Morphological and anatomical changes in the petioles of Nymphaea alba L. and Nuphar luteum (L.) Sm. caused by oscillations of the water level in lakes

Abstract

In this study we present morphological and anatomical changes in the petioles of Nymphaea alba and Nuphar luteum from two lakes greatly differing from each other in respect to the oscillation of their water level (Lake Salno -a stabilized natural reservoir, used for comparison; Lake Kwiecko -a natural reservoir for the Hydroelectric Plant in Żydowo, where the changes in the water level oscillate up to 3.1 m during a day under conditions of maximum retention). Nonrhytmic and turbulent water flows in Lake Kwiecko cause the elongation of petioles, a decrease in their diameter, and to a significant degree, the reduction of supporting elements - collenchyma, vascular bundles and idioblasts. These changes take place to a lesser extent in Numphar luteum. Although this species has a very wide ecological amplitude and does not need to adapt to changing habitat conditions, through anatomical modifications the oscillations in the water level have an unfavorable effect on its population in Lake Quick.