Rapeseed (Brassica napus L.), as one of the most important oil crops around the world, has been affected by drought considerably, particularly at flowering when crops are most sensitive to water stress. It has been shown that film antitranspirant (AT) can effectively reduce the yield loss of droughted crops if applied at the critical stage. However, the mechanism remains unclear by which AT mitigates drought damage to plants under different rates of water depletion. Two experiments in randomised complete block designs were conducted on spring rapeseed with two levels of irrigation, well-watered (WW) and water-stressed (WS), where slow and fast soil water depletion were imposed during the flowering stage in mesocosms (Expt 1_SD) and pots (Expt 2_FD), respectively, and different concentrations of AT, 0, 0.25%, 0.5%, and 1% and 0, 0.5%, and 1%, were applied. Leaf physiological traits, seed yield, and yield components were determined. The results showed that compared to WW, water stress reduced leaf relative water content (RWC) by 2% and 6% in Expt 1_SD and Expt 2_FD, respectively, and had detrimental effects on stomatal conductance, CO₂ assimilation rate, and intrinsic water use efficiency. Following AT application, a positive linear relationship was observed in leaf RWC against AT concentrations, albeit with large variations. In Expt 1_SD, seed dry weight and aboveground biomass increased significantly with increasing AT concentrations, while no yield responses were observed in Expt 2_FD, indicating that soil water status may play an important role in rapeseed responses to AT application regardless of concentrations. Therefore, the timing of AT application needs to consider soil water conditions in addition to the growth development of rapeseed plants.

Strawberries have a short shelf-life leading to food loss and waste when production unexpectedly exceeds demand. PGRs may have potential to delay production and reduce food loss and waste, but no PGRs are available for delaying strawberry production. The aim of this preliminary study was to investigate re-purposing a stomatal blocking film antitranspirant polymer as a PGR to temporarily delay production. Poly-1-p-menthene or water was applied during early fruit ripening in two glasshouse experiments, one on a June-bearer cultivar and one on an everbearer cultivar. Ripe strawberries were harvested during the next 23 days, the cumulative yield was recorded, and the production curves were fitted using polynomial regression in groups. The statistical analysis showed that cubic polynomial regression curves could be fitted separately to each treatment. Application of the blocker delayed the production of both cultivars by 1–2 days during the period of rapid berry production. The delay diminished and cumulative yield returned to the water-treated value by 13 and 18 days after application in the June-bearer and everbearer cultivars, respectively. At 23 days after application, the blocker gave 8% greater cumulative yield in the June-bearer, but not in the everbearer. It was concluded that, if a greater delay could be achieved, there may be potential to use stomatal blockers as PGRs in some cultivars of strawberry to delay production and reduce food loss and waste when unanticipated lower demand occurs.

Flavonoid biosynthesis is negatively correlated with seed oil content in Brassica napus. However, the molecular mechanisms of flavonoid metabolism mediated by MYB repressors in B. napus are still not well understood. In this study, we identify an R2R3-MYB transcription factor, BnaC03.MYB56, which regulates flavonoid metabolism and oil content in B. napus. Overexpression of BnaC03.MYB56 reduced flavonoid metabolite levels and significantly increased seed oil content by 11.0% to11.4% compared to the wild type, whereas the mutant lines exhibited the opposite phenotype. BnaC03.MYB56 directly binds to the TAACGA motif in the promoters of BnaC08.TT6, which catalyzes the synthesis of dihydrokaempferol, and represses its expression. In addition, BnaA09.MYB61 interacts with BnaC03.MYB56 and antagonizes its transcriptional repression of BnaC08.TT6. BnaA09.MYB61 positively regulates flavonoid metabolism and oil content through activating the expression of BnaC08.TT6. Collectively, this study develops an antagonistic BnaC03.MYB56-BnaA09.MYB61 module that fine-tunes flavonoid metabolism to modulate seed oil content, providing a new target for improving oil content in B. napus breeding.