrigated cotton fields to maximise yield potential,but plant fertiliser recovery can be low.Identifying the crucial pathways of fertiliser remobilisation internally within cotton plants will lead to greater awareness of the plants’ability to match the N demands of the developing fruiting matter.This study investigated the fate of N fertiliser when applied to cotton at various dates,with the goal to improve N fertiliser recovery in a modern transgenic cotton cultivar.15N-labelled urea(10 atom%)was applied at multiple times and harvested at four key cotton growth stages(first square,early bolls,cut-out and maturity).Remobilised N was determined as the difference in the proportion of N fertiliser in individual plant components against the fertiliser utilised by the whole plant.The application of fertiliser N at first square resulted in 23%greater fertiliser N recovery at plant maturity compared to fertiliser N applied 100%pre-plant(P<0.001).The improvement was in-part due to higher N derived from the fertiliser(Ndff%)in the cotton seed(3%).Conversely,the Ndff%was higher in the stem(4%)and petioles(1%)when the fertiliser was applied pre-plant.In total,73%of plant N was remobilised to another plant organ,predominantly the seed(67%).Applying N fertiliser post-planting improved N recovery and lint yield compared to applying all fertiliser pre-plant.
基金supported in part by a grant to H.C.Jing from the National Natural Science Foundation of China(No.30970252)
文摘Leaf senescence can impact crop production by either changing photosynthesis duration, or by modifying the nutrient remobiliza- tion efficiency and harvest index. The doubling of the grain yield in major cereals in the last 50 years was primarily achieved through the extension of photosynthesis duration and the increase in crop biomass partitioning, two things that are intrinsically coupled with leaf senescence. In this review, we consider the functionality of a leaf as a function of leaf age, and divide a leaf＇s life into three phases： the functionality increasing phase at the early growth stage, the full functionality phase, and the senescence and functionality decreasing phase. A genetic framework is proposed to describe gene actions at various checkpoints to regulate leaf development and senescence. Four categories of genes contribute to crop production： those which regulate （Ⅰ） the speed and transition of early leaf growth, （Ⅱ） photosynthesis rate, （Ⅲ） the onset and （Ⅳ） the progression of leaf senescence. Current advances in isolating and characterizing senescence regulatory genes are discussed in the leaf aging and crop production context. We argue that the breeding of crops with leaf senescence ideotypes should be an essential part of further crop genetic improvement.
