萌发花生胚轴中蛋白质、RNA和DNA合成及PEG渗调和多胺对其影响

不同活力花生种子的蛋白质、RNA和DNA合成能力不同。用PEG渗调或多胺预处理,可提高劣变花生种子的活力和胚轴大分子合成能力。劣变种子在萌发初期(20小时内),~3H—dT渗入量反比高活力种子增高,表明存在非按期DNA合成,这一增多部份可为咖啡碱所抑制,其剩余部分与高活力种子相似。应用PEG渗调或多胺预处理可使非按期DNA合成部分减弱,而萌发后期的复制部分加强。

EFFECTS OF OSMOCONDITIONING ( OC ) WITH PEG AND POLYAMINES PRETREATMENT ON MACROMOLSCULAR SYNTHESIS AND DNA REPAIR IN EMBRYONIC AXES OF GERMINATING PEANUT SEEDS

The synthetic capacities of protein,RNA and DNA are the physiological and biochemical basis of seed vigour.Using OC with PEG or pretreated with polyamines the DNA repair can improve and the synthesis of protein, nucleic acid of ageing seeds increase.The experimental material was cul tivar "Yue-You 116" , a spanish-type of peanut ( Arachis hypogaae L. ) . The germination percentage of high-vigour seeds was 99%, and that of medium-vigour seeds was 78%.Seed were conditioned ( OC ) by 20% PEG solution or pretrested by 0.05mM spermidine, or 0.1mM putrescine (and control by water) .The isotope labelled experiments were performed to analyze the synthesis of macromolecules by using3H-leucine as precursor of protein, 3H-Urd as precursor of RNA and3H-dT as precursor of DNA. Besides, the total amount of DNA was assayed by biochemical method. The synthetic capacities of protein, RNA,and DNA in highvigour seeds were higher than that in medium-vigour seeds. Seeds treated with PEG or polyamines will have higher capacities on synthesis of protein, RNA and DNA than that in the contorl ( CK ) .The incorporation of3H-dT into DNA Was higher in mediun-vigour Seeds during the sarly germination. It is suggested that the increase of incorporation demonstrated the unscheduled DNA synthesis in this seeds.By using caffeine the unscheduled DNA synthesis can be inhibited and incorporation of3H-dT in mediun-vigour seeds decreased to such level which was similar to that in high-vigour seeds.The inhibitory part was considered as DNA repair in medium-vigour seeds.The unscheduled DNA synthesis was declined or diminished by OC with PEG or pretreated with polyamines.