Question

An obligate root parasite among the following is
A. Viscum
B. Striga
C. Loranthus
D. Rafflesia

Answer 1

A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host. Corpse lily or stinking corpse lily is a species of flowering plant in the parasitic genus. It has a very strong and unpleasant odour of decaying flesh, earning it the nickname “corpse flower”.

Step by step answer: A parasitic plant is a plant that derives some or all of its nutritional requirement from another living plant. All parasitic plants have modified roots, called haustoria, which penetrate the host plants, connecting them to the conductive system –either the xylem or phloem or both. For example, the plants like Striga or Rhinanthus connect only to the xylem, via xylem bridges. Alternatively, plants like Cuscuta and Orobanche connect only to the phloem of the host. This provides them with the ability to extract water and nutrients from the host. Parasitic plants are classified depending on the location where the parasite latches onto the host and the amount of nutrients it requires. Some parasitic plants are able to locate their host plants by detecting chemicals in the air or soil given off by host shoots or roots.
Loranthus and Viscum are both partial stem parasites. It sends secondary haustoria which makes connections with the xylem of the host and absorb water and minerals. Plants usually considered holoparasites include broomrape, dodder, Rafflesia, and the hydnoraceae.
Hence option D is correct.
Additional information:
Obligate parasite –a parasite that cannot complete its life cycle without a host.
Facultative parasite –a parasite that can complete its life cycle independent of a host.
Stem parasite – a parasite that attaches to the host stem.
Root parasite –a parasite that attaches to the host root

Note:Rafflesia arnoldi (the corpse flower) produces the world’s largest flowers at about one meter in diameter. It is a tourist attraction in the native habitat. Rafflesia has no leaves, no roots, no stem, no chlorophyll, therefore all its nutrients and water comes from tetrastigma vines in inhabits.