Effect of shading on the English oak (Quercus robur L.) seedlings water regime

Abstract

Shading is a common urban stress in the city due to the light block from buildings. Oaks stands are found as part of park areas, forests and in point gardening in many large cities of the world. In this work we examined anatomical and physiological aspects of the adaptation of oak seedlings to the lack of light. To determine the intensity of transpiration, leaf hydration, and water deficiency, the weight indicators of the leaves were measured. Anatomically, the analysis of the leaf epidermis was carried out by microscopy of varnish prints. Changes were revealed in the anatomical structure of the leaf and were irreversible in the water regime undo shading. It was found the correlation between stomatal apparatus of the leaves and incoming solar radiation amount. With the optimal combination of hydrometeofactors, the evaporation rate in the heavily shaded leaves during the day did not exceed 15 ± 0.9 g/(m2h), which was 30…35% of the transpiration intensity in the well-lit control leaves. Then, shading by 80% reduced transpiration by 50…65 %. The influence of the degree of shading on the water regime of oak seedlings is shown for the first time at forest-steppe region.