Gas exchange and leaf area requirement for yield in Cavendish and Gros Michel Bananas

Abstract The objective was to evaluate gas exchange and the leaf area requirement for yield in Cavendish and Gros Michel bananas. The cultivars Grande Naine, Calipso, Bucaneiro, FHIA-17 and FHIA-23, and two production cycles, were arranged in a completely randomized experimental design, in a factorial scheme, with five replicates. For the physiological characteristics, a 5x9x2 factorial arrangement was considered, with cultivars, evaluation periods and reading times. Cultivars Bucaneiro and Calipso require larger leaf area per unit produced and FHIA-23, smaller, which suggests a greater photosynthetic efficiency per leaf unit for FHIA-23, confirmed by the higher masses of bunches and hands and greater numbers of hands and fruits. Gas exchange varies with cultivars, evaluation periods and reading times. Cultivars FHIA-17 and Calipso, Gros Michel type, respectively showed higher photosynthesis and transpiration rates than Grande Naine, Cavendish type. Net photosynthesis, stomatal conductance, quantum efficiency of photosynthesis, instantaneous water use efficiency and carboxylation efficiency are higher at 8:00 h than at 14:00 h. The month of June allowed the cultivars to express the highest values of photosynthesis rates, incident radiation on leaves, carboxylation efficiency and stomatal conductance.

摘要 本研究旨在评估卡文迪许（Cavendish）香蕉与格罗米歇尔（Gros Michel）香蕉的气体交换特性，以及产量所需的叶面积需求。试验以Grande Naine、Calipso、Bucaneiro、FHIA-17及FHIA-23共5个品种为材料，设置2个生产周期，采用完全随机析因试验设计，每组设置5次重复。针对生理特性指标，试验采用5（品种）×9（测定时期）×2（读取时段）的析因设计，变量涵盖品种、测定周期与读取时刻。结果显示，Bucaneiro与Calipso品种每单位产量所需叶面积更大，而FHIA-23所需叶面积更小，这表明FHIA-23具备更高的单位叶面积光合效率；该结论得到了更高的果穗质量、果梳质量，以及更多的果梳数与果实数的佐证。气体交换参数随品种、测定时期与读取时段的不同而存在显著差异。FHIA-17与Calipso分别属于格罗米歇尔类型，其光合速率与蒸腾速率均显著高于卡文迪许类型的Grande Naine品种。净光合速率、气孔导度、光合量子效率、瞬时水分利用效率与羧化效率均在8:00时显著高于14:00时。6月份供试品种的光合速率、叶片入射辐射、羧化效率与气孔导度均达到最高水平。