Light Culture Conditions Research Articles

The nitrogen deficiency influence on the growth and development of spring two-nuclear barley varieties grown under photoculture conditions

The purpose of the research is to study, the effect of N deficiency in irrigation solutions on the structural and functional characteristics of spring barley (Hordeum vulgare L.), the Oplot variety under controlled environmental conditions, in comparison with the structural and functional characteristics of Takmak barley, which has been the standard in all variety testing sites of the Krasnoyarsk Territory since 2022. The plants were grown under light culture conditions using hydroponics on expanded clay with constant environmental conditions at a photoperiod day/night of 17h / 7h, respectively. The basis for the preparation of irrigation solutions was Knop solution (control) and a solution in which, in order to reduce the concentration of N-NO3, the salt content was changed 2 times so as not to change the concentration of other macronutrients. A comparison of the rate of absorption of macronutrients by barley plants of the Oplot and Takmak varieties, depending on the composition of the irrigation solution, shows a higher demand of the barley of the Oplot variety for the presence of mineral nutrition elements in the irrigation solution in comparison with the barley of the Takmak variety. The deficiency of N in the irrigation solution led to a decrease in total tillering by about 2.5 times, but productive tillering in the barley of the Oplot variety decreased to a greater extent than in the barley of the Takmak variety. When growing on Knop solution the barley of the Oplot variety showed higher productivity than the barley of the Takmak variety. When grown on solutions with a deficiency of N, the grain yield of the barley of the Oplot variety decreased by 2.8 times, and in the barley of the Takmak variety, the differences between the control and experimental variants were unreliable. The barley of the Takmak variety showed higher resistance to N deficiency in the irrigation solution, thereby showing higher plasticity compared to the barley of the Oplot variety.

Development and Optimization of a Rapid In Vitro Micropropagation System for the Perennial Vegetable Night Lily, Hemerocallis citrina Baroni

The perennial herbaceous night lily, Hemerocallis citrina Baroni, is an important vegetable crop with an increasing production and consumption in China. The long lifecycle and slow growth of the night lily are becoming bottlenecks for the large-scale production of elite lines and various genetic and breeding studies. There is a lack of a protocol for rapid and efficient micropropagation for this crop. Here, we reported the systematic investigation and optimization of in vitro plant regeneration through tissue-culture-based organogenesis in the night lily variety ‘Datong Huanghua’. We evaluated various factors affecting the efficiency of callus induction and subculture, shoot regeneration, rooting and plantlet establishment, including explant type and age, inoculation methods, basal culture media and the type and concentration of plant growth regulator (phytohormones) in various growth media. We developed an optimized protocol, as follows. The highest efficiency of callus induction was observed on Murashige and Skoog (MS) medium supplied with 22.7 µM TDZ (thidiazuron) using the young scape (flower stem or stalk) as the explant, which was cut longitudinally in half to produce a segment approximately 0.5 cm in length. Callus subculture and proliferation were more efficient on MS medium containing 9.0 µM 2,4-D (2,4-dichlorophenoxyacetic acid) under light culture conditions. Shoot regeneration showed the highest efficiency on MS medium supplemented with 8.9 µM 6-BA (6-benzylaminopurine) + 5.4 µM NAA (α-naphthaleneacetic acid), while the best rooting medium was MS medium containing 2.7 µM NAA. After transplanting, the transplanted regenerated seedlings showed the highest survival rate (96%) on a substrate mixture with a 2:1:1 ratio of peat/perlite/vermiculite. A protocol and flowchart for the rapid in vitro micropropagation of night lily plants is proposed that will facilitate various genetic, genomic and breeding studies on this crop.

Influence of light absorption rate on the astaxanthin production by the microalga Haematococcus pluvialis during nitrogen starvation

Large amounts of astaxanthin (about 4% DW) can be produced under nitrogen starvation of Haematococcus pluvialis in photobioreactors (PBRs) exposed to high light conditions to induce a light stress. However, in PBR, the large biomass concentration usually achieved leads to strong light attenuation conditions, which makes complex the analysis of this “light stress”. This study aims to elucidate the role of light transfer in astaxanthin cell content and productivity from the microalga Haematococcus pluvialis during nitrogen starvation. Haematococcus pluvialis was cultivated in a flat-panel PBR in a batch mode with sudden nitrogen starvation conditions and an incident photon flux density (PFD) of 250 µmolhν m−2 s−1. Different initial biomass concentrations ({C}_{{x}_{0}}) were evaluated, 0.21, 0.52, 1.39 and 2.21 kg m−3. As a result, spectral mass absorption cross-sections of Haematococcus pluvialis were measured at different times during nitrogen starvation, and were used to relate the mean rate of photon absorption (MRPA) to the astaxanthin productivity. A minimum initial MRPA of 7000 ± 500 µmolhν kgx−1 s−1 was found necessary to trigger large accumulation of astaxanthin in Haematococcus pluvialis cells (up to 3.21% DW) during nitrogen starvation conditions. The results also demonstrated the link between the MRPA and the daily astaxanthin productivity of Haematococcus pluvialis cultures, introducing then the MRPA as a physical quantity of interest for a rational optimization of the light culture conditions in PBRs.Graphical

Experimental Modeling of the Influence of Mineral Nutrition Conditions on Spring Two-Row Barley Plants under Light Culture Conditions

Experimental Modeling of the Influence of Mineral Nutrition Conditions on Spring Two-Row Barley Plants under Light Culture Conditions

FEATURES OF GROWTH AND INULIN CONTENT IN CALLUS CULTURES Cichorium intybus L. in vitro

In vitro callus cultures of common chicory (Cichorium intybus L.) were obtained and their growth and biochemical characteristics depending on the hormonal composition of the MS medium and the spectral composition of light were studied. The study of the effect of light culture on callus tissue formation and inulin accumulation in it was carried out in opaque grow tents with radiation aligned with the flux density of pho- tosynthetic photons and different ratios of its levels in the region of 660 nm (R, red) and 730 nm (FR, far red). The control variant was placed under white linear fluorescent lamps. The resulting cultures were character- ized by high proliferative activity and the capability for morphogenesis. It has been established that the inter- action of two factors—the presence of auxins in the nutrient medium (IAA or NAA at a concentration of 7.5 mg/L in combination with BAP 0.5 mg/L) and cultivation under light culture conditions (FR R, FR = R, FR R)—had a significant impact on the biosynthetic potential of cell cultures. In the obtained cultures, a study of the quantitative content of inulin was carried out. It has been shown that the high content of inulin (7.55–7.95%) in callus cultures was on the MS medium in combination with IAA at FR R illumination. This is probably due to the fact that well proliferating and highly morphogenic callus tissue was formed under these conditions. The obtained results confirm the hypothesis about the specificity of cultured cells to in vitro synthesize and accumulate secondary metabolites in dedifferentiated cells and the dependence of this process on factors of chemical and physical nature.

Influence of substrate and nutrient solution on biometric performance and net productivity of garden strawberry seedlings photosynthesis under photoculture conditions

The effect of substrate and nutrient solution on biometric parameters and net photosynthesis productivity of strawberry seedlings of the White Swede variety obtained in vitro under light culture conditions at irradiation power of 126.8 and 172.3 mmol/m2/s was investigated. The highest seedlings with a horn diameter of 0.8 cm were obtained in variants using a mineral wool substrate and nutrient solutions at an irradiation power of 126.8 mmol/m2/s. The irradiation power of 172.3 mmol/m2/s contributed to the largest number of leaves in the variants MV+ PR and MV + 1 MS of 10.0 ± 0.5 pcs. in both cases, and the active development of the assimilation area of the leaves. The irradiation power of 126.8 mmol/m2/s and the use of a nutrient solution contributes to the better development of the root system. The net photosynthesis productivity on an organic substrate using a nutrient solution (CS+1 MS) is 1.5-2.5 times higher than when using an organic substrate filled with fertilizers (GT+water). The net photosynthesis productivity of the leaf apparatus of seedlings grown on a mineral wool substrate at an irradiation power of 126.8 mmol/m2/s was in the range from 0.27 to 0.33 mg/cm2/day, and at an irradiation power of 172.3 mmol/m2/s - in the range from 0.23 to 0.29 mg/ cm2/day.

Optimization of the spectral composition emission of the combined spectrum led phytoirradiators

The results of the full-fledged vegetation of cucumber plants of the Svyatogor F1 variety under light culture conditions are presented. The studies were carried out on an experimental research hydroponic setup at photosynthetic photon irradiance EPPFD = 250 ± 10 μmol/(s·m2). In the experiment phytoirradiators with high-pressure sodium lamps of the DNaZ type (control variant), as well as LED combined spectrum phytoirradiators are used. Keywords phytoirradiator, LED light source, photoculture, photobiological research, radiation spectrum, photosynthetically active radiation, photosynthetic photon irradiance, cucumber plant

Genetic-Biochemical Studies and Morphobiological Assessment of Small Radish (Raphanus sativus L.) under Artificial Light Culture Conditions

Genetic-Biochemical Studies and Morphobiological Assessment of Small Radish (Raphanus sativus L.) under Artificial Light Culture Conditions

Growth and development of tomato (Lycopersicon esculentum Mill.) under light culture conditions

The article studies the growth and development of three varieties of tomato when grown under conditions of complete light culture with a lighting power of 175±15 µmol/m2/s. The passage of phenological phases by tomato varieties corresponded to the inherent genetic potential. The Andreyka variety has formed larger leaves, compared to cultivation in protected ground. Variety Demidov formed powerful and highly leafy plants. Variety Stepanna formed medium leafy plants with medium leaves. At a lighting power of 175±15 µmol/m2/s, tomato varieties formed more leafy plants with larger leaves compared to plants grown in protected ground, which is a response to lighting conditions.

Application of ESCO phytosystem based on narrow-band light-emitting diodes for growing cucumbers under photoculture conditions

The article deals with the study of photomorphogenesis of different cucumber varieties under light culture conditions. Studies were carried out under laboratory conditions using an experimental phytosystem ESCO based on narrow-band light-emitting diodes, which is equipped with a microcontroller. The microcontroller controls the supplementary light modes. Studies were conducted to develop recommendations for selecting and controlling the spectral composition of light optimal for the life cycle of plants. The aim of our research is to study photomorphogenesis of different cucumber varieties under light-culture conditions using an experimental ESCO phytosystem based on narrow-band light-emitting diodes equipped with a microcontroller that controls the supplementary light modes. Four cucumber hybrids were used to test the ESCO phytosystem. Phytolamps were placed at the height of 1 m in the beginning, then at the height of 1.2 m. Every day we recorded the growth of shoot length, establishment of generative organs (flowers), we recorded the date of flowering and fruit formation. Conditions of humidity, nutrient and air regimes corresponded to biological requirements of growth and development of cucumber plants. Studies have shown that laying of generative organs of cucumber with additional lighting with narrow-band light emitting diodes is good. Female flowers appeared 7-14 days earlier in BV700+RV350+ BF350+FRF350 regime than in plants grown under natural light. The RV light regime had a significant effect on the increase in plant height. Determination of chlorophyll content showed its optimal amount and depended on the varietal characteristics of plants. The best supplementary light mode was BV700+RV350+ BF350+FRF350 during the cultivation of seedlings of different cucumber hybrids. Mode change all to 500 after planting in the ground.

QTL Analysis of the Content of Some Bioactive Compounds in Brassica rapa L. Grown under Light Culture Conditions

The article presents the results of biochemical and QTL (Quantitative Trait Loci) analysis of dry matter content, nutrient and biologically active compounds: sugars, ascorbic acid, chlorophylls a and b, anthocyanins and carotenoids in populations of doubled haploid lines of leaf, root crops, and oilseeds of the Brassica rapa L. species grown in optimal light culture conditions, but with different photoperiod durations. The purpose of this study was to evaluate the effect of the photoperiod on the transition to bolting and the accumulation of biologically active substances, as well as how the localization and identification of chromosomal loci determined the content of certain phytochemicals. The influence of the length of daylight hours on the content of components of the biochemical composition was assessed. It was shown that growing under conditions of a 16 h photoperiod increased the content of dry matter, sugars, vitamin C, and anthocyanins. On the contrary, the content of photosynthetic pigments was higher under the conditions of a 12 h photoperiod. Valuable lines that can be sources of biologically active compounds were revealed. Based on the results of the obtained data, 102 QTLs were mapped, which determine the manifestation of the studied biochemical quality traits in the B. rapa doubled haploid lines under conditions of short and long daylight hours. Molecular markers genetically linked to the selected QTLs were determined. It was revealed that the identified loci controlling all the studied biochemical traits were mainly in the fifth, sixth, seventh, and ninth linkage groups, which correlated with the data obtained in the field and greenhouse. Most of the identified loci controlled several studied traits simultaneously. The identified QTLs and identified molecular markers are of interest for further study of the genetic control of the economically valuable traits determined by them and for the implementation of marker-assisted selection in B. rapa. The data obtained can be used in genetic and breeding work, including for the obtaining of new genotypes, lines and cultivars with a valuable biochemical composition, adapted for cultivation under specific photoperiodic conditions.

Effects of an environmental endocrine disruptor, para-nonylphenol on the cell growth of Euglena gracilis: association with the cellular oxidative stress.

Effects of an environmental endocrine disruptor, para-nonylphenol (NP) on the cell growth of a photosynthetic eukaryotic microorganism, Euglena gracilis were analysed under different cell culture conditions. Although NP did not show significant inhibitory effects on the cell growth of E. gracilis (Z and SM strains) under light culture condition, NP exhibited significant suppressive effects under dark culture condition. Exogenous supplementation with lipophilic antioxidants (α-tocopherol, β-carotene or 6-O-palmitoyl-ascorbic acid) to E. gracilis caused strong preventive effects against NP-induced cell growth inhibition under dark culture condition, but hydrophilic antioxidants [ascorbic acid, glutathione and epigallocatechin gallate (EGCG)] did not show significant preventive effects. NP caused significant generation of reactive oxygen species (ROS) in E. gracilis under dark culture condition, but E. gracilis under light culture condition did not show significant increase in ROS generation. Supplementation with lipophilic antioxidants to E. gracilis caused significant suppressive effects against NP-induced cellular ROS generation under dark culture condition, but hydrophilic antioxidants did not show significant suppressive effects. Furthermore, the productivities of typical cellular antioxidants (α-tocopherol, β-carotene and ascorbic acid) in E. gracilis under light culture conditions were much higher than those under dark culture conditions.

Recommended cucumber hybrids for growing in greenhouses under conditions artificial lighting

For plants, light is a determining factor in growth and development. The use of artificial lighting in greenhouses has a huge impact on the yield, cost and timing of the receipt of vegetable products. The development of light culture in the country allows greenhouse complexes to use their greenhouses year-round,significantly increase plant productivity, receive most of the harvest in the winter months of the year andsell it at a higher price. The use of artificial light made it possible to increase the yield of the cucumber cropto 200 kg from 1 m2or more. From the economic point of view, the cucumber culture is most effective ingreenhouses. Russia is a cucumber country, more than half of the protected ground area is occupied bythis crop. And photoculture in greenhouses began with the cultivation of a cucumber crop. Today we saywith confidence that artificial lighting in greenhouses is more efficient than natural lighting. So to get onekilogram of vegetables using artificial lighting, it is necessary to spend 4.5-5.0 thousand J/cm2, and in thecase of using natural light – 5.0-6.5 thousand J/cm2. This can be explained by the fact that in the conditionsof using artificial lighting in cultivation facilities, we strive to create the most comfortable growing conditions for plants. An increase in the yield of cucumber crops under artificial lighting occurs mainly due to anincrease in the lighting power per unit area of greenhouses to 220 W/m2and more. However, this is not theonly way to increase yields. One of the most important criteria for increasing yields and improving the quality of fruits is the choice of the grown hybrid. Cucumber hybrids for cultivation under light culture conditions will be discussed in this work.The methods used in agronomic science were used. The information base of the research was made up of reference materials from specialized publications on the subject under study (catalogs of breeding companies);materials received from participants in the greenhouse vegetable market (breeding companies, greenhouseplants); own research, articles and reviews in specialized journals.Correctly selected cucumber hybrids provide a significant increase in yields in greenhouses, an improvementin fruit quality and a balanced cultivation technology in specific conditions. An assortment of recommendedcucumber hybrids for cultivation under photoculture conditions is presented, an analysis of their advantagesand disadvantages is made, and the main requirements for hybrids for these conditions are formulated.

Intracanopy Lighting in Phytocenoses and Photobiological Efficiency of Radiation in Photoculture Conditions

The review is devoted to the study of the internal radiation regime in the canopies cultivated under controlled environmental conditions. The expediency of using canopies as an object of research for evaluating the photobiological efficiency of radiation in light culture conditions is justified. The appropriateness of light measurements in multi-tiered canopies is shown, taking into account the role of leaves of different tiers in the formation of an economically useful crop. The main requirements for light devices for their use in measuring artificial radiation in light culture conditions are considered, and a brief analysis of the existing instrument base for performing these studies is given. A number of examples show the complexity and ambiguity of the internal structure of the light field that is forming within canopies in light culture conditions. Conceptual approaches to the choice of spectral and energy characteristics of artificial irradiation for plant light culture are proposed and justified. The necessity of taking into account the light conditions of leaves of different tiers when choosing the spectral and energy characteristics of light sources for the cultivation of multi-tiered canopies is justified. Techniques, methods, and light sources used for additional intracanopy lighting are analysed. The efficiency of using side illumination of plant canopies and conditions for its implementation are considered. The advantages of the volume distribution of canopies on the most common multi-tiered lighting installations are discussed. Based on the presented material, we consider ways to improve methodological approaches for evaluating the photobiological effectiveness of artificial radiation in light culture conditions for canopies of cultivated plants, taking into account the features of their architectonics and internal radiation regime.

BIOLOGICAL FEATURES OF Brassica rapa L. VEGETABLE LEAFY CROPS WHEN GROWING IN AN INTENSIVE LIGHT CULTURE

One of the main components of the successful production of plant products is the choice of crops with a high realization of their production potential under the formed conditions, including in the conditions of intensive light culture. The problem of compensating or eliminating the deficit of green crops is currently quite acute in Russia and in the world. The genetic diversity of the most widespread green brassicas plants of the species Brassica rapa L. for use in protected ground facilities has developed in Southeast Asia and includes numerous morphotypes of Chinese cabbage, pakchoi, tatsoi, wutacai, mizuna, and leafy turnip. In Russia, leafy B. rapa vegetables are used to a limited extent, mainly as salad vegetables. The main areas of B. rapa crops breeding for artificial light culture include a high growth rate (the duration of vegetative period is not more than 28-35 days, depending on the biological characteristics of the crop), the yield is not less than 3-8 kg/m2, depending on crops, a certain compact plant habit, high quality of leaves, valuable biochemical composition, resistance to early bolting, resistance to possible low light and high air temperature, suitability for growing in a thin layer of soil or hydroponics. The biological features of the diversity of B. rapa leafy crops as sources for breeding for intensive light culture conditions have not been sufficiently studied, first of all, this concerns little-known crops (tatsoi, wutacai, mizuna) and certain morphotypes within common crops (Chinese cabbage and pakchoi). In this study, for the first time, we studied the wide genetic diversity from the Russian worldwide B. rapa collection of the Russian Federation, stored in the VIR, and morphotypes within them (72 accessions), including genotypes contrasting in morphological characteristics, under different supply light intensity for the development of energy-saving agro-technologies in intensive light culture. For the first time, correction factors were determined for calculating the leaf surface area from easily measured linear dimensions for each studied crop and type of leaves, which will speed up the calculations of photosynthesis characteristics. A different degree of variation in the variability of the size and weight of plants of various crops, depending on the illumination, is shown, the highest in Chinese cabbage and leafy turnip. It was found that the intensity of the light regime is largely determined the increase in the productivity of plants of all studied crops, mostly of Chinese cabbage and pakchoi and leafy turnip. High-yielding accessions of Chinese cabbage, pakchoi and leafy turnip were identified (more than 6.3 kg/m2 for 28 days of growing season). The studied accessions of wutacai and mizuna are low-yielding and have a longer growing season, but are of interest as vegetables for functional nutrition and for decorative purposes. Semi-cabbage types of Chinese cabbage (Shantung, Santo, Xiao), which are of primary interest for light culture, have been identified. We recommend Chinese cabbage accessions vr.k-1375, Bice (vr.k-1376), and pakchoi k-647 for thickened cultivation,, and pakchoi Extra Dwarf Pack Choi (vr.k-1405 ) and tatsoi Xiao Ba Je Ta Cai (k-695) for growing with a small distance between the shelves of 25 cm. Accessions of Chinese cabbage Chokurei (k-177), Tokyo Bekana (k-395), Zao Shi No. 5 (vr.k-1120), and Fun jen F1 (vr.k-1410) showed the highest salad qualities of the leaves. Under the conditions of a biopolygon, we managed to determine accessions with a stable manifestation of the traits, of early maturity and high productivity, practically independent of light intensity. These are accessions of Chinese cabbage Harumaki Shin Santousai (k-270), Tokyo Bekana (k-395), Xiaobaikou (k-74), pakchoi Kangre 605 (vr.k-1131), Gai Lang Jin Pin 25 F1 (vr.k-1124). In addition, it was shown that the Chinese accession of Chinese cabbage Zao Shi No. 5 (vr.k-1120) and the Russian cultivar of the leafy turnip Selecta (vr.k-1371) have increased the activity of the photosynthetic apparatus. The obtained data on the crops in general and the determined accessions of B. rapa are of interest for the practice of vegetable growing, in the development of elements of cultivar technology of B. rapa crops under conditions of light culture and as sources of valuable traits in breeding programs, including the development of city farming.

БИОЛОГИЧЕСКИЕ ОСОБЕННОСТИ КАПУСТНЫХ ОВОЩНЫХ КУЛЬТУР ВИДА Brassica rapa L. ПРИ ВЫРАЩИВАНИИ В ИНТЕНСИВНОЙ СВЕТОКУЛЬТУРЕ

One of the main components of the successful production of plant products is the choice of crops with a high realization of their production potential under the formed conditions, including in the conditions of intensive light culture. The problem of compensating or eliminating the deficit of green crops is currently quite acute in Russia and in the world. The genetic diversity of the most widespread green brassicas plants of the species Brassica rapa L. for use in protected ground facilities has developed in Southeast Asia and includes numerous morphotypes of Chinese cabbage, pakchoi, tatsoi, wutacai, mizuna, and leafy turnip. In Russia, leafy B. rapa vegetables are used to a limited extent, mainly as salad vegetables. The main areas of B. rapa crops breeding for artificial light culture include a high growth rate (the duration of vegetative period is not more than 28-35 days, depending on the biological characteristics of the crop), the yield is not less than 3-8 kg/m2, depending on crops, a certain compact plant habit, high quality of leaves, valuable biochemical composition, resistance to early bolting, resistance to possible low light and high air temperature, suitability for growing in a thin layer of soil or hydroponics. The biological features of the diversity of B. rapa leafy crops as sources for breeding for intensive light culture conditions have not been sufficiently studied, first of all, this concerns little-known crops (tatsoi, wutacai, mizuna) and certain morphotypes within common crops (Chinese cabbage and pakchoi). In this study, for the first time, we studied the wide genetic diversity from the Russian worldwide B. rapa collection of the Russian Federation, stored in the VIR, and morphotypes within them (72 accessions), including genotypes contrasting in morphological characteristics, under different supply light intensity for the development of energy-saving agro-technologies in intensive light culture. For the first time, correction factors were determined for calculating the leaf surface area from easily measured linear dimensions for each studied crop and type of leaves, which will speed up the calculations of photosynthesis characteristics. A different degree of variation in the variability of the size and weight of plants of various crops, depending on the illumination, is shown, the highest in Chinese cabbage and leafy turnip. It was found that the intensity of the light regime is largely determined the increase in the productivity of plants of all studied crops, mostly of Chinese cabbage and pakchoi and leafy turnip. High-yielding accessions of Chinese cabbage, pakchoi and leafy turnip were identified (more than 6.3 kg/m2 for 28 days of growing season). The studied accessions of wutacai and mizuna are low-yielding and have a longer growing season, but are of interest as vegetables for functional nutrition and for decorative purposes. Semi-cabbage types of Chinese cabbage (Shantung, Santo, Xiao), which are of primary interest for light culture, have been identified. We recommend Chinese cabbage accessions vr.k-1375, Bice (vr.k-1376), and pakchoi k-647 for thickened cultivation,, and pakchoi Extra Dwarf Pack Choi (vr.k-1405 ) and tatsoi Xiao Ba Je Ta Cai (k-695) for growing with a small distance between the shelves of 25 cm. Accessions of Chinese cabbage Chokurei (k-177), Tokyo Bekana (k-395), Zao Shi No. 5 (vr.k-1120), and Fun jen F1 (vr.k-1410) showed the highest salad qualities of the leaves. Under the conditions of a biopolygon, we managed to determine accessions with a stable manifestation of the traits, of early maturity and high productivity, practically independent of light intensity. These are accessions of Chinese cabbage Harumaki Shin Santousai (k-270), Tokyo Bekana (k-395), Xiaobaikou (k-74), pakchoi Kangre 605 (vr.k-1131), Gai Lang Jin Pin 25 F1 (vr.k-1124). In addition, it was shown that the Chinese accession of Chinese cabbage Zao Shi No. 5 (vr.k-1120) and the Russian cultivar of the leafy turnip Selecta (vr.k-1371) have increased the activity of the photosynthetic apparatus. The obtained data on the crops in general and the determined accessions of B. rapa are of interest for the practice of vegetable growing, in the development of elements of cultivar technology of B. rapa crops under conditions of light culture and as sources of valuable traits in breeding programs, including the development of city farming.

SMALL RADISH FOR LIGHT CULTURE: CHALLENGES AND PROSPECTS

Intense light culture, the most impotent part of a regulated agroecosystem, makes it possible to produce high quality plant products all year round in any region of the world in close proximity to the consumer. It is most economically viable to use light culture for growing vegetables in the Far North, where there is an acute shortage of fresh vegetables and vitamins. Our studies of the range of different vegetable crops have shown that when using artificial lighting and low-volume cultivation technologies, many plant species and varieties have low productivity, low adaptability to the relevant conditions, and therefore unprofitable for mass production. To expand the range of vegetable products intended for cultivation in the light culture, it is necessary to do a massive screening of the varieties and hybrids of various crops available in the world assortment with the aim of selecting the best and also purposeful breeding of new forms and varieties maximally adapted to the appropriate cultivation technologies. The purpose of this work was to create new forms of small radish for light culture, having the necessary complex of economically valuable characters. The use of the previously developed methodology of predicting transgressions for economically valuable plant traits allowed us to obtain new promising forms of radish with using purposeful hybridization and subsequent stabilizing selection. Their characteristics are high productivity and early maturity (ripeness to harvesting for 21-25 days from seeding), the ability to produce marketable yield of roots in a small volume of root medium, resistance to bolting at higher temperatures. A number of the obtained forms also has a compact rosette of leaves and an almost glabrous leaf of the salad type. Marketable productivity of new forms of radish in intense light culture conditions reaches 5,5 kg/m2 (for hybrids F1) and 4 kg/m2 for stable lines, which is twice or more than the productivity of the parental cultivars and one and a half times more than the best in productivity cultivars that were tasted in light culture.

Study on Light Intensity Attenuation Characteristics of <i>Chlorella</i> Sp. Culture and the Growth of <i>Chlorella</i> Sp. with the Gradient Light Illuminate Culture

Based on the photoautotrophic characteristics of the freshwater microalage, light intensity attenuation characteristics in the cell culture system for Chlorella sp. were studied. Micralgae was cultured with a constant and the gradient light illuminate culture conditions, the cell growth of Microlagae was detected respectively, By means of regression analysis, mathematical models of illuminance intensity attenuation are gotten under different culture conditions. Results show algae cell density under gradient light culture conditions is higher than constant light, so the gradient light is more suitable for the cultivation of microalgae.

Environmental control of phosphorylation pathways in a branched two‐component system

NblS, the most conserved histidine kinase in cyanobacteria, regulates photosynthesis and acclimatization to a variety of environmental conditions. We used in silico, in vivo and in vitro approaches to identify RpaB and SrrA as the cognate response regulators of NblS and to characterize relevant interactions between components of this signalling system. While genetic analysis showed the importance of the NblS to RpaB phosphorylation branch for culture viability in Synechococcus elongatus PCC 7942, in vitro assays indicated a strong preference for NblS to phosphorylate SrrA. This apparent discrepancy can be explained by environmental insulation of the RpaB pathway, achieved by RpaB-dependent repression of srrA under standard, low light culture conditions. After a strong but transient increase in srrA expression upon high light exposure, negative regulation of srrA and other high light inducible genes takes place, suggesting cooperation between pathways under environmental conditions in which both RpaB and SrrA are present. Complex regulatory interactions between RpaB and SrrA, two response regulators with a common evolutionary origin that are controlled by a single histidine kinase, are thus emerging. Our results provide a paradigm for regulatory interactions between response regulators in a branched two-component system.

Salicornia europaea L. (fam. Chenopodiaceae) Plants as Possible Constituent of Bioregenerative Life Support Systems’ Phototrophic Link

The work is devoted to investigation of productivity, biochemical and mineral composition of Salicornia europaea grown under intensive light culture conditions as applied to bioregenerative life support systems (BLSS). Furthermore influence of amide form of nitrogen on plants growth is investigated in the work. Biochemical composition of the Salicornia europaea edible part showed that raw protein was contained in the highest degree. The water-soluble sugars content and the polysaccharides number (except cellulose) were not high in the Salicornia europaea edible part. It was shown that the plants lipids are characterized by a high unsaturation degree mainly due to alpha linolenic and linoleic acids. Nitrogen nutrition form did not significantly affect the Salicornia europaea productivity. Sodium and its concentrations predominated in the plants mineral composition. Hence Salicornia europaea vegetable plants not only contribute to involvement of sodium chloride in BLSS matter turnover, but also can be the source of several biochemical substances and essential fatty acids for a human.