Question

Balanophora / Orobanche is a
A. Total root parasite
B. Partial root parasite
C. Partial stem parasite
D. Total stem parasite

Answer 1

Hint:- In an ecosystem, interaction of species with other species plays an essential role in maintaining the ecosystem. Due to the increase in different species in community, interaction of food, habitat and light also start between them. These interspecific interactions may develop positive effects or negative effects to one or more interacting species. Negative interactions are of three types namely - exploitation, amensalism and competition. The exploitation type of interaction includes predation and parasitism.

Complete Answer:-
The interaction called parasitism involves the individuals of two species of different sizes in which the smaller organism (parasite) is benefitted and the larger organism (host) is harmed. The parasite derives nourishment and shelter from the host but does not kill the host.
The parasite harms the host by reducing its survival, growth and reproduction and ultimately reduces the population density. Many parasites have evolved to be host specific in such a way that both the host and parasite tend to co-evolve. Thus, if the host evolves a special mechanism for rejecting or resisting parasites, the parasite has to evolve mechanisms to counteract or neutralise them in order to be successful with the same host species.
There are two major types of parasites namely- holo parasite and hemi parasite. Parasites which are totally dependent upon the host for their survival are called holo parasites (total stem and total root parasites) while those which are partially dependent on the host are called hemi parasites (partial stem and partial root parasites). A common example of total stem parasite is a non photosynthetic plant called Cuscuta. While Orobanche/ Balanophora is a total root parasite. It attaches to the root of the plant and absorbs water and nutrition from the soil thus restricting the plant from absorbing water and nutrition.
Thus, the correct answer is option A.

Note:- Viscum and Loranthus are examples of partial stem parasites. In accordance with their lifestyles, parasites evolve special adaptations such as the loss of unnecessary sense organs, presence of adhesive organs or suckers to cling on to the host, loss of digestive system and high reproductive capacity. The life cycle of a parasite is often complex, involving one or two intermediate hosts or vectors to complete their life cycle.