Soleh Mochamad Arief, Tanaka Yu, Nomoto Yuko, Iwahashi Yu, Nakashima Keiichiro, Fukuda Yasuko, Long Stephen P, Shiraiwa Tatsuhiko
Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
Faculty of Agriculture, Padjadjaran University, Jalan Raya Bandung-Sumedang km 21, Jatinangor, 45363, Indonesia.
Plant Cell Environ. 2016 Mar;39(3):685-93. doi: 10.1111/pce.12674. Epub 2016 Jan 12.
Crop leaves are subject to continually changing light levels in the field. Photosynthetic efficiency of a crop canopy and productivity will depend significantly on how quickly a leaf can acclimate to a change. One measure of speed of response is the rate of photosynthesis increase toward its steady state on transition from low to high light. This rate was measured for seven genotypes of soybean [Glycine max (L.) Merr.]. After 10 min of illumination, cultivar 'UA4805' (UA) had achieved a leaf photosynthetic rate (Pn ) of 23.2 μmol · m(-2) · s(-1) , close to its steady-state rate, while the slowest cultivar 'Tachinagaha' (Tc) had only reached 13.0 μmol · m(-2) · s(-1) and was still many minutes from obtaining steady state. This difference was further investigated by examining induction at a range of carbon dioxide concentrations. Applying a biochemical model of limitations to photosynthesis to the responses of Pn to intercellular CO2 concentration (Ci ), it was found that the speed of apparent in vivo activation of ribulose-1:5-bisphosphate carboxylase/oxygenase (Rubisco) was responsible for this difference. Sequence analysis of the Rubisco activase gene revealed single nucleotide polymorphisms that could relate to this difference. The results show a potential route for selection of cultivars with increased photosynthetic efficiency in fluctuating light.
作物叶片在田间会受到不断变化的光照强度影响。作物冠层的光合效率和生产力将很大程度上取决于叶片适应变化的速度。反应速度的一个衡量指标是从低光过渡到高光时光合作用速率向其稳态增加的速率。对七种大豆基因型[Glycine max (L.) Merr.]进行了该速率的测定。光照10分钟后，品种‘UA4805’（UA）的叶片光合速率（Pn）达到23.2 μmol·m⁻²·s⁻¹，接近其稳态速率，而最慢的品种‘Tachinagaha’（Tc）仅达到13.0 μmol·m⁻²·s⁻¹，距离达到稳态仍需数分钟。通过在一系列二氧化碳浓度下检测诱导情况进一步研究了这种差异。将光合作用限制的生化模型应用于Pn对细胞间二氧化碳浓度（Ci）的响应，发现核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco）在体内的表观激活速度导致了这种差异。Rubisco活化酶基因的序列分析揭示了可能与这种差异相关的单核苷酸多态性。结果显示了在波动光照下选择光合效率提高的品种的潜在途径。
