CSIRO Agriculture and Food, PO Box 1700, Canberra, Australian Capital Territory, 2601, Australia.
Plant Science Division, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, 2601, Australia.
Plant Cell Environ. 2017 Aug;40(8):1552-1564. doi: 10.1111/pce.12953. Epub 2017 Jun 2.
We examined the effects of leaf temperature on the estimation of maximal Rubisco capacity (V ) from gas exchange measurements of wheat leaves using a C photosynthesis model. Cultivars of spring wheat (Triticum aestivum (L)) and triticale (X Triticosecale Wittmack) were grown in a greenhouse or in the field and measured at a range of temperatures under controlled conditions in a growth cabinet (2 and 21% O ) or in the field using natural diurnal variation in temperature, respectively. Published Rubisco kinetic constants for tobacco did not describe the observed CO response curves well as temperature varied. By assuming values for the Rubisco Michaelis-Menten constants for CO (K ) and O (K ) at 25 °C derived from tobacco and the activation energies of V from wheat and respiration in the light, R , from tobacco, we derived activation energies for K and K (93.7 and 33.6 kJ mol , respectively) that considerably improved the fit of the model to observed data. We confirmed that temperature dependence of dark respiration for wheat was well described by the activation energy for R from tobacco. The new parameters improved the estimation of V under field conditions, where temperatures increased through the day.
我们利用 C 光合作用模型，考察了叶片温度对利用气体交换测量估算春小麦（Triticum aestivum (L)）和黑小麦（X Triticosecale Wittmack）叶片最大 Rubisco 容量（V ）的影响。在温室或田间生长的春小麦和黑小麦品种，分别在生长箱中（2 和 21% O ）或在田间中在控制条件下于一系列温度下进行测量，以利用自然的日间温度变化。用于烟草的已发表的 Rubisco 动力学常数不能很好地描述随着温度变化而观察到的 CO 响应曲线。通过假设从烟草得出的 Rubisco 米氏常数（K ）和 O （K ）在 25°C 的值以及从烟草得出的小麦的 V 和光呼吸的活化能（R ），我们得出了 K 和 K 的活化能（分别为 93.7 和 33.6 kJ mol ），这大大改善了模型对观测数据的拟合。我们证实，烟草的 R 活化能很好地描述了小麦暗呼吸的温度依赖性。新参数提高了对田间条件下 V 的估算，在田间条件下，温度全天升高。
