The effect of three types of street lighting on the morphology and physiology of the common hackberry (Celtis occidentalis L.) leaves

ABSTRACT Our studies covered the responses of the common hackberry (Celtis occidentalis L.) to artificial lighting at night. We analyzed the effect of three types of lamps used in public lighting: high-pressure sodium lamp (HPS) and two types of LED lamps. Physiological, macro- and micromorphological measurements were carried out during the research. Common hackberry tree was affected by the night light of street lamps, although the tested individuals received natural lighting during the day. Moreover, there were differences observed between the effects of the investigated lamp types. The high-pressure sodium lamp (HPS) resulted in histologically thicker leaves with higher photosynthetic yields, together with more efficient stomatal movements. The LED lamp with a color temperature of 3000 K enhanced the establishment of the photosynthetic apparatus and the growth of the palisade parenchyma. The physiology and histological development of leaves illuminated at night with a narrow-spectrum LED with a color temperature of 1900–2400 K remained inferior compared to those on shoots kept in the dark at night. Our results confirm that the type of the light source is a relevant factor in considering the effects or prevention of light pollution on plant anatomy.