LIMITING OXYGEN FLUX DENSITIES FOR OAT ROOT EXTENSION
LIMITING OXYGEN FLUX DENSITIES FOR OAT ROOT EXTENSION
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DOI：
10.1007/bf02197762
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发表时间：
1983-01-01
期刊：
影响因子：
4.9
通讯作者：
WELLS, EA
中科院分区：
文献类型：
--
作者：
BLACKWELL, PS;WELLS, EA
将冬燕麦的幼苗生长在生长箱中的“有机玻璃”管中的土壤柱中，该生长箱具有恒定温度（10 ℃）。或7度。C）和相当于秋季日光的照明通量密度。幼苗出苗后1周，土壤淹水。根沿着倾斜的“有机玻璃”管壁生长，并测量了根尖位置、到裸铂电极的O2通量、O2扩散速率和溶解O2浓度。硝酸盐和乙烯在土壤溶液和根和冠的尺寸进行了测量，根结构进行了检查。在10 ℃下，当O2通量密度小于56 ng cm-2 min-1，O2扩散速率小于121 ng cm-2 min-1，溶解O2浓度等于或低于15%vol/vol时，在淹水土壤中的根延伸比在自由排水土壤中慢。C.在某些简化假设下，仅需要限制O2通量来维持根尖组织的不受限制的呼吸。当O2通量有效地为零且溶解O2浓度非常接近于零时，根延伸停止。然后O2扩散速率为7.8 ±。1.2 ng cm ~（-2）min ~（-1），这可能是由H_2解离引起的。淹水后根系直径的测量表明，O2限制的生长是径向优先于轴向。
Seedlings of winter oat were grown in columns of soil packed in ''Perspex'' tubes in a growth cabinet with constant temperatures (10.degree. or 7.degree. C) and an illumination flux density equivalent to autumn daylight. The soil was waterlogged 1 wk after seedlings emerged. Roots grew along the walls of sloping ''Perspex'' tubes and measurements were made of root tip position, O2 flux to a bare platinum electrode, the O2 diffusion rate and the concentration of dissolved O2. Nitrate and ethylene in the soil solution and root and shoot dimensions were measured, and root structure was examined. Root extension was slower in waterlogged soil than in freely-drained soil at O2 flux densities less than 56 ng cm-2 min-1, at O2 diffusion rates less than 121 ng cm-2 min-1 and at concentrations of dissolved O2 at or below 15% vol/vol at 10.degree. C. With some simplifying assumptions the limiting O2 flux was just needed to maintain unrestricted respiration of root tip tissue. Root extension stopped when O2 flux was effectively zero and dissolved O2 concentration was very close to zero. The O2 diffusion rate was then 7.8 .+-. 1.2 ng cm-2 min-1 which was probably caused by H2 dissociation. Measurement of root diameters after waterlogged suggested that O2-limited growth was radial in preference to axial.