Involvement of Cl⁻ in the Increase in Proline Induced by ABA and Stimulated by Potassium Chloride in Barley Leaf Segments

Abstract

Stimulation by sodium or potassium chloride of the ABA-induced increase in proline was synergistically enhanced by CaCI2 or MgCI2 as well as by 1,3-bis[tris(hydroxymethyl)methylamino] propane chloride (BTP-CI), N-methyl-D-glucamine chloride (NMGCl), or 2-amino-2-hydroxymethyl-1,3-propandiol chloride (TRISCl). This enhancing effect did not depend on the osmolarity and occurred when Clr was higher than K+ in the incubation medium, but not vice versa. When CaC12 or MgCI2 or NMG-CI were added, the higher the CI-:K ratio in the extemal solution the higher was the increase in proline. When the excess of Clr to K was obtained with BTP-CI the highest enhancing effect resulted with a Cl-:K+ ratio of 3:1 while, at a 5:1 ratio, the KCI stimulation was completely suppressed. The inhibiting effect of proline accumulation by NH4+ and 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene was reversed to varying degrees depending on the magnitude of the excess of Clr on K+ concentration in the medium. Also, the inhibition of proline accumulation obtained by tetraethylammonium chloride, monensin, and D-mannose was similarly reverted. These data suggest that Clr elicits an increase in ABA-induced proline which needs the simultaneous presence of K+ (or Na+) to take place.

Abscisic acid and osmotic relations in Phaseolus vulgaris L. Shoots under salt stress

“…Our data show that 6 h after applying 80 mM NaCI a two to threefold times increase in endogenous ABA is observed which parallels an enhancement of CI-and Na § uptake, as well as of K § to some extent ( Table 1). The increase in these three ions has been related to ABA-induced proline accumulation, whereas it has been shown that Ca 2+ and Mg 2+ are not involved in it (Pesci 1989). On the other hand, our results on stomatal conductance and transpiration rates (Table 2) clearly point to a role of ABA as a mediator in the effect of NaCl on these physiologic parameters.…”

“…The application of salt or ABA to plants has frequently been associated with the accumulation of proline (Huber et al 1977, Rajagopal and Andersen 1978, Pesci 1989, 1992. Nevertheless, there are few studies in which endogenous ABA, as well as the incorporation of ABA exogenously applied to the root system, have been measured (Downton andLoveys 1981, Schussler et al 1991).…”

Tissue Culture in the Improvement of Salt Tolerance in Plants

“…Proline biosynthesis may be modulated by ABA (Stewart 1980;Stewart et al 1986;Pesci 1987Pesci , 1989. Pesci and Beffagna (1985) suggest that the ABA-and isobutyric acid-induced changes in proline level in barley leaves might be mediated by changes in the intracellular pH.…”

Proline Accumulation in Maize (Zea mays L.) Primary Roots at Low Water Potentials (I. Requirement for Increased Levels of Abscisic Acid)

“…It seems reasonable to suggest that the primary action of ABA in growing root cells may be similar, and that resulting changes in cytoplasmic ionic concentrations in tum induce the accumulation of Pro. In fact, it has been noted by others that K+ (Hasson and Poljakoff-Mayber, 1983), C1- (Pesci, 1989), and pH (Beffagna, 1992) can influence ABAor water deficit-induced Pro accumulation in plartt tissues. As an initial step to investigate these interrelation:ships, we are using electrophysiological approaches to explare the effects of endogenous ABA manipulation on ion tranjport and cytoplasmic ionic concentrations in the root growth zone at low $,,,.…”

“…Applied ABA can induce increased Pro concentrations in a range of species under well-watered conditions, e.g. in barley leaves (Stewart and Voetberg, 1985;Pesci, 1989) and roots (Rajagopal and Anderson, 1978), in rice leaves (Chou et al, 1991), and in pea roots and shoots (Hasson and Poljakoff-Mayber, 1983). Also, the abil and abi2 mutants of Arabidopsis, which have decreased sensitivity to ABA, have a decreased ability to accumulate Pro after treatment with ABA (Finkelstein and Somerville, 1990).…”