Effects of Gibberellin and Weak Acid on Seed Germination and Physiological Characteristics of the Eelgrass Zostera marina

Abstract

The effects of gibberellin and weak acid on the germination and physiological characteristics of eelgrass (Zostera marina) seeds were studied under laboratory conditions. The cumulative seed germination and seedling establishment rates were calculated. The dynamic changes in seed dry weight, water content, respiration rate, soluble sugar, starch, gibberellin, abscisic acid content, and α-amylase and β-amylase activities during seed germination were monitored. The effect of two exogenous germination-promoting treatments on seed germination was explored, and the physiological response process of the seeds to these treatments was analyzed. The results showed that the treatments effectively promoted seed germination and seedling establishment. The gibberellin treatment had the best germination-promoting effect, and the seed germination and seedling establishment rates were 1.6 times higher than those under the control. During the germination period of seeds in the two treatments, the α-amylase activity first increased and then decreased, the starch content showed a downward trend, and the soluble sugar content continued to increase. At the end of the experiment, the soluble sugar content of seeds in the gibberellin treatment attained the highest value, which was 3.3 times higher than the value before germination and was significantly higher than that in the weak acid treatment and control (P 0.05). Principal component analysis showed that α-amylase activity and starch and soluble sugar contents of seeds were the key factors in seed germination. Comprehensive analysis showed that exogenous gibberellin treatment was an effective method to break seed dormancy. This effect was mainly achieved by regulating amylase activity, increasing starch decomposition rate, and increasing soluble sugar content to provide energy for seed germination. The results provide a theoretical and scientific basis for the rapid germination technology of eelgrass seeds.

Keywords

• gibberellin
• germination rate
• seed dormancy
• nutrients
• zostera marina