NEET BIOLOGY

Detailed explanation-1: -The exogenous application of plant growth regulators (PGRs) can alter various characteristics of flower crops including growth promotion and retardation, number of flowers, flowering, flower life, breaking dormancy, improving seed germination and vase life.

Detailed explanation-2: -The growth retardants include (1) onium compounds such as chlormequat chloride (Cycocel, CCC) and meliquat chloride, (2) pyrimidines such as ancymidol and flurprimidol, and (3) triazoles, including paclobutrazol, uniconazole, BAS III, triadimefon, and triapenthanol.

Detailed explanation-3: -Abscisic acid (ABA) is a general plant-growth inhibitor. It induces dormancy and prevents seeds from germinating; causes abscission of leaves, fruits, and flowers; and causes stomata to close.

Detailed explanation-4: -Ancymidol (A-Rest® or Abide®), flurprimidol (Topflor®), paclobutrazol (Bonzi®, Downsize®, Paczol®, or Piccolo®), and uniconazole (Concise® or Sumagic®) are all listed together due to their similar chemical structures. They all inhibit GA production at similar sites in the GA production process.