Genetic Uniformity of two Aquatic Plants, Egeria densa PLANCH. and Elodea nuttallii (PLANCH.) ST. JOHN, Introduced in Japan

Abstract

Genetic variation in two plants introduced into Japan, Egeria densa and Elodea nuttallii, was investigated by enzyme electrophoresis. As a result, no polymorphism in allozyme patterns was found among 44 and 26 populations, respectively, of Egeria densa and Elodea nuttalii naturalized in Japan. This result suggests that the populations of the two species are rametes of the same clone which have spread by vegetative means from a single source, though the possibility of multiple introduction is not excluded. The ecological implication of genetic uniformity was briefly discussed in relation to the cause of decline in the population after the peak of abundance.