Question

Pollen grains germinate only on the?

• A. Dry soil
• B. Wet soil
• C. Damp place
• D. Stigma

Answer 1

The correct option is A Dry soil

D. Stigma

Reason: The first requirement for pollen to germinate is their hydration which takes from a few seconds to a few minutes. Pollen absorbs secretion of stigma (sugar, gum, resins and other liquid) and swells up. Exine ruptures and intine comes out in the form of pollen tube. Secretion of stigma is sticky and also prevents pollen as well as stigma from desiccation. The stigmas which secrete exudates are called wet stigmas (petunia) and those which do not are called dry stigmas (cotton). The pollen tubes pierces through papilla into tissue of style.