Apoplastic and symplastic solute concentrations contribute to osmotic adjustment in bean genotypes during drought stress

Guler N. , SAĞLAM A. , Demiralay M., KADIOĞLU A.

TURKISH JOURNAL OF BIOLOGY, vol.36, no.2, pp.151-160, 2012 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 36 Issue: 2
  • Publication Date: 2012
  • Doi Number: 10.3906/biy-1101-177
  • Page Numbers: pp.151-160


The present study investigates changes in the inorganic ions, proline, and endogenous abscisic acid (ABA) contents of the apoplastic and symplastic compartments of leaves from drought-tolerant (Yakutiye) and drought-sensitive (Zulbiye) cultivars of the common bean (Phascolus vulgaris L.). Drought stress caused a decrease in leaf water potential and stomatal conductance in both cultivars. Concentrations of proline in the drought-tolerant and drought-sensitive cultivars increased in response to drought stress in both compartments. The symplastic K+ concentration decreased in both cultivars. However, the opposite trend was observed concerning K+ concentrations in the apoplastic areas. While the symplastic Na+ concentrations significantly decreased in the drought-tolerant cultivar, the apoplastic Na+ concentrations increased during drought stress. However, Na+ concentrations did not significantly change in either of the compartments in the drought-sensitive cultivar. The Ca2+ concentrations in the sensitive cultivar significantly decreased in both compartments during drought stress. In the tolerant cultivar, the Ca2+ concentration significantly increased in the symplast but decreased in the apoplast. Cl- concentrations in the tolerant cultivar did not significantly change in either compartment. In the sensitive cultivar, the Cl- concentration increased in the apoplastic area but decreased in the symplastic area. In addition, while the symplastic sap of the leaves exhibited a constant pH value, it diminished in the apoplast during drought stress. Symplastic and apoplastic ABA concentrations significantly increased in both cultivars. It might be said that inorganic ions (especially Na+, K+, and Ca2+) and ABA concentrations changed between the apoplastic and symplastic spaces to contribute to osmotic adjustment under drought stress. In addition, the drought-tolerant cultivar showed a much higher capacity to maintain osmotic adjustment between the symplast and the apoplast.