Abstract:
This study examines the ability of Graci/aria changii and Graci/aria edulis to
propagate vegetatively from thallus segments (apical segments, mid segments and
basal segments) in different culture media. Graci/aria samples were collected from
Middle Banlc, Penang Island and brought back to the laboratory in Universiti
Malaysia Terengganu for further cultivation. Culture media chosen were Natural aged
seawater, Enriched natural seawater (ES) medium and Plymouth Erd-schreiber (PE)
media with soil extracts prepared from soil samples obtained from Sandakan, Setiu
Wetland and Garden soil. Effects of culture media on Graci/aria segments were
observed and expressed in the form of number of branches, length of newly formed
branches and specific growth rate ( compiled as daily growth rate and weekly growth
rate). Cultivated apical segment in all media showed overall elongation rather than
branch formation while mid and basal segments showed the opposite. Highest branch
number for all cultivated segments of Graci/aria changii was observed in PE (Garden
Soil) medium (16 on apical segments, 80 on mid segments and 85 on basal segments).
As for Graci/aria edulis, all highest branch numbers were observed in Natural aged
seawater: 229 branches were recorded for apical segments, 268 on the mid segments
and 242 on the basal segments. In terms of branch length, longest branches were
observed in ES medium and recorded as 9mm (apical segments), 9mm (mid segments)
and 10mm (basal segments) for Graci/aria changii; 18mm (apical segments), 27mm
(mid segments) and 23mm (basal segments) for Graci/aria edulis. Generally, it was
observed that ES medium and PE (Setiu) medium provided the best results for most of
the segments. Highest specific daily growth rate based on fresh weight recorded in ES
medium were 0.0096 day"1 for Graci/aria changii apical segments, 0.0155 day
°1 and 0.0149 day·1 for Graci/aria edulis mid and basal segments respectively. As for the PE
xiii (Setiu) medium, the highest daily specific growth rate observed were 0.0033 dal and
0.0034 day-1 for Graci/aria changii mid and basal segments respectively, and 0.0275
day-1 for Graci/aria edulis apical segments. The highest daily specific growth rate
based on length was highest in ES medium for both Graci/aria changii and
Graci/aria edulis (0.0084 day"1 and 0.0105 day"1 respectively). Thus, ES medium and
PE (Setiu) medium are suitable for culture purposes in laboratory.
