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प्रश्न
What happens to the moonflower
- during the daytime, and
- at night?
What is this phenomenon known as?
उत्तर
- The petals of a moonflower close during the day.
- They open during the night.
This phenomenon is known as photonasty.
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संबंधित प्रश्न
Give the scientific terms used to represent the Growth of a pollen tube towards ovule.
What does a Mimosa pudica plant do in response to touch? What is this phenomenon known as?
What is meant by positive tropism and negative tropism? Explain with examples.
The bending of the shoot of a plant in response to light is called :
(a) geotropism
(b) phototropism
(c) thigmotropism
(d) photonasty
A growing seedling is kept in a dark room. A burning candle is placed near it for a few days. The top part of seedling bends towards the burning candle. This is an example of :
(a) chemotropism
(b) hydrotropism
(c) phototropism
(d) geotropism
Which of the following are not tropisms?
(i) growing of pollen tube in response to a sugary substance
(ii) folding up of leaves of sensitive plant in response to touch
(iii) winding of tendril around a support in response to touch
(iv) opening up of the leaves of a daisy flower in response to light
(a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (ii) and (iv)
The chemical substance P is made and secreted by the meristematic tissue at the tip of stem (or shoot) of a plant. The chemical substance P is responsible for a phenomenon Q in plants in which the stem bends towards a source of light. The same chemical substance P has an opposite effect on the root of a plant. It causes the root of a plant to bend away from the source of light in a process called R.
(a) What is the chemical substance P?
(b) State whether P prefers to remains in the sunlit side of a stem or in shade.
(c) What is the effect of substance P on the rate of growth of (i) a root, and (ii) a stem?
(d) What is the name of process (i) Q, and (ii) R?
(e) What is the general name of chemical substances like P? Name another substance which belongs to this class of chemical substances.
The tropic movement that helps the climbing vines to find a suitable support is ______.
Which flowering plant shows a photo nasty just opposite to that of a Dandelion?
Why do roots of halophytes show negative geotropism?
