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Changes in metabolism of nucleic acids during senescence of mung bean cotyledons

Wen Jiangqi, Liang Houguo

Lab. Plant Physiol., Lanzhou Univ.

Abstract

The contents of both DNA and RNA decreased during the senescence of mung bean cotyledons (Fig. 1). Electrophoresis analysis indicated that the decline of nuclear DNA and 18 S rRNA was responsible for the decrease of DNA and RNA levels, respectively (Fig. 2,3). During incipient senescence (2 to 3 days), the contents of poly(A) super(+)-mRNA increased markedly (Fig. 5). The synthetic rates of nucleic acids were tested by super(3)H-nucleoside incorporation. It was shown that in the early stage of senescence (3 to 4 days), the synthesis of nucleic acids increased obviously, expecially RNA (Fig. 7). This gave an implication that the early decline of total nucleic acid levels was not due to the failure of synthesis. The results from the determination of DNase and RNase activities showed that the enhancedhydrolysis of nucleic acids was the main cause of the decline of total nucleic acid levels.

Key words: Mung bean;Cotyledons;Senescenc;Nucleic acid metabolism

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Citing This Article：

Wen Jiangqi, Liang Houguo. Changes in metabolism of nucleic acids during senescence of mung bean cotyledons. Acta Physiol Sin 1991; 43 (2): (in Chinese with English abstract).