On-line version ISSN 1678-992X
MARUR, Celso Jamil. Pressure-volume curves and leaf expansion in cotton cultivars under water deficit . Sci. agric. [online]. 1999, vol.56, n.3, pp. 563-569. ISSN 1678-992X. http://dx.doi.org/10.1590/S0103-90161999000300008.
The response of two cotton cultivars to water deficit was studied using leaf expansion and pressure-volume curves method to compare their ability in relation to osmotic adjustment. The osmotic potential at full saturation and at the turgor loss point, for 'IAC 13-1', were 0.1 MPa lower than for `IAC 20' under later stress. Osmotic adjustment at full saturation was 0.15 and 0.03 MPa, and at turgor loss point was 0.18 and 0.07 MPa for 'IAC 13-1'and 'IAC 20', respectively. The low osmotic potential values observed for 'IAC 13-1' suggests that the tissues support water deficit longer, before cells reach plasmolysis. The values for bulk modulus of elasticity were higher when both cultivars were under water deficit, and at 'IAC 13-1' seems to have cell walls greater elasticity. Leaf expansion stopped at water potential, before sunrise, at -1.04 and -0.98 MPa for 'IAC 13-1' and 'IAC 20', respectively.
Keywords : total water potential; osmotic adjustment; osmotic potential; full saturation; turgor loss point.