枯水椪柑果肉挥发性物质及萜烯类合成途径基因表达特征

运用GC-MS和RNA-Seq技术研究椪柑果实在发生枯水时,果肉挥发性物质组分及含量和萜烯类化合物合成途径相关基因表达的变化特征。研究结果发现:(1)椪柑果肉挥发性组分共13种,其中萜烯类物质7种,相对含量超过85%;(2)椪柑枯水时,果肉挥发性物质含量降为正常果实的32%,其中萜烯类物质下降为正常果实的22%,另外挥发性物质的组分种类不变,有5种挥发性物质的含量发生显著改变,分别是β-月桂烯、d-柠檬烯、γ-松油烯、瓦伦西亚烯和十二醛;(3)鉴定到8个萜烯类化合物合成途径的差异表达基因,在枯水时全部下调。研究表明椪柑枯水时果肉挥发性物质的含量显著下调,与萜烯类合成途径相关基因表达降低密切相关,为进一步深入研究椪柑枯水发生的分子机制提供依据。

Effects of methionine treatment on storage quality and antioxidant activity of postharvest jujube fruit

Jujube fruits usually suffer from physiological disorders or infectious diseases during storage,leading to quality deterioration,softening,or rotting.Therefore,this study aims to investigate the effect of methionine soaking treatment on the postharvest jujube fruit decay rate and storage quality.Methionine treatment significantly reduced the decay rate of postharvest jujube fruit and effectively maintained fruit color and titratable acid.Methionine treatment effectively delayed the decrease of firmness,soluble solids,ascorbic acid,and lignin contents in jujube fruit.Methionine treatment reduced the content of alanine and phenylalanine,and increased the content of glycine in jujube fruit,but displayed no significant effect on total amino acid content.In addition,jujube fruits in the methionine treatment group had a higher total phenolic and flavonoid content and antioxidant capacity,both in free and bound forms.Compared with the control,methionine treatment also significantly increased the content of individual phenolic acid fractions(gallic acid,vanillic acid,and syringic acid)and flavonoid fractions(catechin,epicatechin,rutin)in free form as well as individual phenolic acid fractions in bound form(gallic acid and ferulic acid)in jujube fruits.Overall,this study suggested that the methionine treatment could be used as a prospective preservative to reduce the postharvest decay of jujube fruit and alleviate its nutritional quality deterioration during cold storage at 4°C.

丹池地区泥盆纪地层序列在右江裂陷盆地的延伸

独具特色的丹池序列是深水海槽——丹池带中沉积的一套具有特殊岩性的泥盆纪地层,以往的认识是丹池带所特有的产物。通过近年来的区域地质矿产调查,在广西长里背斜核部也发现该套地层的完整序列,突破了以往的地质认识,结合右江盆地西部正在开展的区域地质调查,也同样发现在右江西部有该套地层序列出露,从而说明丹池地区泥盆纪深水地层序列并不仅限于丹池带,而在整个右江裂陷盆地中深水海槽区均有沉积。这一认识,对右江盆地的岩相古地理及演化历史的研究具有重要的地质意义。