FFA Floriculture Practice Test

What is the result of a zero DIF in greenhouse plant growing?

1. Longer plants compared to those with positive DIF

2. Shorter plants compared to those with positive DIF

3. Higher flower yield

4. Faster growth rate

The correct answer is: Shorter plants compared to those with positive DIF

A zero Difference in Temperature (DIF) indicates that there is no temperature differential between the day and night cycles in a greenhouse setting. This condition has a unique effect on plant growth, as plants tend to respond to the variation in temperature by altering their growth patterns. When a zero DIF is maintained, plants generally exhibit shorter internodes compared to those grown under conditions with a positive DIF, where daytime temperatures are higher than nighttime temperatures. In the context of plant growth, a positive DIF tends to encourage taller plants because the warmer daytime conditions promote elongation. Thus, when DIF is neutral or zero, the lack of a temperature differential does not stimulate this elongation, leading to the development of shorter plants instead. This effect is particularly critical in greenhouse management, as controlling plant height can be essential for aesthetics, stability, and overall cultivation strategies. Therefore, the correlation between zero DIF and shorter plants aligns with the physiological processes influenced by temperature variations, making it the right understanding in this context.