Effects of Salt on the Growth and Physiological Characteristics of Sunflower Seedlings

It has great significance to research salt tolerance mechanism for salt resistance breeding of sunflower.This paper studied the effect of different salt stress levels on seedlings′growth and physiological characteristics such as germination rate,leaf area,overground and underground biomass yield,malondialdehyde content,producing rate of oxygen free radicals,SOD activity,POD activity and CAT activity to five cytoplasmic male sterile lines by using pot experiment simulating 0.35% and 0.50% soil salinity.The result indicated that low salt stress had acceleration effect on seedling germination.Under moderate stress,seedling germination and growth were both suppressed and leaf relative conductivity increased.But at the same time SOD,POD and CAT activity increased significantly while O-·2 producing rate and MDA content showed no significant difference to control group.Strong reactive oxygen scavenging capacity is one of sunflower′s physiological mechanisms of salt-tolerance characteristics.Five self-selection sterile lines vary in salt tolerance from each other.