Interactive influences of light and temperature on the growth and morphology of submersed freshwater macrophytes

Abstract

ABSTRACT (Continued) .Total biomass production in all species generally increased with both increasing light and increasing temperature (to at least 28C).However, variations in biomass and other parameters as well were highly influenced by the interactive relationship between light and temperature.Shoot density correlated directly with biomass production in these species under all experimental conditions .In con trast , light and temperature elicited opposing responses in shoot length, which decreased with increasing light but increased with increasing temperature.The extent of variations in leaf morphology differed among species, apparently reflecting intrinsic differences in heterophyllous capab ilities.Light and temperatur e appear to interact in influencing lower limits of macrophyte depth distribution and r elated variations in the duration of seasonal growth .Temperature is like ly to assert a strong influence on the latitudinal distribution of submersed freshwater macrophytes, dependent upon species-specific differences in res ponse to temperature and basic differences in macrophyte life cycle .