Nutrient Supply Is Essential for Shifting Tree Peony Reflowering Ahead in Autumn and Sugar Signaling Is Involved

Abstract

The flowering time of tree peony is short and concentrated in spring, which limits the development of its industry. We previously achieved tree peony reflowering in autumn. Here, we further shifted its reflowering time ahead through proper gibberellin (GA) treatment plus nutrient supply. GA treatment alone initiated bud differentiation, but it aborted later, whereas GA plus nutrient (G + N) treatment completed the opening process 38 days before the control group. Through microstructural observation of bud differentiation and starch grains, we concluded that GA plays a triggering role in flowering induction, whereas the nutriment supply ensured the continuous developing for final opening, and both are necessary. We further determined the expression of five floral induction pathway genes and found that PsSOC1 and PsLFY probably played key integral roles in flowering induction and nutrient supply, respectively. Considering the GA signaling, PsGA2ox may be mainly involved in GA regulation, whereas PsGAI may regulate further flower formation after nutrient application. Furthermore, G + N treatment, but not GA alone, inhibited the expression of PsTPS1, a key restricting enzyme in sugar signaling, at the early stage, indicating that sugar signaling is also involved in this process; in addition, GA treatment induced high expression of PsSnRK1, a major nutrient insufficiency indicator, and the induction of PsHXK1, a rate-limiting enzyme for synthesis of sugar signaling substances, further confirmed the nutrient shortage. In short, besides GA application, exogenous nutrient supply is essential to shift tree peony reflowering ahead in autumn under current forcing culture technologies.

Integrated transcriptome, metabolome and phytohormone analysis reveals developmental differences between the first and secondary flowering in Castanea mollissima

“…Some plants, such as pear trees ( Wei et al., 2022 ) and magnolias ( Xuan et al., 2022 ), exhibit an anomaly in flowering twice a year under certain conditions. For ornamental plants, the second flowering is due to its extended flowering period and popularity ( Iwata et al., 2012 ; Xuan et al., 2022 ; Xue et al., 2022 ); however, for perennial fruit trees, the second flowering and fruiting consume large amounts of nutrients, weakening the tree. The cold resistance of plants during winter is weakened, resulting in a reduced number of flowers and fruit production in the following year ( Qiu et al., 2019 ).…”