Fladung Matthias, Hesselbach Josef
Max-Planck-Institut für Züchtungsforschung, D-5000, Köln 30, Federal Republic of Germany.
Oecologia. 1989 May;79(2):168-173. doi: 10.1007/BF00388473.
CO exchange characteristics and the activity of the carboxylating enzymes phosphoenolpyruvate carboxylase (PEP-C, E.C. 4.1.1.31) and ribulose 1,5-bisphosphate carboxylase (RuBP-C, E.C. 4.1.1.39) during one year in the greenhouse and at two levels of light and temperature in growth chambers were determined in the C-C intermediate species P. milioides Nees ex. Trin. These results were compared with those of P. bisulcatum Thumb. (C) and P. maximum Jacq. (C). Under all tested conditions, and even when the influence of leaf surface temperature on photosynthetic rates and CO compensation points were measured, the biochemical and physiological behaviour of the C-C intermediate was more similar to that of the C plant than the C species. The C plant P. maximum, however, responded positively, mainly in terms of PEP-C activity and photosynthetic rate, to the regime of high light and temperature. The results presented indicate that in the C-C Panicum grown in high light and temperature no direct relationships between a low CO compesation point and superior growth are evident. It has still to be clarified why in nature a photosynthetic-photorespiratory pathway leading to an intermediate CO compensation value has evolved in P. milioides.
在温室中以及生长箱内两种光照和温度水平下，对C₃ - C₄中间型物种黍稷（Panicum milioides Nees ex. Trin.）在一年中的CO₂交换特性以及羧化酶磷酸烯醇式丙酮酸羧化酶（PEP - C，E.C. 4.1.1.31）和核酮糖1,5 - 二磷酸羧化酶（RuBP - C，E.C. 4.1.1.39）的活性进行了测定。将这些结果与双槽黍（Panicum bisulcatum Thumb.）（C₃）和大黍（Panicum maximum Jacq.）（C₄）的结果进行了比较。在所有测试条件下，即使测量了叶片表面温度对光合速率和CO₂补偿点的影响，C₃ - C₄中间型的生化和生理行为与C₃植物的更相似，而非C₄物种。然而，C₄植物大黍主要在PEP - C活性和光合速率方面对高光和高温条件有积极响应。所呈现的结果表明，在高光和高温下生长的C₃ - C₄黍稷中，低CO₂补偿点与优越生长之间没有明显的直接关系。仍有待阐明为什么在自然条件下，黍稷会进化出导致中间CO₂补偿值的光合 - 光呼吸途径。
