作物持绿性的遗传、生理基础及其应用前景

Genetics,Physiological Basis of Grop Stay Green and Its Application Prospects

随着温室效应的加剧,形成了全球气候变暖的趋势,干旱对作物产量的影响也日趋严重,选育抗旱的品种已成为育种家们努力的目标。持绿性是植物的重要抗旱机制,在多种植物中被发现,引起了作物育种家们的极大兴趣。作物持绿性状的遗传及生理基础研究已经取得很大进展。许多作物持绿性基因数量性状位点(QTL)标记及连锁图构建已经实现。研究表明:在生理基础上持绿性决定于籽粒灌浆期氮素供求关系的平衡,即持绿型品种叶片氮浓度高于非持绿型品种。持绿型品种在干旱条件下,表现出高的蒸腾效率和光合能力,最终获得较高的籽粒产量。大量对持绿基因QTL及其标记的研究和定位,为持绿基因克隆、分子标记辅助育种及转基因育种打下坚实基础,将加快持绿性品种的选育与利用。高粱具有典型的持绿型种质资源,是持绿性研究的样板作物。在高粱上鉴定和分离克隆到的基因也可以直接转化到其他作物中去,为作物改良提供一个很好的变异来源。通过利用高粱的持绿性状来改良高粱、玉米、小麦及其他禾本科作物的抗旱性将是切实可行的。

The global warming trend has been developed as the increase of green house effects, resulting in more significant af- fects of drought stress on crop production, and therefore drought-resistant plant breeding has become more concerned by plant breeders. Stay green is characterized by the plant＇s ability to tolerate post-flowering drought stress and has been found in many crop plants, which has aroused a great interest from plant breeders. Significant progress has been obtained on the researches of genetics and physiological basis of stay green. Stay green QTLs and their mapping in many crop species have been identified and built. In physiology, stay green is intimately related to leaf nitrogen status, and at a whole plant level, stay-green can be viewed as a consequence of the balance between nitrogen demand by the grain and its supply during grain filling. Plants with stay green trait exhibit higher transpiration efficiency and photosynthetic rate, resulting in higher grain yield. The many stay green QTLs researches and mapping that have been done will provide a solid foundation for stay green gene cloning, molecular marker-assisted breeding and transgenic breeding, thus enhancing the process of stay green variety breeding and utilization of the trait. Sorghum is typical for possessing the stay green trait, and has been studied as a model species. The identified and cloned stay green genes in sorghum can be directly transferred into other plant species, which makes sorghum as an ideal drought-resistant gene resource. It will be capable for using sorghum＇s stay green genes to improve drought tolerance of sorghum, maize, wheat and other species of grasses.