紫外线刺激玫瑰细胞中KHCO₃的外流：细胞质pH的调节
Ultraviolet-Stimulated KHCO(3) Efflux from Rose Cells: Regulation of Cytoplasmic pH.
作者信息
Murphy T M, Matson G B, Morrison S L
机构信息
Department of Botany, University of California, Davis, California 95616.
出版信息
Plant Physiol. 1983 Sep;73(1):20-4. doi: 10.1104/pp.73.1.20.
Suspension-cultured cells of Rosa damascena that have been irradiated with ultraviolet light (254 nanometers, 2.1 x 10(4) joules per square meter) rapidly lose K(+) and HCO(3) (-) ions to the medium. If the HCO(3) (-) is derived from respiratory CO(2) inside the cell, then loss of HCO(3) (-) should be accompanied by an acidification of the cytoplasm. Estimates of the pH of control and ultraviolet-irradiated cells by (31)P-nuclear magnetic resonance spectroscopy indicated that, following irradiation, the pH of both cytoplasm and vacuole dropped by 0.2 to 0.3 units. This change was not as great as was predicted from the observed HCO(3) (-) loss. Analysis of nitrogenous compounds in the cell suggested that reduction of nitrate and synthesis of gamma-aminobutyric acid absorbed some of the protons formed by the synthesis and dissociation of bicarbonate.
用紫外线（254纳米，2.1×10⁴焦耳每平方米）照射过的大马士革蔷薇悬浮培养细胞会迅速将钾离子和碳酸氢根离子释放到培养基中。如果碳酸氢根来自细胞内呼吸产生的二氧化碳，那么碳酸氢根的流失应该伴随着细胞质的酸化。通过³¹P核磁共振光谱对对照细胞和紫外线照射细胞的pH值进行估计，结果表明，照射后，细胞质和液泡的pH值均下降了0.2至0.3个单位。这种变化不如根据观察到的碳酸氢根流失所预测的那么大。对细胞中含氮化合物的分析表明，硝酸盐的还原和γ-氨基丁酸的合成吸收了一些由碳酸氢盐合成和解离形成的质子。
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