EFFECTS OF VERY SMALL DOSES OF IONIZING RADIATION AND HYPOMAGNETIC FIELD CHANGE PHYSIOLOGICAL CHARACTERISTICS OF HIGHER PLANT SEEDS.

Effects of a 40-times weakened geomagnetic field and its combination with low a- and y-radiation doses on the physiological characteristics of higher plant seeds and water redox properties were studied. Germination rate was found decreased and seedlings development retarded equally when exposure to the hepomagnetic field was direct or mediated by water. Besides, water-mediated irradiation by low y-doses moderated and by low a-doses augmented the negative HMF effect on seeds growth. In other words, ionizing radiation dominated in this combination. The redox potential of water (ROP) was noted to rise due to low-intensity a-radiation (9Pu) that was nonlinear and polymodal. Comparing to a-irradiation, the range of ROP changes due to y-irradiation ('37Cs) was narrow which was reflected in growth processes in seeds. Water ROP increases as the magnetic field induction attenuates which implies a natural reduction of water molecules internal energy and bettering of water oxidative qualities. In our view, this was the cause for retarded seed germination. Water is believed to be the determinant for the factors in this study as their effects on seeds were modified by changes in water qualities and structure.

[Ecopsychological investigations in 520-day isolation].

Assessment of the importance of higher plants for emotions and relations within the group of test-subjects was performed in the long-duration chamber experiment MARS-500 designed as an imitation of an exploration mission. It was shown that the degree of involvement with the plants dictated the magnitude and character of the ecopsychological effect. Subjects with high psychological stability and dominating introversion were more inclined to interact with plants. Remoteness of the greenhouse from recreation areas weakened the ecopsychological effect and denied the crew the opportunity to interact with plants. At the same time, the presence of the plant growth unit with decorative plants in the lounge had certainly a positive psychological effect. The crew gave preference to big bright flowers that did not demand much care. This observation should be taken into consideration by designers of psychological recreation environments. Choice of plants to be grown as a dietary supplement for the crew in isolation and confinement should be made with allowance for cultural preferences of crew members.

[Effect of thermal shock on seed resistance].

The work was performed in order to evaluate possible negative effect of high temperatures on biological properties of seeds in space experiment BIORISK-MSN-2. Laboratory experiments showed that seeds possess high enough resistance to extended exposure to high temperatures. Results of studying effects of positive temperatures in the region of 40 to 100 degrees C on biological properties of seeds of 19 species and varieties of higher plants belonging to three different families lead to the conclusion that heat stability of seeds depends on temperature value, period of exposure, species, variety and individual peculiarities of plants. These data can be useful in future interpretation of results of experiment BIORISK-MSN-2.

[Stress response genes expression analysis of barley Hordeum vulgare under space flight environment].

Transcriptome of barley Hordeum vulgare grown aboard International Space Station (ISS) was analyzed by means of microarray. It was revealed 500 genes with mRNA level, changed more than two folds in space environment. Among them are genes encoding stress response proteins, videlicet Heat Shock Proteins (HSP), Pathogenesis-Related Proteins (PR) and Antioxidant Proteins. Further analysis of these genes by real time PCR showed enhanced transcription level of Reactive oxygen Species (ROS) scavenging genes. The mRNA level of superoxide dismutase (sod) was 6 folds higher in space environment when compare to Earth conditions. Glutamyl transferase gene expression was enhanced 24 times in space. Transcription of catalase gene (cat) was increased 18 times and of ascorbate peroxidase was increased 3 times in space in comparison with ground control. For the first time it was shown that space flight environment may induce oxidative stress in plants.

[Effects of low doses of ionizing radiation on substrate and germination of higher plants seeds].

The investigation had the aim to evaluate the effects of low doses (< 1-10 cGy) of ionizing radiation on the physical-chemical qualities of high-purification water. It had also the goal to study germination rate and energy and sprouting of four species of higher plants exposed directly and indirectly (watering) to alpha- and beta-radiation from radionuclids sources. When compared with intact water, after exposure to beta-particles electrical currents in water-filled containers consistently tended upward and downward after exposure to alpha-particles. Radiation-induced changes in water parameters were observed throughout the experiment with higher plant seeds. Evaluation of the effect of irradiated water on sprouting showed that plant sensitivity varied with species and depended on type of radiation particles. Neither alpha- nor beta particles affected the wheat sprouts; however, both types of particles inhibited growth of mustard and accelerated growth of lentil and haricot Mash as compared with control crops. The investigation suggests that plant species for space greenhouses should be selected with account of their radioresistance and radiosensitivity.

[Biological systems of life support for space crews: some results and anticipations].

One of the challenges for space biology and medicine is resolution of lots of problems of biomedical support of humans in the extreme environment of space flight. These problems include also designing of robust and efficiently functioning life support systems (LSS). The paper gives an overview of the investigations of ground-based BLSS with human subjects conducted in Russia and other countries. Also, it contains the basic data of studying the BLSS photoautotrophic components (higher plants) in the series of experiments with the total duration of 630 days fulfilled on orbital complex Mir and the series of experiments with the total duration of 820 days in the ISS Russian segment. Analysis of the results from the BLSS investigations on Earth and in space flights drives to the conclusion that some of the BLSS components, greenhouses specifically, can be integrated even now into the currently used systems of space crew life support.

[The study of the genetic effects in generation of pea plants cultivated during the whole cycle of ontogenesis on the board of RS ISS].

Results of studies on growth and development of offspring of two genetically marked dwarf pea lines planted during the whole ontogenesis cycle in the Lada space greenhouse on board of Russian Segment of International Space Station (RS ISS) are presented. The offspring of M1 and M2 plants grown from seeds formed during space flight was examined under conditions of Earth-based. Cultivation. It had been shown that growth and developmental characteristics, frequency of chromosome aberrations in primary root meristem and level of molecular polymorphism revealed in individual plants via RAPD method show no significant differences between offspring of "space-grown" and control seeds.

[Gas-exchange profiles of different algae communities as applied to biological system of human life support].

Previous modeling of the human-chlorella-microorganisms system showed that the absolute balance of atmospheric oxygen and carbon dioxide is unattainable because of inequality of the human respiration factor and chlorella assimilation factor. Analysis of patterns of gas-exchange regulation in a system with open trophic human-algae interrelations revealed that the sine qua non condition for this balance is identity of synthesized algal biomass and digestible part of human ration which is impractical with cultivation of only one algal species. We undertook experimental testing of this supposition with three algae communities: chlorella-chlamydomonas, spirulina-chlamydomonas and spirulina-chlamydomonas-clorella during accumulative cultivation. Investigation of their gas-exchange profiles made it clear that the assimilation factor of such photosynthetic component varies with community structure. The data can be useful in choosing the algae species and specifying their ratio that would permit to keep good balance of oxygen and carbon dioxide in atmosphere of closed systems.

[Parametric control of the yield characteristics and species composition dynamics of algal poly-culture].

There are several experimental models of biological life support systems (BLSS) designed to incorporate a chlorella pool. These BLSS can be optimized if populated by algal associations that could take up more functions within the closed cycling system than a single alga species. Introduction of a Spirulina and Chlamydomonas poly-culture with differing in gas exchange and biochemical composition resulted in a tighter closure of linkages within the system. The factors determining the size of a species population in intensive continuous poly-cultures are, first and foremost, pH and suspension flow rate. Experimental testing of this supposition brought us to the conclusion that parametric control of alga productivity and species composition dynamics makes it possible to create a steady intensive poly-culture as part of the LSS for humans. Flow rate and pH can be the parameters for control of the Spirulina and Chlamydomonas populations during continuous cultivation of this poly-culture.

[Growth, development and genetic status of pea plants cultivated in space greenhouse "LADA"].

In the period between March 2003 and April 2005 five crops of genetically marked dwarf pea were cultivated in greenhouse LADA on the ISS Russian segment to study morphology and genetics in consecutive generations. Results of the first space experiment were analyzed and characteristics of ground plants grown from space seeds were studied. It was shown that parameters of growth, development and genetic status of pea plants that completed the ontogenetic cycle in LADA did not differ substantially from the laboratory control and that plants cultivated in space flight do not incur losses in the reproductive function and form viable seeds. Genetic analysis of plants from the first generation of space and ground seeds using the methods of RAPD-primers (10 markers) and chromosomal aberration analysis failed to reveal genetic polymorphism which means that the spaceflight factors had no effect on the genetic apparatus of the first generation of space-grown plants.

The biological component of the life support system for a Martian expedition.

Ground-based experiments at RF SSC-IBMP RAS (State Science Center of Russian Federation--Institute of Biomedical Problems of Russian Academia of Science) were aimed at overall studies of a human-unicellular algae-mineralization LSS (life support system) model. The system was 15 m3 in volume. It contained 45 L of algal suspension with a dry substance density of 10-12 g per liter; water volume, including the algal suspension, was 59 L. More sophisticated model systems with partial substitution of unicellular algae with higher plates (crop area of 15 m2) were tested in three experiments from 1.5 to 2 months in duration. The experiments demonstrated that LSS employing the unicellular algae play not only a macrofunction (regeneration of atmosphere and water) but also carry some other functions (purification of atmosphere, formation of microbial cenosis etc.) providing an adequate human environment. It is also important that functional reliability of the algal regenerative subsystem is secured by a huge number of cells able, in the event of death of a part of population, to recover in the shortest possible time the size of population and, hence, functionality of the LSS autotrophic component. For a long period of time a Martian crew will be detached from Earth's biosphere and for this reason LSS of their vehicle must be highly reliable, robust and redundant. One of the approaches to LSS redundancy is installation of two systems with different but equally efficient regeneration technologies, i.e. physical-chemical and biological. At best, these two systems should operate in parallel sharing the function of regeneration of the human environment. In case of failure or a sharp deterioration in performance of one system the other will, by way of redundancy, increase its throughput to make up for the loss. This LSS design will enable simultaneous handling of a number of critical problems including adequate satisfaction of human environmental needs.

Plant growth during the Greenhouse II experiment on the Mir orbital station.

We carried out three experiments with Super Dwarf wheat in the Bulgarian/Russian growth chamber Svet (0.1 m2 growing area) on the Space Station Mir. This paper mostly describes the first of these NASA-supported trials, began on Aug. 13, 1995. Plants were sampled five times and harvested on Nov. 9 after 90 days. Equipment failures led to low irradiance (3, then 4 of 6 lamp sets failed), instances of high temperatures (ca. 37 degrees C), and sometimes excessive substrate moisture. Although plants grew for the 90 d, no wheat heads were produced. Considering the low light levels, plants were surprisingly green, but of course biomass production was low. Plants were highly disoriented (low light, mirror walls?). Fixed and dried samples and the root module were returned on the U.S. Shuttle Atlantis on Nov. 20, 1995. Samples of the substrate, a nutrient-charged zeolite called Balkanine, were taken from the root module, carefully examined for roots, weighed, dried, and reweighed. The Svet control unit and the light bank were shipped to Moscow. An experiment validation test (EVT) of plant growth and experimental procedures, carried out in Moscow, was highly successful. Equipment built in Utah to measure CO2, H2O vapor, irradiance, air and leaf (IR) temperature, O2, pressure, and substrate moisture worked well in the EVT and in space. After this manuscript was first prepared, plants were grown in Mir with a new light bank and controller for 123 d in late 1996 and 39 days in 1996/1997. Plants grew exceptionally well with higher biomass production than in any previous space experiment, but the ca. 280 wheat heads that were produced in 1996 contained no seeds. Ethylene in the cabin atmosphere was responsible.

[Biological processes of the human environment regeneration within the Martian crew life support systems]. / Biologicheskie protsessy regeneratsii sredy obitaniia v sisteme zhizneobespecheniia ékipazha marsianskoi ékspeditsii.

Five ground-based experiments at RF SRC-IBMP had the purpose to make a thorough investigation of a model of the human-unicellular algae-mineralization life support system. The system measured 15 m3 and contained 45 liters of alga suspension; the dry alga density was 10 to 12 g/l and water volume (including the alga suspension) amounted to 59 l. More sophisticated LSS models where algae were substituted by higher plants (crop area in the greenhouse equaled 15 m2) were investigated in three experiments from 1.5 mos. to 2 mos. in duration. It was found that the alga containing LSS was able to fulfill not only the macrofunction (air and water regeneration) but also several additional functions (air purification, establishment of microbial cenosis etc.) providing an adequate human environment. This polyfunctionality of the biological regenerative processes is a weighty argument for their integration into space LSSs. Another important aspect is that the unicellular algae containing systems are highly reliable owing to a huge number of species-cells which will be quickly recovered in case of the death of a part of the population and, consequently, functionality of the LSS autotrophic component will be restored before long. For an extended period of time the Martian crew will have no communication with the Earth's biosphere which implies that LSS should be absolutely reliable and redundant. Redundancy can be achieved through installation aboard the vehicle of two systems constructed on different principles of regeneration, i.e. physical-chemical and biological. Each of the LSSs should have the power to satisfy all needs of the crew. The best option is when two systems are functioning in parallel sharing the responsibility for the human environment. Redundancy in this case will mean that in the event of failure or a drastic decrease in performance of one system the other one will make up for the loss by increasing its share in the overall regeneration process.

[Comparison of productivity of different vitamin green technologies under the space station conditions]. / Sravnenie éffektivnosti razlichnykh metodov polucheniia vitaminnoi zeleni v usloviiakh kosmicheskoi stantsii.

At present, fresh plant products for nutrition of the International space station (ISS) crews are delivered from Earth in small quantities. Regular supply of additional fresh greens could be positive for improvement as of nutrition, so psychophysical state of ISS crews. Vitamin greens can be produced with the use of various technologies: planting leaf cultures in greenhouses, forcing the greens from onions and root vegetables (onion, garlic, chicory, beet, parsley etc.), and germinating seeds. Purpose of this study was to compare productivity of these technologies in order to specify inputs for designers of a vitamin greenhouse to be mounted in the space station and a Martian vehicle. Based on comparison of the productivity of various technologies, specific productivity of different greenhouses per a unit of power consumption, and a volume unit it will be maximal if used for germinating seeds and minimal if used for growing leaf vegetables in a greenhouse with a cylindrical crop surface.

Main characteristics of biological components of developing life support system observed during the experiments aboard orbital complex MIR.

Since 1990, the orbital complex MIR has witnessed several incubator experiments for determination of spaceflight effects on embryogenesis of Japanese quail. First viable chicks who had completed the whole embryological cycle in MIR microgravity hatched out in 1990; it became clear that newborns would not be able to adapt to microgravity unaided. There were 8 successful incubations of chicks in the period from 1990 to 1999. In 1995-1997 the MIR-NASA space science program united Russian and US investigators. As a result, experiments Greenhouse-1 and 2 were performed with an effort to grow super dwarf wheat from seed to seed, and experiment Greenhouse-3 aimed at receiving two successive generations of Brassica rapa. But results of these experiments could not be used for definitive conclusions concerning effects of spaceflight on plant ontogenesis and, therefore, experiments Greenhouse-4 and 5 were staged within the framework of the Russian national space program. The experiments finally yielded wheat seeds. Some of the seeds was left on the space station and, being planted, gave viable seedlings which, in their turn, produced the second crop of space seeds.

[Growth and development of plants in a sequence of generations under the conditions of space flight (experiment Greenhouse-3)]. / Rost i razvitie rastenii v riadu pokolenii v usloviiakh kosmicheskogo poleta v éksperimente "Oranzhereia-3".

The purpose was to study characteristic features of growth and development of several plant generations in space flight in experiment GREENHOUSE-3 as a part of the Russian-US space research program MIR/NASA in 1997. The experiment consisted of cultivation of Brassica rapa L. in board greenhouse Svet. Two vegetative cycles were fully completed and the third vegetation was terminated on day 13 on the phase of budding. The total duration of the space experiment was 122 days, i.e. same as in the ground controls. In the experiment with Brassica rapa L. viable seeds produced by the first crop were planted in space flight and yielded next crop. Crops raised from the ground and space seeds were found to differ in height and number of buds. Both parameters were lowered in the plants grown from the space seeds. The prime course for smaller size and reduced organogenic potential of plantTs reproductive system seems to be a less content of nutrients in seeds that had matured in the space flight. Experiment GREENHOUSE-3 demonstrated principle feasibility of plant reproduction in space greenhouse from seeds developed in microgravity.

[Embryological investigation of super-dwarf wheat grown in laboratory experiment with elevated content of ethylene in atmosphere]. / Embriologichesoe issledovanie superkarlikovoi pshenitsy, vyrashchennoi v nazemnom éksperimente v usloviiakh povyshennogo soderzhaniia étilena v atmosfere.

Data of the cytoembryological analysis of plants of super-dwarf wheat grown in laboratory experiment with elevated ethylene content in atmosphere were compared with results of space experiment and the ground control with ambient ethylene concentration. It was shown that crop barrenness in both the space and ground experiments was caused by exposure to increased ethylene throughout the whole ontogenesis which made pollen nonviable. The cytogenetic analysis revealed that male sterility of the wheat flowerlets in space flight evolved, as a rule, earlier and was deeper by character, i.e. pollen did not progress farther than the one-nucleus phase, whereas in the laboratory experiment with ethylene the pollen grains reached sometimes even the three-nucleus phase.

[Growth and development of plants in a row of generations under the conditions of space flight (experiment Greenhouse-5)]. / Rost i razvitie rastenii v riadu pokolenii v usloviiakh kosmicheskogo poleta v éksperimente "Oranzhereia-5".

Results of the experiment aimed at harvesting a second space generation of wheat var. Apogee in Mir greenhouse Svet (experiment GREENHOUSE-5) are presented. In space flight, germination rate of space seeds from the first crop made up 89% against 100% of the ground seeds. The full biological ripeness was observed in 20 plants grown from the ground seeds and one plant grown from the space seeds following 80- to 90-d vegetation. The plant of the second space generation was morphologically different neither from the species in the first space crop nor from the ground controls. To study the biological characteristics of Apogee seeds gathered in the first and second crops in spaceflight experiment GREENHOUSE-5, the seeds were planted on their return to the laboratory. Morphometric analysis showed that they were essentially similar to the controls. Hence, the space experiments in Mir greenhouse Svet performed during 1998-1999 gave proof that plants cultivated in microgravity can pass the ontogenetic cycle more than once. However, initial results of the investigations into growth and development of plants through several generations are still in-sufficient to speak of possible delayed effects of the spaceflight factors (microgravity, multicomponent radiation, harmful trace contaminants etc.).

[Development of a cultivation technology and selection of leaf vegetable cultures for space greenhouse]. / Razrabotka tekhnologii vyrashchivaniia i vybor ovoshchnykh listovykh kul'tur dlia kosmicheskikh oranzherei.

We plan to perform space experiments on development of a technology for cultivation of leaf vegetables that might be a component of future life support systems for space crews. For this purpose, we are going to fly research greenhouses with the crop area from 0.03 up to 0.1 m2 inside the universal docking module of the ISS Russian segment. To prepare for future space experiments, ground investigations were made in order to compare crop capacity of various artificial soils used to grow leaf vegetables in greenhouse Svet. Useful life of root module Svet can be extended with a new technology based on resupply of fibrous substrate with nutrients. The most effective volume of soil per a plant was determined which sustains high productivity of leaf vegetables in Svet. To select leaf vegetables for in-space cultivation, we conducted investigations of productivity, morphometric and biochemical characteristics, and palatability of 18 cultures including alternative greens highly popular in Japan and China which have been earlier tested neither in laboratory nor in space within the closed eco-system projects. We would prioritize mizuna, pak choi, tatsoi, rapina or broccoli raab, and red giant mustard as objects for in-space investigations.