Dietary selenium supplementation is the main way for people to take in selenium. Selenium bioaugmentation technology can effectively improve the selenium content of crops. In this study, the material was common buckwheat variety Xinong 9976, and sodium selenite was used as the selenium source. The application rates of pure selenium in the field were 0 (Se0), 5 (Se5), and 20 g hm-2 (Se20), respectively. The changes of photosynthetic characteristics, dry matter accumulation and transport, agronomic traits, and yield of common buckwheat were explored during two consecutive crop growing seasons from 2020 to 2021, and the effects of selenium content in organs, selenium transport factors and selenium utilization rate in grains of common buckwheat under different exogenous selenium concentrations were analyzed. The results showed that foliar spraying sodium selenite could improve the photosynthetic substance production capacity of common buckwheat leaves, and the chlorophyll content (SPAD), net photosynthetic rate (Pn), transpiration rate (Tr), intercellular CO2 concentration (Ci), and water use efficiency (WUE) of leaves increased by 13.12%, 11.50%, 5.48%, 5.95%, and 5.77% on average compared with the control. Selenium spraying significantly increased the maximum photochemical efficiency (Fv/Fm), actual photochemical efficiency (ΦPSII), and photochemical quenching coefficient (qp) of buckwheat leaf photosystem II, decreased the non-photochemical quenching coefficient (NPQ), enhanced the ability of capturing and transforming light energy, reduced the loss of ineffective light energy, and improved the utilization ability of high light. Under two different selenium application rates, the dry matter accumulation of stem and leaf of Fagopyrum esculentum was significantly higher than that of Se0 treatment, but the distribution ratio was significantly lower. The dry matter accumulation and dry matter distribution ratio of grain were improved. The dry matter transport capacity, migration rate, and contribution rate of stem and leaf to grain reached the maximum at Se5 and Se20 concentrations, respectively. Selenium spraying increased the number of 1000-grain weight, grain number per plant, and yield by 3.1%-11.3%, 13.5%-32.0%, and 4.9%-23.2% compared with the control, respectively. The selenium content and transport factors in different parts of common buckwheat reached the maximum under Se20, while the utilization rate of selenium in grain was higher under Se5. In conclusion, foliar spraying of sodium selenite can improve photosynthesis and chlorophyll fluorescence parameters of common buckwheat, increase the accumulation of dry matter in various organs, and promote the transport of dry matter to grains, thus increasing the grain yield of common buckwheat. In addition, the selenium content in all parts of common buckwheat was significantly increased after foliar spraying with selenium, and the selenium utilization rate of grain was the highest under Se5 treatment, and the selenium content of grain met the national grain selenium-enriched standard, which was suitable for popularization and application in Loess Plateau area.
WeChat
WeChat