Salt tolerances of 3 cultivars, Menemen puccinellia (Puccinellia ciliata Bor), Tyrrell and Dundas [tall wheatgrass, Thinopyrum ponticum (Podp.) Z. W. Liu and R. R. C. Wang], were compared with respect to their seed germination, adaptive responses to salt and waterlogging, seedling emergence, plant growth, shoot osmolality and mineral contents in a series of salt-stress experiments. An inverse normal distribution provided good fits for the time to seed germination. Under NaCl stress, 50% of the control (distilled water) seed germination rates of Menemen, Tyrrell and Dundas were achieved in 178.8, 300.9 and 296.8 mmol/L NaCl, respectively. Fifty percent of the control seedling emergence rates of these 3 cultivars were in 92.7, 107.2 and 113.5 mmol/L NaCl, respectively. The seed germination rates of these 3 cultivars under both salt and waterlogging stress were far lower than those germinated only under salt stress at the same salt level. Seed pretreatment by soaking seed in NaCl solutions greatly increased the seed germination rate under salt stress for Menemen and under both salt stress and waterlogging for Dundas. Tyrrell and Dundas were very similar in their tolerance to salt stress, and were significantly (P<0.05) more salt tolerant than Menemen in terms of seed germination and seedling emergence rate. Both shoot height and dry matter of these 3 cultivars were not statistically different among all salt stress levels during the seedling elongation period, indicating that the established plants of these 3 cultivars were very salt tolerant. The salt tolerance mechanisms of these 3 cultivars are possibly related to their abilities to maintain high osmolality in shoots by regulating high sodium and potassium contents, and reducing calcium deficiency under salt stress.
Effect of NaCl on seed germination in some Centaurium Hill. Species (Gentianaceae)
