查看更多>>摘要：It is well-known that abscisic acid (ABA) inhibits seed germination, but the mechanism is still unclear. In this study, after removing the seed coats, the seeds treated with 1 ppm ABA to inhibit embryo germination. A total of 715 compounds that were involved in 271 metabolic pathways were identified from a broadly targeted metabolome. Of these compounds, the number of flavonoids is most and accounting for 21%. Moreover, compared to the control embryos, over 80% of the differentially accumulated compounds (DACs) were downregulated in the ABA-treated embryos, while only 46 compounds were up-regulated. These differentially accumulated compounds were involved in 26 metabolic pathways. Transcriptome analysis showed that 6348 genes were differentially expressed between ABA-treated and control embryos. These differentially expressed genes (DEGs) were enriched into 28 metabolic pathways including photosynthesis. Interestingly, both DEG and DAC analyses had identified the 10 common metabolic pathways, including oxidative phosphorylation, phenylpropanoid biosynthesis, flavonoid biosynthesis, pyrimidine metabolism, ascorbate and aldarate metabolism, galactose metabolism, glycolysis/gluconeogenesis, carbon metabolism, amino sugar and nucleotide sugar metabolism, and valine, leucine and isoleucine degradation. Taken together, ABA represses the expression of the genes involved in photosynthesis and those 10 metabolic pathways to suppress the secondary metabolism of the embryos, resulting in the inhibition of embryo germination.
查看更多>>摘要：Sweet cherries are susceptible to mechanical damages, resulting in difficulties in the process of the storage as well as transportation. In this study, drop the sweet cherry fruits at the height of 50 cm in the hypothetical situation, causing some possible mechanical damages, then soak the damaged sweet cherries in 0.15 mM methyl jasmonate (MeJA) and 0.5 mM salicylic acid (SA) for 10 min, respectively. The results showed that MeJA and SA treatment effectively ameliorated the mechanical injury of sweet cherries, as well as inhibited the increase of weight loss, the decrease of firmness and the accumulation of active oxygen species. Meanwhile, the increase of membrane lipid degradation-related enzyme activity was also inhibited. What's more, MeJA and SA maintained high levels of antioxidant contents, antioxidant enzyme activity, and higher capability of phenylpropanoid metabolism. Thus, MeJA and SA have the potential ability to maintain the quality of sweet cherries and reduce the loss caused by mechanical damages after the postharvest.
查看更多>>摘要：Periods of high nighttime temperature may induce carbohydrate (CH) shortage by increased dark respiration. Metamitron is a thinning agent that inhibits photosynthesis and enhances fruit abscission due to a reduction in CH production. To clarify how both interact in apple tree physiologic mechanisms and on fruit abscission, five field trials were carried out in Lleida, Girona and Sint-Truiden (2017 + 2018), using orchards of 'Golden' apple trees. At the stage of 12-14 mm fruit diameter, four treatments were established: (A) CTR - control, trees under natural environmental conditions; (B) HNT - high nighttime temperature, trees exposed to artificially increased nighttime temperature during 5 nights after the day of spraying, without metamitron application; (C) MET 247.5 ppm of metamitron application and (D) MET + HNT trees submitted to the combined exposure to metamitron application (MET) and to artificially increased nighttime temperature (HNT). HNT did not affect metamitron absorption, net photosynthesis (Pn) and stomatal conductance however, promoted significant reductions in leaf CH content mainly before sunrise, especially in sucrose (18-45%) and in sorbitol (19-26%). Metamitron significantly reduced Pn to about 50% of CTR, which resulted in decreases in leaf sucrose and sorbitol, reaching minimum values 5 days after spraying, between 21 and 57% and 19-26%, respectively. Fruit growth rate of both treatments was retarded by 30%, 2 days after either metamitron application or HNT. Both treatments originated a similar reduction in the number of fruits and size improvement. The combined exposure (MET+HNT) promoted similar Pn reductions as MET, but showed the greatest sucrose (44-60%) and sorbitol (73-84%) decreases which resulted in the strongest thinning efficacy. Lipid peroxidation was not affected by the treatments however, antioxidant enzyme activity showed moderate changes with activity increases mainly under MET and MET + HNT, accompanied by a rise in glutathione content and reduction in ascorbate. This work shows that the overlap of photosynthesis inhibition (reducing CH production) by means of metamitron spraying, and likely greater respiration (increased CH consumption), by HNT imposition, translates less CH production than the growing fruits demand (negative CH balance) leading to a metamitron thinning effect enhancement. Periods of high nighttime temperature must be considered when deciding the best metamitron rate to achieve an optimal crop load result.
Kumarihami, H. M. Prathibhani C.Kim, Yun-HeeKwack, Yong-BumKim, Joonyup...
8页
查看更多>>摘要：Chitosan, a natural polysaccharide derived from the deacetylation of chitin, has a great potential for a wide range of applications. As an edible coating material chitosan, has been reported to be highly effective in extending the postharvest life of many crops while reducing moisture loss, respiration, ethylene production, ripening, softening, controlling the decay, and maintaining fruit quality, along with storability. This review discussed the applications of chitosan and its potential effects on the postharvest life and quality attributes of kiwifruit. The application of chitosan, the possible mechanisms of action, and its perspectives as a coating material for kiwifruit are discussed.
NSTL
Elsevier