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Science of Plants

Plants and their behaviour play an important role in our daily life. What is the Science behind their behaviour?

Why do Night-Queen (Raat-ki-Rani) flowers bloom only at night?
When few flowers have pleasant smell, many have attractive colours. Some flowers will have both beautiful colours as well as delightful scent. Plants grow towards sunlight. Most of the flowers of the plants bloom during day time. But flowers like Night-Queen bloom only during night.

These colours and scents of flowers have their own purpose. Many insects like butterflies and bees and small birds suck nectar (sweet juice) from flowers and these scents and colours of flowers attract these birds and insects. When these insects sit on flowers to suck the nectar. The pollen grains of the flowers stick to their small feet and wings. When these insects sit on other flowers of the same kind, the pollen grain on their bodies fell on these flowers and pollination takes place. But for this process a flower cannot form into a fruit. Birds also carry pollen from flowers of one plant to the flowers of another plants of the same kind as pollen stick to their beaks while they are sucking the nectar.

Some insects are busy during the day while the others are active during night. To attract night-insects flowers like Night-Queen (Raat-ki-Rani) bloom only during night emitting delightful smell. They are white in colour so that they can be easily located by the insects during night against dark background.

The leaves of 'Touch Me Not' curl op when we touch them. Why?
'Touch Me Not' plant will have leaves like that of a 'tamarind tree'. By observing carefully one can see tiny bulges where the leaflets are attached to the stalk. At the places where leaf is attached to the stem will also show a bulge. In these bulges there will be many thin walled cells which swell when they absorb water like a rubber balloon and are deflated when they lose water.

The 'Touch Me Not' plant leaves are very sensitive. When we touch its leaf, the water from the thin walled cells is drawn into the stem and the cells shrink. Due to this the leaf looses its stiffness and curls up. If one holds the all the leaves even gently all of them will curl up which happens with in few seconds. But the recovery time is more than thirty minutes.

But unfortunately, we can describe how the leaves of 'Touch Me Not' plant curl up but not why it happens!!
Lakshmi Emani
Published date : 02 Oct 2012 01:11PM

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