Question

Response of plants due to reversible turgor change in pulvinus as a result of touch is
A. Photonasty
B. Thermonasty
C. Seismonasty
D. Chemonasty

Answer 1

Turgor pressure is the force inside the cell that pushes the semipermeable membrane against the cytomembrane. It is conjointly referred to as fluid mechanics pressure and outlined because of the pressure measured by a fluid, measured at a particular purpose inside itself once at equilibrium. Generally, state pressure is caused by the diffusion flow of water and happens in plants, fungi, and microorganisms.

Complete answer:
Photonasty is the nastic movement shown by plant structure in response to lightweight. Generally, the tendency ensures plant species to reply to light-weight by developing sufficient cellular force or growth on one facet of associate degree axis to vary the shape or position of the axis, as within the gap and shutting of the flowers of four-o'clock.
Thermonasty is that the nastic movement is shown by plant structure in response to warm temperature or the tendency inbound plant species to retort to temperature changes by developing enough cellular force or growth on one aspect of the associate axis to alter the shape or position of the axis, as within the closing or folding of rhododendron leaves in cold air.
Seismonasty is that the nastic movement shown by plant structure in response to the touch. The response of plants because of reversible state in pulvinus as a result of touch is because of seismonasty.
Chemonasty is the nastic movement shown by plant structure in response to the chemical. I.e. response to chemical information. Examples: Closing/Bending of organ hairs of the carnivorous plant in response to gas compounds from Associate in Nursing insect to forestall the escape of such insect; Movement of roots towards the additional nutrient-rich components of the soil.

So, C is the correct option.

Additional info: Seismonasty or Thigmonasty is that nastic response of a plant or flora to the touch or vibration. Conspicuous samples of thigmonasty embody several species within the herbaceous plant subfamily Mimosoideae, active carnivorous plants like Dionaea and a large variety of fecundation mechanisms.

Note:
Turgor pressure among cells is regulated by diffusion and this conjointly causes the cytomembrane to expand throughout growth. at the side of size, the rigidity of the cell is additionally caused by state pressure; a lower pressure ends up in a stale cell or plants part (i.e. leaf, stalk). One mechanism in plants that regulate state pressure is its membrane, that solely permits some solutes to travel in and out of the cell, which may conjointly maintain a minimum quantity of pressure.