To clarify detailed patterns of responses to blue light associated with decreasing phytochrome activity, the growth and morphology traits of arugula, cabbage, mustard, and kale microgreens were compared under the treatments: (1) R, pure red light; (2) B, pure blue light; (3) BRF0, (4) BRF2, (5) BRF4, and (6) BRF6: unpure blue lights created by mixing B with low-level (6%) R, and further adding 0, 2, 4, and 6 μmol m-2 s-1 of far-red light, respectively. The calculated phytochrome photostationary state (PPS) value, indicating phytochrome activity, gradually decreased in the order of R (0.89), BRF0 (0.69), BRF2 (0.65), BRF4 (0.63), BRF6 (0.60), and B (0.50). Generally, the elongation growth (including stem extension rate, hypocotyl length, or petiole length) under blue lights increased with the decreasing PPS values, showing the highest and lowest sensitivity for arugula and mustard, respectively. However, the elongation promoted by blue lights gradually became saturated once the PPS values decreased below 0.60, a level which deactivates phytochrome. Other plant traits, such as biomass allocation and plant color, varied with increasing shade-avoidance responses to blue lights with decreasing PPS values relative to R, and these traits reached saturation at a similar PPS value as elongation. The response sensitivity was highest in elongation growth for arugula and cabbage, and highest in plant color for kale and mustard. This suggests that deactivated phytochrome contributes to the maximum elongation promotion as a shade-avoidance response induced by blue light, although the response sensitivity varies with plant traits and species.
How to translate text using browser tools
6 December 2019
Maximum elongation growth promoted as a shade-avoidance response by blue light is related to deactivated phytochrome: a comparison with red light in four microgreen species
Yun Kong,
Katherine Schiestel,
Youbin Zheng
ACCESS THE FULL ARTICLE
It is not available for individual sale.
This article is only available to subscribers.
It is not available for individual sale.
It is not available for individual sale.
Canadian Journal of Plant Science
Vol. 100 • No. 3
June 2020
Vol. 100 • No. 3
June 2020
de-etiolated seedling
hypocotyl length
light quality
petiole length
phytochrome photostationary state
stem extension rate