Howell W M, Keller G E, Kirkpatrick J D, Jenkins R L, Hunsinger R N, McLaughlin E W
Department of Biology, Samford University, Birmingham, AL, USA.
Genet Mol Res. 2007 Feb 15;6(1):50-8.
The purpose of the present study was to determine the effects of the steroidal plant hormone, 24-epibrassinolide (BL), on the mitotic index and growth of onion (Allium cepa) root tips. The classical Allium test was used to gather and quantify data on the rate of root growth, the stages of mitosis, and the number of mitoses in control and BL-treated groups of onions. Low doses of BL (0.005 ppm) nearly doubled the mean root length and the number of mitoses over that of controls. Intermediate doses of BL (0.05 ppm) also produced mean root lengths and number of mitoses that were significantly greater than those of the controls. The highest dose of BL (0.5 ppm) produced mean root lengths and number of mitoses that were less than control values, but the differences were not statistically significant. Examination of longitudinally sectioned root tips produced relatively similar results. This study confirms the suppositions of previous authors who have claimed that exogenously applied BL can increase the number of mitoses in plants, but failed to show cytogenetic data. This is the first report detailing the effects of BL on chromosomes and the cell cycle.
本研究的目的是确定甾体类植物激素24-表油菜素内酯（BL）对洋葱（葱属）根尖有丝分裂指数和生长的影响。采用经典的洋葱试验收集并量化对照和BL处理组洋葱的根生长速率、有丝分裂阶段和有丝分裂数量的数据。低剂量的BL（0.005 ppm）使平均根长和有丝分裂数量比对照几乎增加了一倍。中等剂量的BL（0.05 ppm）也产生了显著大于对照的平均根长和有丝分裂数量。最高剂量的BL（0.5 ppm）产生的平均根长和有丝分裂数量低于对照值，但差异无统计学意义。对纵向切片根尖的检查产生了相对相似的结果。本研究证实了先前作者的推测，他们声称外源施用BL可增加植物中的有丝分裂数量，但未能展示细胞遗传学数据。这是第一份详细阐述BL对染色体和细胞周期影响的报告。
