Garrido Marco, Silva Herman, Franck Nicolás, Arenas Jorge, Acevedo Edmundo
Soil-Plant-Water Relations Laboratory, Agricultural Production Department, Faculty of Agronomical Sciences, Universidad de Chile, Santiago, Chile.
Faculty of Natural Renewable Resources, Desert Agriculture, Universidad Arturo Prat, Iquique, Chile.
Front Plant Sci. 2018 Apr 9;9:453. doi: 10.3389/fpls.2018.00453. eCollection 2018.
Water extraction from the underground aquifers of the Pampa del Tamarugal (Atacama Desert, Chile) reduced the growing area of , a strict phreatic species endemic to northern Chile. The objective of this work was to evaluate the effect of various architectural and morpho-physiological traits adjustment of subjected to three groundwater depletion intervals (GWDr): <1 m (control), 1-4 m and 6-9 m. The traits were evaluated at three levels, plant [height, trunk cross-section area, leaf fraction (GCC), and crown size], organ [length of internodes, leaf mass per unit area (LMA), leaflet mass and area], and tissue level [wood density (WD), leaf C, O isotope composition (δ), and intrinsic water use efficiency (iWUE)]. In addition, soil water content (VWC) to 1.3 m soil depth, pre-dawn and midday water potential difference (ΔΨ), and stomatal conductance (g) were evaluated. At the deeper GWDr, experienced significant growth restriction and reduced GCC, the remaining canopy had a significantly higher LMA associated with smaller leaflets. No differences in internode length and WD were observed. Values for δC and δO indicated that as GWDr increased, iWUE increased as a result of partial stomata closure with no significant effect on net assimilation over time. The morpho-physiological changes experienced by allowed it to acclimate and survive in a condition of groundwater depletion, keeping a functional but diminished canopy. These adjustments allowed maintenance of a relatively high g; ΔΨ was not different among GWDrs despite smaller VWC at greater GWDr. Although current conservation initiatives of this species are promising, forest deterioration is expected continue as groundwater depth increases.
从智利阿塔卡马沙漠的潘帕德尔塔马鲁加尔地下蓄水层抽取水源，导致智利北部特有的严格依赖潜水层的物种——[物种名称未给出]的生长区域缩小。本研究的目的是评估[物种名称未给出]在三种地下水水位下降区间（GWDr）：<1米（对照）、1 - 4米和6 - 9米条件下，各种结构和形态生理特征的调整效果。这些特征在三个层面进行评估，即植株层面[高度、树干横截面积、叶面积比例（GCC）和树冠大小]、器官层面[节间长度、单位面积叶质量（LMA）、小叶质量和面积]以及组织层面[木材密度（WD）、叶片碳、氧同位素组成（δ）和内在水分利用效率（iWUE）]。此外，还评估了土壤深度达1.3米处的土壤含水量（VWC）、黎明前和中午的水势差（ΔΨ）以及气孔导度（g）。在更深的GWDr条件下，[物种名称未给出]经历了显著的生长受限且GCC降低，剩余树冠的LMA显著更高，且小叶更小。节间长度和WD未观察到差异。δC和δO值表明，随着GWDr增加，由于部分气孔关闭，iWUE增加，且随着时间推移对净同化没有显著影响。[物种名称未给出]经历的形态生理变化使其能够在地下水水位下降的条件下适应并存活，保持一个功能正常但面积减小的树冠。这些调整使得g维持在相对较高水平；尽管在更大的GWDr条件下VWC较小，但不同GWDr之间的ΔΨ并无差异。尽管目前针对该物种的保护举措很有前景，但随着地下水位加深，预计森林退化仍将继续。
