Phenotyping of Potato Plants Using Morphological and Physiological Tools.

Potato (Solanum tuberosum L.) is one of the main non-grain agricultural crops and one of the main sources of food for humanity. Currently, growing potatoes requires new approaches and methods for cultivation and breeding. Phenotyping is one of the important tools for assessing the characteristics of a potato variety. In this work, 29 potato varieties of different ripeness groups were studied. Linear leaf dimensions, leaf mass area, number of stems, number of tubers per plant, average tuber weight, signs of virus infection, dry weight, pigment content, and number of stomata per unit leaf area were used as phenotyping tools. The strongest positive relationship was found between yield and bush area in the stage of full shoots (R = 0.77, p = 0.001), linear dimensions of a complex leaf (R = 0.44, p = 0.002; R = 0.40, p = 0.003), number of stems (R = 0.36, p = 0.05), and resistance to viruses X (R = 0.42, p = 0.03) and S (R = 0.43, p = 0.02). An inverse relationship was found between growth dynamics and yield (R = -0.29, p = 0.05). Thus, the use of morphological and physiological phenotyping tools in the field is informative for predicting key agricultural characteristics such as yield and/or stress resistance.

Detergent-Resistant Membranes in Chloroplasts and Mitochondria of the Halophyte Salicornia perennans under Salt Stress.

Halophytes represent important models for studying the key mechanisms of salt tolerance. One approach to the development of new knowledge of salt tolerance is to study the properties of detergent-resistant membranes (DRMs). In this work, the lipid profiles of DRMs of chloroplasts and mitochondria of euhalophyte Salicornia perennans Willd, before and after their exposure to shock concentrations of NaCl, have been investigated. We found that DRMs of chloroplasts are enriched in cerebrosides (CERs) and that sterols (STs) dominate the mass of mitochondrial DRMs. Also, it has been proven that (i) the impact of salinity provokes obvious growth in the content of CERs in DRMs of chloroplasts; (ii) the content of STs in DRMs of chloroplasts does not change under the influence of NaCl; (iii) salinity also causes some elevation in the content of monounsaturated and saturated fatty acids (FAs). Considering the fact that DRMs represent integral parts of both chloroplast and mitochondrial membranes, the authors have come to the conclusion that the cells of euhalophyte S. perennans, under the impact of salinity, presumes the choice (by the cell) of some specific composition of lipids and FAs in the membrane. This may be considered as a specific protection reaction of the plant cell against salinity.

Effect of Salinity on Leaf Functional Traits and Chloroplast Lipids Composition in Two C3 and C4 Chenopodiaceae Halophytes.

Salt stress is one of the most common abiotic kinds of stress. Understanding the key mechanisms of salt tolerance in plants involves the study of halophytes. The effect of salinity was studied in two halophytic annuals of Chenopodiaceae Salicornia perennans Willd. and Climacoptera crassa (Bied.) Botsch. These species are plants with C3 and C4-metabolism, respectively. We performed a comprehensive analysis of the photosynthetic apparatus of these halophyte species at different levels of integration. The C3 species S. perennans showed larger variation in leaf functional traits-both at the level of cell morphology and membrane system (chloroplast envelope and thylakoid). S. perennans also had larger photosynthetic cells, by 10-15 times, and more effective mechanisms of osmoregulation and protecting cells against the toxic effect of Na+. Salinity caused changes in photosynthetic tissues of C. crassa such as an increase of the mesophyll cell surface, the expansion of the interface area between mesophyll and bundle sheath cells, and an increase of the volume of the latter. These functional changes compensated for scarce CO2 supply when salinity increased. Overall, we concluded that these C3 and C4 Chenopodiaceae species demonstrated different responses to salinity, both at the cellular and subcellular levels.

Balance of Δ5-and Δ7-sterols and stanols in halophytes in connection with salinity tolerance.

Sterols (STs) have a key role in regulating the fluidity and permeability of membranes in plants (phytosterols) that have wide structural diversity. We studied the effect of structural STs diversity on salt tolerance in halophytes. Specifically, we used gas chromatography-mass spectrometry (GC-MS), including two-dimensional gas chromatography-mass spectrometry (GCxGC-MS), to assess the STs composition in leaves of 21 species of wild-growing halophytes from four families (Asteraceae, Chenopodiaceae, Plumbaginaceae, Tamaricaceae) and three ecological groups (Euhalophytes (Eu), recretophytes (Re), salt excluders (Ex)). Fifteen molecular species of STs from three main groups, Δ5-, Δ7-and Δ0- STs (stanols), were detected. Plants of the genus Artemisia were characterized by a high content of stigmasterol (30-49% of the total STs), while ß-sitosterol was the major compound in two Limonium spp., where it comprised 84-92% of the total STs. Species of Chenopodiaceae were able to accumulate both Δ5-and Δ7-STs and stanols. The content of the predominant Δ5-STs decreased in the order Ex → Re → Eu. Molecular species with a saturated steroid nucleus were identified in Eu and Re, suggesting their special salt-accumulating and salt-releasing functions. The structural analogues of stigmasterol, having a double bond C-22, were stigmasta-7,22-dien-3ß-ol (spinasterol) and stigmast-22-en-3ß-ol (Δ7--sitosterol). The ratio of Δ5-stigmasterol/Δ5-ß-sitosterol increased in Ex plants, and spinasterol/Δ7--sitosterol and 22-stigmastenol/sitostanol increased in Eu plants. These data support the well-known role of stigmasterol and its isomers in plant responses to abiotic and biotic factors. The variability in STs types and their ratios suggested some involvement of the sterol membrane components in plant adaptation to growth conditions. The balance of Δ5-, Δ7-and stanols, as well as the accumulation of molecular analogues of stigmasterol, was suggested to be associated with salt tolerance of the plant species in this investigation.

Effect of NaCl, copper and cadmium ions on halophytes with different types of salt resistance: accumulation, physiological and biochemical reactions.

The capacities of the euhalophyte SaLi-Cornia perennans Willd. and glycohalophyte Artemisia santonica L. to accumulate NaCl, Cu, and Cd, as well as their physiological and biochemical responses to these compounds, was investigated. Seeds were germinated in distilled water for 1-3 days and then sown in containers with sand. Plants were watered with Robinson's nutrient solution. After 3 months, plants were divided into two groups: experimental and control. In the experimental group, soil was treated with 1M NaCl, 10 mM Cu(NO3)2, and 10 mM Cd(NO3)2 for 24 h. The exposure to high concentration of NaCl in the experiment did not affect the baseline level of Na, which was twice as high in S. perennans as in A. santonica. Plant exposure to Cu and Cd caused their accumulation in the aboveground parts of both species. The accumulation capacity of the euhalophyte was many times higher than that of the glycohalophyte. We analysed functional parameters of leaves by measuring photosynthetic pigments, structural parameters of membranes by assessing the lipid profile, and the balance of pro/antioxidant processes. Using data on changes in several biochemical parameters, the sensitivity of the two different halophytes to metal ions was as follows: for S. perennans - Cu > Na > Cd; for A. santonica - Na > Cu > Cd. Our findings suggest that S. perennans can be used for heavy metal extraction from soil in phytoremediation, whereas A. santonica will be more effective for greening of polluted territories.

Detergent-resistant microdomains (lipid rafts) in endomembranes of the wild halophytes.

In the present work, we studied detergent-resistant membrane microdomains (DRM) of chloroplasts and mitochondria - organelles that provide photosynthesis and respiration in a plant cell. The objects of the study were euhalophyte Salicorniaperennans Willd., which relates to salt-accumulating plants and glycohalophyte Artemisia santonica L., which relates to salt-excluder plants. To get DRM, the chloroplast and mitochondria fractions were solubilised with a solution containing Triton X-100. The resulting material was introduced in sucrose gradient of 35-25-15-5% and centrifuged at 200000 g, 2 h. The presence of an opalescent detergent-resistant zone of membranes in 15% sucrose layer and a specific lipid composition of this zone were the signs of successful rafts obtaining of. The isolated DRM are sterol- and cerebroside-enriched (27-89% of the sum of membrane lipids) domains with a high degree of saturation of fatty acids composition (more than 50% of the sum). The main DRM-specific lipids of chloroplast of A. santonica glycohalophyte are cerebrosides, whereas those of S. perennans euhalophyte are sterols. The revealed differences in the composition of raft-forming lipids in chloroplast and mitochondria halophyte membranes, differing in the salt-resistance strategy, suggest the participation of rafts in salt-resistance mechanisms.

Structural and molecular strategy of photosynthetic apparatus organisation of wild flora halophytes.

Structural and molecular parameters of photosynthetic apparatus in plants with different strategies for the accumulation of salts were investigated. CO2 gas exchange rate, content of pigments, mesostructure, chloroplast ultrastructure and the biochemical composition of the membrane structural components in leaves were measured. The objects of the study were euhalophytes (Salicornia perennans, Suaeda salsa, Halocnemum strobilaceum), crynohalophyte (Limonium gmelinii), glycohalophyte (Artemisia santonica). Euhalophytes S. perennans and S. salsa belong to the plants of the halosucculent type, three other species represent the xerophilic type. The highest photosynthetic activity estimated by the average parameters of CO2 gas exchange rate in the leaves was observed in S. perennans plants. Plants of the xerophyte type including both H. strobilaceum euhalophyte and cryno- and glycohalophytes are described by lower values of these characteristics. Larger cells with a great number of chloroplasts and a high content of membrane glycerolipids and unsaturated C18:3 fatty acid, but with smaller pigment and light-harvesting complexes size characterise the features of euhalophytes with a succulent leaf type. Thus, features of the mesostructure, ultrastructure, and supramolecular interactions of the halophyte PA were closely related to the functional parameters of gas exchange, and were characterised by the strategy of species in relation to the accumulation of salts, the life form of plants, and the attitude to the method of water regulation.

Photosynthetic parameters and redox homeostasis of Artemisia santonica L. under conditions of Elton region.

Structural and functional parameters and redox homeostasis in leaves of Artemisia santonica L. under environment conditions of Elton lake (the southeast region of the European part of Russia) were measured. The highest photosynthetic apparatus (PA) activity in A. santonica leaves on CO2 gas exchange as well as the highest content of green pigments was observed in the morning. Maximum share of violaxanthin cycle key pigments - zeaxanthin (Zx) and antheraxanthin (Ax) was observed in the afternoon and decreased in the evening. Lipids/chlorophyll (Chl) ratio increased in the evening due to the decrease in Chl concentration, and content of linolenic acid (С18:3n3) was decreased in the middle of the day. The content of TBA-reacting products increased 1.4-fold in the middle of the day, and decreased approximately 2-fold in the evening. The decrease of the activity was observed in diurnal dynamics of superoxide dismutase (SOD) and polyphenol oxidase (PPO). Increased accumulation of phenols and flavonoids, as well as free amino acids (FAA) in A. santonica leaves was observed in the middle of the day. Thus, the ability of A. santonica plants to resist the soil salinization, high levels of solar illumination and temperature consists of a number of protectively-adaptive reactions of metabolic and photosynthetic control.

Seasonal dynamic of morpho-physiological properties and the lipid composition of Plantago media (Plantaginaceae) in the Middle Volga region.

The changes in morpho-physiological properties and lipid composition have been studied in the leaves of the plant Plantago media collected from two different places in the Middle Volga region during the summer of 2010. The plants gathered from the first plot (P1 plants) grew on plain ground in the midst of typical meadow-steppe perennial plants. The plants of the second group (P2 plants) grew on a flat slope of the South-West exposition, in the grass community. The leaves of the plants Р1 had lower specific area densities but larger areas and masses; they accumulated more levels lipid peroxide products. The changes in lipid compositions depended on the growth phase and habitats. Correlations between morpho-physiological parameters and certain lipids have been established. The amounts of galactolipids (GL) have been shown to correlate with the leaf areas. When the leaf areas were reduced, a ratio between phosphatidylcholines (PC) and phosphatidylethanolamines (PE) decreased. The result of our study showed that gradual changes of morphometrical parameters were accompanied by the alterations in biomass structure and modifications in lipids and fatty acids (FA).

Membrane-forming lipids of wild halophytes growing under the conditions of Prieltonie of South Russia.

The composition of membrane-forming lipids has been examined for 10 wild halophyte species growing in southern Russian on alkaline soil. The plants belong to seven taxa of family rank: by their life form, which are semi-shrubs, herbaceous annuals, and perennial plants; their salt tolerance, which are classified as the euhalophytes, crynohalophytes, and glycohalophytes; and by their sensitivity to water, classifications of mesoxerophytes and xeromesophytes. Parallels have been found between the lipid composition and the ecological status of the plants. It has also been revealed that the similarity in the glyco- and phospholipid composition of different plant groups relates to the water factor and the type of salt accumulation, respectively. The fatty acid compositions of the examined plants is determined at the species level.

The effect of copper ions on the lipid composition of subcellular membranes in Hydrilla verticillata.

The paper studies changes in the content and composition of lipids in the membranes of chloroplasts, mitochondria and microsomes of the aquatic plant Hydrilla verticillata exposed to copper ions (100 µM; 1, 3, 6 and 24 h). The rate of copper accumulation and the coefficient of its extraction by the plant were also determined. The presence of copper in the incubation medium and its accumulation in the plant tissues decreased the content of photosynthetic pigments, stimulated lipid peroxidation and enhanced membrane permeability. The gradual accumulation of copper in the plant tissues was accompanied by specific changes in the composition of lipids: the content of sulfolipids (SQDG) in chloroplasts declined; the content of monogalactosyl diacylglycerols (MGDG), digalactosyl diacylglycerols (DGDG) and phosphatidyl glycerols (PG) in chloroplasts and mitochondria grew after an hour of copper exposure; and the content of all the lipids except phosphatidic acids (PA) decreased after 3 h of exposure. The decline in the content of phosphatidyl cholines (PC) was first observed in the membranes of microsomes (after an hour of exposure) and later in the membranes of chloroplasts and mitochondria (after 3-6 h of exposure). The experiments with incorporation of [2-(14)C]sodium acetate into fatty acids of polar lipids showed that in parallel with lipid destruction, there took place an intensive and specific renewal of the lipid pool of subcellular membrane fractions.