Phototropism
Trending Questions
(a) Define phototropism. Give one example of phototropism.
(b) How does phototropism occur in a plant stem (or shoot)? Explain with the help of labelled diagrams.
(c) What is meant by positive phototropism and negative phototropism ? Give one example of each type.
How does plant detect the touch, and how do the leaves move in response?
Which plant hormone bend towards the light?
Which hormone does stop premature leaf fall?
Why do plant roots grow away from sunlight?
The bending of the shoot of a plant in response to light is called :
(a) geotropism
(b) phototropism
(c) thigmotropism
(d) photonasty
Why is auxin not considered a hormone?
What is the stimulus in :
(a) phototropism
(b) geotropism
(c) chemotropism
(d) hydrotropism
(e) thigmotropism
Plant parts show two types of movements, one dependent on growth and the other independent of growth. Give one example of the movement in plant parts:
(a) which depends on growth
(b) which does not depend on growth
Name the plant organs which are :
(a) positively phototropic
(b) positively geotropic
(c) negatively geotropic
(d) positively hydrotropic
- Positive Phototropism
- Negative Phototropism
- Negative Geotropism
- Positive Geotropism
The movement of a shoot towards light is:
(a) geotropism
(b) hydrotropism
(c) chemotropism
(d) phototropism
Question 10
The movement of the shoot towards light is
(a) geotropism
(b) hydrotropism
(c) chemotropism
(d) phototropism
One of the following plant hormones is responsible for the phenomenon of phototropism in plants. This is :
(a) giberellin
(b) eltroxin
(c) cytokinin
(d) auxin
A chemical substance P is made and secreted by the meristematic tissue at the tip of the 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 sunlight 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.
A potted plant is growing in a transparent glass jar. In this plant, X and Y are the two growing parts having a lot of meristematic tissue. It is observed that the part X of this plant exhibits positive geotropism but negative phototropism. On the other hand, part Y of this plant exhibits negative geotropism but positive phototropism.
(a) Name the part X of the plant.
(b) Name the part Y of the plant.
(c) Which part of the plant, X or Y, will exhibit positive hydrotropism?
(d) Which part of the plant, X or Y, can have tendrils on it?
(e) Which phytohormone causes the part X to exhibit negative phototropism?
- gravitropism
- phototropism
- chemotropism
- hydrotropism
Which of the following plant part exhibits negative phototropism ?
(a) root
(b) branch
(c) leaves
(d) stem
The process by which a plant shows bending towards the light.
A growing seeding is kept in a dark room. A burning candle is placed near it for a few days. The top part of seeding bends towards the burning candle. This is an example of :
(a) chemotropism
(b) hydrotropism
(c) phototropism
(d) geotropism
- True
- False
- enzymes
- animal hormones
- antibiotics
- plant hormones
The bending of the stem of a plant towards a source of light is caused by the action of a phytohormone known as :
(a) abscisic acid
(b) auxin
(c) gibberellins
(d) cytokinin
since plants do not have a nervous system they do not show any kind of coordination. do you agree with this statement.
Question 40
What is a tropic movement? Explain with an example.
- True
- False
How do control and coordination take place in plants?
Hormone stimulating internodal growth in plants
Auxin
Cytokinin
Gibberillin
ABA
