Effects of Different Ultraviolet (UV) Electro Magnetic Radiation in Growth Traits of Viola x wittrockiana

Grade:

10

Teacher:

Elyse Wexler

The purpose of this experiment was to determine how different wavelengths of light-emitting diodes (LED lights) affect the growth and flowering of Viola x wittrockiana (garden pansies) in an indoor environment. Three plants were exposed to separate lighting conditions: red, blue, and full spectrum (control). All plants were grown under identical conditions, including the same soil, watering schedule, distance from the light (15 cm), and a 12-hour light cycle for three weeks. Plant height and number of flowers were measured every other day to evaluate growth and the number of mature flowers. The claim was that light color influences plant growth patterns, with blue light promoting the greatest vertical growth and full-spectrum light producing the most balanced overall development. By the end of the three weeks, the plant under blue light reached a height of 16.5 cm, compared to 14 cm under full-spectrum light and 7 cm under red light. However, the full-spectrum plant produced 29 additional flowers, exceeding the blue (8 flowers) and red (3 flowers) treatments. Growth under red light was consistently the lowest in both height increase (7 cm) and flower production. Blue wavelengths stimulate vegetative growth responses such as stem elongation and leaf development through phototropins, while full-spectrum light provides a range of wavelengths that support both photosynthesis and flowering. Red light alone lacks the wavelengths needed for strong growth, resulting in weaker performance. These findings suggest that full-spectrum lighting is most effective for overall plant health in controlled environments, while blue light may be useful when height growth is the primary goal.

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