Fr Wt Research Articles

Influence of 5-aminolevulinic acid on physiological and biochemical characteristics of winter wheat varieties with different levels of anthocyanins in coleoptiles

Physiological and biochemical characteristics of two varieties of winter wheat seedlings with red (Et W5) and green (Vladi) coleoptiles have been studied. Variety Et W5 with high content of anthocyanins (on average 412 ± 52 μmol/g fr wt), chlorophylls (Chl) and carotenoids and a low level of heme and proline in coleoptiles had high frost resistance (88 % of surviving plants exposed to temperatures of ‒8 °C for 5 h at the age of 7 days) and a high ability to continue growth and development after undergoing cooling. Variety Vladi with a low content of anthocyanins (on average 12.5 ± 1.2 μmol/g fr wt), Chl and carotenoids, but a higher level of heme and proline in coleoptiles compared to varieties Et W5 had low level of frost resistance (80 % of surviving plants) and was characterized by a low ability to continue growth and development after undergoing cooling. Soaking wheat seeds in a solution of exogenous ALA (50 mg/l) for 2 h before sowing increased the germination of seeds of both varieties, enhanced the length of plants of the Et W5 variety by 10 %, 1.4 times the content of anthocyanins in the coleoptiles of this variety plants and also increased their frost resistance up to 97 %. Under action of ALA frost resistance of Vladi seedlings increased up to 93 %.

Initial comparison between monoline and tube net method of farming in red agarophyte Gracilaria dura: Evidence from hydrodynamic CFD simulations

Seaweed cultivation is fast emerging as the preferred supplementary livelihood opportunity that can consistently fetch revenue to the coastal rural fishermen. The proportion of farmed biomass has been continuously on rise each year and currently stands at 32.4 million tons. The diversification and technological innervations are needed to improve the prospects of regional species, which cater to the domestic market. We herein reported the initial comparison between monoline and tube net method of farming in agarophyte Gracilaria dura conducted for seven crop cycles. The average DGR ranged from 3.11 ± 0.85 to 5.26 ± 1.41% day−1 and 2.01 ± 0.69 to 2.61 ± 0.74% day−1 for monoline and tube net method respectively. The yield fluctuated between 6.64 ± 1.56 kg fr wt m−1 cycle −1 to 20.43 ± 12.12 kg fr wt m−1 cycel−1 and 22.23 ± 7.08 m−1 cycle−1 to 33.21 ± 7.65 kg fr wt m−1 cycle−1 for monoline and tube net method respectively. The fold increase in biomass growth registered from 4.47 ± 1.04 to 13.80 ± 8.09 in for monoline method and 2.44 ± 0.69 to 3.40 ± 1.51 for tube net method. CFD model was developed that allowed us to predict the velocity distribution associated with the flow of nutrients under two contrasting farming systems. CFD simulations confirmed good availability nutrients under monoline mode that led to higher growth. The both farming techniques were found to be successful and needs to be adopted in alternative matter to derive benefits gainfully for commercial operations. The sufficient production of farmed biomass would supply the adequate feed-stock for industrial processing of agarose on one hand and reduce the un-abated exploitation of natural resource on other hand.

Photoregulation of the Cytoplasmic PGA Dehydrogenase Complex in Wheat Leaves

Experiments were performed with 10-day-old seedlings of wheat (Triticum aestivum L.) grown on sand saturated with Knop’s solution at a temperature of 22/18°С by natural light (16 h, 200 µmole quanta/(m2 s). Phytochrome was activated by means of an array of light diodes emitting light in the red spectral region (RL, λ = 656 nm, λ1/2 = 26 nm), inactivation was induced with an array of light diodes emitting far red light (FRL, λ = 737 nm, λ1/2 = 30 nm). At the end of the night period (8 h), activity of the NAD-dependent PGA-dehydrogenase complex (3-phosphoglycerate: ATP phosphotransferase and D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase) in the direction of 3-PGA → 1,3-BPG → G3P was 6.0–7.0 µmoles of oxidized NADH/(min g fr wt). At the highest dose of RL radiation (20 min, 17.6 kJ/m2) incident on intact plant leaves, enzyme activity decreased by 35–40%. Longer exposure to RL (30 and 40 min) did not cause additional changes in enzyme activity. When exposure to RL was followed by FRL (20 min, 3.00 kJ/m2), the inactivating effect of RL on the enzyme complex was negated. It was shown that 5-min-long exposure to RL already caused a decrease in the rate of NADH oxidation by 10–15%, and enzyme activity decreased linearly when the dose rose. When plants exposed to RL were accommodated in the dark for up to 120 min, the half-life of the RL-inactivated state of the NAD-PGA dehydrogenase complex was 30–45 min. Thus, a dynamic regulation of the energy-transforming phase of glycolysis in wheat leaves mediated by the phytochrome system was shown and investigated. Such a photocompetent low-energy system can operate as a regulator of total oxidative processes (glycolysis + the Krebs cycle) in the course of daily transition from dark to light and back.

Accumulation of Biomass and Phenolic Compounds by Calluses Oxycoccus palustris Pers. and O. macrocarpus (Ait.) Pers. in the Presence of Different Cytokinins

The purpose of the present work was to compare calluses of European cranberry (Oxycoccus pal-ustris Pers.) and American cranberry (O. macrocarpus (Ait.) Pers.) by their ability to accumulate biomass and phenolic compounds in the presence of different cytokinins in nutrient medium. In European cranberry, callusogenesis appeared to be more intensive upon the addition of kinetin (Kin) to the medium, while accumulation of phenolic compounds and biomass was most pronounced on the medium with isopentenyladenine (iP). In American cranberry, callusogenesis appeared to be more intensive upon the addition of iP to the medium and in respect to accumulation of biomass and phenolic compounds (in the onset of the cultivation), somewhat higher values were obtained upon addition of benzylaminopurin (BAP). Maximum of phenolic compounds accumulation was observed upon the transition of callus cultures to the stationary growth phase, during the fifth week of the passage on average, except on the medium with BAP. The content of soluble phenolic compounds in European cranberry calluses did not exceed 11 mg/g fr wt, while that in American cranberry calluses did not exceed 17 mg/g fr wt. Cranberry callus cultures under long-term cultivation displayed a decrease in the level of all groups of phenolic compounds, including flavonoids to a higher extent. For European cranberry calluses after 6–10 passages, stabilization of the secondary synthesis was noted, first of all on the medium with iP. In general, more stable accumulation of phenolic compounds in calluses of both cranberry species was observed in the presence of Kin.

Estimation of operational cost, evaluation and comparing the performance of four different paddy threshers

Litchi is one of the fascinating fruit crops due to its high demand and export potentiality. Enhancing its productivity is one of the great achievements. Increasing photosynthetic activity through exploiting photosynthetic components are major target. The carotenoid and chlorophyll content are considered to be one of the major indicative of the physiology and phenology of plants. Therefore the present work has been shaped to analysed photosynthetic activity at chlorophyll level at initial stage of flush emergence. Five varieties like Purbi, Bedana, Shahi, China and Dehrarose have been taken as study materials for quantification of chlorophyll content in leaves of three different flush. Chlorophyll is directly related with photosynthetic efficiency of plants and it makes an indirect estimation of possible nutrient status in crop plants. Data were analysed and result revealed variation in chlorophyll content and carotenoids among the varieties and also in different flushes. Bedana showed highest in chlorophyll‘a’ (1.01 mg g-1 fr wt), b (0.59 mg g-1 fr wt) and total chlorophyll (1.8 mg g-1 fr wt) as compared to rest of the variety studied whereby China showed lowest. Second, highest chlorophyll ‘a’content was noticed in Dehrarose, Chlorophyll ‘b’ was highest in Bedana. In early variety like Shahi the chlorophyll content showed maximum in the first flush than from the second and third flush. However, in the mid variety like purbi and Bedana chlorophyll content showed maximum in third and first flush as compared to all three flush as well as in late variety like China and Dehrarose chlorophyll content showed maximum in second flush as compared to first and third flush. Carotenoid content was also measured maximum in Bedana (0.12 mg g-1 fr wt) followed by Shahi (0.11 mg g-1 fr wt), Dehrarose (0.087 mg g-1 fr wt), Purbi (0.079 mg g-1 fr wt) and China (0.056mg g-1 fr wt).

Phytochrome B-dependent regulation of reductive phase of photosynthetic carbon assimilation

The experiments were conducted with 10-day-old seedlings of wheat (Triticum aestivum L). Phytochrome B was activated using an array of light diodes emitting light in the red spectral region (RL) and inactivated by an array of light diodes emitting far-red light (FRL). At the end of the night dark period (8 h), activity of the chloroplastic GAP-dehydrogenase complex (the sequence of reactions: 3-PGA → 1,3-PGA → 3-GAP) was 1.0−1.2 μmol of oxidized NADPH/(min g fr wt of the leaf). When the leaves of intact plants were exposed to a maximal dose of RL (20 min at 17.5 kJ/m2), enzyme activity rose by 100–120%. Longer exposure to RL (30 and 40 min) did not cause further activation. Successive exposure to RL and FRL (20 min at 3.0 kJ/m2) completely negated a stimulatory effect of RL. It was shown that as little as 5-min-long exposure to RL increased the rate of 3-GAP formation by 20–25%, and enzyme activity rose linearly when radiation dose was elevated. Determination of the lifetime of RL-activated state by its decrease in plants placed in darkness showed that decay occurred with τ1/2 of 50−60 min when RL was switched off. Thus, a phytochrome B-induced regulation of reducing enzyme complex governing the reductive pentose phosphate cycle was discovered. Judging from the kinetics of attenuation of the activated state, phytochrome B apparently does not affect de novo synthesis of the enzyme. Since the investigated metabolic process consists of two coupled reactions controlled by kinase and dehydrogenase, the place and mechanism of action of the phytochrome system remain unknown.

Physiological and proteomic response of Limonium bicolor to salinity

Medicinal halophyte Limonium bicolor (Bag.) Kuntze was treated with 200 mM NaCl, the physiological parameters including fresh weight, dry weight, salt gland number, MDA levels and root activity were investigated, comparative proteomic analyses of leaf and root were carried out using 2D-PAGE combined with MALDI-TOF/TOF-MS. The results showed that L. bicolor performed a positive effect on its growth under NaCl stress since increase in different extent of fr wt, dry wt, salt gland number, MDA level and SOD activity of leaves and roots, as well as root activity. More than 460 protein spots in leaves and 600 protein spots in roots were visualized and matched in 2D gels, the results of proteomic analyses showed that 45 proteins were identified in leaves and 49 proteins in roots to be differentially expressed. Based on their functions, these proteins were grouped into categories covering a wide range of molecular processes, including carbohydrate, energy, lipid, nucleotide and amino acid metabolism, glycan biosynthesis and metabolism, metabolism of cofactors and vitamins, biosynthesis of secondary metabolites, redox homeostasis, transcription, cytoskeleton and transport, as well as folding, sorting and degradation. The upregulating and downregulating of differentially- expressed proteins with different physiological function were also reflected in the physiological parameters. These results are helpful for further research work on salt response mechanisms and medicinal utilization of L. bicolor.

Tube-net farming and device for efficient tissue segregation for industrially important agarophyte Gracilaria edulis (Rhodophyta)

According to the Food and Agricultural Organisation of United Nations seaweeds are being increasingly farmed rather than gathered. It is evident that, seaweed mariculture holds considerable promise for diversifying the livelihood of low-income, artisanal fishermen. Nevertheless, increased labour constraints have been realised as a bottleneck for the sustainability of farming in developing countries, where spending on infrastructure cost is meager. We herein report a tube-net farming for industrially important red alga Gracilaria edulis and also a new design for a harvester. The average biomass yield reported for the tube-net method over a 45day growth cycle was 11.93±2.55kg fr wt raft−1; while the average daily growth rate was 3.40±0.57% day−1. Harvesting is a critical step which determines the quality of a product. However, traditional methods do not allow segregation of product-rich (SAP and hydrocolloid) older thallus, from the growing apical tips. A two stage harvesting operation successfully achieved segregation of 33.87–55.56% of the clean apical biomass and 35.95–65.02% of the basal portion of the alga, leaving behind an empty tube for re-stocking. The tube-net farming method, coupled with an improved harvesting efficiency was aimed at developing appropriate management strategies for commercial farming of seaweeds.

No effect of plant growth retarding compounds and growth stimulators on indolo-3-acetic acid oxidase activity in greening cucumber cotyledons

Cotyledons dissected from 5-day-old etiolated cucumber seedlings were incubated in solutions on AMO-1618, B-Nine, CCC and Phosfon D for 48 h in light. In some tests the retardants were applied in mixed solutions with GA<sub>3</sub> or BAP. IAA oxidase was extracted and purified by means of molecular sieving through a bed of Sephadex G-25. The retardants inhibited chlorophyll synthesis by 50 % or more, and had essentially no effect on IAA oxidase activity per cotyledon basis. GA<sub>3</sub> and BAP also had no effect on enzyme activity in spite of a fact that the compounds stimulated growth of the cotyledons. The crude enzyme extract from B-Nine treated cotyledons showed lower IAA oxidase activity in comparison with the water treated control, the effect being due to a longer lag-phase preceding the initiation of IAA oxidation. KNO<sub>3</sub> strikingly stimulated expansional growth of the cotyledons, the effect being correlated with the accelerated chlorophyll accumulation. KNO<sub>3</sub> had no effect on IAA oxidase activity per cotyledon and decreased it per gram fr wt. It is concluded that [1] the growth rate of cucumber cotyledons is not correlated with IAA oxidase activity, and ;[2] the growth retarding compounds do not affect IAA oxidase system is this tissue.

Exogenous proline alleviates the effects of H2O2-induced oxidative stress in wild almond species

The effect of proline on the antioxidant system in the leaves of eight species of wild almond (Prunus spp.) exposed to H2O2-mediated oxidative stress was studied. The levels of endogenous proline (Pro) and hydrogen peroxide, and the activities of total superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), and guaiacol peroxidase (POD) were measured. The degradation of chlorophyll but not carotenoids occurred in leaves in the solution of 5 mM H2O2. An increase in membrane lipid peroxidation was observed in H2O2 treatment, as assessed by MDA level and percentage of membrane electrolyte leakage (EL). Significant increases in total SOD and CAT activities, as well as decreases in APX and POD activities, were detected in H2O2-treated leaves. The three SOD isoforms showed different behavior, as Mn-SOD activity was enhanced by H2O2, whereas Fe-SOD and Cu/Zn-SOD activities were inhibited. In addition, Pro accumulation up to 0.1 μmol/g fr wt, accompanied by significant decreases in ascorbate and glutathione levels, was observed in H2O2-treated leaves. After two different treatments with 10 mM Pro + 5 mM H2O2, total SOD and CAT activities were similar to the levels in control plants, while POD and APX activities were higher if compared to the leaves exposed only to H2O2. Pro + H2O2 treatments also caused a strong reduction in the cellular H2O2 and MDA contents and EL. The results showed that Pro could have a key role in protecting against oxidative stress injury of wild almond species by decreasing membrane oxidative damage.

Development of Tolerance of Egg Plant (Solanum melangena L.) to Field Application of Dimethoate

Dimethoate, at field concentration (1.419 mg g(-1) fr wt), caused inhibition of photosynthesis, transpiration and stomatal conductance of Solanum melangena L. on first treatment but subsequent treatments caused adaptation and recovery of these parameters. The variable fluorescence (F(v)), dissipation (DI(0)/RC), 2 ms relative variable fluorescence (V(j)), net rate of PS II closure (M(0)), and maximum trapping rate of active PS II (TR(0)/RC) increased initially but reduced to the control value with repetition of treatment. However, fluorescence yield (TR(0)/Abs), electron transport probability (ET(0)/TR(0)) and activity of RC (ET(0)/RC) increased with each treatment. With each subsequent treatment there was enhancement of activities of esterases and decrease of insecticide content of leaves.

Proline controls the level of polyamines in common sage plants under normal conditions and at UV-B irradiation

Common sage (Salvia officinalis L.) plants grown in water culture to the stage of 4–5 true leaves were treated for 12, 24, 36, or 48 h with proline added to nutrient medium to a final concentration of 5 mM, or irradiated with UV-B light (12.3 kJ/m2 for 10 min), or subjected to combined action of these factors. In these plants, activity of proline dehydrogenase (PDH), the content of proline, and the contents of free and conjugated polyamines were determined in the leaves and roots. It was shown that, in control plants, the content of endogenous proline was close to zero. In the presence of proline in medium, its total content in the roots was 9 μmol/g fr wt in 12 h of exposure, whereas in the leaves the content of proline increased only in 24 h and achieved only 1 μmol/g fr wt. The content of free putrescine increased in the leaves and especially in the roots after 10-min irradiation with UV-B light. The biosynthesis of putrescine was induced in the presence of proline in medium and was observed earlier than after UV-B irradiation. UV-B irradiation affected not only the synthesis of putrescine but also that of spermidine and spermine; it also induced accumulation of their soluble conjugates. Exogenous proline enhanced putrescine synthesis but inhibited the formation of polyamine soluble conjugates. At combined treatment of the two factors, the content of free putrescine in the leaves displayed a tendency to the rise and in the roots, to the decrease. At the same time, the content of polyamine free conjugates increased in both leaves and roots. All these facts could be considered as an indirect indication of relationship between proline and polyamine biosyntheses. We can also state that an artificially created high proline concentration in common sage tissues characterized of its low constitutive level resulted in disturbances in the homeostasis of low-molecular cell metabolites and induced a requirement in its restoration by diverse ways. This agrees with activation of PDH, a key enzyme of proline degradation. Induction of polyamine biosynthesis and changes in the content of their soluble conjugates might be one of the ways for such restoration. Under stress conditions, the high proline concentration is not toxic for plants because polyamines and proline are the components of the plant defense system, thus weakening damaging effects of abiotic stressors.

Age-dependent changes in the content of lipids, fatty acids, and pigments in brown alga Costaria costata

The contents of lipids and pigments were compared in juvenile and adult algae Costaria costata [Turn.] Saund (Laminariaceae) collected in April. The total content of lipids and that of particular lipid classes increased markedly with age. In adult algae, the contents of total lipids, glyceroglycolipids, and neutral lipids doubled as compared with juvenile algae and was equal to 5.70, 1.78, and 0.81 mg/g fr wt, respectively. The content of free sterols increased with age by three times; it was equal to 0.11 mg/g fr wt in juvenile algae and 0.38 mg/g fr wt in adult algae. Total content of phospholipids changed with age to a lesser extent: 0.72 mg/g fr wt in juvenile vs. 0.92 mg/g fr wt in adult algae. Substantial changes were observed in the content of particular polar lipids. The absolute amounts of monogalactosyldiacylglycerols, sulfoquinovosyldiacylglycerols, digalactosyldiacylglycerols, phosphatidylcholines, phosphatidylglycerols, and phosphatidylinosites increased markedly with age, whereas the amount of phosphatidyl-O[N-(2-hydroxyethyl)glycines] declined. The amount of phosphatidylethanolamines did not depend on algal age. A small amount of diphosphatidylglycerols was detected only in juvenile algae. The content of photosynthetic pigments (carotenoids and chlorophylls) approximately doubled with age and, in adult algae, was equal to 0.57 and 1.23 mg/g fr wt, respectively. Total lipids of juvenile and adult algae did not differ in fatty acid composition. At all developmental stages, polyunsaturated fatty acids predominated early in spring and comprised about 80% of fatty acids. The acids of ω-3-series predominated among them.

고구마 품종별 수확시기 잎의 저분자항산화물질 함량분석

Sweetpotato [Ipomoea batatas (L.) Lam] leaves are excellent source of low molecular weight antioxidants such as polyphenols, anthocyanins and carotenoids compared to other leafy vegetables. Endogenous antioxidants in sweetpotato help our bodies to prevent ageing, heart diseases and cancer. In this study, to develop the proper cultivars for the functional feed materials, we investigated the contents of anthocyanin, <TEX>$\beta$</TEX>-carotene, and polyphenols as well as DPPH radical scavenging activity in leaves of 14 different cultivars at the time of the harvest. They showed a diverse antioxidation activity. In DPPH radical scavenging activity, cultivars of Nanjing 9, Yulmi and Shinzami showed higher activity, whereas cv. Huiza 6 showed the lowest. Cultivars of Shinzami and Shinhwangmi had the highest anthocyanin (3.5 mg/g fr wt) and polyphenol (15.8 mg/g fr wt) content, respectively. Interestingly, there was a high correlation between cultivars with colorful pigments in storage roots and antioxidants activity in leaves. These results suggest that sweetpotato leaves with high antioxidant activity at harvest would be suitable for functional feed materials.

Analysis of salicylic acid in willow barks and branches by an electrochemical method

An electrochemical method for measuring free salicylic acid (SA) was optimized and used to detect its content in barks and branches of thirteen Salix species. We utilized square wave voltammetry method in com- bination with pencil lead, the detection limit of which was 1.7 ng/ml of salicylic acid. The highest contents of free SA were observed in the bark of S. laponum (3.0 mg/g fr wt) and in the branches of S. purpurea , cv. Nana (2.1 mg/g fr wt) and S. planifolia (2.2 mg/g fr wt). The technique utilized for determination of SA in willow tissues has a much broader dynamic range and lower limit of detection in comparison to both linear sweep and cyclic voltammetry because of its efficient discrimination of capacitance current.

Auxin and flavonoids in the progame phase of fertilization in petunia

The contents of IAA and flavonoids (Fls) were monitored in developing anthers, in vitro growing pollen tubes, and in the in vivo pollen-pistil system of two petunia (Petunia hybrida L.) clones, self-compatible and self-incompatible. In both clones, the development of male gametophytes was accompanied by the increase in the IAA (from 10 to 60–70 ng/g fr wt) and Fls (from 2 to 20 mg/g fr wt) contents. In both clones, pollen grain germination was accompanied by a substantial (by 10–30%) increase in the IAA content during the first two hours and Fl content during the first hour. Treatments with IAA and Fls stimulated both in vitro pollen grain germination and pollen tube growth by 25–30%. Male gametophyte germination in vivo, on the pistil surface, was accompanied by the increase in the IAA content from 90 to 200 ng/g fr wt during 8 h, whereas the content of Fl increased from 2 to 3 mg/g fr wt during the first hour and was maintained later at this level. In the pollen-pistil system, IAA and Fls were distributed evenly in the tissues of stigma, style, and ovary. On the basis of data obtained, we concluded that Fls might be endogenous mediators of IAA transport, which is one of the principal regulators of male gametophyte growth and development in the progame phase of fertilization, but are not involved in the mechanism of gametophyte incompatibility.

Effect of water deficit on respiration of conducting bundles in leaf petioles of sugar beet

Isolated fibrovascular bundles from source leaf petioles of sugar beet (Beta vulgaris L.) and hog-weed (Heracleum sosnovskyi L.) were used to study the influence of long-term drought on the oxygen uptake rate and activities of mitochondrial oxidases, i.e., cytochrome oxidase and salicylhydroxamic acid-sensitive alternative oxidase (AO). Under normal soil moisture content (70% of full water-retaining capacity, WRC), the oxygen uptake by sugar beet conducting bundles was characterized by a high rate (> 700 μl O2/(g fr wt h)) and by distinct cytochrome oxidase-dependent manner of terminal oxidation (up to 80% inhibition of respiration in the presence of 0.5 mM KCN). After long-term water deficit (40% of WRC), the bundle respiration proceeded at nearly the same rate but featured an elevated resistance to cyanide. At early drought stage (10 days), a decrease in the activity of cytochrome-mediated oxidation pathway was largely counterbalanced by activation of mitochondrial AO, whereas long-term dehydration of plants was accompanied by activation of additional oxidative systems insensitive to both KCN and SHAM. Similar but even more pronounced changes in activities of terminal oxidases were discovered in conducting bundles of wild-grown hogweed plants exposed to long-term natural drought. It is supposed that the suppression of cytochrome-mediated oxidation coupled with ATP synthesis in the cells of sugar beet source leaves impedes the translocation of assimilates and their accumulation in the taproot, which represents an important factor of drastic decrease in the yield of this agricultural crop under conditions of water deficit.

Osmolyte accumulation in different rape genotypes under sodium chloride salinity

Physiological mechanisms of two rape (Brassica napus L.) genotype adaptation to chlorine salinity were investigated. The plants of two cultivars (Olga and Westar) differing in salt tolerance were grown in the pots filled with Perlite on the Hoagland and Snyder’s medium under controlled conditions. At a stage of 3–4 true leaves, the plants experienced 7-day-long salinity induced by a single addition of NaCl to the nutrient medium in order to attain desired final salt concentration (from 50 to 400 mM). The obtained results showed that a greater salt tolerance of cv. Olga plants (as compared with cv. Westar) could be accounted for by a capability of their root cells to uptake water under high salinity (300–400 mM NaCl), which is evident from a greater content of water in the tissues of cv. Olga. This was ensured by a sharp fall of the osmotic potential of the cellular contents (down to −2.3 MPa) at a low water potential of nutrient solution owing to more active uptake of Na+ (57–61 µeq/g fr wt) and K+ (210–270 µeq/g fr wt) as well as active accumulation of proline (30–50 µmol/g fr wt). The latter is caused by a reduced activity of proline dehydrogenase and retarded degradation of this osmolyte. It is important that, in contrast to less tolerant genotype, the rape plants of salt-resistant cultivar were able to maintain the K+/Na+ ratio at a rather high level at salinity of different degree, which made it possible to preserve ionic homeostasis under adverse conditions.

Antioxidant Activity and Total Phenolic Content of Kale Genotypes Grown in Kashmir Valley

Green leafy vegetable extracts of six genotypes of kale (Brassica oleracea acephala) were evaluated for ascorbic acid, carotenoids, total phenolics and antioxidant activity. Ascorbic acid ranged from 142 mg per 100 g in Wappal Hakh to 164 mg per 100 g fr wt in Knol khol. Wild genotypes Wappal and Pumb, had significantly high phenolic content (285 and 227 mg per 100 g fr wt) and possessed highest antioxidant activities (840 and 780 µmol FRAP per g fr wt) than cultivated genotypes. A positive and strong correlation (R2 = 0.807) between total phenolic content and antioxidant activity suggests that kale has enormous potential to enhance the antioxidant potential of our daily food supply. Wild genotypes, Wappal and Pumb can be incorporated into the breeding programmes in order to increase the antioxidant potential of cultivated varieties.

Structural and Functional Grounds for Ephedra sinica Expansion in Mongolian Steppe Ecosystems

Morphological and structural characteristics of photosynthetic organs, diurnal changes in photosynthetic and transpiration rates, and the efficiency of water use were studied in three plant species from mountain-steppe ecosystems in Mongolia, Ephedra sinica Stapf, Stipa glareosa P. Smirn., and Allium polyrhizum Furcz. ex Regel. The species studied differed in the structural and functional mechanisms for the adaptation of photosynthetic apparatus to arid conditions. E. sinica has thick, vertical assimilating shoots, which are characterized by a high density (620 mg/cm3) and a small proportion of photosynthetic tissues (13%). The proportion of meso-phyll in the leaves of A. polyrhizum and S. glareosa was two and three times higher, respectively. The low content of phototrophic tissues in E. sinica shoot was compensated for by a high photosynthetic activity of single chloroplasts (25 mg CO2/(109 chloroplast h)), which was six times higher, than in two other species. Daily course of photosynthesis and transpiration inE. sinica differed from those of A. polyrhizum and S. glareosa by the absence of the midday depression. E. sinica had the highest efficiency of water use (45 mg CO2/g H2O) due to a low transpiration rate (0.25 g/g fr wt h). It is concluded that, in E. sinica, the main strategy for adaptation to arid stress is to develop in the shoot a few photosynthesizing cells of high assimilation activity. Such structural organization of photosynthetic organs in ephedra contributes to its higher efficiency of water use and stability of physiological characteristics under changing environmental conditions. These specific features of the structure of assimilating organs and their functional features contribute to a greater expansion of E. sinica with increasing climate aridization in Mongolia.