Question

Fruit of water chestnut /Trapa is:
(a) Nut
(b) Cypsela
(c) Caryopsis
(d) Drupe

Answer 1

Hint: The fruit is a ripened ovary developing after ovules have matured. The fruit has a pericarp formed from the wall of the ovary and seeds formed from ovules. Simple fruit is a type of fruit that develops from a flower with a single pistil.

Complete answer:
Three main types of fruits are observed in nature- Simple, Aggregate, Composite. A simple fruit has emerged from a flower with a single pistil. An aggregate fruit emerges from a polycarpellary and apocarpous ovary while a composite fruit is formed from a whole inflorescence.
Drupe is a simple fleshy fruit that arises from a single ovary of an individual flower. The fruit of the water chestnut or Trapa is a drupe. In Trapa, the epicarp and mesocarp are extremely thin and thus get decayed by the time they hit maturity. The stony and spiny endocarp encloses a single seed that has two unequal white cotyledons. These cotyledons are large and filled with food.
- The simple fruit can have dry pericarp or fleshy. In case the fruit wall is dry, it can be divided into three types based on the number of seeds into achenial, capsular, and schizocarpic. In achenial fruits, a single seed is present which is indehiscent and dry.
- The nut is a type of achenial fruit wherein the fruit wall is woody or sometimes leathery. E.g. Cashewnut.
- Caryopsis is also a type of achenial fruit wherein the thin dry pericarp is completely fused with the wall of seed or testa. Such types of fruits may develop from monocarpellary superior and unilocular ovary. E.g. Maize, Wheat.
- Cypsela is a type of achenial fruit where the fruit wall is attached to the seed at one point. Such types of fruits develop from an inferior and unilocular ovary. E.g. Dandelion.
So, the correct answer is ‘(d) Drupe.’

Note:
- Fruits are an important source of vitamins and therefore should be included in one’s diet.
- The fruit also forms a protective covering against the desiccation of seeds while they grow and mature.
- The bitter taste of unripe fruits is due to the accumulation of tannins, bitter alkaloids, and acids. Once it is ripped, the development of sweet taste attracts animals and humans. They help to disperse the seeds enclosed within.