The response of plant species to environmental conditions influences changes in functional traits associated with the process that determines biological fitness and ecosystem processes. However, documenting these responses remain largely elusive in cultivation systems. We analyzed how environmental variables and leaf traits have effects on the transpiration rate of cocoa (Theobroma cacao L.) trees compared among different cultivation systems. Fieldwork was carried out at the Sara Ana experimental station in Alto Beni, La Paz, Bolivia. We sampled four trees in each of eight plots; four plots for each cultivation system (organic monoculture vs. organic agroforestry). From each tree, two mature, sunlit and healthy leaves were collected to make measurements of foliar traits and environmental variables. We found that canopy cover was higher in the agroforestry system. The specific leaf area was greater in agroforestry but the stomata size was significantly higher in the monoculture system. Temperature had a positive relationship with transpiration, whereas canopy cover and specific leaf area had a negative relationship in the agroforestry system. Cultivation system caused changes in microenvironmental conditions and on the expression of leaf traits that regulate water flow through the plant. Thus, the mutual effects of canopy cover, larger leaves and smaller stomatal size may drive a more efficient water use by reducing the transpiration rate of plants growing in agroforestry systems.

中文翻译：

---

不同栽培系统下环境变量和叶面性状对可可（Theobroma cacao L.）蒸腾速率的影响

植物物种对环境条件的反应会影响与决定生物适应性和生态系统过程的过程相关的功能性状的变化。然而，在栽培系统中记录这些反应在很大程度上仍然难以捉摸。我们分析了环境变量和叶片性状如何影响可可 (Theobroma cacao L.) 树在不同栽培系统中的蒸腾速率。实地考察是在玻利维亚拉巴斯 Alto Beni 的 Sara Ana 实验站进行的。我们在八个地块中的每一个中抽取了四棵树；每个栽培系统的四个地块（有机单一栽培与有机农林业）。从每棵树上收集两片成熟、阳光照射和健康的叶子，以测量叶面特征和环境变量。我们发现农林业系统的树冠覆盖率更高。农林业的比叶面积更大，但单一栽培系统的气孔大小显着更高。温度与蒸腾作用呈正相关，而在农林复合系统中，冠层盖度和比叶面积呈负相关。栽培系统引起微环境条件的变化和调节通过植物的水流的叶片性状的表达。因此，冠层覆盖、较大的叶子和较小的气孔尺寸的相互影响可能会通过降低在农林复合系统中生长的植物的蒸腾速率来提高用水效率。温度与蒸腾作用呈正相关，而在农林复合系统中，冠层盖度和比叶面积呈负相关。栽培系统引起微环境条件的变化和调节通过植物的水流的叶片性状的表达。因此，冠层覆盖、较大的叶子和较小的气孔尺寸的相互影响可能会通过降低在农林系统中生长的植物的蒸腾速率来提高用水效率。温度与蒸腾作用呈正相关，而在农林复合系统中，冠层盖度和比叶面积呈负相关。栽培系统引起微环境条件的变化和调节通过植物的水流的叶片性状的表达。因此，冠层覆盖、较大的叶子和较小的气孔尺寸的相互影响可能会通过降低在农林系统中生长的植物的蒸腾速率来提高用水效率。