According to Fig. 3, the mean growth index of H. callitrichoides
after
fifteen days of cultivation for control media (Media A and
Media B) were 8.29
0.85 g/g and 3.82
0.35 g/g. The maximum
mean growth index (8.46
0.49 g/g) was achieved when H.
callitrichoides was inoculated in media E. This was because the
explant inoculated in media E had all the essential nutrients
required for the propagation of H. callitrichoides as those in Media
A. The effect of 1/2 strength POME in media E on the growth index
of H. callitrichoides was not significant when compared to control
media (Media A) (P > 0.05). This could probably due to the lower concentration of ammonia, nitrate ions and phosphate ions that
presented in POME as reported from the previous section (referred
to Table 3).
Based on Fig. 4, the explant inoculated in Media A was not
propagating in a healthy manner as compared to explant
inoculated in Media E. The leaves of explant inoculated in Media
A had undergone several morphological changes such as having a
darker green color, stunted and presented with short and dense
leaves formation as shown in Fig. 5. This kind of symptoms were
similar to those morphological changes for phosphorus deficiency
in plants such as severe stunting, thin stems and erect and dark
green leaves [17]. When phosphorus is deficient, the cell and leaf
expansion will be retarded resulting in stunted growth on the older
leaves of the plants [17]. At the same time, the plant will
accumulate higher chlorophyll in the leaves [17]. As a result, the
chlorophyll content in the leaves will increase causing the leaf
color to turn into a darker green shade [17]. In addition, this phenomena can be exaggerated by the imbalance nutrient
concentration (excess N) or excess light that were experienced
by the explant in Media A which induced stress on the explants and
in turn causing the abnormal morphogenesis of H. callitrichoides
[17,18]. This abnormal morphogenesis of H. callitrichoides had
occurred in 3 out of 12 of the replicates in the experiments. This
could be cause by the different section of explant having different
tolerance level towards high salt concentration in MS medium.
However, the explant inoculated in Media E did not exhibit such
morphological changes in the growth of the plantlet. The 1/
2 strength POME in Media E had helped to suppress the effect of
imbalance nutrients or excessive light towards the explant and as a
result, the explants cultured in Media E exhibit a better growth
than those in Media A.