Browsing by Author "Ruklani, N. C. S."

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Taxonomic survey of bryophytes in man-made habitats within the University of Peradeniya, Sri Lanka
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Samarakoon, S. M. S. E. M.; Ruklani, N. C. S.; Rubasinghe, S. C. K.
Bryophytes are the first plant group that evolved on land and play a major role in soil formation providing a surface for new plants and microorganisms. They have a dominant gametophyte phase in their life cycle and the sporophyte depends on the gametophyte plant. This heterogeneous plant group includes three phyla: Marchantiophyta (liverworts), Bryophyta (mosses), and Anthocerotophyta (hornworts). In addition to natural ecosystems, these plants have adapted to thrive in man-made ecosystems where they are colonized on different man-made substrates such as concrete, cement, clay, and plastic substrates. Man-made habitats are environments designed by humans for specific purposes. Bryophytes possess special adaptations that enable their survival in these ecosystems. However, the diversity of bryophytes in man-made habitats in Sri Lanka remains poorly studied. This research aims to taxonomically identify bryophytes thriving in different man-made habitats within the University of Peradeniya, Sri Lanka including buildings, walls, pavements, drains, gardens, footpaths, and artificial water bodies. For this study, 12 man-made habitats in the University of Peradeniya were selected and 30 bryophyte samples were collected into resealer bags. The morphological characters of these samples such as leaf arrangement, leaf cell structure, the presence or absence of papillae, and capsule features were observed using a light microscope. Identification was carried out using identification keys, monographs, and field guides. 11 bryophyte species, Hyophila involuta, Barbula unguiculata, Bryum argenteum, Bryum coronatum, Pohlia wahlenbergii, Entodon sp. 1, Entodon sp. 2, Fissidens sp. 1, and Fissidens sp. 2. were frequently found in the selected areas. Most bryophytes thrive on accumulated dead and decaying biotic matter on concrete and other man-made substrates, which provide nutrients and increase moisture retention, rather than growing directly on these surfaces. This adaptation allows bryophytes to survive in these harsh man-made environments. Additionally, bryophytes possess desiccation tolerance, enabling them to survive in extremely dry conditions. The unique ability of bryophytes to adapt to man-made habitats warrants further analysis by researchers. These findings contribute to understanding the features and ecological importance of bryophytes and aid in developing strategies for their conservation.
Temperature effects on growth and photosynthetic lamellae development in Pogonatum urnigerum (Bryophyta)
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Senevirathne, R. T. R.; Dharaka, B. D. P.; Ruklani, N. C. S.; Rubasinghe, S. C. K.
Pogonatum species are renowned for their photosynthetic efficiency and adaptability, playing significant roles in terrestrial ecosystems. However, their responses to changing temperature regimes remain relatively understudied. Understanding how temperature influences the growth rate of Pogonatum spp. can provide insights into their ecological resilience and adaptation strategies. This study assessed the correlation between varying temperatures and the growth rate of Pogonatum urnigerum, investigating the variation of biomass accumulation, considering the dry weight change of the plants and height change of the photosynthetic lamellae development of leaves over time. Plant samples of P. urnigerum were freshly collected from the natural habitat. After a three-week acclimation period, P. urnigerum specimens were cultivated in sterilized sand under controlled environmental conditions in a growth chamber, maintaining different temperature treatments: 30 °C, 26 °C, and 22 °C separately. The plants were watered and treated with a nutrient ion solution, three times daily at consistent intervals. The dry weight of the plants was measured by oven-drying at 70 °C constant temperature and the lamellae height was recorded weekly using a calibrated microscope. The change of dry weight was the highest at 26 °C followed by 22 °C and 30 °C, and the height change of the photosynthetic lamellae showed the greatest increment at 30 °C, followed by 26 °C and 22 °C according to the gradients of the linear trendlines of graphs. The Pearson Correlation Coefficient (PCC) analysis indicated a significant, very strong correlation between average increments in the height of the photosynthetic lamellae, and temperature suggesting the elongation of photosynthetic lamellae at higher temperatures to facilitate photosynthesis. The observed responses underscore the importance of temperature in shaping the growth and photosynthetic capacity of P. urnigerum. These findings contribute to our understanding of how climate change, a major driver of global temperature fluctuations, may impact bryophyte populations and their ecological functions across diverse habitats. Further research on broader temperature ranges is necessary to elucidate molecular mechanisms governing these temperature-dependent responses, emphasizing the need for continued investigation amidst shifting climatic conditions.