Tag: biology

Thigmonasty is the response of a plant to touch or vibration. The Venus Flytrap an insectivorous plant shows thigmonasty. When an insect lands on its trap, the tentacles present on the two curved lobes of a single leaf, rapidly close. Hence the insect gets trapped and later killed. Thus the correct answer is option C.

Plant in order to flower require a particular day length or light period called photoperiod and response of the plants to photoperiod in terms of flowering is called photoperiodism. Photoperiodism is the response to duration and timing of light and dark periods.

On touching the Mimosa leaves the water concentration inside the plant changes due to which the plant leaves tend to get closed. This movement or response of plant is called seismonastic movement.

The branches of the secondary roots are called tertiary roots. Some of the lateral organs possess little or no geotropic sensitivty. It is thus termed as ageotropic. Example of such a plant: corolloid root of cycas.

In the case mentioned here, the plant is able to undergo flowering during all seasons of the year. it shows that the plant is insensitive to light. Photoperiodism has no great effect on the plant.

Thigmonastic movements occur in some plants in response to tactile stimuli. The movements may be defensive or offensive-response to the touch of an herbivore interested in ingesting the plant or by contrast, in response to the touch of an insect that may serve as a potential meal for a carnivorous plant.

Phototaxis - is a kind of taxis or locomotory movement, that occurs when a whole organism moves towards or away from stimulus of light. It is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite
So, the correct answer is 'Phototaxis'

Bulliform cells are large, bubble-shaped epidermal cells present in the leaves of many grasses that lose water and cause the leaves to fold or roll during drought.

Stimulus for flowering will be accepted by young leaves. Apart from light and chemical stimulus for flowering, temperature is also one important stimulus that a lot of plant species use to flower, e.g., some orchid species.