The root tip and accelerating region suppress elongation of the decelerating region without any effects on cell turgor in primary roots of maize under water stress
The root tip and accelerating region suppress elongation of the decelerating region without any effects on cell turgor in primary roots of maize under water stress
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DOI：
10.1104/pp.105.062091
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发表时间：
2005-09-01
期刊：
影响因子：
7.4
通讯作者：
Hirasawa, T
中科院分区：
文献类型：
--
作者：
Shimazaki, Y;Ookawa, T;Hirasawa, T
要确定的区域，在该区域中的根感知到环境中的水的潜力，并改变其伸长速率，我们采用了两个琼脂块（1 - 31 - 31毫米3）与低水的潜力双边玉米（玉米）的主根在不同的位置沿着根。当将具有-1.60 MPa（-1.60- MPa块）或更低的水势的琼脂块附着到根尖时，伸长速率降低。这种减少不是由于伸长细胞的水状态的任何变化造成的，并且当-0.03-MPa块替换-1.60- MPa块时也没有逆转。当-1.60- MPa块分别应用于伸长区和成熟区的所谓减速区时，速率略有下降，但不受影响。然而，速率明显下降，至少在几个小时内没有恢复，当这样的块连接到加速区。在这种情况下，伸长细胞的膨压在施加块后立即降低，并在此后恢复。施加到根尖的21.60-MPa块引起的伸长率降低不受施加到加速区域的额外-0.03-MPa块的影响，反之亦然。我们的结论是，在根生长的显着减少，可以诱导由水分胁迫在根尖，以及在加速区的伸长区，和一些信号从这些地区的减速区的传输可能有助于抑制伸长区的细胞伸长。
To identify the region in which a root perceives a decrease in the ambient water potential and changes its elongation rate, we applied two agar blocks ( 1 31 31 mm 3) with low water potential bilaterally to primary roots of maize (Zea mays) at various positions along the root. When agar blocks with a water potential of -1.60 MPa ( -1.60- MPa blocks) or lower were attached to a root tip, the rate of elongation decreased. This decrease did not result from any changes in the water status of elongating cells and was not reversed when the -1.60- MPa blocks were replaced by -0.03-MPa blocks. The rate decreased slightly and was unaffected, respectively, when -1.60- MPa blocks were applied to the so-called decelerating region of the elongating zone and the mature region. However, the rate decreased markedly and did not recover for several hours at least when such blocks were attached to the accelerating region. In this case, the turgor pressure of the elongating cells decreased immediately after the application of the blocks and recovered thereafter. The decrease in elongation rate caused by 21.60-MPa blocks applied to the root tip was unaffected by additional -0.03-MPa blocks applied to the accelerating region and vice versa. We concluded that a significant reduction in root growth could be induced by water stress at the root tip, as well as in the accelerating region of the elongating zone, and that transmission of some signal from these regions to the decelerating region might contribute to the suppression of cell elongation in the elongation region.