Variations in the growth rate and nutritional composition of different prickly pear species is poorly understood. Therefore, we conducted an experiment using three species―Nopalea cochenillifera, Opuntia ficus-indica, and Opuntia mesacantha―and compared their cladode growth rates and fiber and mineral contents. All measured growth characteristics (vertical length, horizontal length, width, average fresh weight, and total fresh weight) were highest in O. ficus-indica among the three species. Yield differences were substantial, with the total fresh weight of the first-daughter cladodes in O. ficusindica being approximately six times greater than that of the other species. The total fiber content of cladodes was highest in O. mesacantha, followed by O. ficus-indica and N. cochenillifera. The mineral contents (calcium, copper, iron, magnesium, manganese, phosphorus, and zinc) of the three species were also analyzed. For example, calcium was the most abundant macromineral. No notable difference was observed between N. cochenillifera and O. mesacantha, whereas O. ficusindica had the lowest calcium content. These findings provide valuable insights into the growth and nutritional characteristics of prickly pear and can guide the selection and expansion of cultivation areas.

　Photosynthesis plays a central role in crop productivity. However, measuring canopy-scale photosynthetic rates typically requires expensive chamber systems that limit practical agricultural applications. Here, we developed a low-cost system that visualizes the spatial photosynthetic distribution in crop canopies by combining Red, Green, Blue (RGB) imagery with a biochemical photosynthesis model. RGB values showed strong correlation with photosynthetic photon flux density (PPFD) at both leaf and canopy scales. Our canopy photosynthetic index (A_RGB), which was calculated based on the estimated light intensity from the images, showed strong agreement with the chamber-based measurements. This approach eliminates the need for direct measurement of canopy photosynthetic rates, allowing rapid and easy adaptation to newly introduced crop species. Intuitive visualization of the spatial distribution of photosynthesis has considerable potential as a decision-support tool for cultivation management. This approach offers a practical middle ground for high-precision research tools and field-level monitoring.

　Water stress strongly constrains photosynthetic performance and yield in greenhouse-grown strawberry, making appropriate vapor pressure deficit (VPD) control essential for stable production. Recently, decision tree-based analyses have been proposed to identify VPD thresholds for water stress detection; however, the physiological validity of statistically derived thresholds remains unclear. Here, we evaluated whether water stress responses identified by decision tree analysis are insightful from a photosynthetic perspective. Leaf gas exchange measurements were conducted on strawberry plants under varying VPD conditions (0.8, 1.0, 2.0, and 3.0 kPa) at ambient and elevated CO₂ concentrations (400 and 800 μmol mol^-1). Across both CO₂ conditions, stomatal conductance (g_sw) and net photosynthetic rate (P_n) peaked at VPD = 1.0 kPa. Compared to ambient CO₂, under elevated CO₂, P_n was enhanced, whereas g_sw was reduced and showed lower sensitivity to increasing VPD. Intercellular CO₂ concentration was higher at elevated CO₂ and followed VPD-dependent patterns similar to those of g_sw. These results indicate that the VPD threshold identified by decision tree analysis (～1.0 kPa) reflects photosynthetic responses irrespective of CO₂ enrichment. These findings provide physiological support for decision tree-based water stress assessment in greenhouse-grown strawberries.