Question

What is the type of movement that occurs during opening and closing of flowers?
A. Nastic movement
B. Tactic movement
C. Tropic movement
D. Nutation

Answer 1

Hint : Plants mainly show two types of movement. Growth dependent movement is known as the tropic movement and non-growth dependent movements known as a nastic movement.

Complete step by step solution : To answer this answer, first, we need to learn about the different movement of flowers. Plants do not move from one position to another, but they also make movements in response to external stimuli. There are different types of movement shown by plants. It may or may not be a movement for growth. Plants mainly show two types of movement. Growth dependent movement is known as the tropic movement and non-growth dependent movements known as a nastic movement.

Now, let us find the solution from the given options -

The movement of a plant part in response to an external stimulus in which the direction of response is not determined by the direction of stimulus is known as a nastic movement. It's also known as the Nasties. Stimulus may be defined as light, heat, touch or contact, etc. Nastic movement is not a spatial movement of the part of the plant with a stimulus-response. The movement of flower during opening and closing is a type of nastic movement.

Tactic movements are locomotive movements that are triggered by other unidirectional external stimuli. The direction is influenced by the direction of the stimulus. Based on the nature of the stimulus, these movements can be classified as phototactic, chemotactic, and thermotactic.

Growth movements that occur in response to unidirectional external stimuli and result in the positioning of the part of the plant in the direction of stimulus are considered to be tropical movements. Based on the essence of the stimuli, these movements can be classified as phototropism, geotropism, hydrotropism and chemotropism.

Nutrition refers to the bending movement of roots, stems, leaves and other plant organs caused by differences in growth in different body parts. Simple nutation occurs in flat leaves and flower petals, caused by uneven growth on both sides of the surface.

Thus, the right answer is option A. i.e., Nastic movement.
Note : Nutation is a spontaneous movement of plants whereas; tropic, tactic, and nastic movements are induced movement of plants.