Variation of the chemical and biochemical responses to salinity during germination and early growth of seedlings of two populations of Agave durangensis Gentry

Agave durangensis (Asparagaceae) supports a mescal industry in Mexico. The primary reproductive strategy of the species is through seeds. The growing demand for agave-based beverages prompts producers to explore new cultivation areas. However, over half of the country's territory comprises arid and semiarid zones, which are significantly impacted by salinity. The objective of the current study was to assess whether salinity induces distinct seed germination potential and varied biochemical and chemical responses in seedlings of 2 populations of A. durangensis, potentially leading to different tolerance levels to salinity. Seeds from each population were subjected to four salinity treatments. Germination potential, as well as growth parameters and biochemical and chemical attributes of seedlings, were analyzed. Despite reduced germinability and slower germination speed, seeds from both populations were capable of germinating even under the highest NaCl concentration (100 mM) evaluated. Effects on the growth parameters were recorded; however, the seedlings of both populations survived throughout the experiments, exhibiting increased chlorophyll content and cell viability in most saline treatments. The enzymatic defense mechanism and the accumulation of proline were activated in a saltdependent manner, a response not observed with phenolic compounds. However, notable accumulation of monomeric anthocyanin occurred under the 2 strongest NaCl concentrations evaluated. Significant interpopulation differences were observed in each type of response, with varied regulation under different NaCl concentrations, some of which were more pronounced than others under specific saline conditions. Seeds from the Durango population were more sensitive to salinity.