Multidecadal records of intrinsic water-use efficiency in the desert shrub Encelia farinosa reveal strong responses to climate change
Multidecadal records of intrinsic water-use efficiency in the desert shrub Encelia farinosa reveal strong responses to climate change
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DOI：
10.1073/pnas.2008345117
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发表时间：
2020-08-04
影响因子：
11.1
通讯作者：
Ehleringer, James R.
中科院分区：
文献类型：
--
作者：
Driscoll, Avery W.;Bitter, Nicholas Q.;Ehleringer, James R.
虽然树木年轮能够对气候对树木的影响进行年际检查，但对大多数灌木来说，这是不可能的。在这里，我们利用一个几十年的记录，每年的叶面碳同位素比收集再加上39年的调查数据，从两个人口的干旱落叶沙漠灌木Encelia farinosa提供洞察用水动态和气候。这种碳同位素记录提供了一个独特的机会，以检查沙漠灌木对气候迅速变化地区温度和水分胁迫的反应。种群平均碳同位素比值波动可预测的年际变化的温度，蒸汽压赤字，降水量和个人之间的反应是相似的。我们利用叶片碳同位素比值和细胞内与环境CO2浓度的比值之间的关系来计算植物的内在水分利用效率（iWUE），并量化植物对长期环境变化的响应。在研究期间，种群平均iWUE值增加了53%至58%，远远超过森林中测量的20%至30%的增加[J. Penuelas，J. G.卡纳代尔河小川屋，环球。生物地理生态学20，597-608（2011）]。变化与CO2浓度增加和水分胁迫增加有关。个体的寿命跨越整个研究期间表现出的iWUE的增加是非常相似的人口平均值，这表明有显着的可塑性，而不是在人口规模的选择在个人。
While tree rings have enabled interannual examination of the influence of climate on trees, this is not possible for most shrubs. Here, we leverage a multidecadal record of annual foliar carbon isotope ratio collections coupled with 39 y of survey data from two populations of the drought-deciduous desert shrub Encelia farinosa to provide insight into water-use dynamics and climate. This carbon isotope record provides a unique opportunity to examine the response of desert shrubs to increasing temperature and water stress in a region where climate is changing rapidly. Population mean carbon isotope ratios fluctuated predictably in response to interannual variations in temperature, vapor pressure deficit, and precipitation, and responses were similar among individuals. We leveraged the well-established relationships between leaf carbon isotope ratios and the ratio of intracellular to ambient CO2 concentrations to calculate intrinsic water-use efficiency (iWUE) of the plants and to quantify plant responses to long-term environmental change. The population mean iWUE value increased by 53 to 58% over the study period, much more than the 20 to 30% increase that has been measured in forests [J. Penuelas, J. G. Canadell, R. Ogaya, Glob. Ecol. Biogeogr. 20, 597-608 (2011)]. Changes were associated with both increased CO2 concentration and increased water stress. Individuals whose lifetimes spanned the entire study period exhibited increases in iWUE that were very similar to the population mean, suggesting that there was significant plasticity within individuals rather than selection at the population scale.