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My research project is based on the well-documented process of leaf abscission (dropping of leaves) in deciduous trees. This is a normal seasonal process as photosynthesizing pigments breakdown (which causes colour change in the leaves) or one that can arise when an angiosperm is experiencing stressful conditions such as drought or disease. One of the roles of leaves is to bear microscopic openings (stomata) that allow the exchange of gases and release of water vapour through the process of transpiration. This process allows waste oxygen produced during photosynthesis to be released and the evaporation of liquid water to create a difference in water pressure between the leaves and roots, which causes water to flow up xylem tissues of the trunk and to the disparate parts of the plant. My hypothesis supposes that particulate matter in the air from nearby construction excavations and a roadway might interfere with the role of stomata and that the tree might preferentially drop these “under-performing” leaves, as it does when photosynthetic pigments begin to lose their function.
Some keywords that might accompany this paper would be: Prunus, premature leaf abscission, particulate pollution, transpiration.
good concise description