Abstract
Halophytes were found to accumulate HM ions in their tissues; therefore, they are potentially useful for remediation of soil contaminated by salt or HM. In this study, we evaluated the ...effect of Cd
2+
on the characteristics of mesophyll, pigments, and lipid profile of the photosynthetic organelles of the halophyte
Suaeda salsa
. Seeds were sprouted 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 200 µM Cd(NO
3
)
2
for 24 hours. Our findings suggest that Cd
2+
causes changes in the anatomical structure of the leaf and the ultrastructure of the photosynthetic organelles in
S. salsa
due to alterations in the composition of lipids and fatty acids.
The lipid composition of detergent-resistant membranes (rafts) of mitochondria and chloroplasts from annual runners of the wild halophyte
Halocnemum strobilaceum
was studied for the first time. Raft ...structures was observed in the opalescence band obtained by centrifugation of biological material treated with Triton X-100 detergent in a sucrose gradient. Raft structures differed from chloroplast and mitochondrial membranes by high contents of sterols and cerebrosides and a high degree of unsaturation in fatty acids. In general, the lipid profiles of both membranes and raft structures in chloroplast and mitochondrial membranes had specific lipid compositions.
The complex chemical characteristics of leaves of the representative species Globularia punctata were studied. The plant leaves contained large amounts of phenolic compounds (31% of the total ...analyzed constituents) followed by water-soluble proteins, total lipids, amino acids (AAs), and water-soluble sugars. A total of 22 AAs and two amides were identified with asparagine, glutamine, and proline dominating. An analysis of the lipids showed high concentrations of mono- and digalactosyldiacylglycerols and phosphatidylcholine. The fatty acids were dominated by dienoic and trienoic acids. The main source of linolenic acid was the glycolipid fraction, especially the MGDG and DGDG classes. The phospholipid fraction was more enriched in oleic and linoleic acids. The neutral lipid fraction contained various amounts of linoleic and linolenic acids.
Effects of 1 M NaCl on the lipid profile of detergent-resistant membranes in chloroplasts and mitochondria of salt-accumulating halophyte plants of family Amaranthaceae,
Salicornia perennans
Willd. ...and
Suaeda salsa
(L.) Pall. were studied. The composition of lipids and fatty acids in detergent-resistant membranes differed from total lipids of chloroplast and mitochondrial membranes by the abundance of cerebrosides and sterols. Under the given salinity level, a manyfold increase in the relative content of cerebrosides was noted in the composition of detergent-resistant chloroplast membranes of
S. perennans
. A similar salinity-related increase in cerebroside content was detected in detergent-resistant mitochondrial membranes of
S. salsa
. The opposite effect was observed for sterols: their relative content decreased under the action of salt. The results indicate that the detergent-resistant membranes are involved in the interactions of chloroplasts and mitochondria in the cell response of halophytes to salinity.
Modern concepts on structural, physiological, and biochemical aspects of salt tolerance of higher plants were considered. Integral physiological processes, such as growth and photosynthesis of ...glycophytes and halophytes in the context of their ecological plasticity, variety of their adaptive strategies developed in the course of their evolution, and natural selection, were discussed. Analysis of the known anatomical and morphological adaptations of halophytes (succulence, special salt-excreting structures, features associated with special tissues growth, leaf kranz-anatomy and mesostructure) providing their salt tolerance was conducted. The most important physiological and biochemical adaptations of such plants to salinity related to uptake, accumulation and excretion of Na
+
and Cl
–
, peculiarities of membrane composition and the pigment system, and protection against osmotic and oxidative stresses were described. The association of physiological and biochemical peculiarities of halophytes with ecological salt tolerance strategy was discussed.
The ecological, morphological, physiological, and biochemical characteristics of representatives of the genus
Galium
(Rubiaceae) have been studied. The objects of study are the hybrid (nothospecies)
...Galium
×
affrenum
(Klokov) Ostapko (=nothospecies) and its parental species
G. ruthenicum
Willd., and
G. octonarium
(Klokov) Pobed. s. l.
G.
×
affrenum
is habitually closer to
G. ruthenicum;
however, it differs from the latter in pale lemon flowers. Based on the method of artificial neural networks, it is shown that the nothospecies is closer to the parental species
G. octonarium
with respect to physiological and biochemical features. The leaf biomass of
G.
×
affrenum
is characterized by an increased content of photosynthetic pigments and a greater variability in the concentration of photosynthetic pigments and lipid metabolism, which may be key to its greater stability and viability.
Interrelation between the morphology, physiology, biochemistry, and productivity of potato plants was shown for the first time using the example of a mid-season-ripening variety (v.) Siversky and a ...mid-early Tretyakovka v. The yield of Siversky v. turned out to be 1.6 times higher than the yield of Tretyakovka. Aboveground biomass of Siversky v. was distinguished by an increased content of photosynthetic pigments, a greater variability of the protein and lipid metabolism indicators, and more intense oxidation processes and antioxidant protection, which can be the key to its greater productivity. Multivariate statistical analysis showed that the greatest relationship in the climatic conditions of central Russia in 2020 was found for productivity and such indicators as the stomata number per unit leaf area, the number of stems, and the content of pigments, phospholipids, neutral lipids, and water-soluble part of the protein. Thus, both morphological and physiological–biochemical properties can influence the course and direction of the production process, and, hence, the yield of a certain variety.
The mesophyll structure and the lipid profile of membranes were examined in leaves of four Chenopodiaceae halophytes with different types of photosynthesis. The analyzed plants represented the annual ...species with photosynthesis of C
3
type (
Salicornia perennans
),C
3
–C
4
intermediate type (
Sedobassia sedoides
), and C
4
-NAD type (
Climacoptera crassa
) as well as a perennial half-shrub
Kochia prostrate
with photosynthesis of C
4
-NADP type; the chosen species inhabited biotopes with various salinity and soil moisture content. The annual species with succulent leaves accumulated 7–15 times larger amounts of Na
+
than the perennial half-shrub. A strong positive correlation was found between the leaf thickness and leaf water content (
r
= 0.98,
P
= 0.04) and the total amount of elements accumulated in leaves (
r
= 0.96,
P
= 0.04). Mesophyll cells of the C
3
species
S. perennans
were substantially larger than the mesophyll and bundle sheath cells of the C
4
species; the number of chloroplasts per cell in the C
3
species was 1.5–3.5 times higher than in the C
4
species. The species with Kranz anatomy differed between one another in terms of the size and the relative number of bundle sheath and mesophyll cells. The total surface area of chloroplasts per unit leaf area in plants with Kranz anatomy was higher in mesophyll cells than in the bundle sheath cells. The assimilating surface areas of mesophyll and chloroplasts in plants with the C
3
and C
3
–C
4
types of photosynthesis were similar, as was that in species with C
4
-NAD and C
4
-NADP types of photosynthesis. The total number of cells and the number of chloroplasts in mesophyll cells correlated positively with the content of total lipids per unit leaf area (
r
= 0.95,
P
= 0.04). The content of 18:2(n-6) fatty acid decreased, while the content of 18:1(n-9) increased in the series C
3
→ C
3
–C
4
→ C
4
-NAD → C
4
-NADP species. It is concluded that differences among the examined species in terms of the volume and surface area of cells and chloroplasts in mesophyll and bundle sheath tissues become larger, while the content of membrane lipids in cells, chloroplasts, and mitochondria per unit leaf area decreases along with the extent to which the C
4
syndrome is pronounced. The composition of lipids and fatty acids is suited to support the metabolic activity of chloroplasts and mitochondria according to the type of photosynthesis.
The purpose of the study is to identify the relationship between drought resistance indicators and the yield of potato plants under unfavorable conditions. A xeromorphic leaf structure is considered ...to be a diagnostic sign of plant drought resistance. The objects of the study were 24 potato varieties. Planting of seeds, preplanting tillage, harvesting, and crop recording were carried out in the period of 2020–2022 on the territory of the Samara Research Institute of Agriculture (branch of the Samara Scientific Center, Russian Academy of Sciences). Growing conditions for 2021 and 2022 were characterized by elevated temperatures and insufficient moisture. The number and size of stomata per unit leaf area were chosen as the criterion for xeromorphism. The studied varieties were divided into two groups (
n
= 12 each) according to the number of stomata. In the first group, the average number of stomata was 26 000 pcs./cm
2
of leaf, and that in the second group was 35 000 pcs. (
F
= 41,
p
= 0.03). More developed structural features of xeromorphism and the accumulation of certain types of metabolites in the second group of varieties led to a 1.6 times greater yield than in the first less xeromorphic group (
F
= 9,
p
= 0.004). The second group was characterized by a large number of mesophyll cells per unit leaf area (584 000 pcs./cm
2
vs. 557 000 pcs.), high content of phospholipids (36 mg/g dry weight vs. 31 mg/g), dry weight (0.19 vs. 0.17 g/g wet weight), and the ratio of membrane lipids to membrane proteins (1.4 vs. 1.2). In the less xeromorphic group of plants, the level of oxidative stress, assessed by LPO products, was 0.050 μM/g fresh weight and was 12% higher than in the more xeromorphic group (
F
= 6,
p
= 0.08). The revealed positive correlation between yield and xeromorphic genotypes indicates the prospects of using this criterion in potato breeding or creating a variety model.
Background.
One of the important indicators of the nutritional value of amaranth is the high content of protein and lipids in seeds. Hence, obtaining and identifying such forms of amaranth through ...breeding, so that they also possessed resistance to abiotic stressors, is an important task.
Materials and methods.
Leaves and seeds of Amaranthus cruentus L. and mutants of the second inbred generation obtained by treatment with sodium azide were analyzed. The Bradford assay was used to measure the content of total soluble protein, lipid analysis was performed by thin-layer chromatography, the state of the antioxidant system was assessed according to catalase and peroxidase activities and the rate of superoxide anion formation. Mathematical data were processed using the Statistica 10.0 software.
Results.
The highest concentration of total protein in seeds was 13.78 mg/g in one of the mutants obtained after treatment with 3 mM sodium azide. Fifteen fatty acids were found in amaranth seeds, and in four mutants a significant increase in the percentage of omega-6 unsaturated linoleic acid was recorded. An increase in salt tolerance compared to the control was observed in mutants No. 2 and No. 3. Mutant No. 2 under salinization demonstrated higher peroxidase activity and mutant No. 3 higher catalase activity; both mutants showed a reduced rate of superoxide anion formation compared to the control.
Conclusion.
Amaranth mutants identified for higher stress resistance, protein content and linoleic acid content can be recommended for further breeding to produce new cultivars of amaranth with economically valuable traits.
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