Impact of temperature and light on the physiology and morphology of Chara hispida L. (Charophyceae).

Chara hispida L. is a widely distributed charophyte species belonging to the subsection Hartmania, where species discrimination mainly relies on quantitative characters rather than qualitative ones. To obtain data on morphological and physiological response to environmental variation, laboratory incubations were conducted that mimicked the broad range of temperature and irradiance conditions under which the species thrives. In general, reduced irradiation as well as high temperatures promoted elongation, and other morphological characters exhibited high variability. Photosynthetic efficiency increased under moderate temperatures and low light but decreased under chilling or high-light conditions. Protective mechanisms, such as non-photochemical quenching and adjustments in pigment composition were observed, although their capacity was limited at very low temperatures. Overall, Chara hispida exhibits morphological and physiological plasticity, enabling survival across a wide range of light and temperature conditions. • Chara hispida morphology is influenced by light and temperature • Low light and high temperature promote elongation; further characters are variable • Photosynthesis performance is limited by low temperature and high light • Chara hispida adapts to a wide range of environmental conditions