Manipulating Light Quality to Improve Growth Attributes of High-value Specialty Crops in Controlled Environments

摘要

Manipulating light quality with light-emitting diodes (LEDs) can regulate crop traits and responses including plant architecture, quality characteristics, and flowering time. We investigated how different radiation wavebands, especially far-red (FR; 700-800 nm), could be delivered in controlled environments to produce specialty crops with desired attributes. We utilized end-of-day (EOD) photoperiodic lighting in greenhouses to determine whether FR radiation would promote extension growth without influencing the flowering of poinsettia. EOD FR lighting promoted poinsettia extension growth, and at a low-intensity it was not perceived as a long day, but it was at a higher intensity. In another study, we determined the impacts of photoperiodic lighting (to increase leaf area) and supplemental lighting (SL) (to increase photosynthesis) on growth, pigmentation, and sensory attributes of greenhouse-grown lettuce. EOD lighting had few effects on lettuce growth, but greenhouse SL, especially from blue (B; 400-500 nm) and red (R; 600-700 nm) LEDs, increased lettuce growth and coloration but sensory attributes were less preferred by consumers than plants grown without SL. In a third study, we quantified how a variety of floriculture crop seedlings respond to the addition of FR radiation to B+R sole-source LED lighting. The addition of 40 micromol˙m--2˙s --1 of FR radiation promoted stem elongation of some species and accelerated the flowering of snapdragon. Collectively, this research shows the potential applications of including FR in a radiation spectrum to elicit specific plant growth, quality, and flowering attributes of horticultural crops.