Which combination of factors negatively affects pollen tube growth?

• A. Wind, rain, cold temps.
• B. Wind, water stress, hot temps.
• C. Gentle breeze and humidity.
• D. Dry heat waves.

Answer: (C)

Pollen tube growth relies on adequate moisture and stable conditions to hydrate the pollen and fuel the elongation of the tube through the style. Desiccation and heat stress reduce pollen viability and slow or halt tube extension. A gentle breeze with humidity tends to support germination rather than hinder it, making that scenario favorable for growth. Rain or cold can disrupt deposition or slow growth, but the combination of wind, water stress, and hot temperatures creates multiple simultaneous stresses—desiccation, impaired turgor, and heat-related enzyme and metabolic strain—that most strongly hinder pollen tube growth.