Question

Water hyacinth float on the water surface due to the presence of
A. parenchyma
B. Aerenchyma
C. Sclerenchyma
D. Collenchyma

Answer 1

Hint: Water hyacinth is a water plant that freely floats over the water, they are hydrophytes and are native to the tropical and subtropical part of America. It can rise to 3 feet from the water surface and its scientific name is Eichhornia crassipes.

Complete answer: Pontederia crassipes is the common water hyacinth, which is a native aquatic plant of Amazon basin and it is an invasive species. In aquatic plants that float over the surface of the water, they possess some kind of air-filled tissues called aerenchyma which provides buoyancy to the plant and allows them to float on the water. This plant bears a blue-violet flower for the pollination.
a) Parenchyma is a simple permanent living tissue that is made up of thin-walled and isodiametric cells. It is the most common and abundant cell in the plant. They can be oval, round or polygonal in shape, and provide rigidity. It also provides turgidity to softer parts and helps in storing food.
b) Sclerenchyma is also a simple permanent tissue which is highly thick-walled with little or no protoplasm. The thickening of the cell wall is made up of cellulose, lignin or both. It is further two types of the name as sclerenchyma fibre and sclereids.
c) Collenchyma is also a simple permanent tissue which is a refractile non lignified living cell that possesses thickening in specific areas of walls. Depending upon thickening, it is of three types that are named as angular collenchyma, laminate collenchyma and lacunar collenchyma.
Hence, the correct answer is option B.

Note: Water hyacinth plant show phytoremediation property, i.e. they can accumulate high amounts of metal and other contaminants that pollute the groundwater and soil. It removes heavy metal elements like cobalt, zinc, cadmium, mercury, lead and many more.