Morphological and physiological characteristics of abnormal berry development in Vitis amurensis

Heterogeneity among grape berries directly affects wine quality and restricts the wine-grape industry’s development. To study the heterogeneous development of Vitis amurensis berries, the morphology and physiology of three different types—large berry, medium berry, and live green ovary (LGO)—in the same clusters of wine-making cultivar ‘Shuangfeng’ were monitored at different growth stages from June to September. External differences in berry development were distinguishable at 12 days after full bloom (DAF). The pedicel, berry size, fresh weight, and seed length of the medium berries were intermediate between those of large berries and LGOs. Seeds are crucial for fruit set and normal berry development. The activity levels of soluble acid invertase and cell-wall-bound acid invertase in large berries increased earlier, at 18 DAF, than the accumulation of sugar. Abscisic acid concentrations in medium berries and LGOs were greater than that in large berries at 18 DAF. The greater endogenous indole-3-acetic acid concentration in the medium berries compared with LGOs might protect the former from abscission.

Overexpression of Sucrose Phosphate Synthase Enhanced Sucrose Content and Biomass Production in Transgenic Sugarcane

Sucrose phosphate synthase (SPS) is a key enzyme in sucrose synthesis, which controls sucrose content in plants. This study was designed to examine the efficacy of the overexpression of SoSPS1 gene on sucrose accumulation and carbon partitioning in transgenic sugarcane. The overexpression of SoSPS1 gene increased SPS activity and sucrose content in transgenic sugarcane leaves. More importantly, the overexpression enhanced soluble acid invertase (SAI) activity concomitant with the increase of glucose and fructose levels in the leaves, whereas sucrose synthase activity exhibited almost no change. In the stalk, a similar correlation was observed, but a higher correlation was noted between SPS activity and sugar content. These results suggest that SPS overexpression has both direct and indirect effects on sugar concentration and SAI activity in sugarcane. In addition, SPS overexpression resulted in a significant increase in plant height and stalk number in some transgenic lines compared to those in non-transgenic control. Taken together, these results strongly suggest that enhancing SPS activity is a useful strategy for improving sugarcane yield.

Lignin Accumulation in Three Pumelo Cultivars in Association with Sucrose and Energy Depletion

Lignification, which occurs in many horticultural fruit and vegetables, brings about undesirable texture and unfavorable consumer preference. However, this problem has rarely been studied. In this work, three pumelo cultivars cvs “Hongroumiyou” (HR), “Bairoumiyou” (BR), and “Huangroumiyou” (HuR) were stored at 25 °C for 90 days, and juice sacs were sampled to explore the lignin accumulation and its relationship to sucrose and energy depletion were investigated. The results displayed that HuR contained lower sucrose content, lower ATP level, but higher lignin content compared to BR and HR during postharvest storage, indicating that the sequence according to storage resistance on the basis of lignin content is as follows: HuR < BR < HR. Furthermore, sucrose degradation attributed to enhanced activities of neutral invertase (NI), soluble acid invertase (S-AI), cell wall-bound invertase (B-AI), and energy deficit on account of declined ATP level, showed significantly negative correlation with lignin accumulation, suggesting that lignin accumulation occurrence could induce sucrose degradation and energy deficit during postharvest storage. Additionally, higher activities of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD) could accelerate lignin synthesis and resulted in lignin accumulation during postharvest pumelo storage.