Kennedy R A, Barnes J E
Department of Botany, University of Iowa, Iowa City, Iowa 52240.
Plant Physiol. 1977 Apr;59(4):600-3. doi: 10.1104/pp.59.4.600.
The pattern of photosynthetic carbon metabolism was determined in tissue cultures of Portulaca oleracea. Four-carbon acids are the most heavily labeled photosynthetic products during short term exposure to (14)CO(2), containing greater than 40% of the total radioactivity incorporated. Phosphoglyceric acid and sugars account for only 10% of the label after equal exposure times. Other features of the CO(2) assimilation pattern in Portulaca callus tissue include a relatively large percentage of label located in various minor products throughout the time course studied, and a greater incorporation of (14)C into sugars in tissue cultures than occurs in leaves. Ultrastructurally, the chloroplasts and cells of the callus are like those in the mesophyll cells of Portulaca leaves. The requirement for Kranz anatomy for operation of functional C(4) physiology is discussed.
马齿苋组织培养中光合碳代谢模式已被确定。在短期暴露于¹⁴CO₂期间，四碳酸是标记程度最高的光合产物，其所含放射性占总掺入放射性的40%以上。经过相同暴露时间后，磷酸甘油酸和糖类仅占标记的10%。马齿苋愈伤组织中CO₂同化模式的其他特征包括，在整个研究的时间进程中，有相对较大比例的标记位于各种次要产物中，并且与叶片相比，¹⁴C在组织培养中的糖类中掺入量更多。在超微结构上，愈伤组织的叶绿体和细胞与马齿苋叶片叶肉细胞中的叶绿体和细胞相似。文中讨论了功能性C₄生理运作对花环结构的需求。
