Effects of total daily light integral from blue and broad-band red LEDs on flowering of saffron (Crocus sativus L.)

Abstract

Present indoor cultivation of saffron (Crocus sativus L.) only depends on artificial planting experience, so that flower number and stigma yield are seriously affected in case of cloudy or rainy days and temperature changes. In this study, a luminaire was used at 10-h photoperiod combined 450 nm blue LEDs with 660 nm broad-band red LEDs, which respectively had full width at half maximum (FWHM) of 15 nm and 85 nm, in a ratio of blue: red: far-red light = 20%: 62%: 18%. The influence of total daily light integral (TDLI) was evaluated on flowering characteristics, stigma quality, as well as leaf morphological characteristics. The results showed that flower number, daily flowering proportion, stigma dry weight and crocetin esters content were significantly correlated with TDLI (P < 0.01). The increasing TDLI could slightly promote leaf width and leaf area beyond buds, but had no significant effect on bud length and leaf length. Both the average flower number per corm and dried stigma yield was the highest under the 150 mol m−2 TDLI treatment, up to 3.63 and 24.19 mg respectively. The former was 0.7 more than that under original natural light treatment, while the later was 50% higher. Totaling, combining blue LEDs with a broad-band red LEDs of the 150 mol m−2 TDLI was the most favorable condition for flower number and stigma quality of saffron in this study.

Diverse Flowering Response to Blue Light Manipulation: Application of Electric Lighting in Controlled-Environment Plant Production

“…For these medicinal plants, regulation of the flowering process through lighting technology can directly affect their harvesting time and crop yield. For example, saffron flower number and stigma yield are negatively affected by low light conditions such as cloudy or rainy weather [95]. Also, the level of secondary metabolites in saffron is affected by environmental factors such as light [92].…”

“…Possibly, the contrasting response to BL was due to an interaction of light spectral with light amount, which was proven to be an important affecting factor. A study under sole-source lighting with RBFR-LED (20% B) indicated that when total daily light integral (TDLI; TDLI = DLI × days = PPFD × photoperiod × days) varied from 79 to 166 mol m −2 due to different lighting days, flower number, daily flowering proportion, stigma dry weight, and crocetin esters content were significantly correlated with TDLI, and the 150 mol m −2 of TDLI was the most favorable condition for flower number and stigma quality of saffron [95].…”

The Combined Analysis of the Transcriptome and Metabolome Revealed the Possible Mechanism of Flower Bud Formation in Amorphophallus bulbifer

“…Dimocarpus longan and Litchi chinensis (L. chinensis) need a period of low-temperature treatment before flower bud differentiation [13]. Light can affect plant photoregulatory receptors (phytochromes, cryptochromes, and UV receptors) and thus regulate plant flowering [14][15][16]. The illumination time can also affect the flowering time of plants.…”