Water relations of evergreen and drought-deciduous trees along a seasonally dry tropical forest chronosequence.
Water relations of evergreen and drought-deciduous trees along a seasonally dry tropical forest chronosequence.
复制标题
DOI：
10.1007/s00442-010-1725-y
复制
发表时间：
2010-12
期刊：
影响因子：
2.7
通讯作者：
Santiago, Louis S.
中科院分区：
文献类型：
--
作者：
Hasselquist, Niles J.;Allen, Michael F.;Santiago, Louis S.
季节性干燥热带森林（SDTF）的特点是降雨具有明显的季节性，因此这些森林中的树木必须忍受土壤水分有效性的季节性变化。此外，墨西哥尤卡坦半岛北部的SDTF受到了扰动的影响，从而形成了一个由不同的几个阶段组成的马赛克，经历了二次演替。为了更好地了解树木克服季节性水分限制的策略，我们研究了六种冠层树种的水分状况，它们代表了不同时期的不同叶片物候（常绿与干旱落叶）。早生林土壤水分蒸发量大，土壤水分含量低，因此早生林正午体积叶水势（ΨL）较晚生林低，分别为- 1.01±0.14 MPa和- 0.54±0.07 MPa。虽然ΨL在常绿树木和干旱落叶树木之间没有差异，但稳定同位素分析的结果表明克服季节性水分限制的策略不同。在早期阶段，常绿树种的木质部水分δ18O值明显低于干旱落叶树种（分别为- 2.6±0.5‰和0.3±0.6‰），说明常绿树种利用了较深的水源。而干旱落叶乔木叶片18O（∆18Ol）和13C的富集程度较高，说明气孔导度较低，水分利用效率较高。因此，深根的快速发育似乎是使常绿物种克服季节性水分限制的重要策略，而干旱落叶树木除了失去部分叶子外，还可以最大限度地减少干旱季节剩余叶子的水分损失。
Seasonally dry tropical forests (SDTF) are characterized by pronounced seasonality in rainfall, and as a result trees in these forests must endure seasonal variation in soil water availability. Furthermore, SDTF on the northern Yucatan Peninsula, Mexico, have a legacy of disturbances, thereby creating a patchy mosaic of different seral stages undergoing secondary succession. We examined the water status of six canopy tree species, representing contrasting leaf phenology (evergreen vs. drought-deciduous) at three seral stages along a fire chronosequence in order to better understand strategies that trees use to overcome seasonal water limitations. The early-seral forest was characterized by high soil water evaporation and low soil moisture, and consequently early-seral trees exhibited lower midday bulk leaf water potentials (ΨL) relative to late-seral trees (−1.01 ± 0.14 and −0.54 ± 0.07 MPa, respectively). Although ΨL did not differ between evergreen and drought-deciduous trees, results from stable isotope analyses indicated different strategies to overcome seasonal water limitations. Differences were especially pronounced in the early-seral stage where evergreen trees had significantly lower xylem water δ18O values relative to drought-deciduous trees (−2.6 ± 0.5 and 0.3 ± 0.6‰, respectively), indicating evergreen species used deeper sources of water. In contrast, drought-deciduous trees showed greater enrichment of foliar 18O (∆18Ol) and 13C, suggesting lower stomatal conductance and greater water-use efficiency. Thus, the rapid development of deep roots appears to be an important strategy enabling evergreen species to overcome seasonal water limitation, whereas, in addition to losing a portion of their leaves, drought-deciduous trees minimize water loss from remaining leaves during the dry season.
登录
查看更多内容
影响因子：
6.4
作者：
ALLISON, GB;HUGHES, MW
通讯作者：
HUGHES, MW
影响因子：
64.8
作者：
DAWSON, TE;EHLERINGER, JR
通讯作者：
EHLERINGER, JR
影响因子：
7.4
作者：
Farquhar, Graham D.;Cernusak, Lucas A.;Barnes, Belinda
通讯作者：
Barnes, Belinda
影响因子：
2.3
作者：
Farrington, P;Turner, JV;Gailitis, V
通讯作者：
Gailitis, V
影响因子：
1.7
作者：
Goode, Laurel K.;Allen, Michael F.
通讯作者：
Allen, Michael F.