Example of a PGR and its purpose.

• A. Paclobutrazol to increase shoot length
• B. Paclobutrazol to brighten color
• C. Glyphosate to kill weeds
• D. Paclobutrazol to reduce shoot length and improve density and mowing frequency

Answer: (D)

Growth regulators change how much and how fast a plant grows. Paclobutrazol is a growth regulator that blocks gibberellin production, so turf shoots stay shorter and the canopy becomes more compact. That reduced elongation increases density and creates a more uniform turf, which also affects mowing by keeping growth in check and allowing for more predictable mowing intervals. The other options don’t fit this role: paclobutrazol isn’t used to brighten color and isn’t about increasing shoot length, and glyphosate is a weed killer, not a growth regulator. So the example that fits a PGR and its purpose is paclobutrazol to reduce shoot length and improve density and mowing frequency.