Carbohydrate availability affects growth and metabolism in peach fruit

Abstract

Along with sucrose, sorbitol represents the main photosynthetic product and form of translocated carbon in peach. This study aimed at determining whether peach fruit carbohydrate metabolism is affected by changes in source-sink balance, and specifically whether sorbitol or sucrose availability regulates fruit enzyme activities and growth. In various trials, different levels of assimilate availability to growing fruits were induced in vivo by varying crop load of entire trees, leaf : fruit ratio (L:F) of fruiting shoots, or by interrupting the phloem stream (girdling) to individual fruits. In vitro, fruit tissue was incubated in presence/absence of sorbitol and sucrose. Relative growth rate (RGR), enzyme activities and carbohydrates were measured at different fruit growth stages of various peach cultivars in different years. At stage III, high crop load induced higher acid invertase (AI, EC 3.2.1.26) activities and hexose : sucrose ratios. Both sorbitol and sucrose contents were proportional to L:F, while sorbitol dehydrogenase (SDH, EC 1.1.1.14) activity was the only enzyme activity directly related to L:F in both fruit growth stages. Girdling reduced fruit RGR and all major carbohydrates after 4 days and SDH activity already after 48 h, but it did not affect sucrose synthase (SS, EC 2.4.1.13), AI and neutral invertase (NI, EC 3.2.1.27). Fruit incubation in sorbitol for 24 h induced higher SDH activities than in buffer alone. In general, assimilate availability affected both sorbitol and sucrose metabolism in peach fruit, and sorbitol may function as a signal for modulating SDH activity. Under highly competitive conditions, AI activity may be enhanced by assimilate depletion, providing a mechanism to increase fruit sink strength by increasing hexose concentrations.

Metabolic variation between japonica and indica rice cultivars as revealed by non-targeted metabolomics

“…In addition, four seed metabolites (stachydrine, mannitol, arabinol, and arabitol) negatively correlate with filled seed number per panicle (FSNPP) but two metabolites (1-MGPC and 1-OGPC) positively correlate with ESNPP, revealing the competition for nutrition among the seeds in the same plant. The similar competitive phenomenon was observed in other species including badamu46, apple47, citrus48, papaya49, and tomato50. Furthermore, two seed metabolites (GPC and mannitol) negatively correlate with plant height.…”

Agronomical Parameters, Sugar Profile and Antioxidant Compounds of “Catherine” Peach Cultivar Influenced by Different Plum Rootstocks

“…Yield was positively correlated with TCSA, yield efficiency, fruit weight and anthocyanins, but negatively correlated with SSC, sucrose, flavonoids, vitamin C and RAC. Negative correlations between yield and some fruit components, such as SSC or sucrose, can be due to the sink competition of more fruits in development compared to fruit quality [29]. Fruit weight was significantly and positively correlated with SSC, sucrose, glucose, total sugars, phenolics and flavonoids as also reported by Cantín et al [30] in different peach and nectarine progenies.…”

The Influence of Fruit Load on the Tomato Pericarp Metabolome in aSolanum chmielewskiiIntrogression Line Population

“…Given that fruit thinning is known to reduce the competition for carbohydrate source, and thus promote fruit size and sugar content in several species including peach (Prunus persica; Morandi et al, 2008), apple (Malus domestica; Link, 2000), mandarin orange (Citrus reticulata; Kubo et al, 2001), papaya (Carica papaya; Zhou et al, 2000), and tomato (Heuvelink, 1997;Prudent et al, 2009), we next directly compared the levels of each metabolite between HL and LL cultivation. Many significant changes could be observed in this comparison (see the heat map in Fig.…”