Research paper
Yoko Miyama
Abstract
Intumescence is a physiological disorder in which cell walls are disrupted. Intumescence causes leaf deformation, browning and defoliation, and commonly affects tomato plants. This is a limitation in seedling production. The causes of intumescence are not known; however, ultraviolet (UV) deficiency is ...
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Intumescence is a physiological disorder in which cell walls are disrupted. Intumescence causes leaf deformation, browning and defoliation, and commonly affects tomato plants. This is a limitation in seedling production. The causes of intumescence are not known; however, ultraviolet (UV) deficiency is considered as one of the causes of intumescence. Other possible causes include high humidity and rapid changes in the water environment. In this study, tomato seedlings were grown in a commercially-available closed seedling production system under either newly installed LEDs with a low UV light intensity or conventional fluorescent lamps sources. The relationship between the shoot/root (S/R) ratio and incidence of intumescence was evaluated. In addition, the effects of different light sources were evaluated on the xylem pressure potential in the seedlings under rapidly fluctuating water conditions. As a result, the S/R ratio of seedlings grown under LEDs, with low UV intensity, was greater than that of seedlings grown under fluorescent lamps. There was a positive correlation between the S/R ratio and the incidence of intumescence of four types of seedlings with different combinations of light sources and varieties. Xylem pressure potential decreased more in seedlings grown under LEDs, compared to seedlings grown under fluorescent lamps and dry conditions, but increased significantly when irrigated. These results suggest that reducing the occurrence of intumescence in seedling production systems can be possible by a light source that can help seedlings grow with small S/R ratios and reduce fluctuations in the water condition.
Research paper
Mahnaz Aghdasi; Morteza Mofid Bojnoordi; Rezvan Ramezannezhad; Mohammad Fatemi
Abstract
As a valuable industrial compound, cichoric acid has antiviral, antioxidant, and anti-inflammatory properties. It is effectively used in obesity prevention and for neuroprotective purposes. Here, we aimed to compare the effects of plant growth regulators and UV-B radiation on the induction of cichoric ...
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As a valuable industrial compound, cichoric acid has antiviral, antioxidant, and anti-inflammatory properties. It is effectively used in obesity prevention and for neuroprotective purposes. Here, we aimed to compare the effects of plant growth regulators and UV-B radiation on the induction of cichoric acid production under tissue culture conditions. For this purpose, Lactuca undulata, an herbaceous medicinal plant, was used as a new source of cichoric acid. Leaf explants were initially cultured on ½ MS (Murashige and Skoog) medium containing 0.1, 1 mg/L Kinetin (Kin) and 2,4-Dichlorophenoxyacetic acid (2,4-D). The callus was then exposed to different UV-B exposure times (0, 20, 40, and 60 min) and was harvested after 5, 10, and 15 days. The highest amounts of total phenol, cichoric acid, chlorogenic acid, and caffeic acid were achieved in callus samples that were treated with 20 and 40 minutes of UV-B radiation for 10 days. Cichoric acid content reached an amount of 6.15±0.292 mg/g DW after 20 min of radiation. Pearson’s correlation coefficient analysis (PCC) showed that Phenylalanine Ammonia Lyase (PAL) activity did not correlate with the production of caffeic acid derivatives. These results suggested that UV-B irradiation can be used as an elicitor to induce the production of cichoric acid in Lactuca undulata callus cultures.
Research paper
Vences C Valleser; Glenn Dayondon; Andrew Melencion
Abstract
The massive establishment of new plantations supported by the basic needs of a crop are technical approaches for an increased crop productivity. Water and decreased light levels by shade (i.e. intercropping) are considered basic needs of cacao plants, especially during the early vegetative growth stage. ...
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The massive establishment of new plantations supported by the basic needs of a crop are technical approaches for an increased crop productivity. Water and decreased light levels by shade (i.e. intercropping) are considered basic needs of cacao plants, especially during the early vegetative growth stage. Thus, this study aimed to evaluate the influences of irrigation, intercropping, and intercrops on the performance of 39 cacao plantations at the establishment phase. The performance of each cacao plantation, after establishment, was evaluated and rated from 1 to 7 (1- poor; 3- satisfactory; 5- very good; and 7- outstanding) as a rating scale. In general, the results revealed that cacao plantations supplied with irrigation or under decreased light levels by intercrops (regardless of their nature), as well as a combination of these, made the plants perform better than those in plantations without irrigation and when plants were highly exposed to sunlight. The results suggested the importance of irrigation and decreased light levels by intercropping as prerequisites for a successful establishment of cacao plantations.
