At a fruit stall, Neel buys a banana and a coconut…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
At a fruit stall, Neel buys a banana and a coconut. The banana has no seeds to speak of. (a) Why is the banana called a parthenocarpic fruit? (b) What kind of fruit is a coconut? (c) How is the mesocarp of a coconut different from that of a mango? (d) From what kind of ovary does a drupe grow?
Need a reminder? The key ideaShow
A fruit is a mature ovary; a parthenocarpic fruit forms without fertilisation, as in banana. The pericarp has epicarp, mesocarp and endocarp. Mango and coconut are drupes from a monocarpellary superior ovary, with one seed. A seed has a seed coat (testa and tegmen), hilum, micropyle and an embryo. Dicot seeds such as gram and pea have two cotyledons and no endosperm; castor keeps endosperm. Maize has a membranous coat fused with the fruit wall, a bulky endosperm, an aleurone layer, one cotyledon called the scutellum, the coleoptile and the coleorhiza.
The worked solution
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Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The banana. Its fruit develops without fertilisation of the ovary, so it is parthenocarpic.
Step 2. The coconut. It is a drupe.
Step 3. The mesocarp. In a mango it is fleshy and edible. In a coconut it is fibrous.
Step 4. The ovary. A drupe grows from a monocarpellary, superior ovary and holds one seed.
Answer: (a) it forms without fertilisation; (b) a drupe; (c) fibrous, not fleshy; (d) a monocarpellary, superior ovary.
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