IMEM "Ramon Margalef", University of Alicante, Apdo. 99, Alicante, 03080, Spain.
Department of Ecology, University of Alicante, Apdo. 99, Alicante, 03080, Spain.
Plant Cell Environ. 2018 Aug;41(8):1926-1934. doi: 10.1111/pce.13340. Epub 2018 Jun 15.
We investigated stem radial growth and water storage dynamics of 2 conifer species differing in hydraulic carbon strategies, Juniperus monosperma and Pinus edulis, under conditions of ambient, drought (∼45% reduction in precipitation), heat (∼4.8 °C temperature increase), and the combination of drought + heat, in 2013 and 2014. Juniper maintained low growth across all treatments. Overall, the relatively isohydric piñon pine showed significantly greater growth and water storage recharge than the relatively anisohydric juniper across all treatments in the average climate year (2014) but no differences in the regionally dry year (2013). Piñon pine ceased growth at a constant predawn water potential across all treatments and at a less negative water potential threshold than juniper. Heat has a greater negative impact on piñon pines' growth and water storage than drought, whereas juniper was, in contrast, unaffected by heat but strongly impacted by drought. The whole-plant hydraulic carbon strategies, in this case captured using the isohydric/anisohydric concept, translate into alternative growth and water storage strategies under drought and heat conditions.
我们研究了 2 种针叶树种（Juniperus monosperma 和 Pinus edulis）的茎径向生长和水分储存动态，这 2 种树种的水力碳策略不同，在环境条件下、干旱（降水减少约 45%）、热（温度升高约 4.8°C）以及干旱+热的组合条件下，在 2013 年和 2014 年进行了研究。Juniper 在所有处理中均保持低生长。总体而言，相对等水势的 piñon pine 在平均气候年（2014 年）的所有处理中比相对非等水势的 juniper 表现出显著更大的生长和水分储存补给，但在区域干旱年（2013 年）没有差异。piñon pine 在所有处理中都在恒定的黎明前水势下停止生长，并且比 juniper 的水势阈值更小。热对 piñon pines 的生长和水分储存的负面影响大于干旱，而 juniper 则相反，不受热的影响，但受干旱的强烈影响。在这种情况下，使用等水势/非等水势概念来捕获整个植物的水力碳策略，转化为干旱和热条件下的替代生长和水分储存策略。
