Sowing and transplantation of Adonis ramosa (Ranunculaceae) for the establishment of a new population in a seminatural broad-leaved deciduous forest floor

Abstract

Adonis ramosa (Ranunculaceae) is a plant whose risk of extinction is increasing in Japan. In this study, we show that there is a significant possibility of establishing an A. ramosa population by sowing seeds or transplanting plants in a seminatural broad-leaved deciduous forest floor. Immediately after seed collection in early June, seeds were sown either in pots that were watered periodically or in a deciduous forest floor where the soil surface was prepared. In the following spring, 30-40% of the seeds germinated. Of the oneyear-old plants buried at a depth of 2 cm and two-yearold plants buried at a depth of 2 or 8 cm in the fall, 96% sprouted leaves in the following spring. However, 79% of the one-year-old plants buried at a depth of 8 cm sprouted leaves. In spring, the number of leaves, the widths of individual plants, and the heights of the two-year-old plants were greater than those of the oneyear-old plants. The dry weights of one-and two-yearold plants in fall after one spring growing season increased by 1.6-2.3 times and by 2.3-5.1 times, respectively, compared to the dry weight at the time of transplanting. Also, the dry weights of the plants transplanted at a depth of 8 cm were higher than those of plants transplanted at a depth of 2 cm for both oneand two-year-old plants. The results suggest that the growth conditions at a depth of 8 cm are more favorable than those at a depth of 2 cm.