Which of the following is ineffective on transpiration?

Stomata in angiosperms open and close due to

Stomata in angiosperms do not open during:

Explain: transpiration is an 'avoidable' event.

Which of the following factors is the most important in the regulation of transpiration?

Read the following statements carefully and choose the right answer from the codes given below:
$I$. $PMA$ and silicon oil of low viscosity are considered as antitranspirants.
$II$. $BAP$,$NAA$,and cobalt chloride are also used as antitranspirants.
$III$. Abscisic acid $(ABA)$ affects the mechanism of opening and closing of stomata.
$IV$. Starch of guard cells is converted into $PEP$ (phosphoenolpyruvate) ions by the process of hydrolysis.
$V$. Potometer works on the principle of potential difference between the tip of the tube and that of the plant.
$VI$. Transpiration rate is directly proportional to the relative humidity.