GENOTYPIC DIFFERENCES IN LEAF WATER RELATIONS BETWEEN BRASSICA-JUNCEA AND BRASSICA-NAPUS

Various kinds of measurement of tissue water status were made several times during water stress and recovery in Brassica juncea (cv Canadian Black) and B napus (cv Drakkar) Unstressed plants of the two species had similar leaf water potentials (1PW), solute ('PJ and turgor potentials (IP) Values of relative water content (RWC) and the slope of the linear relationship between !P and RWC (dV’p/dRWC) were greater in B napus than in B juncea Statistical correlations of pooled data for the watered and stressed treatments differentiated the relationships among RWC, Vw and its components in the two species The major statistical difference was that A’BJARWC was related to RWC in B napus and to 1PW and IP, in B juncea A decline in A f’p/dRWC with decreasing IP, in B juncea may be a mechanism for maintaining IP at low soil water potentials through maintenance of more elastic cell walls. © 1992 Annals of Botany Company.