Question

The plants that grow on saline soils with high concentration of NaCl, $MgSO_4$ and $MgCl_2$ are called as
A) Succulents
B) Mesophytes
C) Xerophytes
D) Halophytes

Answer 1

Hint: The salinity of soil is defined by the amount of salts dissolved in it. It should usually be more than 12g/L. The salt-tolerant plants can grow in high concentrations of NaCl, $MgSO_4 $ and $MgCl_2$.

Complete answer:
Let us analyse all the options to find the correct answer
Option A: Succulents are the plants which are drought- resistant. They are adapted to live in arid conditions and have water storing tissues in their fleshy roots, stems or leaves. Such an adaptation gives them a swollen appearance. These plants are usually found in dry areas like deserts and semi deserts. Examples include the Cactus plant. Hence, this is an incorrect option.

Option B: Mesophytes are terrestrial plants which are adapted to survive in average or normal water conditions and are found in temperate meadows. They have a very well developed vascular system and no special adaptive features are found in them. Examples include Corn and Lilac. Hence, this is an incorrect option.

Option C: Xerophytes are the plants which are adapted to live in dry conditions where water availability is scarce. They are a type of succulent. The waxy leaves help them to lose less water and fleshy stems help in preserving water. Examples include Pineapple and Cacti. Hence, this is an incorrect option.

Option D: Halophytes are also known as salt-tolerant plants because they are able to grow in soil with high concentrations of salt which are found in mangrove swamps, semi-deserts, seashores, etc. They have adaptive mechanisms like resistance, tolerance and avoidance. Examples include Anemopsis californica and Dunaliella. Hence, this is the correct option.

Thus, the correct answer is Option (D) Halophytes.

Note:
i) The measure of salt tolerance in plants is called halo tolerance and it varies for different halophytes.
ii) Halophytes account for only 2% of all plant species in the world.