Comparative leaf morphometrics of two urban tree species: an assessment to air pollution impacts
By: Lowell G. Aribal, Earla Jade Naiza Llamos, Angela Grace T. Bruno, Michael Arieh Medina
Key Words: Leaf morphometrics, Air pollution, Philippines.
J. Bio. Env. Sci. 9(1), 106-115, July 2016.
Leaf-size indices of two urban tree species namely: Pterocarpus indicus forma echinatus Willd. and Sweitenia macrophylla King growing in polluted and non-polluted areas of Cagayan de Oro City, Philippines were compared to verify if air pollution could directly affect leaf morphology. The streets with the heaviest influx of vehicles per day were considered as the polluted area while the non-polluted area was the peri-urban ecotourism village located approximately 2 kilometers away from the main highway. Fifty mature leaves from sampled trees were collected and measured to determine the variables such as length, width, area, petiole length including color, shape and deformities. Collected samples undergo tissue analysis to determine plant nutrient status. Results show that leaves of both species growing in the polluted area were significantly inferior in length, width, and area compared to those in the non-polluted site. However a variation in petiole length was observed with P.indicus forma echinatus being longer in polluted area than in non-polluted area. In contrast S. macrophylla has shorter petiole length in polluted area than non-polluted area. This implies a diverse effect of air pollution to leaf morphology. Statistical analysis for all variables evaluated revealed a significant difference at p<0.005 level. Moreover, both species in the polluted area exhibits pale green color while a dark green color in the non-polluted site. The shape of P. indicus forma echinatus in polluted area exhibited lobes and deformations while the most visible injury includes appearance of white streak lesions and scorched leaf apex for S. macrophylla.