Physiological responses and salt-tolerance of sunflower (Helianthus annuus) under salt stress injury

Sunflower seedlings growing in vermiculite were stressed in various NaCl concentrations. Growth and physiological related responses were measured in 20d and 40d. It indicated that growth of sunflower seedlings were significantly injury, and plant height was more sensitive than leaf area; marked increase the cell membrane permeability index, and went up with salt stress time; content of proline showed a tendency from increase to decrease; decreasing of photosynthesis activity had a related with concentration of salt, it was predominantly stomatal limitation in lower salt-concentration, or no-stomatal limitation in higher-concentration.