Effects of Exogenous α-Naphthaleneacetic Acid and 24-Epibrassinolide on Fruit Size and Assimilate Metabolism-Related Sugars and Enzyme Activities in Giant Pumpkin

Abstract

Size is the most important quality attribute of giant pumpkin fruit. Different concentrations and application frequencies of α-naphthaleneacetic acid (NAA) and 24-epibrassinolide (EBR) were sprayed on the leaves and fruits of giant pumpkin at different growth stages to determine their effects and the mechanism responsible for fruit size increase. NAA+EBR application improved source strength, and further analysis indicated that NAA+EBR markedly boosted net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and the expression level and activity of galactitol synthetase (GolS), raffinose synthetase (RS), and stachyose synthetase (STS), resulting in an increase in the synthesis of photoassimilate, especially stachyose. Concomitantly, NAA+EBR spray increased stachyose and sucrose contents throughout pumpkin fruit growth and the concentrations of glucose and fructose at 0 and 20 days post-anthesis (DPA) in peduncle phloem sap, implying that such treatment improved the efficiency of assimilate transport from the peduncle to the fruit. Furthermore, it improved the expression and activity of alkaline α-galactosidase (AGA), facilitating assimilate unloading, providing carbon skeletons and energy for fruit growth, and increasing fruit weight by more than 44.1%. Therefore, exogenous NAA and EBR increased source capacity, transportation efficiency, and sink strength, overall promoting the synthesis and distribution of photoassimilate, ultimately increasing fruit size.

EBR and JA regulate aroma substance biosynthesis in ‘Ruidu Hongyu’ grapevine berries by transcriptome and metabolite combined analysis

“…These further authenticated that the increase of terpenes and aldehydes contents might be regulated by exogenous EBR and JA signals. The outcomes were more consistent with previous findings that the exogenous EBR and JA were involved in regulating the biosynthesis of several metabolites, including monosaccharides, anthocyanins, fatty acids, amino acids, and so on, with significantly higher levels than the CK group ( Mao et al., 2017 ; Vergara et al., 2018 ; Nakajima et al., 2021 ; Chen et al., 2022 ; Li et al., 2022 ; Lv et al., 2022a ). Results of this study provided reference information for verifying the interaction of EBR and JA in regulating aroma substances biosynthesis.…”

Synergistic effects of gamma-aminobutyric acid and melatonin on seed germination and cadmium tolerance in tomato

“…GABA reduced Cr uptake and upregulated nonenzymatic antioxidants and the activities of enzymatic antioxidants and finally reduced oxidative damage 46 . However, high concentrations of plant growth regulators can induce stress in plants, which adversely affects plant growth 47 . Treatment with 200 µM MT had higher MDA content and lower POD and CAT activities than those of 150 µM.…”

LC–MS and GC–MS Metabolomics Analyses Revealed That Different Exogenous Substances Improved the Quality of Blueberry Fruits under Soil Cadmium Toxicity

“…Meanwhile, exogenous Spd promoted fruit coloration and synergized with ABA, IAA, and ethylene pathways to promote fruit ripening, which is consistent with our findings. In addition, ESs can promote cell division and elongation and play a positive role in fruit expansion. − In our study, exogenous SA, Spd, EBR, and MT treatments also significantly increased the single-fruit weight of blueberry fruits under Cd toxicity compared with CK ( p < 0.05) (Figure A).…”