Water Relations of Evergreen Sclerophylls. I. Seasonal Changes in the Water Relations of Eleven Species from the Same Environment

Rhizopoulou, Sophia; Mitrakos, K.

doi:10.1093/oxfordjournals.aob.a087921

Cited by 91 publications

(47 citation statements)

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“…Although the ψ md experienced were far below the ψ threshold for increased embolism initiation (Martínez-Vilalta et al 2002), the water deficit did not surpass the lethal level as we did not observe any significant leaf dessication damage. In agreement with previous results (De Fontanella 1992, Rhizoupoulou andMitrakos 1990), P. latifolia showed a lower water potential operative range than Q. ilex as indicated by the ca. 3.0 MPa difference in ψ pd between species during summer drought.…”

Section: Plant and Tissue Water Relationssupporting

confidence: 93%

Contribution of physiological and morphological adjustments to drought resistance in two Mediterranean tree species

Serrano¹,

Peñuelas²

2005

Biol. plant.

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Plant water potential (ψ), its components, and gas exchange data of two Mediterranean co-occurring woody species (Quercus ilex L. and Phillyrea latifolia L.) were measured in response to seasonal changes in water availability over two consecutive years. The relative contribution of physiological and morphological adjustments to drought resistance was assessed through Principal Component Analyses. There were large adjustments in stomatal conductance (~36 % of accounted variance). Net photosynthetic rate and water use efficiency were closely tuned to water availability and accounted for ~17 % of variance. The slope of the water potential vs. relative water content (dψ/dRWC 0 ) below zero pressure potential increased as a result of seasonal and ontogenic increases in apoplastic water fraction and accounted for ~20 % variance. This tolerance mechanism was accompanied by an increased range of positive pressure potential, suggesting a functional role of sclerophylly in these Mediterranean evergreens. Similarly, changes in the slope of dψ/dRWC in the range of positive pressure potential (~13 % of accounted variance) were associated to variations in cell wall elasticity and resulted in lower RWC at zero pressure potential. When considering the species studied separately, the results indicated the primary role of stomatal regulation in the drought resistance of Q. ilex, while increased apoplastic water fraction had a major contribution in the drought resistance of P. latifolia.Additional key words: drought stress, Phillyrea latifolia, net photosynthetic rate, plant and tissue-water relations, Quercus ilex, stomatal conductance, water potential.

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Section: Plant and Tissue Water Relationssupporting

confidence: 93%

Contribution of physiological and morphological adjustments to drought resistance in two Mediterranean tree species

Serrano¹,

Peñuelas²

2005

Biol. plant.

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“…Conditions of high soil water availability may limit the explanatory power of the plant-water physiological measurements reported in this study, as many of them are known to be strongly affected by water availability (Hinckley et al 1980;Davis and Mooney 1986;Rhizopoulou and Mitrakos 1990;Abril and Hanano 1998;Salleo and Nardini 2000;Serrano et al 2005;Galmes et al 2007). Thus, the values reported here may differ substantially from those that may be obtained under field (drier) conditions.…”

Section: Discussionmentioning

confidence: 95%

“…Thus, the values reported here may differ substantially from those that may be obtained under field (drier) conditions. While we would expect low water availability to alter the mean values of TRc, RWC tlp , Rh, SLW and Width for each guild, we would also expect dry conditions to increase the relative differences of these traits between guilds (Hinckley et al 1980;Davis and Mooney 1986;Rhizopoulou and Mitrakos 1990;Abril and Hanano 1998;Salleo and Nardini 2000;Serrano et al 2005;Galmes et al 2007). We then consider our measurements under well-watered conditions to be under estimates of drought tolerance for these species and a conservative estimate of differences in drought tolerance between guilds.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, Mediterranean climates differing in severity of summer drought may produce variable adaptive responses. We predict that grasses with different growth forms and life history as well as from regions with differing summer rainfall regimes, will exhibit different leaf ecophysiological traits (Hinckley et al 1980;Davis and Mooney 1986;Rhizopoulou and Mitrakos 1990;Abril and Hanano 1998;Salleo and Nardini 2000;Serrano et al 2005;Galmes et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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California perennial grasses are physiologically distinct from both Mediterranean annual and perennial grasses

et al. 2011

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In the Central Valley of California, native perennial grass species have been largely replaced by Eurasian annual species, while in many parts of the Mediterranean Basin native perennial grasses continue to dominate, even on disturbed or degraded sites. We assessed whether differences in summer rainfall patterns have lead to the development of different plant-water strategies between grasses from these two regions. We compared six measures of plant-water physiology for three guilds of grasses: California perennial grasses, Mediterranean perennial grasses, and Mediterranean annual grasses. Discriminant analysis distinguished between the three guilds; Mediterranean perennial grasses were characterized by a more conservative water-relations physiology than Mediterranean annual grasses, whereas California perennial grasses were in some ways intermediate between the two Mediterranean grass guilds. For individual traits, California perennial grasses were either intermediate or more like Mediterranean annuals than Mediterranean perennials. Our results suggest California perennials are more drought tolerant than Mediterranean annuals but less drought tolerant than Mediterranean perennials, despite the fact that California's Central Valley has a more intense summer drought than the Mediterranean Basin. These patterns may help explain why Mediterranean annuals, but not Mediterranean perennials, have been more successful invaders of interior California grasslands.

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“…Evergreen shrub species in the Mediterranean area may suffer considerable water stress during the summer dry season (Tenhunen et al 1985;Lo Gullo & Salleo 1988;Rhizopoulou & Mitrakos 1990), and may thus be affected by any climate change that increases or decreases available soil moisture. According to General Circulation Models, plant communities of Mediterraneantype ecosystems will have to face more severe drought conditions (Mitchell et al 1990).…”

Section: Introductionmentioning

confidence: 99%

Seasonal patterns of tissue water relations in three Mediterranean shrubs co‐occurring at a natural CO₂ spring

Tognetti

Raschi²,

Jones

2000

Plant Cell & Environment

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Seasonal changes in tissue water relations of Erica arborea L., Myrtus communis L. and Juniperus communis L., grown in a Mediterranean environment, were analysed under field conditions over a 12 month period by comparing plants grown in the proximity of a natural CO 2 spring (about 700 mmol mol -1 atmospheric CO 2 concentration, [CO 2 ]) with plants in ambient conditions. Tissue water relations varied in response to changes in water availability, but the seasonal course of tissue water relations parameters was also related to ontogeny. Tissue water relations of these co-occurring shrubs were not alike. Osmotic potentials and saturated mass/dry mass ratio were lowest during peak drought stress periods. Diurnal changes in osmotic potential at the point of turgor loss were least early in the season, maximal in mid-season, and decreased again in autumn. Turgor potentials decreased as drought progressed and were highest in late fall and mid-winter. Symplastic water fraction was highest in mid-spring for E. arborea and M. communis and decreased during the summer, while the opposite was observed for J. communis. Common to all species, under elevated [CO 2 ], was an increase of turgor pressure, particularly during the summer months. Other parameters showed species-specific responses to long-term elevated [CO 2 ]. In particular, exposure to elevated [CO 2 ] increased osmotic potentials in E. arborea under drought, while the opposite was the case for J. communis. Site differences in predawn to midday shifts were not strong in any of the species. Differences in tissue water relations suggest that the coexistence of these shrubs in the same environment with similar water availability are partially based on differential water relations strategies and water use patterns. Regardless of the mechanisms, growth of these shrubs in elevated [CO 2 ] may be either less, similarly or more affected by drought stress than plants in ambient [CO 2 ] depending on the species and season.

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Water Relations of Evergreen Sclerophylls. I. Seasonal Changes in the Water Relations of Eleven Species from the Same Environment

Cited by 91 publications

References 0 publications

Contribution of physiological and morphological adjustments to drought resistance in two Mediterranean tree species

Contribution of physiological and morphological adjustments to drought resistance in two Mediterranean tree species

California perennial grasses are physiologically distinct from both Mediterranean annual and perennial grasses

Seasonal patterns of tissue water relations in three Mediterranean shrubs co‐occurring at a natural CO₂ spring

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Water Relations of Evergreen Sclerophylls. I. Seasonal Changes in the Water Relations of Eleven Species from the Same Environment

Cited by 91 publications

References 0 publications

Contribution of physiological and morphological adjustments to drought resistance in two Mediterranean tree species

Contribution of physiological and morphological adjustments to drought resistance in two Mediterranean tree species

California perennial grasses are physiologically distinct from both Mediterranean annual and perennial grasses

Seasonal patterns of tissue water relations in three Mediterranean shrubs co‐occurring at a natural CO2 spring

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Product

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Seasonal patterns of tissue water relations in three Mediterranean shrubs co‐occurring at a natural CO₂ spring