Kubiske M E, Abrams M D
School of Forest Resources, Forest Resources Laboratory, The Pennsylvania State University, 16802, University Park, PA, USA.
Oecologia. 1991 Feb;85(4):537-542. doi: 10.1007/BF00323766.
Seasonal pressure-volume (P-V) analyses were conducted on rehydrated and non-rehydrated leaves of Quercus rubra, Q. ilicifolia, Q. prinus, and Fraxinus americana in central Pennsylvania, U.S.A., to test the hypothesis that rehydration-induced shifts in P-V parameters occur in woody species from a non-arid region, and that the magnitude of these shifts increases with species drought tolerance and drought conditions. The species from a xeric ridge (Q. ilicifolia and Q. prinus) displayed increases of about 0.4-0.6 MPa in the osmotic potentials at full and zero turgor and a concurrent loss of symplastic solutes following 12 h and 24 h rehydration, particularly during a late-season drought. In contrast, the mesic, valley species (Q. rubra and F. americana) did not display significant shifts in osmotic parameters with rehydration at any time. In several instances, the relative water content at zero turgor (RWC) increased by about 6% (e.g., from 85% to 91%) and the bulk elastic modulus (ε) decreased by about 4.0 MPa following rehydration and correction for the plateau effect; the magnitude of these shifts was greatest in the xeric species. However, when data were not corrected for the plateau effect, RWC decreased by about 4% in some of the species/date combinations. Plateaus were also responsible for some of the decrease in ε with rehydration, but not for the shifts in osmotic potentials. The largest increases in osmotic potentials corresponded with decreases in tissue osmotic solute content. Rehydration-induced shifts in P-V parameters were responsible for masking or reducing most of the species and seasonal differences exhibited in nonrehydrated samples.
在美国宾夕法尼亚州中部，对红栎、冬青栎、栗栎和美国白蜡树重新水化和未重新水化的叶片进行了季节性压力-容积（P-V）分析，以检验以下假设：重新水化引起的P-V参数变化发生在非干旱地区的木本物种中，并且这些变化的幅度随着物种耐旱性和干旱条件的增加而增大。来自干旱山脊的物种（冬青栎和栗栎）在重新水化12小时和24小时后，尤其是在季节后期干旱期间，在完全膨压和零膨压下的渗透势增加了约0.4-0.6兆帕，并同时损失了共质体溶质。相比之下，中生的山谷物种（红栎和美国白蜡树）在任何时候重新水化时渗透参数都没有显著变化。在几个实例中，重新水化并校正平台效应后，零膨压下的相对含水量（RWC）增加了约6%（例如，从85%增加到91%），体积弹性模量（ε）降低了约4.0兆帕；这些变化在旱生物种中最为明显。然而，当数据未校正平台效应时，在一些物种/日期组合中，RWC下降了约4%。平台效应也是重新水化后ε降低的部分原因，但不是渗透势变化的原因。渗透势的最大增加与组织渗透溶质含量的降低相对应。重新水化引起的P-V参数变化掩盖或减少了未重新水化样品中表现出的大多数物种和季节差异。
