Salinity Stress Inhibits Bean Leaf Expansion by Reducing Turgor, Not Wall Extensibility 1
AUTOR(ES)
Neumann, Peter M.
RESUMO
Treatment of bean (Phaseolus vulgaris L.) seedlings with low levels of salinity (50 or 100 millimolar NaCl) decreased the rate of light-induced leaf cell expansion in the primary leaves over a 3 day period. This decrease could be due to a reduction in one or both of the primary cellular growth parameters: wall extensibility and cell turgor. Wall extensibility was assessed by the Instron technique. Salinity did not decrease extensibility and caused small increases relative to the controls after 72 hours. On the other hand, 50 millimolar NaCl caused a significant reduction in leaf bulk turgor at 24 hours; adaptive decreases in leaf osmotic potential (osmotic adjustment) were more than compensated by parallel decreases in the xylem tension potential and the leaf apoplastic solute potential, resulting in a decreased leaf water potential. It is concluded that in bean seedlings, mild salinity initially affects leaf growth rate by a decrease in turgor rather than by a reduction in wall extensibility. Moreover, longterm salinization (10 days) resulted in an apparent mechanical adjustment, i.e. an increase in wall extensibility, which may help counteract reductions in turgor and maintain leaf growth rates.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1055555Documentos Relacionados
- Expansion of Bean Leaves and its Suppression by Salinity 1
- Salinity-Induced Inhibition of Leaf Elongation in Maize Is Not Mediated by Changes in Cell Wall Acidification Capacity1
- Control of Leaf Expansion by Nitrogen Nutrition in Sunflower Plants 1: ROLE OF HYDRAULIC CONDUCTIVITY AND TURGOR
- Long-Term Inhibition by Auxin of Leaf Blade Expansion in Bean and Arabidopsis1
- Roles of Extensibility and Turgor in Gibberellin- and Dark-stimulated Growth 1