Effect of removal of host-shoot on growth, metabolism and mineral nutrition of Orobtmche aegyptiaca and Orobanche cernua was studied by allowing them to grow for fifteen days in the absence of host-shoot in field where they were growing. Host-shoot removal decreased the growth of Orobanche aegyptiaca and Orobanche cermia. Under these conditions the plants drained on their own reserved carbohydrates causing reduction in acid-hydrolyzable carbohydrates. Synthesis of protein and organic phosphate fractions, such as nucleic acid, and phosphoproteins was also retarded. Orobanche species showed limited capacity to absorb minerals through their own root system. Hence concentration of N, P, K, Ca and Mg decreased in the absence of the host-shoot. It is believed that the resrticted availability of some specific factor due to host-removal was perhaps responsible for reduced growth and hampered metabolism.
