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Trehalose is a disaccharide and is often foliar applied by farmers aiming at increasing stress resistance or crop production. However, the physiological effect of exogenously applied trehalose on crops remains obscure. Here, we explored the effect of foliar trehalose application on style length of solanaceous crops, Solanum melongenaand S. lycopersicum. Trehalose application promotes pistil to stamen ratio by gaining style length. Another disaccharide consisting of two glucose molecules, maltose, showed the same effect on style length of S. lycopersicum, while monosaccharide glucose did not. Trehalose is found to affect style length through uptake via roots or interaction with rhizosphere but not through absorption by shoots in S. lycopersicum. Our study suggests that yield improvement of solanaceous crops by trehalose application under stressed conditions is brought about by suppression of the occurrence of short-styled flowers. This study suggests that trehalose holds potential to act as a plant biostimulant in preventing short-styled flowers in solanaceous crops.

Grain color of wheat is one of the important quality parameters that affect the flour color and its product such as bread and noodles. R‐1gene, a regulator of grain color, is located on chromosomes 3A, 3B, and 3D, and at least one dominant allele is responsible for the red color of the grain. It has been thought that the number of dominant R‐1allele relates to the deepness of the red color of grain; however, methods to quantify grain pigments have not been established yet. The aim of this work was to establish a method for quantifying pigments using 4‐dimethylaminocinnamaldehyde (DMACA), which reacts with precursors of which constitute major pigments of wheat grain. Wheat proanthocyanidins were detectable in immature seeds by the DMACA method but became undetectable as the grains matured. Comparison between lines with the same flowering time and genetic background revealed that the amount of pigment was determined by the number of dominant R‐1alleles. We established the DMACA method for quantifying wheat seed pigments and used that to clarify the relationship between the number of R‐1alleles and pigment content. Since the method developed in this study is not affected by other pigments such as chlorophyll, it can be universally applied to other plants and tissues in addition to wheat grains.

In flowering plants, different lineages have independently transitioned from the ancestral hermaphroditic state into and out of various sexual systems1. Polyploidizations are often associated with this plasticity in sexual systems2,3. Persimmons (the genus Diospyros) have evolved dioecy via lineage-specific palaeoploidizations. More recently, hexaploid D. kakihas established monoecy and also exhibits reversions from male to hermaphrodite flowers in response to natural environmental signals (natural hermaphroditism, NH), or to artificial cytokinin treatment (artificial hermaphroditism, AH). We sought to identify the molecular pathways underlying these polyploid-specific reversions to hermaphroditism. Co-expression network analyses identified regulatory pathways specific to NH or AH transitions. Surprisingly, the two pathways appeared to be antagonistic, with abscisic acid and cytokinin signalling for NH and AH, respectively. Among the genes common to both pathways leading to hermaphroditic flowers, we identified a small-Myb RADIALIS-like gene, named DkRAD, which is specifically activated in hexaploid D. kaki. Consistently, ectopic overexpression of DkRADin two model plants resulted in hypergrowth of the gynoecium. These results suggest that production of hermaphrodite flowers via polyploidization depends on DkRADactivation, which is not associated with a loss-of-function within the existing sex determination pathway, but rather represents a new path to (or reinvention of) hermaphroditism.

The sensitivity of the embryo to abscisic acid (ABA) has been reported to play an important role in seed dormancy. Using ditelocentric lines of wheat cv. Chinese Spring (CS, nondormant and ABA insensitive), F$\_2$ seeds between monosomic lines of CS and a wheat line Kitakei-1354 (dormant, ABA sensitive) and deletion lines of CS chromosome 4A, germinability of seeds and embryo-half seeds incubated in water and ABA were examined. The results indicated that the long arm of chromosome 4A carried major gene(s) for the embryo sensitivity to ABA and dormancy. Chromosome 2D might be also involved in the sensitivity to ABA.

Seed dormancy develops latein embryogenesis after a period of potential prematuregermination and has been associated with levels ofabscisic acid (ABA) in, and sensitivity to, ABA ofembryos. In wheat (Triticum aestivumL.)embryos, there are two peaks in levels of ABA duringdevelopment: the first occurs 25 days afterpollination (DAP) and the second from 35 to 40 DAP. The first peak of ABA appears to be associated withthe development of the embryo's sensitivity to ABAsince such sensitivity was altered in seeds on earsthat were incubated in a solution of ABA from 15 and20 DAP. In the embryos of Kitakei wheat, a line thatexhibits dormancy, the second peak, at around 35 DAP,was more prolonged in comparison to Chihoku, anon-dormant line. The results support the proposedinvolvement of ABA in the formation and maintenance ofseed dormancy during middle and late embryogenesis. When developing embryos were incubated in water,embryonic ABA leaked out from the embryos, inparticular between 30 and 40 DAP. Prematuregermination observed between 30 and 40 DAP might berelated to such leakage of ABA from embryos.