Chueca A, Barón M, López-Gorgé J
Rev Esp Fisiol. 1982;38 Suppl:315-20.
The "photosynthetic inhibition" component in the whole context of plant toxicity, when different concentrations of the bis-carbamate phenmedipham are supplied through the roots or foliar application to spinach plants grown in hydroponic media have been determined. Chloroplasts were isolated after eight days of the herbicide addition, and then determined: electron transport H2O leads to NADP+, H2O leads to ferrycyanide and ascorbate/DPIP leads to NADP+, cyclic and non cyclic photophosphorilation, CO2 assimilation rate and intermediate patterns of CO2 fixation. We have also determined in foliar disks the O2 evolving and the CO2 assimilation capabilities. Type A and type B chloroplasts showed increased inhibition, respectively, of the Phot. II dependent electron transport chains H2O leads to NADP+ and H2O leads to ferricyanide, to the extent that the phenmedipham concentration increased in the hydroponic media and the spraying solution, so that a 50% inhibition of both processes was obtained at 100 microM and 10 microM, respectively, against 0.2 microM in the in vitro experiments. Non cyclic photophosphorylation showed a stronger inhibition than the cyclic one. Concerning the Phot. I dependent electron transport ascorbate/DPIP leads to NADP+, the chloroplast preparations showed a negligible inhibition. We have found a synergistic effect of the above two factors on the CO2 assimilation. The intermediate patterns of CO2 assimilation showed a decrease of the 3C-compounds P-glycerate and trioses-P, with a parallel increase of the sugar mono and diphosphates as well as disaccharides and amino acids.
当通过根系或叶面喷施向水培介质中生长的菠菜植株供应不同浓度的双氨基甲酸酯甜菜宁时，已确定了植物毒性整体背景下的“光合抑制”成分。在添加除草剂八天后分离叶绿体，然后测定：电子传递（H₂O 到 NADP⁺、H₂O 到铁氰化物以及抗坏血酸/DPIP 到 NADP⁺）、循环和非循环光合磷酸化、CO₂同化率以及 CO₂固定的中间模式。我们还在叶圆片中测定了 O₂释放和 CO₂同化能力。A 型和 B 型叶绿体分别对依赖光系统 II 的电子传递链（H₂O 到 NADP⁺和 H₂O 到铁氰化物）表现出增强的抑制作用，其程度随水培介质和喷施溶液中甜菜宁浓度的增加而增加，以至于在水培介质和喷施溶液中，分别在 100 μM 和 10 μM 时这两个过程受到 50%的抑制，而在体外实验中为 0.2 μM。非循环光合磷酸化的抑制作用比循环光合磷酸化更强。关于依赖光系统 I 的电子传递（抗坏血酸/DPIP 到 NADP⁺），叶绿体提取物表现出可忽略不计的抑制作用。我们发现上述两个因素对 CO₂同化有协同作用。CO₂同化的中间模式显示 3C 化合物 3-磷酸甘油酸和丙糖磷酸减少，同时单糖和二糖磷酸以及二糖和氨基酸平行增加。
