Kraklow Vachel, Dickman L Turin, Ryan Max G, Lathrop Emma, Heneghan Jack, Musa Dea, Sevanto Sanna
Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
Integral Ecology Group, Los Alamos, NM, 87545, USA.
Sci Rep. 2025 May 12;15(1):16476. doi: 10.1038/s41598-025-00582-6.
Stomatal Closure Point (SCP) has commonly been used to describe drought response strategies in plants, with isohydric species maintaining relatively high, constant SCP compared to anisohydric species that can lower SCP with increasing drought severity. However, there is evidence that, within these groups, SCP may respond dynamically to environmental conditions. Here, we explored how increasing water availability affects SCP in classically isohydric piñon pine and anisohydric one-seed or Utah juniper at various spatial- (i.e., from branch, to tree, to ecosystem) and temporal- (i.e., hours to decades) scales. Our results show that short-term increases in water availability decreased SCP in isohydric piñon pine, making it more anisohydric, while short-term rehydration had no effect on SCP in anisohydric juniper. Increasing mean annual precipitation, on the other hand, increased SCP in both species. Our findings are consistent with documented differences in the use of ABA to control stomata in iso- and aniso-hydric species on short timescales, and with structural acclimation in both species at long timescales. These results illustrate that the local environment plays a large role in determining SCP.
气孔关闭点（SCP）通常用于描述植物的干旱响应策略，与等水物种相比，同水物种的SCP相对较高且保持恒定，而异水物种的SCP会随着干旱程度的增加而降低。然而，有证据表明，在这些类别中，SCP可能会对环境条件做出动态响应。在这里，我们探讨了增加水分供应如何在不同的空间尺度（即从树枝到树木再到生态系统）和时间尺度（即从数小时到数十年）上影响典型的同水型矮松和异水型单籽松或犹他桧的SCP。我们的结果表明，短期增加水分供应会降低同水型矮松的SCP，使其更具异水特性，而短期复水对异水型桧的SCP没有影响。另一方面，年平均降水量的增加会使两个物种的SCP都升高。我们的研究结果与记录的同水型和异水型物种在短时间尺度上使用脱落酸控制气孔的差异一致，也与两个物种在长时间尺度上的结构适应一致。这些结果表明，当地环境在决定SCP方面起着很大的作用。
