Burgess Alexandra J, Retkute Renata, Herman Tiara, Murchie Erik H
Division of Plant and Crop Sciences, School of Biosciences, University of NottinghamLoughborough, UK.
Crops For the FutureSemenyih, Malaysia.
Front Plant Sci. 2017 May 17;8:734. doi: 10.3389/fpls.2017.00734. eCollection 2017.
The arrangement of leaf material is critical in determining the light environment, and subsequently the photosynthetic productivity of complex crop canopies. However, links between specific canopy architectural traits and photosynthetic productivity across a wide genetic background are poorly understood for field grown crops. The architecture of five genetically diverse rice varieties-four parental founders of a multi-parent advanced generation intercross (MAGIC) population plus a high yielding Philippine variety (IR64)-was captured at two different growth stages using a method for digital plant reconstruction based on stereocameras. Ray tracing was employed to explore the effects of canopy architecture on the resulting light environment in high-resolution, whilst gas exchange measurements were combined with an empirical model of photosynthesis to calculate an estimated carbon gain and total light interception. To further test the impact of different dynamic light patterns on photosynthetic properties, an empirical model of photosynthetic acclimation was employed to predict the optimal light-saturated photosynthesis rate ( ) throughout canopy depth, hypothesizing that light is the sole determinant of productivity in these conditions. First, we show that a plant type with steeper leaf angles allows more efficient penetration of light into lower canopy layers and this, in turn, leads to a greater photosynthetic potential. Second the predicted optimal responds in a manner that is consistent with fractional interception and leaf area index across this germplasm. However, measured , especially in lower layers, was consistently higher than the optimal indicating factors other than light determine photosynthesis profiles. Lastly, varieties with more upright architecture exhibit higher maximum quantum yield of photosynthesis indicating a canopy-level impact on photosynthetic efficiency.
叶片材料的排列对于确定光照环境以及随后复杂作物冠层的光合生产力至关重要。然而，对于田间种植的作物，在广泛的遗传背景下，特定冠层结构特征与光合生产力之间的联系却知之甚少。利用基于立体相机的数字植物重建方法，在两个不同生长阶段获取了五个遗传多样的水稻品种的结构——一个多亲本高世代杂交（MAGIC）群体的四个亲本创始品种加上一个高产菲律宾品种（IR64）。采用光线追踪技术以高分辨率探究冠层结构对所得光照环境的影响，同时将气体交换测量与光合作用经验模型相结合，以计算估计的碳增益和总光截获量。为了进一步测试不同动态光照模式对光合特性的影响，采用光合适应经验模型预测整个冠层深度的最佳光饱和光合速率（ ），假设在这些条件下光是生产力的唯一决定因素。首先，我们表明叶角较陡的植物类型能使光线更有效地穿透到冠层下层，进而导致更大的光合潜力。其次，预测的最佳 以与该种质的分数截获和叶面积指数一致的方式响应。然而，实测的 ，尤其是在下层，始终高于最佳 ，这表明除了光之外的其他因素决定了光合作用分布。最后，具有更直立结构的品种表现出更高的光合最大量子产率，表明冠层水平对光合效率有影响。
