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Diurnal and seasonal variation in root xylem embolism in neotropical savanna woody species: impact on stomatal control of plant water status.

Publication ,  Journal Article
Domec, JC; Scholz, FG; Bucci, SJ; Meinzer, FC; Goldstein, G; Villalobos-Vega, R
Published in: Plant, cell & environment
January 2006

Vulnerability to water-stress-induced embolism and variation in the degree of native embolism were measured in lateral roots of four co-occurring neotropical savanna tree species. Root embolism varied diurnally and seasonally. Late in the dry season, loss of root xylem conductivity reached 80% in the afternoon when root water potential (psi root) was about -2.6 MPa, and recovered to 25-40% loss of conductivity in the morning when psi root was about -1.0 MPa. Daily variation in psi root decreased, and root xylem vulnerability and capacitance increased with rooting depth. However, all species experienced seasonal minimum psi root close to complete hydraulic failure independent of their rooting depth or resistance to embolism. Predawn psi root was lower than psi soil when psi soil was relatively high (> -0.7 MPa) but became less negative than psi soil, later in the dry season, consistent with a transition from a disequilibrium between plant and soil psi induced by nocturnal transpiration to one induced by hydraulic redistribution of water from deeper soil layers. Shallow longitudinal root incisions external to the xylem prevented reversal of embolism overnight, suggesting that root mechanical integrity was necessary for recovery, consistent with the hypothesis that if embolism is a function of tension, refilling may be a function of internal pressure imbalances. All species shared a common relationship in which maximum daily stomatal conductance declined linearly with increasing afternoon loss of root conductivity over the course of the dry season. Daily embolism and refilling in roots is a common occurrence and thus may be an inherent component of a hydraulic signaling mechanism enabling stomata to maintain the integrity of the hydraulic pipeline in long-lived structures such as stems.

Duke Scholars

Published In

Plant, cell & environment

DOI

EISSN

1365-3040

ISSN

0140-7791

Publication Date

January 2006

Volume

29

Issue

1

Start / End Page

26 / 35

Related Subject Headings

  • Xylem
  • Water
  • Tropical Climate
  • Trees
  • Soil
  • Seasons
  • Plant Roots
  • Plant Leaves
  • Plant Biology & Botany
  • Circadian Rhythm
 

Citation

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Domec, J. C., Scholz, F. G., Bucci, S. J., Meinzer, F. C., Goldstein, G., & Villalobos-Vega, R. (2006). Diurnal and seasonal variation in root xylem embolism in neotropical savanna woody species: impact on stomatal control of plant water status. Plant, Cell & Environment, 29(1), 26–35. https://doi.org/10.1111/j.1365-3040.2005.01397.x
Domec, J. C., F. G. Scholz, S. J. Bucci, F. C. Meinzer, G. Goldstein, and R. Villalobos-Vega. “Diurnal and seasonal variation in root xylem embolism in neotropical savanna woody species: impact on stomatal control of plant water status.Plant, Cell & Environment 29, no. 1 (January 2006): 26–35. https://doi.org/10.1111/j.1365-3040.2005.01397.x.
Domec JC, Scholz FG, Bucci SJ, Meinzer FC, Goldstein G, Villalobos-Vega R. Diurnal and seasonal variation in root xylem embolism in neotropical savanna woody species: impact on stomatal control of plant water status. Plant, cell & environment. 2006 Jan;29(1):26–35.
Domec, J. C., et al. “Diurnal and seasonal variation in root xylem embolism in neotropical savanna woody species: impact on stomatal control of plant water status.Plant, Cell & Environment, vol. 29, no. 1, Jan. 2006, pp. 26–35. Epmc, doi:10.1111/j.1365-3040.2005.01397.x.
Domec JC, Scholz FG, Bucci SJ, Meinzer FC, Goldstein G, Villalobos-Vega R. Diurnal and seasonal variation in root xylem embolism in neotropical savanna woody species: impact on stomatal control of plant water status. Plant, cell & environment. 2006 Jan;29(1):26–35.
Journal cover image

Published In

Plant, cell & environment

DOI

EISSN

1365-3040

ISSN

0140-7791

Publication Date

January 2006

Volume

29

Issue

1

Start / End Page

26 / 35

Related Subject Headings

  • Xylem
  • Water
  • Tropical Climate
  • Trees
  • Soil
  • Seasons
  • Plant Roots
  • Plant Leaves
  • Plant Biology & Botany
  • Circadian Rhythm