The life stages of Alocasia zebrina schott ex van houtte

Date

2010

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Virginia C. Cuevas

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Abstract

The life stages of a threatened endemic species, Alocasia zebrina Schott ex Van Houtte, were identified. This plant species is classified as ornamental and is listed to have a vulnerable to threatened status due to over collection and habitat destruction. Therefore conservation measures must be instituted. Basic information on population ecology is important to provide proper conservation management strategy. An A. zebrina population located on a patch of secondary forest at 300 m above sea level (asl) northeastern slope of Makiling Forest Reserve was monitored in situ for 9 months from July 2009 to April 2010. The associated vegetation with the studied population was recorded using Point Center Quarter Method (PCQM) for plants with dbh > 1 cm, and Line Intercept Method for the understory vegetation. A total of 37 individuals belonging to 21 subpopulations were labeled with aluminum tags and their development was followed through the entire study duration. Morphometric parameters (i.e. leaf area index, plant height, and number of leaves) were taken from all individuals. Additional data such as fruit counts, inflorescence count, and spadix length were gathered for individuals at the reproductive stage. A seed germination experiment was also conducted in situ. Mann-Whitney U and t-test statistical tools were used to determine significant differences on all the abovementioned morphometric parameters between vegetative and reproductive individuals. Pearson correlation analysis was

used to determine the correlation strength between the observed increase in the number of leaves and the recorded increase on total monthly sunshine obtained from the National Agro Meteorological Station at UPLB. Results from the PCQM vegetation analysis highlighted the dominance of Swietenia macrophylla and presence of members of the Palm family in the study site. The LIM on the other hand, showed the presence of Amorphophallus sp., and Heliconia sp. adjacent to the A. zebrina subpopulation. Open space, in terms of ground cover, was also significantly high within the population. These observations point to a secondary forest with high light conditions. The life stages exhibited by the A. zebrina population were derived from the morphometric parameters measured and observed mode of reproduction. These life stages are seed, small juvenile (1-3 leaf stage), large juvenile (4 leaf stage) and adult (> 5 leaf stage). The large juveniles are capable of asexual reproduction through production of ramets while the adults are able to reproduce both asexually and sexually. From the seed germination experiment, only 1 out the 85 sown fruits germinated. Dormancy induced by the decrease in monthly rainfall throughout seed germination experiment was assumed to influence the low percent germination. Statistical analysis had shown that the attainment of large size is a prerequisite for flowering. The measured morphometric parameters were significantly higher among individuals at the reproductive stage compared to that of vegetative individuals. Furthermore, statistical analysis had shown a positive correlation between recorded increase of total monthly minutes of sunshine and an increase in the number of leaves. The amount of light influences the transition between life stages. The information generated from the field observations has shown that high light conditions favor the establishment, growth and development of the A. zebrina population. The results of this study are important inputs for conservation strategies for this threatened species.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Document Type

Thesis

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