COMPARTMENTATION ANALYSIS OF PARAQUAT FLUXES IN MAIZE ROOTS AS A MEANS OF ESTIMATING THE RATE OF VACUOLAR ACCUMULATION AND TRANSLOCATION TO SHOOTS
COMPARTMENTATION ANALYSIS OF PARAQUAT FLUXES IN MAIZE ROOTS AS A MEANS OF ESTIMATING THE RATE OF VACUOLAR ACCUMULATION AND TRANSLOCATION TO SHOOTS
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DOI：
10.1104/pp.102.2.467
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发表时间：
1993-06-01
期刊：
影响因子：
7.4
通讯作者：
KOCHIAN, LV
中科院分区：
文献类型：
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作者：
DITOMASO, JM;HART, JJ;KOCHIAN, LV
采用5个不同长度（2、6、12、18或24 h）的负荷期后进行的外排分析研究了[C-14]百草枯在玉米（Zea mays L.）幼苗24小时内，玉米根对百草枯的净吸收（吸收溶液中百草枯浓度= 25 μ m）呈线性（56.7 nmol g-1根鲜重h-1）。对2、6、12、18和24小时负荷期后液泡、细胞质和细胞壁中百草枯含量变化的估计表明，细胞壁迅速饱和，而液泡中百草枯的积累量在24小时内呈线性增加（12.4 nmol g-1根鲜重h-1）。与液泡积累相反，细胞质百草枯含量似乎接近饱和。百草枯从细胞壁（16.6 min +/-1.2 SD）和细胞质（58.8 min +/-8.9 SD）流出的半衰期保持相对恒定，与加载时间长短无关，而从液泡流出的半衰期则长得多，并随加载时间的增加而线性增加（6.1-18.7 h）。百草枯易位到地上部的时间过程是线性的，在24小时内暴露于放射性标记的除草剂，但易位没有开始，直到5小时后开始治疗。这些实验中使用的实验方法为研究百草枯在玉米幼苗中的移动提供了一种有价值的方法。结果表明，除草剂在根细胞的液泡中缓慢积累，但也转运到地上部。
Efflux analysis conducted after five loading periods of various lengths (2, 6, 12, 18, or 24 h) was used to investigate uptake, compartmentation, and translocation of [C-14]paraquat in maize (Zea mays L.) seedlings. The time course for net paraquat uptake (paraquat concentration in uptake solution = 25 mum) into maize roots was linear (56.7 nmol g-1 root fresh weight h-1) for 24 h. Estimates of changes in paraquat content in the vacuole, cytoplasm, and cell wall after 2-, 6-, 12-, 18-, and 24-h loading periods indicated that the cell wall saturated rapidly, whereas accumulation of paraquat into the vacuole increased linearly (1 2.4 nmol g-1 root fresh weight h-1) over 24 h. In contrast to vacuolar accumulation, cytoplasmic paraquat content appeared to approach saturation. The half-time for paraquat efflux from the cell wall (16.6 min +/-1.2 SD) and cytoplasm (58.8 min +/- 8.9 SD) remained relatively constant regardless of the length of the loading period, whereas the half-time for efflux from the vacuole was considerably longer and increased linearly with increased loading time (6.1-18.7 h). The time course for paraquat translocation to the shoot was linear within a 24-h exposure to radiolabeled herbicide, but translocation did not begin until 5 h after initiation of treatment. The experimental approach used in these experiments provides a valuable method for examining the movement of paraquat in maize seedlings. Results indicate that the herbicide slowly accumulates in the vacuole of root cells but is also translocated to the shoot.