【摘要】 为了阐明UV-B辐射对水稻籽粒中原花青素含量和分布的影响,通过大田原位种植元阳梯田传统水稻品种——白脚老粳,在水稻的生长期进行不同强度UV-B辐射处理(0、2.5、5.0、7.5 kJ·m^-2·d^-1),研究不同强度UV-B辐射对水稻籽粒形态与原花青素含量分布的影响。结果表明:UV-B辐射会抑制水稻籽粒的粒长、粒宽、千粒质量、每株籽粒生物量和产量。粒长和粒宽受到了UV-B辐射的抑制,7.5 kJ·m^-2·d^-1时显著下降了11.6%和5%,千粒质量和籽粒生物量会随着UV-B辐射的增强显著降低,7.5 kJ·m^-2·d^-1时达到最低17.41 g与20.84 g·株^-1。产量在高强度UV-B辐射(7.5 kJ·m^-2·d^-1)下显著降低,稻壳中原花青素含量在不同UV-B辐射下呈现单峰曲线,在5.0 kJ·m^-2·d^-1时达到最大值4.06μg·g^-1·d^-1。糙米中原花青素含量在低强度UV-B辐射下无显著变化,当UV-B辐射达到7.5 kJ·m^-2·d^-1时显著降低。原花青素在水稻籽粒中呈现由外到内逐渐减少的规律,原花青素主要聚集在果皮和胚乳表层,不同UV-B辐射强度下,原花青素面积占比有显著差异,在垂直结构上（平行于芒和小穗轴连线）,UV-B辐射增强会抑制原花青素面积占比,在水平结构上（垂直于芒和小穗轴连线）,UV-B辐射增强会促进原花青素面积占比。UV-B辐射增强会改变籽粒结构,促进稻壳中原花青素合成,过高的UV-B辐射强度会抑制稻壳和糙米中原花青素合成。UV-B辐射会影响原花青素的分布,UV-B辐射增强原花青素水平结构上的面积占比显著高于垂直结构。更多还原

【Abstract】 In order to elucidate the effect of UV-B radiation on the content and distribution of proanthocyanidins in rice grains, Baijiaolaojing, a traditional rice variety in Yuanyang Terraces, was planted in a rice paddy field in situ, under different intensities of UV-B radiation treatments(0 kJ·m^-2·d^-1, 2.5 kJ·m^-2·d^-1, 5.0 kJ·m^-2·d^-1, and 7.5 kJ·m^-2·d^-1)during the rice growing period. The effect of UV-B radiation on grain morphology, content, and distribution of proanthocyanidin in rice were investigated. Results showed that the grain length, width,1000-grain weight, biomass, and yield of rice grains per plant were inhibited under UV-B radiation. The grain length and width, as inhibited by UV-B radiation, decreased significantly by 11.6% and 5%, respectively, with a UV-B radiation intensity of 7.5 kJ·m^-2·d^-1. The1000-grain weight and grain biomass decreased significantly with the enhanced UV-B radiation, reaching their minimum of 17.41 g and20.84 g, respectively, with the same UV-B radiation intensity. The yield also decreased significantly at the same UV-B radiation intensity.The proanthocyanidin content in rice husk showed a single-peak curve under different UV-B radiation treatments, reaching a maximum of4.06 μg·g^-1·d^-1 at the intensity of 5.0 kJ·m^-2·d^-1. The proanthocyanidin content in brown rice did not change significantly under the same UV-B radiation intensity, but decreased significantly when the intensity was 7.5 kJ·m^-2·d^-1. Proanthocyanidin content in rice grains decreased from the outside to inside. Proanthocyanidins were mainly concentrated on the surface of pericarp and endosperm. In the vertical structure（parallel to the line connecting awn and spikelet axes）, the area proportion of proanthocyanidins was inhibited under enhanced UV-B radiation. In the horizontal structure（perpendicular to the line connecting awn and spikelet axes）, the area proportion of proanthocyanidins was promoted under UV-B radiation. In summary, the results indicate that the enhanced UV-B radiation can change the grain structure and promote the synthesis of proanthocyanidins in rice husk. The synthesis of proanthocyanidins in rice husk and brown rice is inhibited under a UV-B radiation intensity of 7.5 kJ·m^-2·d^-1. UV-B radiation can affect the distribution of proanthocyanidins; the area proportion of proanthocyanidins of the horizontal structure enhanced by the UV-B radiation is significantly higher than that of the vertical structure in rice grains.更多还原