Thomas Howard, Ougham Helen
IBERS, Edward Llwyd Building, Aberystwyth University, Ceredigion SY23 3FG, UK
IBERS, Edward Llwyd Building, Aberystwyth University, Ceredigion SY23 3FG, UK.
J Exp Bot. 2014 Jul;65(14):3889-900. doi: 10.1093/jxb/eru037. Epub 2014 Mar 5.
Stay-green (sometimes staygreen) refers to the heritable delayed foliar senescence character in model and crop plant species. In a cosmetic stay-green, a lesion interferes with an early step in chlorophyll catabolism. The possible contribution of synthesis to chlorophyll turnover in cosmetic stay-greens is considered. In functional stay-greens, the transition from the carbon capture period to the nitrogen mobilization (senescence) phase of canopy development is delayed, and/or the senescence syndrome proceeds slowly. Yield and composition in high-carbon (C) crops such as cereals, and in high-nitrogen (N) species such as legumes, reflect the source-sink relationship with canopy C capture and N remobilization. Quantitative trait loci studies show that functional stay-green is a valuable trait for improving crop stress tolerance, and is associated with the domestication syndrome in cereals. Stay-green variants reveal how autumnal senescence and dormancy are coordinated in trees. The stay-green phenotype can be the result of alterations in hormone metabolism and signalling, particularly affecting networks involving cytokinins and ethylene. Members of the WRKY and NAC families, and an ever-expanding cast of additional senescence-associated transcription factors, are identifiable by mutations that result in stay-green. Empirical selection for functional stay-green has contributed to increasing crop yields, particularly where it is part of a strategy that also targets other traits such as sink capacity and environmental sensitivity and is associated with appropriate crop management methodology. The onset and progress of senescence are phenological metrics that show climate change sensitivity, indicating that understanding stay-green can contribute to the design of appropriate crop types for future environments.
持绿（有时也写作staygreen）指的是模式植物和作物物种中可遗传的叶片衰老延迟特性。在外观持绿现象中，损伤会干扰叶绿素分解代谢的早期步骤。人们考虑了合成作用对外观持绿中叶绿素周转的可能贡献。在功能性持绿现象中，冠层发育从碳捕获期向氮素动员（衰老）阶段的转变被延迟，和/或衰老综合征进展缓慢。在高碳作物（如谷类）和高氮物种（如豆类）中，产量和成分反映了与冠层碳捕获和氮素再分配的源库关系。数量性状位点研究表明，功能性持绿是提高作物胁迫耐受性的一个有价值的性状，并且与谷类作物的驯化综合征有关。持绿变异揭示了树木中秋季衰老和休眠是如何协调的。持绿表型可能是激素代谢和信号传导改变的结果，特别是影响涉及细胞分裂素和乙烯的网络。WRKY和NAC家族成员，以及越来越多其他与衰老相关的转录因子，可通过导致持绿的突变来识别。对功能性持绿进行实证选择有助于提高作物产量，特别是当它作为一种还针对其他性状（如库容量和环境敏感性）的策略的一部分，并且与适当的作物管理方法相关联时。衰老的开始和进程是显示气候变化敏感性的物候指标，这表明了解持绿有助于为未来环境设计合适的作物类型。
