Almeida R L, Silveira N M, Miranda M T, Pacheco V S, Cruz L P, Xavier M A, Machado E C, Ribeiro R V
Laboratory of Plant Physiology 'Coaracy M. Franco', Center for Agricultural and Post-Harvest Biosystems, Agronomic Institute (IAC), Campinas, SP, Brazil.
Laboratory of Crop Physiology (LCroP), Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil.
Photosynthetica. 2022 Oct 20;60(4):521-528. doi: 10.32615/ps.2022.045. eCollection 2022.
Increasing the efficiency of photosynthesis in sugarcane canopies is the key for improving crop yield. Herein, we evaluated the photosynthetic performance along the canopy of ten sugarcane cultivars and three species. Canopy morphological traits were evaluated, and leaf gas exchange was measured in the first (sun-exposed, +1) and the fourth (shaded, +4) fully expanded leaves and under low- and high-light conditions. Similar photosynthetic capacity was found in leaves +1 and +4 under high light in genotypes with a high leaf area index and a high fraction of the sky blocked by the foliage (> 85%). Interestingly, such canopy characteristics cause low light availability to leaves +4, suggesting the photosynthetic acclimation of these leaves to self-shading in some genotypes. We highlight IACCTC06-8126 and CTC4 as those genotypes with higher canopy photosynthetic capacity, presenting high leaf area, high photosynthetic rates in sun-exposed leaves, and high responsiveness of shaded leaves to increasing light availability.
提高甘蔗冠层的光合作用效率是提高作物产量的关键。在此，我们评估了十个甘蔗品种和三个物种冠层的光合性能。评估了冠层形态特征，并在第一片（阳光照射，+1）和第四片（遮荫，+4）完全展开的叶片上以及在低光和高光条件下测量了叶片气体交换。在叶面积指数高且叶冠遮挡天空比例高（>85%）的基因型中，在高光条件下，+1和+4叶片具有相似的光合能力。有趣的是，这种冠层特征导致+4叶片的光照可用性低，这表明在某些基因型中，这些叶片的光合作用适应了自我遮荫。我们强调IACCTC06 - 8126和CTC4是那些具有较高冠层光合能力的基因型，它们具有高叶面积、阳光照射叶片的高光合速率以及遮荫叶片对光照可用性增加的高响应性。
