Abstract
The plant growth regulator abscisic acid (ABA) is involved in triggering responses to various environmental stresses such as freezing and desiccation in higher plants but little is known about its role in lower plants, especially in liverworts. In the present study, effect of ABA on sugar accumulation and stress tolerance was examined using the liverwort Marchantia polymorpha. It was found that isolated gemmae of M. polymorpha cultured in a medium containing ABA accumulated higher amount of soluble sugars than did gemmae cultured without ABA. The sugar accumulation was further enhanced by addition of sucrose in the medium. The gemmae responded to ABA better than thalli in respect of sugar accumulation. Freezing tests showed that survival rate after freezing of 10μM ABA-treated samples increased as the sucrose concentration in the medium increased, but the survival was very little in non-treated samples. Desiccation tests showed the highest survival rate in samples treated with 5% sucrose and 10μM ABA. These results indicate that ABA plays a role in accumulation of sucrose in gemmae and enhances stress tolerance in liverworts.
