Osmotic Adjustment and Solute Constituents in Leaves and Roots of Water-stressed Cherry (Prunus) Trees

Abstract

<jats:p>Tissue osmotic potential(Ψ<jats:sub>π</jats:sub>) and solute constituents were evaluated in leaves and roots of well-watered and water-stressed <jats:italic>Prunus avium</jats:italic> L. × <jats:italic>pseudocerasus</jats:italic> Lindl. `Colt' and <jats:italic>Prunus cerasus</jats:italic> L. `Meteor'. Osmotic potential at full turgorΨ<jats:sub>π,sat</jats:sub> decreased in response to water stress for leaves and roots of both cultivars. For `Colt', a cultivar with an indeterminate growth habit,Ψ<jats:sub>π,sat</jats:sub> decreased by 0.56 MPa and 0.38 MPa for terminal expanding leaves and older expanded leaves, respectively. For `Meteor', a cultivar with a determinate growth habit,Ψ<jats:sub>π,sat</jats:sub> decreased by ≈0.47 MPa in both terminal and older leaves. RootΨ<jats:sub>π,sat</jats:sub> was alike for both cultivars and showed a similar decrease of 0.20 MPa in response to water stress. Roots had considerably higherΨ<jats:sub>π,sat</jats:sub> than did leaves in both cultivars, irrespective of irrigation treatment. Soluble carbohydrates and potassium (K<jats:sup>+</jats:sup>) were the major solute constituents in both cultivars. Of the soluble carbohydrates, sorbitol was found in the greatest concentration and accounted for the bulk of water stress-induced solute accumulation in both cultivars. Regardless of the irrigation treatment, mature leaves of `Meteor' consistently had lowerΨ<jats:sub>π,sat</jats:sub> (typically 0.4 MPa) than `Colt'. This variation in Ψ<jats:sub>π,sat</jats:sub> between <jats:italic>Prunus</jats:italic> cultivars suggests the potential for selection of cultivars with low Ψ<jats:sub>π,sat</jats:sub> and possibly superior drought resistance.</jats:p>

Changes in water status and osmolyte contents in leaves and roots of olive plants (Olea europaea L.) subjected to water deficit

“…As in some other woody plants (Ranney et al 1991;Lo Bianco et al 2000), mannitol is preferentially accumulated in olive leaves in response to water deficit (Table 1). At the maximum level of water deficit, mannitol content was 1.3 times higher in leaves of SP than in CP, confirming that this alditol plays a key role in osmotic adjustment of leaf tissues during water deficit.…”

“…Osmotic adjustment of Rosaceous fruit trees, such as apple (Malus domestica [L.] Borkh.) (Wang and Stutte 1992) and cherry (Prunus cerasus L. and P. avium x pseudocerasus) (Ranney et al 1991) during water deficit is mainly accompanied by the accumulation of sorbitol formed by glucose reduction. Mannitol, another alditol, is the most widely distributed hexitol in nature (Williamson et al 2002) and has been identified as the major active solute, which increases its level in leaves of Fraxinus excelsior L. under water deficit conditions (Guicherd et al 1997).…”

Association between winter anthocyanin production and drought stress in angiosperm evergreen species

“…Solutes most commonly involved in osmotic adjustment are sugar alcohols, monosaccharides, amino acids, and inorganic ions (commonly K + ) (Handa et al , 1983; Ranney et al , 1991; Wang and Stutte, 1992). In addition to lower osmotic potential, red-leafed species also had cell walls which were significantly harder (lower elasticity) than green-leafed species during summer and winter (Table 1).…”

Antisense inhibition of sorbitol synthesis leads to up-regulation of starch synthesis without altering CO2 assimilation in apple leaves

“…When sorbitol is transported to sink tissues, it is converted to fructose by sorbitol dehydrogenase for further metabolism (Loescher et al 1982). In addition, sorbitol is implicated in responses of sorbitol-synthesizing plants to abiotic and biotic stresses, such as osmotic adjustment under water stress (Lo Bianco et al 2000;Ranney et al 1991;Wang and Stutte 1992), cold hardiness (Raese et al 1978), mobility of boron in the phloem and tolerance of boron deficiency (Brown et al 1999;Hu et al 1997), and disease resistance (Suleman and Steiner 1994).…”