High production of flavonols and anthocyanins in Eruca sativa (Mill) Thell plants at high artificial LED light intensities

Overexpression of the constitutively-active AtCPK1 mutant in tobacco plants confers cold and heat tolerance, possibly through modulating abscisic acid and salicylic acid signalling

Calcium-dependent protein kinases (CDPKs) are very effective calcium signal decoders due to their unique structure, which mediates substrate-specific [Ca2+]cyt signalling through phosphorylation. However, Ca2+-dependence makes it challenging to study CDPKs. This work focused on the effects of the overexpression of native and modified forms of the AtCPK1 gene on the tolerance of tobacco plants to heat and cold. We studied the interaction between the calcium and signalling systems of abscisic acid (ABA) at various temperatures. The hormonal state, stress-induced senescence, and expression of important corresponding genes were investigated. We showed that inactivation of the autoinhibitory domain of the modified constitutively active form of AtCPK1 has a positive effect on resistance not only to long-term cold but also to heat. We showed that the constitutively active form of AtCPK1 under nonstressed conditions activated biosynthesis of ABA, but a decrease in ABA content was detected upon heat exposure. On the basis of our results, we can assume that this effect is achieved through the CPK-dependent activation of salicylic acid (SA) signalling. The obtained data shed light on heat-associated molecular processes and support the possibility of using intradomain modifications of CDPK both for comprehensive study of its functional features and as a bioengineering tool.

Lowering the target daily light integrals following days with excessive lighting can reduce lettuce production costs

Given the fluctuating availability of natural lighting throughout the year, supplemental light is frequently employed to maintain the optimal daily light integral (DLI) levels necessary for adequate plant growth. However, the use of supplemental light translates into higher operational costs. Recent reports suggest that plants can tolerate a day with low DLI following exposure to a day with high DLI from natural light. This was referred to as the 'carryover' effect. In such cases, supplemental lighting may not be necessary, resulting in energy savings. In this study, we determined if plants can withstand such DLI fluctuations over multiple days without compromising plant growth. Additionally, we calculated the energy requirements for trese treatments to evaluate the potential energy savings of the carryover effect. To test this, we cultivated lettuce plants (Lactuca sativa cv. 'Waldmand's Dark Green' and 'Rouxai') in a walk-in grow chamber, subjecting them to six different lighting treatments. Each treatment consisted of a day with a high DLI of 22.5 mol·m-2·d-1 followed by a varying number of consecutive days with low DLI, ranging from 1 to 5 days, with DLIs of 7.5, 11.25, 12.5, 13.13, and 13.5 mol·m-2·d-1 respectively. The combined DLI for each treatment, calculated as the average DLI across high and low DLI days, was maintained at 15 mol·m-2·d-1. Additionally, we included a control treatment where plants were exposed to a constant DLI of 15 mol·m-2·d-1. We measured plant growth rate, final fresh and dry weights, leaf number, leaf area, specific leaf area, light use efficiency, and relative pigment content to assess differences in plant growth under the different lighting regimes. We observed a decrease in biomass accumulation, as indicated by a 13% reduction in final dry weight only for the treatment involving one day of high DLI followed by one day of low DLI, compared to our control. We discovered that plants can tolerate multiple days of low DLI following a day with high DLI, in contrast to the optimal values reported in the literature. This finding can lead to reduced energy consumption for supplemental lighting and consequent operational cost savings.

Nutrient-efficient catfish-based aquaponics for producing lamb's lettuce at two light intensities

BACKGROUND

Aquaponic systems are sustainable processes of managing water and nutrients for food production. An innovate nutrient-efficient catfish-based (Clarias gariepinus) aquaponics system was implemented for producing two cultivars of two leafy vegetables largely consumed worldwide: lamb's lettuce (Valerianella locusta var. Favor and Valerianella locusta var. de Hollande) and arugula (Eruca vesicaria var. sativa and Eruca sativa). Different growing treatments (4 × 2 factorial design) were applied to plants of each cultivar, grown at two light intensities (120 and 400 μmol m-2 s-1). During growth, several morphological characteristics (root length, plant height, leaf number, foliage diameter and biggest leaf length) were measured. At harvest, plants were weighed and examined qualitatively in terms of greenness and health status. Additionally, leaf extracts were obtained and used to determine total phenolic contents, antioxidant capacities, and levels of cytotoxicity to Caco-2 intestinal model cells.

RESULTS

After a 5-week growth period, both lamb's lettuce cultivars presented high levels of greenness and health status, at both light intensities, particularly the var. de Hollande that also showed higher average performance in terms of plant morphology. In turn, arugula cultivars showed lower levels of greenness and health status, especially the cultivar E. vesicaria var. sativa submitted to direct sunlight during growth. In addition, plant specimens submitted to higher levels of light intensity showed higher contents in antioxidants/polyphenols. Cultivars with a higher content in antioxidants/polyphenols led to higher Caco-2 cell viability.

CONCLUSION

For successful industrial implementation of the aquaponics technology, different and optimized acclimatizing conditions must be applied to different plant species and cultivars. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Chemical Profile and Healthy Properties of Sicilian Diplotaxis harra subsp. crassifolia (Raf.) Maire

This study was aimed at investigating the phytochemical profile and bioactivity of Diplotaxis harra subsp. crassifolia (Brassicaceae), a species from central-southern Sicily (Italy), where it is consumed as a salad. For this purpose, LC-ESI/HRMSn analysis of the ethanolic extract was performed, highlighting the occurrence, along with flavonoids, hydroxycinnamic acid derivatives, and oxylipins, of sulfated secondary metabolites, including glucosinolates and various sulfooxy derivatives (e.g., C13 nor-isoprenoids, hydroxyphenyl, and hydroxybenzoic acid derivatives), most of which were never reported before in the Brassicaeae family or in the Diplotaxis genus. Following ethnomedicinal information regarding this species used for the treatment of various pathologies such as diabetes and hypercholesterolemia, D. harra ethanolic extract was evaluated for its antioxidant potential using different in vitro tests such as 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), Ferric Reducing Ability Power, and β-carotene bleaching tests. The inhibitory activity of carbohydrate-hydrolyzing enzymes (α-amylase and α-glucosidase) and pancreatic lipase was also assessed. In the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid assay, an IC50 value comparable to the positive control ascorbic acid (2.87 vs. 1.70 μg/mL, respectively) was obtained. The wild-wall rocket salad extract showed a significant α-amylase inhibitory effect. Obtained results indicate that Sicilian wild-wall rocket contains phytochemicals that can prevent hyperglycemia, hyperlipidemia, and obesity.

Morpho-physio-biochemical, molecular, and phytoremedial responses of plants to red, blue, and green light: a review

Light is a basic requirement to drive carbon metabolism in plants and supports life on earth. Spectral quality greatly affects plant morphology, physiology, and metabolism of various biochemical pathways. Among visible light spectrum, red, blue, and green light wavelengths affect several mechanisms to contribute in plant growth and productivity. In addition, supplementation of red, blue, or green light with other wavelengths showed vivid effects on the plant biology. However, response of plants differs in different species and growing conditions. This review article provides a detailed view and interpretation of existing knowledge and clarifies underlying mechanisms that how red, blue, and green light spectra affect plant morpho-physiological, biochemical, and molecular parameters to make a significant contribution towards improved crop production, fruit quality, disease control, phytoremediation potential, and resource use efficiency.