The reorientation of microtubules (MTS) in roots of Oryza sativa L. treated with 2,4-D was studied using confocal laser scanning microscopy. In the control (the roots were not treated with 2,4-D), different distribution patterns of MTS were observed in the different growth zones of root tips. MTS of the cortical cells were randomly aligned in the zone of cell division. They were transversely arranged in the cortical cells of the zone of cell elongation; and obliquely oriented in the root hair zone. After treatment with 2,4-D, MTS displayed distinct changes with reorientation in the cortex of the root tip coupling with the inhibition of root growth. MTS changed their orientation in the cortical cells of the zone of cell division from being randomly oriented to transversely oriented when incubated in 1 mg/L 2,4-D for 1 h. However, they were recovered and became randomly oriented when the roots were treated with 1 mg/L 2,4-D for 24 h. An array of MTS, which was different from that in the control, was observed in the cortical cells of the zone of cell elongation in the roots treated with 1 mg/L 2,4-D for 1 h. After treatment with 10 mg/L 2,4-D for 1 h, the MTS in the cortical cells of the zone of cell division became transversely reorientated, but the pattern of MTS distribution was different from that in the 1-hour treatment of 1 mg/L 2,4-D. MTS were hardly detected in the same type of cells when roots were submerged in 10 mg/L 2,4-D for 24 h. When roots were incubated in 10 mg/L 2,4-D for 1 h, the MTS of the cortical cells in the zone of cell elongation became randomly oriented, and much more randomly when the roots were treated for 24 h.
2,4-D 对水稻根尖微管排列的影响
刘向东 卢永根
（华南农业大学植物分子育种研究中心，广州510642）
摘要：摘要： 通过共焦激光扫描显微镜对经过2,4-D 处理水稻（Oryza sativa L. ）根尖的微管骨架的排列进行了研究。结果表明，对照（未经2,4-D 处理）根尖的不同生长区微管呈现不同的排列方式，生长区皮层细胞微管呈随机排列，伸长区微管呈横向排列，根毛区的呈斜向排列。经过2,4-D 处理的根，不但皮层细胞微管表现重新定向，同时也伴随着生长受到强烈抑制。1 mg/L 2,4-D处理1h，分生区细胞微管由随机排列变成横向排列；处理2,4-D 后，微管恢复成随机排列。伸长区皮层细胞在1mg/L. 2,4-D处理1h后，其细胞内出现完全不同于对照同一区域细胞排列方式的微管。10mg/L2,4-D 处理1h使分生区皮层细胞微管排列改变成横向，但不同于10mg/L2,4-D 处理的；处理24h后，分生区皮层细胞内的大部分区域未观察到微管。伸长区细胞在10mg/L 2,4-D 处理1h后，微管变成随机状，处理24h 后随机程度更加明显。
关键词： 水稻；根尖；微管；2,4-D
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