New insights into the role of gibberellins in growth responses of the halophytic woody Prosopis strombulifera (Lam.) Benth plants under different sodium salts.

TRAVAGLIA, CLAUDIA; BIAVA, SANTIAGO; LLANES, ANALIA

Santa Fe

Congreso; XXXIII Argentinian meeting of Plant Physiology; 2021

Sociedad Argentina de Fisiología Vegetal

Phytohormones have essential roles in plant growth responses under salinity. A better understanding of gibberellin (GA) functions in woody plant responses under different sodium salts could help to develop new strategies to improve plant salt tolerance. In this study, Prosopis strombulifera plants were grown in hydroponic solutions and exposed to NaCl, Na2SO4, or their iso-osmotic mixture at -1.0, -1.9, and -2.6 MPa. Control (without salt) and salt treated plants were sprayed with gibberellin A3 (GA3), or chlormequat chloride (CCC), an inhibitor of its synthesis. Growth responses, anatomical alterations and ABA and active GA forms (GA1, GA3 and GA4) and inactive GA forms (GA8 and GA34) endogenous levels were evaluated. Results showed that GA3 application increased growth in control plants more than in salt-treated plants. Roots and leaves of salt-treated plants showed high levels of ABA and active GA forms after exposure to GA3. CCC triggered stress-alleviating responses in these plants, such as an increase in spine length and the number of palisade cell layers, and a reduction in levels of ABA and GA4. Na2SO4-treated plants showed reduced growth, high ABA levels and an active GA metabolism to control the levels of active GA. This study indicates that the suppression of GA signalling would contribute to salt tolerance in the native halophytic woody P. strombulifera plants. These findings contribute to the understanding of how gibberellin biosynthesis regulation is involved in the responses to different sodium salts in soils, which could be used as new tools for forest breeding.