Growth responses and accumulation of osmoprotectants under salinity and drought in woody plants: insights from Parkinsonia praecox (Ruiz & Pav.) Hawkins

This study was performed to analyze the growth and biochemical responses in P. praecox plants exposed to salinity and drought. The results indicate that increased root biomass and length occur in high salt and drought conditions (30% FC and 700 mM). This root response ensures water acquisition to maintain plant water status under arid and saline conditions, a strategy observed in other woody species. Moreover, the study highlights proline, glycine betaine (GB), and carbohydrates as vital osmoprotectants. P. praecox accumulates these compounds primarily in roots and shoots under drought conditions, suggesting significant metabolic adaptations to water deficit. However, under salinity, the roots and leaves of P. praecox plants did not accumulate GB. The accumulation of soluble carbohydrates in P. praecox was pronounced in roots under severe water deficit conditions (30%FC). This metabolic response, along with the accumulation of proline and GB, indicates a strategy to cope with stress-induced damage. Moderate increases in these compounds under high NaCl concentrations suggest an effective osmoregulatory mechanism to mitigate salt conditions. This study enhances our understanding of the mechanisms underlying tolerance in woody plants, particularly P. praecox , and underscores the importance of osmoprotectants and soluble carbohydrates in mitigating adverse environmental conditions.