Anatomical and Morphological Response of Highbush Blueberry to Flooding Stress

Abstract

The purpose of this research was to study the various aspects of root, shoot and reproductive growth of the cultivated highbush blueberry under normal conditions and as influenced by seasonal root zone flooding. These studies were conducted on three cultivars – “Earliblue”, “Bluecrop”, and “Lateblue” for up to three years. Root, shoot, and reproductive growth were measured at intervals throughout the years and the soil temperature and stage of plant development recorded. Growth of white unsuberized roots peaked in early-June and September when soil temperatures were in the range of 14 to 18 °C and was concomitant with shoot growth. Some plants survived more than 26 months of continuous flooding, but growth was decreased after approximately four months. April submerged plants had the greatest percentage of death followed by the August and December flooded plants. Vegetative and reproductive growth were greatly reduced with flooding. Anthesis was delayed by almost one week and fruit abscission was increased in flooded plants. There was an increase in size of epidermal cells of roots from flooded plants. The mid-cortical cells of stems and spongy mesophyll complex of leaves from flooded plants had an increase in intercellular spaces. Flower buds from flooded plants were smaller in size and flower formation appeared delayed.