苹果成熟期间RNA代谢的变化

CHANCES OF RNA METABOLISM DURING APPLE FRUIT RIPENING

苹果在呼吸跃变期总RNA、总poly(A)^+RNA、多聚核糖体RNA和多聚核糖体poly(A)^+RNA含量都显著增加;跃变期后,总RNA和poly(A)^+RNA迅速下降到跃变期前的水平,但多聚核糖体RNA仍维持较高含量。RNA酶活性仅在跃变期后有明显升高。测定poly(A)^+RNA体外翻译活性的结果表明,苹果进入成熟期时mRNA翻译合成蛋白质的能力增加。这些结果初步说明,苹果呼吸跃变期间可能有新的转录子形成,从而指导其成熟变化。

There were abrupt rises in both carbon dioxide and ethylene production during postharvest ripening period of apple fruit (Malus sylvestris Mill cv. White winter pearmain). RNAs were extracted from ripening apple fruits by SDS-phenol method and poly(A)RNA was isolated and purified by two cycles of oligo(dT)-cellulose chromatography. The results showed that the contents of total RNA, total poly(A)-RNA, polysomal RNA, and polysomal poly(A)RNA all increased significantly at climacteric stage, and then declined to the level of preclimacteric stage except polysomal RNA. RNase activity was constant throughout ripening untill postclimacteric when observing a 27% rise. Poly(A)RNA. and polysomal poly(A)RNA from apple fruit at various stages stimulated the incorporation of H-leucine into protein in wheat germ In Vitro translation system, and indicated that the poly(A)-RNAs from climacteric apple fruit has more capacity of synthating protein than that from preclimacteric apple fruit. The ripening of apple fruit may be controllel by the new transcripts formed at climacteric period.