Recent Advances in Parasitic Weed Research: An Overview
Parasitic flowering plants (parasitic weeds) are species unique and unusual in their growth habit and habitats. Because these are not in direct contact with soil and soil factors necessary for growth, development, and existence, these species, for almost the entire growth cycle, have evolved nutritional modes that are clearly different from normal green plants. They have been a peculiar subject since ancient times. Parasitic species are usually attached to other plant species of different genera and plant families (with some species exhibiting self-parasitism) through a haustorium-an absorptive organ developed upon attachment to host tissues. A haustorium (pl. haustoria) is a bridge of tissue connecting the host and parasite, usually a swollen mass consisting of both host and parasite tissue. This acts as a conduit for the flow of water and nutrients from host to parasite. It is a suckerlike structure varied in size, shape, and morphology for different parasitic species.