The application of exogenous plant growth regulator can improve plant resistance to drought stress. The effects of application of exogenous cytokinin (CTK), brassinolide (BR), or gibberellic acid (GA) at the silking time on the grain quality of two waxy maize hybrids under drought stress at grain formation stage were studied. Grain weight of both hybrids was unaffected by exogenous phytohormones under control conditions but increased under drought conditions with the application of BR. The grain starch content in response to drought varied with hybrid and phytohormone. Starch granule size and protein content in grains were increased by drought under all conditions, but various phytohormones exerted different forms of influence. The starch λmax in Yunuo7 was unaffected by single or interaction of phytohormones and water deficit, λmax in Jingkenuo2000 with BR was unaffected but with CTK or GA increased by drought. Relative crystallinity was reduced by drought without the application of phytohormone, but with phytohormones in response to drought it was different. Flour peak viscosity was reduced by drought. The value was increased with BR spraying under control and drought conditions. Retrogradation percentage under drought conditions was unaffected by exogenous phytohormones in Jingkenuo2000. In Yunuo7, retrogradation percentage was unaffected by BR but reduced by CTK and GA. In conclusion, spraying phytohormones at the silking stage can affect grain weight and starch quality, grains with a sticky taste can be improved by applying BR, and grains with low retrograde tendency can be produced by applying CTK.

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Background The COVID-19 pandemic has had a significant influence on the sleep health of healthcare workers (HCWs); however, there are no studies on this aspect in primary HCWs. The purpose of this cross-sectional, web-based study was to explore the prevalence and factors associated with sleep disorders among primary care providers during the first COVID-19 outbreak in 2022 in Shanghai. Methods: From July 12 to August 15, 2022, primary HCWs were invited to participate in a survey of their sociodemographic and work-related characteristics, various sleep dimensions (regularity, quality, daytime sleepiness, timing, efficiency, and duration), and exposure to COVID-19 patients and a screening for common mental disorders (depression, burnout, and stress). Results: A total of 313 primary HCWs participated the survey, representing 11 distinct healthcare roles. 84% of respondents showed a deterioration in at least one sleep dimension compared to those at pre-pandemic levels; sleep quality (decline of 66%) and daytime sleepiness (increase of 56%) were the most strongly affected domains. After excluding 145 primary HCWs with pre-pandemic “poor sleep,” positive depression screening (odds ratio [OR], 3.08; 95% confidence interval [CI], 1.59–5.98), weekly burnout symptoms (OR, 2.57; 95% CI, 1.32–5.03), and high psychological stress (OR, 4.51; 95% CI, 2.09–9.72) were associated with poor sleep patterns during the pandemic. After adjusting for significant differences between groups, for every 1-point increase in the perceived stress scale score, there was an associated 12% increased risk of poor sleep (adjusted OR, 1.12; 95% CI, 1.05–1.21; P=0.002). Conclusion: A majority of the primary HCWs showed a significant worsening of sleep quality, with an increase in daytime sleepiness, during the first wave of the COVID‑19 pandemic in 2022 in Shanghai. HCWs with high stress were at a greater risk of sleep disorders.