Plant and Soil

, Volume 313, Issue 1, pp 113–127

Linking the patterns in soil moisture to leaf water potential, stomatal conductance, growth, and mortality of dominant shrubs in the Florida scrub ecosystem

  • Sonali Saha
  • Theresa M. Strazisar
  • Eric S. Menges
  • Patrick Ellsworth
  • Leonel Sternberg
Regular Article

DOI: 10.1007/s11104-008-9684-3

Cite this article as:
Saha, S., Strazisar, T.M., Menges, E.S. et al. Plant Soil (2008) 313: 113. doi:10.1007/s11104-008-9684-3

Abstract

Patterns in soil moisture availability affect plant survival, growth and fecundity. Here we link patterns in soil moisture to physiological and demographic consequences in Florida scrub plants. We use data on different temporal scales to (1) determine critical soil moisture content that leads to loss of turgor in leaves during predawn measurements of leaf water status (Ψcrit), (2) describe the temporal patterns in the distribution of Ψcrit, (3) analyze the strength of relationship between rainfall and soil moisture content based on 8 years of data, (4) predict soil moisture content for 75 years of rainfall data, and (5) evaluate morphological, physiological and demographic consequences of spring 2006 drought on dominant shrubs in Florida scrub ecosystem in the light of water-uptake depth as determined by stable isotope analysis (δ18O). Based on 1998–2006 data, the soil moisture content at 50 cm depth explained significant variation in predawn leaf water potential of two dominant shrubs, Quercus chapmanii and Ceratiola ericoides (r2 = 0.69). During 8 years of data collection, leaves attained Ψcrit only during the peak drought of 2000 when the soil moisture fell below 1% by volume at 50 and 90 cm depth. Precipitation explained a significant variation in soil moisture content (r2 = 0.62). The patterns in predicted soil moisture for 75 year period, suggested that the frequency of drought occurrence has not increased in time. In spring 2006, the soil reached critical soil moisture levels, with consequences for plant growth and physiological responses. Overall, 24% of plants showed no drought-induced damage, 51% showed damage up to 50%, 21% had intense leaf shedding and 2% of all plants died. Over the drought and recovery period (May–October 2006), relative height growth was significantly lower in plants with greater die-back. All species showed a significant depression in stomatal conductance, while all but deep-rooted palms Sabal etonia and Serenoa repens showed significantly lower predawn (Ψpd) and mid-day (Ψmd) leaf water potential in dry compared to wet season. Plants experiencing less severe die-back exhibited greater stomatal conductance, suggesting a strong relationship between physiology and morphology. Based on results we suggest that the restoration efforts in Florida scrub should consider the soil moisture requirements of key species.

Keywords

Die-backLeaf water potentialOaksPalmsSoil moistureStomatal conductance

Abbreviations

gs

stomatal conductance

Ψpd

predawn leaf water potential

Ψcrit

predawn leaf water potential at turgor loss

Ψmd

mid-day leaf water potential

PWP

permanent wilting point

RWC

relative water content, δ18O = (Rsample / RSMOW − 1) × 1,000, in which Rsample and RSMOW represent the heavy to light isotopes ratio of the sample and standard (Vienna standard mean ocean water) respectively

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Sonali Saha
    • 1
  • Theresa M. Strazisar
    • 1
  • Eric S. Menges
    • 1
  • Patrick Ellsworth
    • 2
  • Leonel Sternberg
    • 2
  1. 1.Archbold Biological StationLake PlacidUSA
  2. 2.Department of BiologyUniversity of MiamiCoral GablesUSA