Aspectos fisiológicos da restrição da radiação solar em arroz - uma revisão

Light is an important factor that influences plant development because it interferes with several metabolic, morphological, anatomical and physiological processes. When not supplied in adequate quantity and quality, light can have implications for the productivity of agricultural crops. The deficit of solar radiation during plant development, which usually occurs in the rainy season due to cloudiness and geographic characteristics of the region, can cause stress and limit production. This review aims to present the effects of solar radiation restriction on the physiology of irrigated rice. This understanding is of utmost importance to aid future research in clarifying the relationship between light intensity and productivity. This will help in the choice of management practices and in the development of breeding strategies and indirect selection of cultivars to increase productivity and grain quality of rice in regions that present a deficit of solar radiation during the crop cycle. This review was based on bibliographic research carried out in national and international databases, from which scientific articles published in the last five decades that met the established inclusion criteria were selected. In rice, the deficit of solar radiation is the main cause of low productivity and reduction in grain quality. The processes most negatively affected are photosynthesis, root dry matter production and the distribution of photoassimilates to the spikelets. The severity of stress due to low light depends on the development stage, intensity, genotype and interaction with other environmental factors. Additional studies, which relate both the quantity and quality of light, are necessary to select tolerant cultivars and optimize management in regions with light restriction, ensuring less impact on yield.