Unité Fonctionnelle de Biotechnologie, Centre Institut Français de Recherche Scientifique pour le Developpement en Cooperation (ORSTOM) de Montpellier, BP. 5045, 34032 Montpellier Cedex France.
Plant Physiol. 1992 Apr;98(4):1270-6. doi: 10.1104/pp.98.4.1270.
The treatment of rubber tree (Hevea brasiliensis) bark with chloro-2-ethyl phosphonic acid (ethrel), an ethylene-releasing chemical, induced, after a lag period of 13 to 21 hours, a marked increase in the total adenine nucleotides (essentially ATP and ADP) of latex cells. This rise in the latex adenylate pool was concomitant with a marked decrease in the [ATP]/[ADP] ratio without significant changes in the adenylate energy charge. The apparent equilibrium constant for the adenylate kinase, which appeared to behave as a key enzyme in maintaining the adenylate energy charge in the latex, was considerably reduced, probably as a consequence of the alkalinization of the latex cytosol induced by the treatment with ethrel. To reduce the "sink effect" and activation of the metabolism induced in Hevea bark by regular tapping, the latex was collected by micropuncture (few drops) at increasing distance (5-50 centimeters) above and below an ethrel-treated area on the virgin bark of resting trees. The effect of ethrel was shown to spread progressively along the trunk. The increase in the adenylate pool (essentially ATP) was detectable as early as 24 hours after the bark treatment and was maximum after 6 or 8 days, 5 centimeters as well as 50 centimeters above and below the stimulated bark ring. The correlative vacuolar acidification and cytosolic alkalinization, i.e. the increase in the transtonoplast DeltapH, induced in the latex cells by ethrel were shown to be concomitant with the rise in ATP content of the latex. This suggests that the tonoplast H(+)-pumping ATPase, which catalyzes vacuolar acidification in the latex, is directly and essentially under the control of the availability of its substrate (i.e. ATP) in the latex. The results are discussed in relation to energy-dependent activation of metabolism, and increased rubber production, as induced by the stimulation of rubber trees with ethrel.
用氯-2-乙基膦酸（乙烯释放剂）处理橡胶树（巴西橡胶树）树皮，在 13 到 21 小时的滞后期后，明显增加了乳胶细胞中的总腺嘌呤核苷酸（主要是 ATP 和 ADP）。这种乳胶腺苷酸库的增加伴随着 [ATP]/[ADP] 比值的显著降低，而腺苷酸能量电荷没有明显变化。看起来作为维持乳胶中腺苷酸能量电荷的关键酶的腺苷酸激酶的表观平衡常数显著降低，这可能是由于用 ethrel 处理诱导乳胶细胞质碱化的结果。为了减少因常规割胶而在橡胶树树皮中引起的“汇效应”和代谢激活，通过微穿刺（几滴水）在休息树的原始树皮上的 ethrel 处理区域上方和下方以逐渐增加的距离（5-50 厘米）收集乳胶。结果表明，ethrel 的作用沿树干逐渐扩散。早在树皮处理后 24 小时即可检测到腺苷酸库（主要是 ATP）的增加，6 或 8 天后达到最大值，在受刺激的树皮环上方和下方 5 厘米和 50 厘米处均达到最大值。在 ethrel 诱导下，乳胶细胞中相关的液泡酸化和细胞质碱化，即跨膜 ΔpH 的增加，与乳胶中 ATP 含量的增加同时发生。这表明，在乳胶中催化液泡酸化的质膜 H(+)-泵 ATP 酶直接且主要受到其底物（即 ATP）在乳胶中可用性的控制。结果与代谢的能量依赖性激活以及用 ethrel 刺激橡胶树引起的橡胶产量增加有关。
