Espinoza Sergio, Magni Carlos, Yáñez Marco, Toro Nicole, Martínez-Herrera Eduardo
Departamento de Ciencias Forestales, Facultad de Ciencias Agrarias y Forestales, Universidad Católica del Maule, Talca 3460000, Chile.
CESAF, Facultad de Ciencias Forestales y de la Conservación de la Naturaleza, Universidad de Chile, Santiago 8820808, Chile.
Plants (Basel). 2025 Aug 27;14(17):2682. doi: 10.3390/plants14172682.
The photochemical efficiency of photosystem II (PSII) was monitored in two-year-old seedlings from six Chilean woody sclerophyllous species differing in foliage habits (evergreen, deciduous, semi-deciduous) and leaf orientation. A common garden experiment was established in July 2020 in a Mediterranean-type climate site under two watering regimes (2 L seedling week for 5 months versus no irrigation). Chlorophyll a fluorescence rise kinetics (OJIP) and JIP test analysis were monitored from December 2021 to January 2022. The semi-deciduous (leaf angle of 65°) exhibited the highest performance in processes such as absorption and trapping photons, heat dissipation, electron transport, and level of photosynthetic performance (i.e., parameters PI F/F, F/F, and ΔV). In contrast, the evergreen (leaf rolling) exhibited the opposite behavior for the same parameters. On the other hand, the deciduous (small compound leaves and leaf angle of 15°) showed the lowest values for minimal and maximal fluorescence (F and F) and the highest area above the OJIP transient (S) during the study period. Irrigation decreased S and the relative contribution of electron transport (parameter ΔV) by 22% and 17%, respectively, but no clear effects of the irrigation treatments were observed among species and dates of measurement. Overall, . and . exhibited the highest photosynthetic performance, whereas . seemed to be more prone to photoinhibition. We conclude that different foliar adaptations among species influence light protection mechanisms more than irrigation treatments.
对六种智利硬叶木本植物的两年生幼苗进行了光系统II（PSII）光化学效率监测，这些植物在叶片习性（常绿、落叶、半落叶）和叶片方向上存在差异。2020年7月，在一个地中海型气候地点建立了一个共同花园实验，设置了两种浇水方案（5个月内每周给幼苗浇水2升与不灌溉）。在2021年12月至2022年1月期间监测了叶绿素a荧光上升动力学（OJIP）和JIP测试分析。半落叶植物（叶角为65°）在吸收和捕获光子、散热、电子传递以及光合性能水平（即参数PI F/F、F/F和ΔV）等过程中表现出最高性能。相比之下，常绿植物（叶片卷曲）在相同参数上表现出相反的行为。另一方面，落叶植物（小复叶，叶角为15°）在研究期间的最小和最大荧光（F和F）值最低，OJIP瞬变曲线以上的面积（S）最高。灌溉分别使S和电子传递的相对贡献（参数ΔV）降低了22%和17%，但在不同物种和测量日期之间未观察到灌溉处理的明显影响。总体而言，……和……表现出最高的光合性能，而……似乎更容易受到光抑制。我们得出结论，物种间不同的叶片适应性对光保护机制的影响大于灌溉处理。
