Brown R H, Byrd G T, Black C C
Department of Agronomy, University of Georgia, Athens, Georgia 30602.
Plant Physiol. 1991 Nov;97(3):985-9. doi: 10.1104/pp.97.3.985.
An analog of phosphoenolpyruvate, 3,3-dichloro-2-dihydroxyphosphinoylmethyl-2-propenoate (DCDP), was used to inhibit phosphoenolpyruvate carboxylase and, therefore, assess the contribution of the C(4) pathway to photosynthesis in detached leaves of several C(3)-C(4) intermediate species. There was no effect of 4 millimolar DCDP on apparent photosynthesis or on inhibition of apparent photosynthesis by 210 milliliters per liter of O(2) for the C(3)-C(4) species Panicum milioides, Moricandia arvensis, and Neurachne minor or the C(3) species Flaveria pringlei. However, when leaves of Flaveria linearis (C(3)-C(4)), Flaveria brownii (C(4)-like), and Flaveria trinervia (C(4)) were fed 4 millimolar DCDP, photosynthesis was reduced 32, 60, and 90%, respectively. Photosynthetic inhibition by 210 milliliter per liter of O(2) was also significantly increased in 4 millimolar DCDP-fed leaves of F. linearis and F. brownii but not in F. trinervia when compared with control values. These results with DCDP clearly demarcate C(3)-C(4) species into species including Panicum, Moricandia, and Neurachne whose reduced photorespiration occurs without any C(4) photosynthetic involvement and species of Flaveria in which C(4) photosynthesis contributes to CO(2) assimilation.
磷酸烯醇丙酮酸的类似物3,3-二氯-2-二羟基膦酰甲基-2-丙烯酸酯（DCDP）被用于抑制磷酸烯醇丙酮酸羧化酶，从而评估C4途径对几种C3-C4中间型物种离体叶片光合作用的贡献。对于C3-C4物种粟米草、田野滨藜和小脉耳草，以及C3物种普氏黄鹌菜，4毫摩尔的DCDP对表观光合作用或210毫升/升氧气对表观光合作用的抑制均无影响。然而，当给线叶黄鹌菜（C3-C4）、布朗氏黄鹌菜（类C4）和三脉黄鹌菜（C4）的叶片饲喂4毫摩尔DCDP时，光合作用分别降低了32%、60%和90%。与对照值相比，在饲喂4毫摩尔DCDP的线叶黄鹌菜和布朗氏黄鹌菜叶片中，210毫升/升氧气对光合作用的抑制也显著增加，但在三脉黄鹌菜中未增加。这些使用DCDP的结果清楚地将C3-C4物种划分为两类：一类包括粟米草、田野滨藜和小脉耳草，其光呼吸降低在没有任何C4光合作用参与的情况下发生；另一类是黄鹌菜属物种，其中C4光合作用对CO2同化有贡献。
