Cytogenetics of Philippine endemic Hoya merrillii Schlechter and Hoya mcgregorii Schlechter

Date

4-2005

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Genaleen Q. Diaz

Co-adviser

simeona V. Siar

Abstract

Chromosome behavior in mitosis and meiosis, chromosome number and chromosome characteristics were determined in two Philippine endemic wax plants namely How merrillii and H. mcgregorts. Normal mitosis were observed in root tip squashes of each How species. Mitotic index was low at 6.5% in H. merrillii and 10% in H. mcgregorii. Karyotypes of prometaphase cells revealed a diploid chromosome number of 2n-22. Chromosomes have mean relative lengths ranging from 0.19 to 1.00 in H. merrillii and 0.32 to 1.00 in H. megreg.rii. Based on the position of centromere, only two types of chromosome were observed. Majority of the chromosomes were found to be submetacentric (63.64%) for H. merrillii and metacentric (54.55%) for H. mcgregorii. A high degree of normality in the meiotic stages was also observed. The number of bivalents were n=11 for both species. However, there are 1011 (22.58%) and 1211 (3.22%) observed. A low percent fertility was observed in H. merrillii. This may be attributed to the cell cycle arrest and the competition among gametes with and without chromosomal aberrations. The high pollen fertility of H. mcgregorii is due to the normal meiosis it exhibited.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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