Question

A partial (stem or root) parasitic plant is one which
A. Draws food from the host only at certain times
B. Takes both water and nutrients from the host plant
C. Takes only water from the host plant
D. Uses the host just for support

Answer 1

Hint: A partial parasitic plant is one which is having chlorophylls and depends on the host for only some of their needs. They can produce their organic substances but sometimes they depend on the host for a few chemical substances for their growth.

Complete answer:
-Partial parasitic plants are usually chlorophyllous and depend on the host for only nutrients and water. Other activities of these plants are handled by their green leaves. Examples of Partial parasitic plants include Dendrophthoe falcata, Viscum album, Santalum album, Loranthus, Mistletoe, etc.

Hence, the correct answer is B.

Additional information:
> Total parasitic plants are achlorophyllous and those which completely depend on their host for their growth and survival. These are usually heterotrophic plants that obtain shelter, water, food, and nutrients from their host. Example: Cuscuta reflexa, Orobanche aegyptiaca, Striga asiatica, etc.
> Parasitic plants in general are the plants that produce special (modified) roots called haustoria, which help them in penetrating inside the host till vascular tissues to draw the food or water required according to their needs.

Note:
Parasitic association in plants is when a plant depends on the host plant for their survival and growth but the host plants do not get anything in return from the parasitic plant. In fact, sometimes the parasitic plant causes extreme damage to the host plant. Note that climbers or mycoheterotrophic are not considered as parasitic plants. As climbers just depend on other plants for support and not for survival or growth. Also, mycoheterotrophic though lack chlorophyll they live in symbiotic association with fungi and not with plants.