We have always heard that plants are intelligent beings. They grow towards the light, respond to stimuli, and know how to adapt to situations. So, it is obvious that plants do have some basic form of intelligence that allows them to carry out such functions. We know that we can carry out these functions because we have a brain. Do plants also have a brain like us?
Do plants have brains?
No, plants do not have brains. There is no scientific basis to show that plants have brains or a central nervous system. However, they do have a basic nervous system that allows them to carry out certain tasks.
So, let us explore how the nervous systems of plants work.
The phenomenon of plants growing towards light is called positive phototropism. It is a natural phenomenon of the plant. It happens due to the presence of auxins. Auxins are plant hormones that control the growth of the plant by promoting cell division.
In the case of stems, the presence of auxins triggers greater growth in them. The shaded sided of the stem contains more auxins. It causes higher cell division and elongation in the shaded area. It forces the plant to grow towards the light.
The roots of the plant tend to grow towards gravity. This natural phenomenon is called geotropism.
Like positive phototropism, geotropism too happens due to auxins. Auxins tend to accumulate in higher concentrations towards the areas of low light. However, auxins in roots cause it to grow slower. So, the auxins accumulate in the lower side of the roots and inhibit root growth.
Hence, the cells on the upper side of the root grow faster and push the roots deeper inside the soil and away from light. This causes the roots to grow downwards towards gravity.
The phytochrome system acts as a biological light switch for the plant. It analyses the level, intensity, duration, and color of environmental light. So, when the plant receives adequate light, it facilitates growth. Similarly, at night when the light is absent, the phytochrome system causes the leaves to close. It also causes germination in the seeds.
The phenomenon of keeping track of the time of the day and night is called photoperiodism. This phenomenon uses the phytochrome system and enables it to control flowering, dormancy, and growth in the plant.
The plants detect the change of seasons using this system and carry out the necessary functions as per the relevant seasons. The plant uses days to keep track of the seasons. Longer days mean summer, while longer nights refer to winters. When the transition between the duration of the days and nights occurs, the plant knows that it is spring and autumn. So, this is how it knows when to flower, grow, germinate and enter dormancy.
Thus, these are a few ways through which the plants carry out the routine functions of survival. So, we can see that plants have no brain but use simple biological factors to survive.