Question

Movement of the pollen tube towards the ovule is
A. Chemotropism
B. Haptotropism
C. Thigmotropism
D. Phototropism

Answer 1

Chemotropism refers to the directional growth movement in response to external chemical stimuli. Haptotropism refers to the growing movement of the plant part in response to the touch stimuli. Thigmotropism refers to the growing movement in response to the touch. Phototropism refers to the growing movement of plant parts in response to the light.

Complete answer:

Option A- Chemotropism
Chemotropism is illustrated as the growth of organisms navigated by chemical stimuli from outside of the organism. It has been discovered in bacteria, plants, and fungi. A chemical gradient can impact the growth of the organism in a positive or negative way.

Option B- Haptotropism
Haptotropism refers to the movement or directional growth of plants or plant organs such as the tendrils of climbing plants in response to the stimulus of touch.

Option C- Thigmotropism
Thigmotropism refers to the directional response of a plant organ to touch or physical contact with a solid object. This directional response is generally induced by the induction of some pattern of differential growth. This phenomenon is clearly demonstrated by the climbing tendrils of some plants, such as the sweet pea.

Option D- Phototropism
Phototropism refers to the growth of an organism in response to a light stimulus. Phototropism is most often detected in plants, but can also occur in other organisms such as fungi. The cells on the plant that are distant from the light have a chemical called auxin that reacts when phototropism occurs.

Hence, the correct answer is option (A).

Note: A pollen tube is defined as a tubular structure produced by the male gametophyte of seed plants when it germinates. Pollen tube elongation is an integral stage in the plant life cycle.