Beyond vegetables: effects of indoor LED light on specialized metabolite biosynthesis in medicinal and aromatic plants, edible flowers, and microgreens.

Specialized metabolites from plants are important for human health due to their antioxidant properties. Light is one of the main factors modulating the biosynthesis of specialized metabolites, determining the cascade response activated by photoreceptors and the consequent modulation of expressed genes and biosynthetic pathways. Recent developments in light emitting diode (LED) technology have enabled improvements in artificial light applications for horticulture. In particular, the possibility to select specific spectral light compositions, intensities and photoperiods has been associated with altered metabolite content in a variety of crops. This review aims to analyze the effects of indoor LED lighting recipes and management on the specialized metabolite content in different groups of crop plants (namely medicinal and aromatic plants, microgreens and edible flowers), focusing on the literature from the last 5 years. The literature collection produced a total of 40 papers, which were analyzed according to the effects of artificial LED lighting on the content of anthocyanins, carotenoids, phenols, tocopherols, glycosides, and terpenes, and ranked on a scale of 1 to 3. Most studies applied a combination of red and blue light (22%) or monochromatic blue (23%), with a 16 h day-1 photoperiod (78%) and an intensity greater than 200 µmol m-2  s-1 (77%). These treatment features were often the most efficient in enhancing specialized metabolite content, although large variations in performance were observed, according to the species considered and the compound analyzed. The review aims to provide valuable indications for the definition of the most promising spectral components toward the achievement of nutrient-rich indoor-grown products. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effects of species and geo-information on the 137Cs concentrations in edible wild mushrooms and plants collected by residents after the Fukushima nuclear accident.

After the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP), much of the wild and edible mushrooms and plants in the surrounding areas were contaminated with radiocesium (137Cs). To elucidate their concentration characteristics, we analyzed 137Cs radioactivity data in edible forest products brought in for food inspection by the residents of Kawauchi Village, 12-30 km away from the FDNPP, from 2012 to 2019. A Bayesian model to estimate 137Cs concentration was constructed. Parameters of the normalized concentration of species (NCsp) for mushrooms were similar to those of the same species obtained in a previous study. Although NCsp values were highly varied among species, mycorrhizal mushrooms tended to have high NCsp values, followed by saprotrophic mushrooms, and wild edible plants values were low. Also, half of mycorrhizal mushroom species (8 of 16) showed an increasing trend in concentration with time; however, saprotrophic mushrooms and wild plants generally demonstrated a decreasing trend (22 of 24). The model considering the sub-village location information decreased the error of individual samples by 40% compared to the model not considering any location information, indicating that the detailed geo-information improved estimation accuracy. Our results indicate that the radioactivity data from samples collected by local residents can be used to accurately assess internal exposure to radiation due to self-consumption of contaminated wild mushrooms and plants.

Nutritional quality, mineral and antioxidant content in lettuce affected by interaction of light intensity and nutrient solution concentration.

Light and nutrient are important factors for vegetable production in plant factory or greenhouse. The total 12 treatments which contained the combination of four light intensity (150, 250, 350 and 450 µmol · m-2 · s-1) and three nutrient solution concentration (NSC) (1/4, 1/2, 3/4 strength NSC) were established for investigation of lettuce growth and quality in a growth chamber. The combination of light intensity and NSC exhibited significant effects on photosynthetic pigment, nutritional quality, mineral content and antioxidant capacity. That a higher light intensity were readily accessible to higher chlorophyll a/b showed in lettuce of treatment of 350 µmol · m-2 · s-1 × 3/4NSC and 450 µmol · m-2 · s-1 × 1/4NSC. Lower total N contents, higher content of soluble protein, vitamin C, soluble sugar and free amino acid exhibited in lettuce under treatment of 250 and 350 µmol · m-2 · s-1 × 1/4NSC or 3/4NSC. With increasing NSC and LED irradiance, the content of total P and K in lettuce increased and decreased, respectively. The highest and lowest total Ca content were found in treatment of 150 µmol · m-2 · s-1 × 1/4NSC and 450 µmol · m-2 · s-1 × 1/4NSC, respectively, and higher content of total Mg and Zn was observed under 250 µmol m-2 s-1 × 1/4NSC and 150 µmol · m-2 · s-1 × 3/4NSC, respectively. The antioxidant contents generally decreased with increasing NSC level. The higher antioxidant content and capacity occurred in lettuce of 350 µmol · m-2 · s-1 × 1/4NSC treatment. The interaction of 350 µmol · m-2 · s-1 × 1/4NSC might be the optimal condition for lettuce growth in plant factory.

Far-red photons have equivalent efficiency to traditional photosynthetic photons: Implications for redefining photosynthetically active radiation.

Far-red photons (701-750 nm) are abundant in sunlight but are considered inactive for photosynthesis and are thus excluded from the definition of photosynthetically active radiation (PAR; 400-700 nm). Several recent studies have shown that far-red photons synergistically interact with shorter wavelength photons to increase leaf photochemical efficiency. The value of far-red photons in canopy photosynthesis has not been studied. Here, we report the effects of far-red photons on single leaf and canopy photosynthesis in 14 diverse crop species. Adding far-red photons (up to 40%) to a background of shorter wavelength photons caused an increase in canopy photosynthesis equal to adding 400-700 nm photons. Far-red alone minimally increased photosynthesis. This indicates that far-red photons are equally efficient at driving canopy photosynthesis when acting synergistically with traditionally defined photosynthetic photons. Measurements made using LEDs with peak wavelength of 711, 723, or 746 nm showed that the magnitude of the effect was less at longer wavelengths. The consistent response among diverse species indicates that the mechanism is common in higher plants. These results suggest that far-red photons (701-750 nm) should be included in the definition of PAR.

Screening test for radioactivity of self-consumption products in Fukushima after the Fukushima Dai-ichi NPP accident in Japan.

A food inspection service system for home grown products or wild plants collected by individual consumers for self-consumption was implemented in Fukushima in Nov. 2012. About 500 NaI(Tl) scintillation spectrometers were distributed to 300 or more temporary testing laboratories which were set up in public halls or meeting places of the municipalities. The screening method for radiocaesium was adapted to the present inspection service system. The performance of the equipment under field conditions was evaluated using sampled data obtained by temporary testing laboratories. From the present results of evaluation the confidence of these inspections was confirmed. Totally about 550,000 food samples have been tested with a pass rate of 90% or more.

Identification of irradiated foodstuffs using ESR microwave saturation.

This study aims primarily to investigate the usage of differences in microwave (MW) saturation behaviour of food samples for identification of radiation treatment. Twenty different samples (dry plant, herbal, spice etc.) which do not have radiation specific satellite ESR signal were especially selected. It is not possible to detect radiation treatment on these samples by European standard (EN 1787, 2000). MW saturation studies were performed on all samples in the range of 0.01-160mW. Our experimental results demonstrate that radiation identification can be possible for ten samples and cannot be possible for the other ten samples by performing the MW saturation studies.

[Radiological control of silvicultural production in Perm Krai].

Results of the studies carried out in 2009-2012 on the 137Cs content in edible fungi, berries and fruits of wild-growing bushes and the low shrubs growing in forest ecosystems of a number of regions of the Perm Krai are presented. It is shown that the activity of radio caesium in the studied samples does not exceed the maximal allowed levels approved in the Russian Federation.

Relevance of Radiocaesium Interception Potential (RIP) on a worldwide scale to assess soil vulnerability to 137Cs contamination.

The extent of radiocaesium retention in soil is important to quantify the risk of further foodchain contamination. The Radiocaesium Interception Potential (RIP -Cremers et al., 1988, Nature 335, 247-249) is an intrinsic soil parameter which can be used to categorize soils or minerals in terms of their capacity to selectively adsorb radiocaesium. In this study, we measured RIP for a large soil collection (88 soil samples) representative of major FAO soil reference groups on a worldwide scale and tested the possibility to predict the RIP on the basis of other easily accessible or measurable soil data. We also compared RIP values with those obtained from separate chemical extraction experiments. The range of measured RIP values (1.8-13300 mmol kg(-1)) was shown to include nearly all possible cases of agricultural soil contamination. Only Podzols, Andosols and Ferralsols were clearly characterized by a very low RIP (<2000 mmol kg(-1)). On a worldwide scale, RIP was in fact slightly related to soil reference type or other simple major physicochemical parameters such as clay percentage or organic matter. Conversely our results indicated a link between the RIP and radiocaesium extractability across very different soils. We showed that, with the proposed scale of RIP values, a simple acid extraction method can provide an operational result highly predictive of potential RIP despite very contrasting soil properties. The RIP could be estimated from the empirical equation: RIP = (-31.701 ∗ log(AER) + 58.886)(2) where AER is the fraction of acid-extractable radiocaesium.

Conceptual approaches for the development of dynamic specific activity models of 14C transfer from surface water to humans.

Carbon-14 is a particularly interesting radionuclide from the perspective of dose estimation. Many nuclear facilities, including power reactors, release 14C into the environment, and much of this is as 14CO2. This mixes readily with stable CO2, and hence enters the food chain as fundamental biomolecules. This isotopic mixing is often used as the basis for dose assessment models. The present model was developed for the situation of 14C releases to surface waters, where there are distinct changes in the water 14C activity concentrations throughout the year. Complete isotopic mixing (equilibrium) cannot be assumed. The model computes the specific activity (activity of 14C per mass of total C) in water, phytoplankton, fish, crops, meat, milk and air, following a typical irrigation-based food-chain scenario. For most of the biotic compartments, the specific activity is a function of the specific activity in the previous time step, the specific activity of the substrate media, and the C turnover rate in the tissue. The turnover rate is taken to include biochemical turnover, growth dilution and mortality, recognizing that it is turnover of C in the population, not a tissue or an individual, that is relevant. Attention is paid to the incorporation of 14C into the surface water biota and the loss of any remaining 14CO2 from the surface water-air interface under its own activity concentration gradient. For certain pathways, variants in the conceptual model are presented, in order to fully discuss the possibilities. As an example, a new model of the soil-to-plant specific activity relationship is proposed, where the degassing of both 14C and stable C from the soil is considered. Selection of parameter values to represent the turnover rates as modeled is important, and is dealt with in a companion paper.

Parameterization of a dynamic specific activity model of 14C transfer from surface water-to-humans.

Carbon-14 is a particularly interesting radionuclide from the perspective of dose estimation because it mixes readily with stable CO2, and hence enters the food-chain as fundamental biomolecules. A model was developed for the situation of 14C releases to surface waters, where there are distinct changes in the water 14C activity concentrations throughout the year. The model computes the specific activity in water, phytoplankton, fish, crops, meat, milk and air, following a typical irrigation-based food-chain scenario. This paper describes the derivation of the required 14C-specific parameter values. Many of the key parameters are not commonly measured, at least not in the context of dose assessment. Thus, inference from other sources of data was required, and this is the scientific contribution described in this paper. The best estimates and appropriate measures of statistical dispersion are provided. This required consideration of both the temporal and spatial averaging domains to ensure they were correct for parameters as defined in the model. The model coupled with these parameter values represents several new developments for modelling 14C transfers.

Using explanatory crop models to develop simple tools for Advanced Life Support system studies.

System-level analyses for Advanced Life Support require mathematical models for various processes, such as for biomass production and waste management, which would ideally be integrated into overall system models. Explanatory models (also referred to as mechanistic or process models) would provide the basis for a more robust system model, as these would be based on an understanding of specific processes. However, implementing such models at the system level may not always be practicable because of their complexity. For the area of biomass production, explanatory models were used to generate parameters and multivariable polynomial equations for basic models that are suitable for estimating the direction and magnitude of daily changes in canopy gas-exchange, harvest index, and production scheduling for both nominal and off-nominal growing conditions.

Differences in the response of wheat, soybean and lettuce to reduced blue radiation.

Although many fundamental blue light responses have been identified, blue light dose-response curves are not well characterized. We studied the growth and development of soybean, wheat and lettuce plants under high-pressure sodium (HPS) and metal halide (MH) lamps with yellow filters creating five fractions of blue light. The blue light fractions obtained were < 0.1, 2 and 6% under HPS lamps, and 6, 12 and 26% under MH lamps. Studies utilizing both lamp types were done at two photosynthetic photon flux levels, 200 and 500 mumol m-2 s-1 under a 16 h photoperiod. Phytochrome photoequilibria was nearly identical among treatments. The blue light effect on dry mass, stem length, leaf area, specific leaf area and tillering/branching was species dependent. For these parameters, wheat did not respond to blue light, but lettuce was highly sensitive to blue light fraction between 0 and 6% blue. Soybean stem length decreased and leaf area increased up to 6% blue, but total dry mass was unchanged. The blue light fraction determined the stem elongation response in soybean, whereas the absolute amount of blue light determined the stem elongation response in lettuce. The data indicate that lettuce growth and development requires blue light, but soybean and wheat may not.

Radiation: microbial evolution, ecology, and relevance to mars missions.

Ultraviolet (UV) radiation has been an important environmental parameter during the evolution of life on Earth, both in its role as a mutagen and as a selective agent. This was probably especially true during the time from 3.8 to 2.5 billion years ago, when atmospheric ozone levels were less than 1% of present levels. Early Mars may not have had an "ozone shield" either, and it never developed a significant one. Even though Mars is farther away from the Sun than the Earth, a substantial surficial UV flux is present on Mars today. But organisms respond to dose rate, and on Mars, like on Earth, organisms would be exposed to diurnal variations in UV flux. Here we present data on the effect of diurnal patterns of UV flux on microbial ecosystems in nature, with an emphasis on photosynthesis and DNA synthesis effects. These results indicate that diurnal patterns of metabolism occur in nature with a dip in photosynthesis and DNA synthesis in the afternoon, in part regulated by UV flux. Thus, diurnal patterns must be studied in order to understand the effect of UV radiation in nature. The results of this work are significant to the success of human missions to Mars for several reasons. For example, human missions must include photosynthetic organisms for food production and likely oxygen production. An evolutionary approach suggests which organisms might be best suited for high UV fluxes. The diurnal aspect of these studies is critical. Terraforming is a potential goal of Mars exploration, and it will require studies of the effect of Martian UV fluxes, including their diurnal changes, on terrestrial organisms. Such studies may suggest that diurnal changes in UV only require mitigation at some times of day or year.

Project of conveyer-type space greenhouse for cosmonauts' supply with vitamin greenery.

Design and advantages of conveyer-type growth chamber PHYTOCYCLE with a cylindrical crop surface are featured. Based on the results of testing, an experimental prototype of conveyer-type vegetable greenhouse VITACYCLE for space vehicles is being developed at the SSC-IBMP in conjunction with a number of institutions of the Russian space industry to provide space crews with fresh greenery. Rated daily production of the greenhouse is 150 g of eatable biomass with power consumption of 1 kW. The system is to be mounted within the Life support module of international space station Alpha (ISSA). Design of the greenhouse is outlined. Brief description, state-of-the-art, and further plans regarding VITACYCLE elaboration and construction are presented.

Different sites of photodamage in chilling-sensitive (sorghum) and chilling-resistant (barley and wheat) plants.

The electron transport chain was affected to varying degrees by high light intensity at low temperature in different crop plants. The PS II was found to be the sensitive site while PS I showed very little change in its activity. Photoinhibition affected the oxidizing side of PS II in all three plants. However, the site of inhibition was different in chilling-sensitive and chilling-resistant plants. In sorghum, the water splitting reaction was damaged while in barley and wheat the damage occurred in the reaction centre itself. It appears that photoinhibition may affect different sites within the PS II in chilling-resistant and sensitive plants.

[The radioecological lessons of Chernobyl]. / Radioékologicheskie uroki Chernobylia.

This paper presents the results of radioecological studies undertaken within the area exposed to ionizing radiation after Chernobyl disaster. Conclusions are made concerning the major regularities in radionuclide migration within various natural media and action of ionizing radiation on natural and artificial ecosystems. The efficiency of basic protective ecological measures in eliminating the accident consequences has been determined. The contribution of radioecological studies to the elimination of Chernobyl disaster sequences assessed.

Fertile asymmetric somatic hybrids between Lycopersicon esculentum Mill. and Lycopersicon peruvianum var. dentatum Dun.

Thirteen nuclear asymmetric hybrids were regenerated under selective conditions following fusion of chlorophyll-deficient protoplasts from cultivated tomato (Lycopersicon esculentum Mill.) and gamma-irradiated protoplasts from the wild species Lycopersicon peruvianum var. dentatum Dun. All hybrid plants were classified as being asymmetric based on morphological traits, chromosome numbers and isozyme patterns. The majority of the hybrids inherited Lycopersicon peruvianum var. dentatum chloroplasts. Mitochondrial DNA analysis revealed mixed mitochondrial populations deriving from both parents in some of the hybrids and rearranged mitochondrial DNA in others. The asymmetric hybrids express some morphological traits that are not found in either of the parental species. Fertile F1 plants were obtained after self-pollination of the asymmetric hybrids in four cases. The results obtained confirm the potential of asymmetric hybridization as a new source of genetic variation, and as a method for transferring of a part of genetic material from donor to recipient, and demonstrate that it is possible to produce fertile somatic hybrids by this technique.

Two-dimensional electrophoresis of plant proteins with phastsystem using nonequilibrium pH gradient separation.

We have adapted a two-dimensional electrophoretic technique described by P. Z. O'Farrell et al. (Cell 12, 1133-1142, 1977) to Phastsystem, resolving both acidic and basic proteins by using nonequilibrium pH gradient electrophoresis in the first dimension and sodium dodecyl sulfate polyacrylamide gel electrophoresis in the second dimension. Protein separation was optimized for the analysis of plant proteins. The use of the Phastsystem apparatus reduced times of preparation and separation, allowing the rapid screening of plant proteins on a large scale of isoelectric points. This technique was used for the immunodetection and characterization of two stress-induced proteins in irradiated tomato leaves.

[The effect of chronic UVB-irradiation on the growth, development and productivity of fodder beet]. / Vliianie khronicheskogo UF-oblucheniia zony B na rost, razvitie i produktivnost' kormovoi svekly.

In a field study in 1989, the effect of additional UV-B-irradiation (with an intensity of 0.34, 0.49 or 0.77 W/m2, daily exposure of 17.3, 26.7 or 39.1 kJ/m2, and total exposure of 1457.3, 2248.8 or 3285.6 kJ/m2) on the growth, development and productivity of fodder beet var. Eckendorf yellow was investigated. The three levels of irradiation caused a delay of plant growth and a significant reduction of plant height (18-26%), air-dry weight of leaves (32-43%), wet weight of leaves (48-52%), and weight of root-crops (48-50%).

Biogenerative life-support system: farming on the moon.

Plants can be used to recycle food, oxygen, and water in a closed habitat (e.g., on the moon, Mars, or in a space craft. A variety of crops might be grown, probably in underground growth units to avoid harmful radiation and micrometeorites. Artificial light will be necessary although some sunlight might be brought in via fiber optics. Transpired water will be condensed in coils exposed to space and shaded from sunlight. Oxygen and CO2 levels will be maintained by controlling photosynthesis and waste oxidation. Plants will be grown hydroponically. Wheat has been produced at the rate of 60 g m-2 d-1, which could feed a human continuously from a farm only 13 m2, but nearly continuous light equivalent to sunlight is required along with ideal temperatures, enriched CO2, suitable cultivars, etc. Lower light results in more efficient photosynthesis but requires a larger farm, as do safety considerations and many crops.