Date of Award

1-1-2000

Thesis Type

Masters

Document Type

Thesis

Divisions

Faculty of Science

Department

Institute of Biological Sciences

Institution

Universiti Malaya

Abstract

From the first experiment, it was found 1ha1 the primary root elongation of Z. elegans was optimum on the fifth day with a value of 40.82 ± 15.39 mm Thus, the root segment with an elongation in the range of25.43 to 56.21 mm has been adopted as the standard length for the m VI VO and m vt/fo cytological studies. In vivo cytological studies on Z. elegans revealed that the mitotic index (MI) measured was 13.47 ± 0.46%, the chromosome number observed was 2n = 23, the average cell and nuclear area values were 113.55 ± 4.44 μm1 and 40.58 ± 0.95 μm2 respectively. The cell doubling time (Cdt) obtained in vivo was 133 hours, whereas from the in vitro study, mitotic index (MI) measured was 15.60 ± 0.20%, the chromosome number observed was 2n = 23, average cell and nuclear area values were 92.40 ± 5. 70 μm1 and 36.86 ± 1.44 μm2 respectively. While the cell doubling time obtained was shorter, i.e. 96 hours. For distribution of nuclear DNA content from in vivo system, it was observed that most of the cells are in G2 (55.62%) phase, followed by polyploid cells (33.75%) and S ( 14.37%) phase of1he cell cycle. Whereas in the in vitro system, the distribution of nuclear DNA content was quite similar with in vivo system with most of the cells are in G2 (41.62%), followed by polyploid (38.38%) and S (20%) phase of the cell cycle. Cytological and morphological studies showed that Z. elegans was stable in culture even though polyploid cells were observed both in in vivo and in vitro systems, but no variation or morphological disorder were detected either in cellular stage or at morphological level. The polyploid cells were observed both in m vivo and in vilro systems because the source of Z. elegans explants was taken from the F1 hybrid plant. Therefore polyploid cells were already found in the cell cycle of the intact plant. By exposing the cells to cul ture conditions, enhance more cells to become polyploid. The rooting of Z. clegans was discovered to be favourable in Murashige and Skoog (MS) media without any hormone additives. Rool cultures cannot regenerate shoots in MS (1962) medium supplemented either with BAP alone (0.5 - 3.0mg/1) or in combination with NAA (0.01-3.0mg/l). Nevertheless, other explants sources were also utilized such as lea( stern, cotyledon and hypocotyl to get an efficient regeneration system for clonal propagation of Z. elegans in in vitro system. All the explants except the hypocotyl were unable to regenerate shoots in MS medium supplemented with cytokinin alone (0.005 - 5.0mg/1) such as BAP, Kinetin or Thidiazuron (TDZ) or in combination with auxin (0.05 - 5.0rtlWI) such as NAA, lAA, IBA or 2,4-D. For shoot multiplication, the optimum medium needed was MS supplemented with 1.0 mg/I Zeatin from the hypocotyl explant. As for Rosa hybrida L. var. 'Christian Dior', the rooting was not observed at all throughout the experiment, while for shoot multiplication, the best result was observed on MS medium supplemented with 3.0 mg/I BAP from the axillary bud explant. Other explants such as leaf, stem and petiole were unable to regenerate shoots in MS medium supplemented with BAP alone (l.0 - 5.0mg/1) or in combination with NAA (1.0 -5.0mg/l).

Initial

snms

Additional Information

Dissertation (M.A) -- Faculty of Science, Universiti Malaya, 2000.

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