SODIUM RELATIONS IN SEEDS AND SEEDLINGS OF Sarcobatus vermiculatus

Sodium content of utricles, utricle bracts, testa, and embryo was determined for Sarcobatus vermiculatus. Immediately after germination, seedlins were grown in H2O, 330 mM NaCl, or 225 mM Na2SO4 solutions, and Na+ content was determined. Sodium content of utricles averaged 38 900 μg·g−1, with highest concentrations in bracts (53 100 μg·g−1), and lowest concentrations (1843 μg·g−1) in embryos. Sodium concentration of washed embryos averaged 954 μg·g−1. Seedlings germinated from debracted utricles and grown 24 h in distilled H2O contained 2965 μg·g−1 Na+. The Na+ content of seedlings germinated and grown 24 h in NaCl or Na2SO4 solutions averaged approximately 24 000 μg·g−1. Rapid uptake of Na+ by the germinating embryos and seedlings is postulated to be an adaptive mechanism for developing and maintaining a favorable water balance in soils with low osmotic potentials.