Me. Balibrea et al., FAST CHANGES IN SOLUBLE CARBOHYDRATES AND PROLINE CONTENTS IN TOMATO SEEDLINGS IN RESPONSE TO IONIC AND NONIONIC ISOSMOTIC STRESSES, Journal of plant physiology, 151(2), 1997, pp. 221-226
Qualitative and quantitative changes in soluble carbohydrates and prol
ine contents were studied in young plants of two tomato cultivars (Lyc
opersicon esculentum L. Mill.) differing in their salt-tolerance (cvs.
Pera and Volgogradskij). Seedlings were treated for 24 h with ionic (
300 mmol L-1) and non-ionic isoosmotic (380 g kg(-1) polyethylene glyc
ol MW 6000) stresses. Salinity provoked a decrease in the hexose conte
nts and it also dramatically enhanced sucrose accumulation in all orga
ns of the plants, and to a greater extent in the salt-sensitive cv. Vo
lgogradskij. The PEG iso-osmotic stress, compared with saline conditio
ns, only affected the hexose contents in a similar way to salinity in
the cv. Volgogradskij, while it increased the sucrose content 2.5 and
4 times in the roots of Pera and Volgogradskij, respectively. Proline
accumulation was more important in the salt-sensitive cultivar under b
oth conditions. The contribution of these solutes to the osmotic poten
tial was up to -0.3 MPa under non-ionic stress, but they had little in
fluence under salinity compared with control plants. The fast changes
observed in soluble carbohydrates and proline composition are discusse
d in relation to the osmotic adjustment under saline and non-permeant
iso-osmotic stresses.