ABSTRACT
Recently, LEDs with various light qualities have been used in closed plant factories, and they are known to have different effects on the growth and quality of crops. Therefore, this study was conducted to investigate the change in growth and quality in mini red romaine lettuce using LEDs with various light qualities. Wide red spectrum (WRS)-LEDs, blue (B)-LEDs, blue + red (BR)-LEDs, red (R)-LEDs, and white (W)-LEDs were used as the artificial light sources. Regarding growth, the R-LED treatment showed the most positive effect, but the leaf shape was not normal and the Hunter b* value was not suitable because it was higher than that of the other treatments. The Hunter a*, SPAD, and NDVI values of the B- and BR-LED treatments were effective, but this was not the case for those of the R- and W-LED treatments. The anthocyanin reflectance index 1 (ARI1) was 20 times higher in the B-LED treatment than in the R-LED treatment, and the ascorbic acid content was the highest in the WRS-LED treatment. In the sensory evaluation, bitterness and sweetness showed opposite tendencies. Regarding the overall preference, the BR-LED treatment received the highest score. Correlation analysis showed that the bitterness was closely correlated with the anthocyanin content and leaf color. Taken together, BR-LEDs provided a good top fresh weight, dark red leaves, and high anthocyanin and ascorbic acid contents, with the highest overall preference; therefore, BR-LEDs were the most suitable for the cultivation of mini red romaine lettuce.
ABSTRACT
This study investigated the effects of supplemental inter-lighting on paprika (cv. Nagano RZ) in South Korea in summer using various LED light sources. The following LED inter-lighting treatments were used: QD-IL (blue + wide-red + far-red inter-lighting), CW-IL (cool-white inter-lighting), and B+R-IL (blue + red (1:2) inter-lighting). To investigate the effect of supplemental lighting on each canopy, top-lighting (CW-TL) was also used. Additionally, a control without supplemental lighting was included for comparison. Significant variations were observed in the plant growth indexes 42 days after treatment. The SPAD values and total chlorophyll content in the last period of cultivation were significantly higher than those of the control. In November, the marketable fruit yield was significantly higher than that of the control. QD-IL, CW-IL, and CW-TL resulted in significantly higher values of total soluble solids than the control, and CW-IL resulted in higher values of ascorbic acid content than the control. Regarding the economic analysis, CW-IL resulted in the highest net income rate (12.70%) compared with the control. Therefore, the light sources of CW-IL were assessed as suitable for supplemental lighting due to the highest total soluble solids, ascorbic acid content, and net income rate obtained.
ABSTRACT
The effect of 10% CO2 pre-storage treatment for 12, 24, and 48 h alongside modified atmosphere packaging (MAP) on chilling injury was determined in this study. This study found significant interactions between chilling injuries and cell membrane damage indicators. The results show that chilling injuries can be somewhat reduced by the use of CO2 treatment for sweet peppers. It was noticed that the fruit's respiration rate increased as the treatment duration increased immediately after the treatments, while the resultant did not affect the ethylene production rate, electrolyte leakage, or malondialdehyde. Similarly, after cold storage and on the final day, no really significant differences were shown in all those parameters except for the weight loss rate, chilling injury, calyx browning, and firmness, which were at the poorest state in the control group. Of all the treatments in this study, MAP appeared to be the best treatment, and preference may be given to the 24 h treatment of pretreated fruits. Weight loss, firmness, calyx browning, and chilling injury were maintained best in MAP due to the presence of CO2 and high humidity.
ABSTRACT
In recent years, light-emitting diode (LED) technology has been applied to improve crop production and induce targeted biochemical or physiological responses in plants. This study investigated the effect of different ratios of blue 450 nm and red 660 nm LEDs on the overall plant growth, photosynthetic characteristics, and total triterpenoid production in the leaves of Hedyotis corymbosa in vitro plants. The results showed that a high proportion of blue LED lights had a positive effect on enhancing photosynthesis and the overall biomass. In addition, blue LED lights were shown to be more effective in controlling the production of the total triterpenoid content compared with the red LED lights. Moreover, it was also found that plants grown under a high proportion of red LEDs exhibited reduced photosynthetic properties and even induced damage to the photosynthetic apparatus, which indicated that the blue or red LED lights played contrary roles in Hedyotis corymbosa.
