陆地棉功能叶不同生育时期酶活性及脂质过氧化作用的研究

The Enzyme Activities and the Levels of Lipid Peroxidation Upland Cotton (G. hirsutum L.) at Different Development Stages

对不同熟性棉花品种功能叶几种酶活性及脂质过氧化水平（以丙二醛含量表示）的研究结果表明,超氧物歧化酶（SOD）活性在吐絮前呈波动上升,吐絮盛期急剧下降;丙二醛（MDA）含量吐絮前缓慢上升,吐絮后明显增加;过氧化氢酶（CAT）活性在结铃以前随叶片发育而上升,结铃后急剧下降;过氧化物酶（POD）活性始终呈上升趋势。进一步对POD同工酶进行电泳发现,其酶谱构成随生育进程而变化,早熟品种在开花期酶带条数最多,其中出现两条慢带,而中早熟、中熟和晚熟品种（包括低酚棉）则在吐絮期最多,此时早熟、中早熟和中熟品种均有一条慢带,但晚熟品种始终未出现慢带,推测慢带可能与品种的成熟期有关。结果还表明,早熟品种三种酶活性在吐絮前与其它品种的差异不明显,有时还比其它品种略高,说明尽管早熟品种生育期较短,但其功能叶的生理生化功能仍很旺盛。低酚棉上述生理指标与有酚棉相比有其不同之处。

The activities of several enzymes and the levels of lipid peroxidation in the functional leaves of upland cotton varieties with different times of maturity were studied at different development stages. The results indicated that the SOD activity rose fluctuatingly before the early boll-opening stage, then dropped rapidly; whereas the MDA content increased slowly before this stage but much more rapidly afterwards. The CAT activity rose with the development of the leaves before the boll-setting stage, then dropped rapidly; whereas the POD activity increased continuously. Electrophoresis studies of the POD isozyme revealed that the zymogram patterns of POD changed with the growth of the plant, and different maturity types had different patterns. Thus, with the early variety, the maximum number of bands appeared at the flowering stage, including 2 slow bands; but with the mid-early, inter-mediate and late-maturity varieties, this happened only at the boll-opening stage. All maturity types had a slow band at this stage except the late-maturity variety, which did not have any slow bands during the whole growth period, implicating that the slow band might be somewhat related to early maturity.The results also revealed that before the boll-opening-maturing stage, there seemed to be no significant difference in activities of the 3 enzymes between the early variety and the other maturity types. Some activity was even higher with the early-maturing variety, indicating that although the growth period of the early-maturity variety is shorter, the physiological-chemical activities of its functional leaves are still rather high.The enzyme activity patterns of the glandless cotton were somewhat different from those of the other glanded varieties.