Changes on Potato Leaf Metabolism and Anatomy Induced by Plant Growth Regulators

The use of growth regulators in potato crop is an alternative to reduce the aerial growth of plants and redirects carbon assimilates and nutrients to the tubers. Therefore, the objective of this study was to evaluate the effects of growth regulators, paclobutrazol and trinexapac-ethyl on plant growth and changes on the anatomy of leaves of cultivar Markies in summer conditions of the southern region of Brazil. Potato plants cv. Markies were in the summer growing season of Southeast region of Brazil and 35 days after planting, the plants were sprayed with paclobutrazol (PBZ) at 0.125 and 0.250 L ha-1 and trinexapac-ethyl (TE) at 1.0 and 2.0 L ha-1. Treatment with PBZ at both doses reduced the height of potato plants, which resulted in higher index of leaf chlorophyll and reduced the content of starch and non-reducing sugars. Both PBZ and TE treated plants exhibited anatomical changes in the leaves, including larger epidermal cells and more elongated palisades cells. These data suggest that such changes in the anatomy of potato leaf in response to the use of PBZ directly influence leaf metabolism.