竹子硝酸还原酶活力的研究

STUDIES ON THE NITRATE REDUCTASE IN LINGNANIA CHUNGII(MCCLURE)MCCLURE

对竹子硝酸还原酶活力的研究表明:因竹叶提取液偏酸,用 pH8.5的25mmol/L 磷酸盐缓冲液(含聚乙烯吡略啉酮(PVP)65mg/ml),提取(最终 pH为7.5)的叶片酶活力最高,酶反应达最高速率时的底物 KNO_3浓度为25mmol/L。在漫射光下,用 50mmol/LKNO_3诱导6h,叶片酶活力达高峰。光照对竹子酶活力具诱导作用,其中以光强5000lx 诱导12h、8000lx 诱导8h 最佳。中龄叶对 KNO_3和光照的诱导反应最敏感,诱导产生的酶活力比嫩叶和老叶高,尚未展开的嫩叶酶活力极低。不同叶龄叶酶活力,与叶片氨基氮和叶绿素含量呈极显著的正相关。在竹根中未能检测出硝酸还原酶活力。

Studies on the activity of nitrate reductase(NR)in Lingnania chungii (McClure)McClure indicated that the activity of NR was up to the highest in the leaf,when using phosphate buffer(25 mmol/L,pH 8.5,the final pH became 7.5)containing PVP(65 mg/ml).The concentration of substrate was 25 mmol/L KNO_3 when the enzymatic reaction up to the highest.The activity of NR in the leaf was up to the highest when the shoot was induced 6 hours in the 50 mmol/L KNO_3 solution under the diffuse light.The best induced effect was at the light intensities of 5000 lx for 12 hours and 8000 lx for 8 hours.The middle aged leaf has the best sensitiveness to the induction of KNO_3 and light.The induced activity of NR in middle aged leaf was higher than that in young leaf and old leaf,that in non-extended young leaf was the lowest.The difference of activities of NR among age-different leaves showed positive correlation with the contents of aminonitrogen and chlorophyll.The roots of this Bamboo lacked NR activity.