Growth of Chrysanthemum in Response to Supplemental Light Provided by Irregular Light Breaks during the Night

Abstract

<jats:p>Circadian rhythms are believed to be of great importance to plant growth and performance under fluctuating climate conditions. However, it is unclear how plants with a functioning circadian clock will respond to irregular light environments that disturb circadian-regulated parameters related to growth. Chrysanthemum (<jats:italic>Chrysanthemum morifolium</jats:italic> ‘Coral Charm’) was exposed to supplemental light provided as irregular light breaks during the night, achieved by controlling the light based on forecasted solar irradiance and electricity prices. Growth, in terms of carbon gain, was linearly correlated to both daylength and daily light integral. This response was observed irrespective of the irregularity of the light breaks and despite circadian-regulated processes of carbohydrate metabolism, chlorophyll fluorescence, and leaf chlorophyll content being affected. Leaf expansion and stem elongation occurred at a faster rate in plants grown in short days with irregular light breaks during the night period compared with plants grown in a climate with a consecutive long light period, showing that low average light intensity promoted expansion of the photosynthetic area of the plants. These results are important to gain an understanding of the relationship between circadian-regulated processes and plant growth. These results will also contribute to increased energy savings in the use of supplemental light in greenhouse production.</jats:p>

Daily Light Integral: A Research Review and High-resolution Maps of the United States

“…Leaf chlorophyll content decreased with increasing DLI apparently due to thicker leaves. Similar observations were reported on chrysanthemum (Chrysanthemum morifolium) (Kjaer and Ottosen, 2011).…”

The Evaluation of Growth Performance, Photosynthetic Capacity, and Primary and Secondary Metabolite Content of Leaf Lettuce Grown under Limited Irradiation of Blue and Red LED Light in an Urban Plant Factory

“…Before extraction, all frozen samples were freeze-dried, weighed, and ground in a mixer mill (MM200; Retsch, Haan, Germany). Carbohydrates were extracted using the method described by Kjaer et al [30]. In brief, 3-7 mg of freeze-dried sample was placed in an Eppendorf tube, and 400 µL of 80% ethanol (96% ethanol/10 mM HEPES = 80:20 (v/v)) was added followed by vortexing.…”

“…The pellet was prepared for starch analysis as described by Kjaer et al [30]. In brief, 1000 µL of distilled water was added to the Eppendorf tube and vortexed.…”

“…After centrifuging at 13,000 rpm for 5 min, the supernatant was collected and filtered through a 0.45 µm syringe filter. The starch and soluble sugar concentration were analyzed by ion chromatography using a Dionex ICS-3000 (Dionex, Sunnywale, CA, Sunnyvale, USA) according to Kjaer et al [30].…”

Evaluation of Cladosporium sp. Mycoparacites as Biocontrol Agents of White Rust Disease on Chrysanthemum

“…These conditions inferred that the effect of rust infection decrement due to Cladosporium and synthetic fungicide applications could not be clearly seen on stalk length. The chrysanthemum vegetative growth mainly progressed until 30 DAP during long day forcing (Kjaer & Ottosen, 2011). The observation of rust infection on Table 2 indicated that the disease incidence up to 35 DAP was still low in all treatment and predictably had not affected the growth quality seriously.…”