पादप कार्यिकी

Analysis of phytohormone functions:

• Ethylene: Gaseous hormone responsible for fruit ripening, leaf abscission, and senescence.
• Abscissic acid: Growth inhibitor mediating stomatal closure and drought stress responses.
• Cytokinin: Primarily promotes cell division (cytokinesis) and delays senescence.
• Auxin: Promotes cell elongation and enlargement through the acid growth hypothesis, increasing cell wall extensibility.

Analysis of antitranspirant action:

• Stomatal closure: Stomatal closing chemicals include phenylmercuric acetate (PMA) and abscisic acid (ABA).
• Forming a film: Selected as the correct answer in the official RPSC answer key, referring to the protective physical barrier/coating formed over the leaf surface.
• Increased reflectance: Kaolin (5% suspension) is scientifically categorized as a reflecting material that reflects solar radiation to lower leaf temperature, though option (B) is the official key response.
• Increased hydration: Not an antitranspirant mechanism.