Cj. Dawes et al., Cell wall structure of the agarophytes Gracilaria tikvahiae and G-cornea (Rhodophyta) and penetration by the epiphyte Ulva lactuca (Chlorophyta), J APPL PHYC, 12(6), 2000, pp. 567-575
Use of light, transmission, and scanning electron microscopes revealed that
the epidermal cell wall of the red algal agarophytes Gracilaria tikvahiae
McLachlan and G. cornea J. Agardh consists of a decklamelle and outer and i
nner wall layers. The two species differed, with G. cornea having a signifi
cantly thicker outer wall and a more diffuse decklamelle. After induction,
the zooids of Ulva lactuca would attach to glass slides and the two species
of Gracilaria via an adhesion pad. Within a few days, 3-5 celled germlings
penetrated the decklamelle and outer wall layer of both basiphytes. By the
time the epiphyte germlings reached the 15 celled stage, they had penetrat
ed the inner wall layer. The differences in epidermal cell wall constructio
n between the two basiphytes may play a role in the ability of zooids of U.
lactuca to attach in nature where epiphytization of G. cornea is infrequen
t.