Abstract Obligate crassulacean acid metabolism (CAM) plants rely heavily on nocturnal CO2 fixation; however, little is known about how changes in CO2 concentration affect the nutrient requirements of these plants. To evaluate the combined effect of CO2 concentration and nutrient provision on obligate CAM plants, we cultivated Phalaenopsis Queen Beer ‘Mantefon’ under two CO2 concentrations (400 or 800 μmol· mol−1) and with four nutrient solutions (EC [electrical conductivity] of 1.0, 2.0, 3.0, or 4.0 dS·m−1) for 17 weeks. Various flowering characteristics of Phalaenopsis (flower spike length, the number of lateral branches, floral buds, and flowers, days to flowering, flower size, and flower color) were then investigated during the reproductive stage. Overall, higher CO2 concentrations enhanced the growth and productivity of Phalaenopsis. More specifically, flower spike lengths were longer and more lateral branches were initiated under 800 μmol·mol−1 CO2 compared to plants cultivated under 400 μmol·mol−1 CO2 with an EC of 3.0 or 4.0 dS·m−1. Additionally, plants cultivated under 800 μmol·mol−1 CO2 had greater number of floral buds and flowers than those cultivated under 400 μmol·mol−1 CO2, regardless of EC. Floral buds and flowers were not linearly increased by increasing EC, regardless of CO2 concentration. Flowering time was faster in plants cultivated under 800 μmol·mol−1 CO2. Altogether, these results suggest that an elevated atmospheric CO2 concentration positively affects the flower spike length and the number of lateral branches, floral buds, and flowers of Phalaenopsis and also indicate that nutrient levels can be adjusted to improve the growth of obligate CAM plants.

中文翻译：

---

蝴蝶兰女王啤酒'Mantefon'在二氧化碳升高和营养供应分级下的开花反应

摘要 专性景天酸代谢 (CAM) 植物严重依赖夜间 CO2 固定；然而，人们对二氧化碳浓度的变化如何影响这些植物的营养需求知之甚少。为了评估 CO2 浓度和养分供应对专性 CAM 植物的综合影响，我们在两种 CO2 浓度（400 或 800 μmol·mol-1）和四种营养液（EC [电导率] 1.0、2.0、3.0 或 4.0 dS·m-1)，持续 17 周。然后在生殖阶段研究蝴蝶兰的各种开花特征（花穗长度、侧枝数、花芽和花、开花天数、花大小和花色）。总体而言，较高的二氧化碳浓度提高了蝴蝶兰的生长和生产力。更具体地说，与在 EC 为 3.0 或 4.0 dS·m-1 的 400 μmol·mol-1 CO2 下培养的植物相比，在 800 μmol·mol-1 CO2 下花穗长度更长并且更多的侧枝被启动。此外，在 800 μmol·mol-1 CO2 下栽培的植物比在 400 μmol·mol-1 CO2 下栽培的植物具有更多的花芽和花，而与 EC 无关。无论 CO2 浓度如何，花蕾和花朵都不会随着 EC 的增加而线性增加。在 800 μmol·mol−1 CO2 条件下栽培的植物开花时间更快。总之，这些结果表明大气 CO2 浓度升高对蝴蝶兰的花穗长度和侧枝、花芽和花的数量有积极影响，并且还表明可以调整营养水平以改善专性 CAM 植物的生长。