Stomatal and non-stomatal limitations to photosynthesis and acclimation of the photosynthetic machinery to repetitive water deficit (WD) events were investigated in oil palms (Elaeis guineensis Jacq.). For this, well-watered plants (control treatment) were compared with plants subjected to one, two, and three WD events imposed by withholding irrigation until their predawn leaf water potential (Ψ_pd) reached around −2.5 MPa. Treatment comparisons were performed over 28 days. The Ψ_pd decreased equally between WD treatments. Decreases in net CO₂ assimilation rate (A) were similar between stressed plants until day 7. In the following days, the A was higher in plants thrice stressed than in those stressed once. Stomatal conductance decreased similarly between WD treatments, but mesophyll conductance to CO₂ was lower in plants subjected to a single WD. Chloroplast CO₂ concentration decreased similarly between plants subjected to one and three WD events until day 14, but it was lower in the former on subsequent days. Plants subjected to a single WD event showed lower Ribulose 1,5 bisphosphate carboxylase/oxygenase (Rubisco) activity, maximum rate of electron transport (J_max), and higher rates of photorespiration and dark respiration than other treatments. Plants subjected to one WD event also showed lower maximum quantum efficiency of photosystem II (PSII) photochemistry and PSII maximum efficiency concomitantly with higher malondialdehyde content. The results support that repetitive WD events induce the acclimation of the photosynthetic machinery in oil palm through adjustments in carboxylase Rubisco activity, J_max, photorespiration, and respiration rates, as well as attenuating oxidative damages to PSII and membrane lipids.

在油棕( Elaeis guineensis Jacq.)中研究了光合作用和光合机械对重复缺水 (WD) 事件的适应和光合作用的气孔和非气孔限制。为此，将浇水充足的植物（对照处理）与经历 1、2 和 3 次 WD 事件的植物进行比较，该事件通过暂停灌溉直到其黎明前叶水势 (Ψ _pd ) 达到约 -2.5 MPa。治疗比较在 28 天内进行。WD 处理之间的 Ψ _pd下降相等。直到第 7 天，受胁迫植物之间的净 CO ₂同化率 ( A ) 的降低相似。在接下来的几天中，A三次胁迫的植物比受胁迫一次的植物更高。气孔导度在 WD 处理之间类似地降低，但在经历单一 WD 的植物中，叶肉对 CO _{2 的}导度较低。直到第 14 天，经历 1 次和 3 次 WD 事件的植物之间的叶绿体 CO ₂浓度类似地降低，但在随后的几天中前者的浓度较低。经历单一 WD 事件的植物表现出较低的核酮糖 1,5 二磷酸羧化酶/加氧酶 (Rubisco) 活性、最大电子传递速率 (J _max)，以及比其他处理更高的光呼吸和暗呼吸率。经历一次 WD 事件的植物还表现出较低的光系统 II (PSII) 光化学最大量子效率和 PSII 最大效率，同时丙二醛含量较高。结果支持重复 WD 事件通过调节羧化酶 Rubisco 活性、J _max、光呼吸和呼吸速率，以及减轻对 PSII 和膜脂的氧化损伤，诱导油棕光合机制的适应。