Effect of Seed Weight and Salinity on the Germination of Garden Orache (Atriplex hortensis L.)

Garden orache (Atriplex hortensis L.), a halophytic forb in the family Chenopodiaceae, is well adapted to dry saline habitats. Here, we presented the results of the effect of salinity and seed weight on seed germination and radicle emergence of A. hortensis. Highest germination percentages were obtained under non-saline conditions and increases in salinity inhibited seed germination with less than 50% of the seeds germinating at 260 mM NaCl. Seeds of A. hortensis exhibited a very pronounced morphological and physiological seed polymorphism. Seed weight varied from 0.11 to 0.19 g. Large seeds had a mean dry weight of 0.19 mg and a mean length of 2.6 mm; medium seeds and mean dry weight of 0.15 mg and mean length of 1.9 mm; small seeds and mean dry weight of 0.11 mg and mean length of 1.1 mm. Seedling dry weight was related to initial seed size. The degree of salt tolerance increased progressively with increasing seed dry weight. Radicle elongation was increased by low salinity and it decreased with an increase in salinity. Based on the observations, it is inferred that the germination percentage of large seed size class of A. hortensis was highest as compared to small seed size class. The seed size is an important factor that influences the germination under normal as well as, salinity stress conditions.