Raub H D, Rajan N, Mcinnes K J, West J B
Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX 77843, USA.
Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843, USA.
Photosynthetica. 2023 May 25;61(3):285-296. doi: 10.32615/ps.2023.018. eCollection 2023.
Woody plant areal encroachment is pervasive throughout the Southern Great Plains, USA. The ability of woody plants to dissipate excess solar radiation - dynamically over the day and sustained periods without recovery overnight - is key for maintaining photosynthetic performance during dry stretches, but our understanding of these processes remains incomplete. Photosynthetic performance and energy dissipation were assessed for co-occurring encroachers on the karst Edwards Plateau (, , and ) under seasonal changes in water status. Only experienced mild photoinhibition from sustained energy dissipation overnight while experiencing the lowest photochemical yields, minimal photosynthetic rates, and the highest dynamic energy dissipation rates at midday during the dry period - indicating susceptibility to photosynthetic downregulation and increased dissipation under future drought regimes. Neither other encroacher experienced sustained energy dissipation in the dry period, though did experience marked reductions in photosynthesis, photochemical yields, and increased regulatory dynamic energy dissipation.
木本植物的区域扩张在美国南部大平原随处可见。木本植物在一天中动态消散多余太阳辐射以及在持续时间段内无需夜间恢复的能力，是在干旱期维持光合性能的关键，但我们对这些过程的理解仍不完整。在岩溶爱德华兹高原（，，和），针对共同出现的入侵植物，在水分状况的季节性变化下评估了光合性能和能量消散情况。只有在干旱期中午经历了最低的光化学产量、最小的光合速率和最高的动态能量消散率，同时因夜间持续能量消散而经历了轻度光抑制——这表明在未来干旱条件下易受光合下调和增加的消散影响。在干旱期，其他入侵植物均未经历持续的能量消散，尽管确实经历了光合作用、光化学产量的显著降低以及调节性动态能量消散的增加。
