Texas FFA Nursery Landscape Practice Exam

The basic principle of using a mist propagation system is to?

1. A. Cool the propagation medium to promote root formation

2. B. Keep the propagation medium uniformly moist and supply moisture to cuttings

3. C. Keep the plant material cool

4. D. Increase humidity around the cutting and reduce transpiration

The correct answer is: D. Increase humidity around the cutting and reduce transpiration

The basic principle of using a mist propagation system focuses on increasing humidity around the cuttings while simultaneously reducing transpiration. This method is essential for successful propagation, particularly for plants that are sensitive to water loss during the rooting process. When cuttings are taken from a parent plant, they lose water through their leaves (a process known as transpiration). If the cuttings lose too much moisture, they can wilt and fail to root. A mist system creates a humid environment that surrounds the cuttings, which helps to reduce the rate of transpiration. The frequent misting keeps the foliage hydrated, allowing the cuttings to maintain turgor pressure while they develop roots. While keeping the propagation medium moist is also important, the primary advantage of a mist propagation system lies in optimizing the environmental conditions that minimize moisture loss. By striking the right balance between humidity and moisture supply, the mist system effectively supports the physiological processes necessary for root development without causing stress to the cuttings.