Cuticular transpiration and epicuticular lipids of primary leaves of barley (Hordeum vulgare)

Abstract

LarssoD, S. and Svenningsson, M. 1986. Cuticular tran^iratioo and epicuticular lipids of primary leaves of barley (Hordeum vulgare) . Twenty cultivars of barley and 15 eceriferum mutants from one of the cultivars have been analysed for cuticular transpiratioii and epicuticular lipids of their primary leaves. The relative cuticular transpiration rates of the cultivars ranged from 0.61 to 1.98. In spite of this variation in transpiration most of the cultivars had almost the same amount of epicuticular lipids per leaf area, about 16 |i.g cm'^. The eceriferum mutaats showed a wider range in amount of epicuticular lipids, from 5.0 to 15.5 ng cm"^. Nevertheless, most of the mutants transpired almost at the same rate. Only a weak correlation was found between cuticular transpiration and total amount of epicuticular lipids. None of the analysed lipid components (aikanes, aldehydes, primary alcohols, esters or fatty acids) was better correlated to the cuticular transpiration than the total amount of lipids. When the cultivars were exposed lo a mild water stress their cuticular transpiration rates decreased by about 31%. This reduction was not accompanied by any corresponding increase in total amount of epicuticular lipids. Tlie most pronounced effect of the water stress treatment was a stimulation in the ester formation and a reduced formation of primary alcohols. This shift in lipid composition could not be correlated to the decreased cuticular transpiration rates of the individual cultivars. From this investigation it is concluded that the cuticular transpiration is poorly correlated to the amount or composition of the epicuticular lipids in this barley material. As a cotisequence it was not possible to use any characteristic of the epicuticular hpids as a selection criterion in breeditig for drought resistance.Additional key word -Drought resistance. 5. Larsson (reprint requests), Svalof AB, S-268 00 Svalov, Sweden and Af. Svenningsson,

Increased Accumulation of Cuticular Wax and Expression of Lipid Transfer Protein in Response to Periodic Drying Events in Leaves of Tree Tobacco

“…A similar correlation of multiple drying events to wax deposition was originally shown for seedlings from five oat cultivars (Bengtson et al, 1978), although a subsequent study found no significant correlation for two of the cultivars (Svenningsson and Liljenberg, 1986). No relationship was found between epidermal conductance and wax load in barley (Hordeum vulgare) cultivars that were subjected to dehydration stress (Larsson and Svenningsson, 1986). However, transpiration rates were significantly higher and yield significantly lower in bloomless cultivars of sorghum than in isogenic normal bloom cultivars of sorghum (Chatterton et al, 1975).…”

Effect of terminal water stress on leaf epicuticular wax load, residual transpiration and grain yield in barley

“…Other authors have also reported a lack of such a relationship in oats (Svenningsson and Liljenberg 1986), barley (Larsson and Svenningsson 1986) and wheat (Araus et al 1991;Haley et al 1993). This lack of a correlation may be due to the barrier to the diffusion of water across the cuticle depending on the structure and distribution of the epicuticular waxes and the type of intracuticular waxes present (Larsson and Svenningsson 1986). In oats it has been reported that changes in the intracuticular lipids occur in parallel with a reduction in the residual transpiration as a response to water stress (Svenningsson and Liljenberg 1986).…”

“…Although the epicuticular wax of all plant species consist of alkanes, primary and secondary alcohols, wax monoesters, aldehydes and free fatty acids, the quantitative distribution differs according to species. In barley, primary alcohols are the main epicuticular wax component (Larsson and Svenningsson 1986;Steinmüller and Tevini 1985).…”

A morpho-physiological approach differentiates bread wheat cultivars of contrasting tolerance under cyclic water stress

“…In their study, wax coverage increased upon terminal drought stress treatment and this was associated with drought tolerance. On the other hand, the significance of high epicuticular wax load in residual transpiration and drought tolerance has been disputed by others (Larson and Svenningson, 1986;Merah et al, 2000). Glaucousness appeared to confer an advantage to near isogenic wheat lines under rain-fed conditions, rather than in very dry environments (Johnson et al, 1983).…”