Sensitivity to ethylene: the key factor in submergence‐induced shoot elongation of Rumex

Abstract

Rosettes of flooding-resistant Rum ex palustris plants show a submergence-induced stimulation of elongation, which is confined to the petioles of young leaves. This response increases the probability of survival. It is induced by ethy lene that accumulates in submerged tissues. Floodingintolerant Rum ex acetosella plants do not show this response. We investigated whether differences in shoot elongation between the species, between old and young leaves and between the petiole and leaf blade of a R. palu s tris plant result from differences in internal ethylene con centration or in sensitivity to the gas. Concentrations of free and con jugated A C C in petioles and leaf blades of R. palustris indicated that ethylene is synthesized throughout the submerged shoot, although production rates varied locally. Nevertheless, no differences in ethylene concentra tion were found between submerged leaves of various ages. In contrast, dose-response curves showed that only elongation of young petioles of R. palustris was sensitive to ethylene. In R. acetosella, elongation of all leaves was insensitive to ethylene. We conclude that variation in ethy lene sensitivity rather than content explains the differ ences in submergence-induced shoot elongation between the two Rum ex species and between leaves of R. palustris.

Ethylene-Induced Differential Growth of Petioles in Arabidopsis. Analyzing Natural Variation, Response Kinetics, and Regulation

“…This may have been the outcome of constitutively high ethylene production in control plants caused by growing the plants on nonaerated hydroponics in their experiment. This is indicated by the high ethylene emission and ACC concentration in their control plants, which are comparable to the elevated values as measured in submerged R. palustris plants (Banga et al, 1996;Vriezen et al, 1999) or infected Arabidopsis leaves (Knoester et al, 1998;Grichko and Glick, 2001b). The high internal ethylene in the plants studied by Arteca and Arteca (2001) may thus have precluded any further response from additional exogenous ethylene.…”

Ethylene and Plant Responses to Abiotic Stress

“…Accumulation of ethylene probably accounts for flooding-induced rapid stem elongation (Kende et al 1998) and aerenchyma formation in roots of plant species welladapted to waterlogging, which provides new internal long-distance gas transport pathways (Jackson and Armstrong 1999;Drew et al 2000), and also for induction of adventitious roots, which in case of Rumex palustris can be explained by increased sensitivity of the root-forming tissue to endogenous IAA (Visser et al 1996). This phenotypic response could be explained by different ethylene sensitivity when compared to R. acetosella (Banga et al 1996b;Voesenek et al 1997). This phenotypic response could be explained by different ethylene sensitivity when compared to R. acetosella (Banga et al 1996b;Voesenek et al 1997).…”

Plant hormones and the control of physiological processes

“…low O 2 ). This response increases the probability of survival by restoring leaf air contact and involves both changes in ethylene concentration and differential sensitivity to ethylene between young and old leaves (Banga et al. , 1996).…”