The Relationships among “STAY-GREEN” Trait, Post-Anthesis Assimilate Remobilization, and Grain Yield in Rice (Oryza sativa L.)

Abstract

The mobilization and translocation of carbohydrates and mineral nutrients from vegetative plant parts to grains are pivotal for grain filling, often involving a whole plant senescence process. Loss of greenness is a hallmark of leaf senescence. However, the relationship between crop yield and senescence has been controversial for many years. Here, in this study, the overexpression and RNA interference lines of gene of OsNYC3 (Non-Yellow Coloring 3), a chlorophyll catabolism gene, were investigated. Furthermore, exogenous phytohormones were applied, and a treatment of alternate wetting and moderate drying (AWMD) was introduced to regulate the processes of leaf senescence. The results indicated that the delayed senescence of the “STAY-GREEN” trait of rice is undesirable for the process of grain filling, and it would cause a lower ratio of grain filling and lower grain weight of inferior grains, because of unused assimilates in the stems and leaves. Through the overexpression of OsNYC3, application of exogenous chemicals of abscisic acid (ABA), and water management of AWMD, leaf photosynthesis was less influenced, a high ratio of carbohydrate assimilates was partitioned to grains other than leaves and stems as labeled by 13C, grain filling was improved, especially for inferior spikelets, and activities of starch-synthesizing enzymes were enhanced. However, application of ethephon not only accelerated leaf senescence, but also caused seed abortion and grain weight reduction. Thus, plant senescence needs to be finely adjusted in order to make a contribution to crop productivity.

Silicon nutrition improves the quality and yield of rice under dry cultivation

“…The photosynthetic capacity and green retention of rice are closely related to the changes of assimilates after anthesis. At the same time, the transfer of carbohydrate nutrients from the vegetative growth part to the grain is also the key to grain filling 41,42 . The present study showed that adding Si enhanced the photosynthetic capacity of rice under dry cultivation and thus increased the material accumulation.…”

“…At the same time, the transfer of carbohydrate nutrients from the vegetative growth part to the grain is also the key to grain filling. 41,42 The present study showed that adding Si enhanced the photosynthetic capacity of rice under dry cultivation and thus increased the material accumulation. From tillering to grouting stage, the aboveground biomass of single plant and single hole was W > DS > D. As reported by Hao et al 43 and Zhang et al 44 , improving source-sink characteristics and coordinating the source-sink relationship are important ways to achieve yield increase.…”