Influence of Acacia dealbata Link bark extracts on the growth of Allium cepa L. plants under high salinity conditions

BACKGROUND Acacia dealbata Link is an invasive plant worldwide. Finding potential uses for its waste that contribute to controling its spread and result in benefits for agriculture has recently become a new topic of research. This study aimed to evaluate the potential biostimulant effect of bark extract derived from the management of A. dealbata (0, 450 or 900 ppm) on onion plants growing under stressful conditions, such as in soils treated with saline solutions (0, 60 or 120 mmol L −1 NaCl) and with reduced irrigation (100%, 50% or 25%). RESULTS A. dealbata Link bark extract significantly increased height as well as leaf, root and total biomass of plants in soils irrigated with NaCl solution (120 mmol L −1 ). These plants also had a higher content of Cl in roots, but a lower content of P in leaves and of K in bulbs. The 450 ppm bark treatment additionally increased the protein content in leaves and decreased the Na and Mg content in bulbs and bulbs and roots, respectively. The bark extract also increased the sugar content in plants under saline conditions. However, the effect of bark extract was negligible on plants that grew under drought stress. CONCLUSION Results revealed that the bark extract might attenuate stress effects in plants growing at high salinity levels, probably by increasing their sugar and protein content and via the accumulation of ions in the roots. Although additional experiments are required, we suggest that the bark extract of A. dealbata has potential applications in agriculture concerned with biostimulant formulations. © 2019 Society of Chemical Industry