Morphological and Ultrastructural Features of Formation of the Skin of Wheat (Triticum aestivum L.) Kernel

The integumentary tissues of plant seeds protect the embryo (new sporophyte) forming in them from unfavorable external conditions; therefore, comprehensive knowledge about the structural and functional specificity of seed covers in various plants may be of both theoretical and practical interest. As a result of our study, additional data were obtained on the morphological and ultrastructural features of the formation of a multilayer skin of wheat (Triticum aestivum L.) kernel (caryopsis). The ultrastructure research analysis showed that differentiation of the pericarp and inner integument of the ovule leads to the formation of functionally different layers of the skin of mature wheat grain. Thus, the differentiation of exocarp and endocarp cells is accompanied by a significant thickening of the cell walls, which reliably protect the ovule from adverse external conditions. The cells of the two-layer inner integument of the ovule differentiate into cuticular and phenolic layers, which are critical for protecting daughter tissues from various pathogens. The epidermis of the nucellus turns into a layer of mucilage, which apparently helps to maintain the water balance of the seed. Morphological and ultrastructural data showed that the formation of the kernel’s skin occurs in coordination with the development of the embryo and endosperm up to the full maturity of the kernel. This is evidenced by the structure of the cytoplasm and nucleus, characteristic of metabolically active protoplasts of cells, which is observed in most integumentary layers at the late stages of maturation. This activity can also be confirmed by a significant increase in the thickness of the cell walls in the cells of two layers of the exocarp and in cross cells in comparison with the earlier stages. Based on these results, we came to the conclusion that the cells of a majority in the covering tissues of the wheat kernel during its ontogenesis are transformed into specialized layers of the skin by terminal differentiation.

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INTERACTION BETWEEN SILICON AND ALUMINUM IN TRITICUM AESTIVUM L. (CV. CELTIC)

Israel Journal of Plant Sciences ◽

10.1080/07929978.1997.10676691 ◽

1997 ◽

Vol 45 (4) ◽

pp. 285-292 ◽

Cited By ~ 18

Author(s):

Kay M. Cocker ◽

Martin J. Hodson ◽

David E. Evans ◽

Allan G. Sangster

Keyword(s):

Triticum Aestivum ◽

Continuous Flow ◽

Cell Walls ◽

Dry Weight ◽

Triticum Aestivum L ◽

Test Solution ◽

Root Tip ◽

Solution Ph ◽

Al Content ◽

Al Treatment

Seedlings ofTriticum aestivumL. (cv. Celtic) were suspended in plastic tubs containing 500 μmol L−1Ca(NO3)2and 31 μmol L−1KC1 as background solution. A1C13(0 and 100 μmol L−1) and Na2SiO3.5H2O (0 and 2000 μmol; L−1) were added to this basal nutrient medium, and solution pH was set at 4.2 or 4.6. Tubs were aerated and supplied with a continuous flow of pH-adjusted test solution. Plants were grown for 4 d in a growth cabinet at 25 °C with a 16 h photoperiod. At pH 4.2 and 4.6 root length of the seedlings was inhibited at 100 μmol L−1Al. An amelioration of Al-induced toxicity symptoms was observed in the 100 μmol L−1A1/2000 μmol L−1Si treatment at pH 4.6, but not at pH 4.2. Both the shoot (S) and root (R) dry weight of seedlings treated with 100 μmol L−1Al were reduced when compared with controls. Treatment with Al increased S:R ratios, and this effect was ameliorated by Si, but only at pH 4.6.Al content of roots treated with 100 μmol L−1Al or 100 μmol L−1Al/2000 μmol L−1Si increased significantly when compared with controls. More Al accumulated in the roots of seedlings of the 100 μmol L−1Al/2000 μmol L−1Si treatment than in the 100 μmol L−1treatment. Al treatment reduced root and shoot K concentrations under both pH regimes, and Si did not ameliorate this effect. Al treatment had little effect on seedling Ca levels.Three treatments were selected for a microanalytical investigation of the basal third of the root, and the zone 3.5 mm behind the root tip: 2800 μmol L−1Si; 75 μmol Al; and a combination of the two. When plants were grown in 2800 μmol L−1Si the major silica deposition sites in the roots were the endodermal walls. In the 75 μmol L−1Al treatment, Al was mainly located in the epidermal and hypodermal walls. Al treatment caused a leakage of phosphorus into these cell walls. When both 2800 μmol L−1and 75 μmol L−1Al were present in the nutrient solution, only Si was deposited in the endodermal walls, while both elements were present in the epidermal walls. Leakage of phosphorus appeared to be prevented in the presence of Si.

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Differences in endosperm cell wall integrity in wheat (Triticum aestivum L.) milling fractions impact on the way starch responds to gelatinization and pasting treatments and its subsequent enzymatic in vitro digestibility

Food & Function ◽

10.1039/c9fo00947g ◽

2019 ◽

Vol 10 (8) ◽

pp. 4674-4684 ◽

Cited By ~ 5

Author(s):

Konstantinos Korompokis ◽

Niels De Brier ◽

Jan A. Delcour

Keyword(s):

Triticum Aestivum ◽

Cell Wall ◽

Cell Walls ◽

Triticum Aestivum L ◽

Cell Wall Integrity ◽

In Vitro Digestibility ◽

Endosperm Cell ◽

Amylolytic Enzymes ◽

Physical Barriers

Intact wheat endosperm cell walls reduce intracellular starch swelling and retard its in vitro digestion by acting as physical barriers to amylolytic enzymes.

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Stimulation of lignin synthesis via the PAL-associated metabolic pathway in wheat plants (Tríticum aestívum L.)

E3S Web of Conferences ◽

10.1051/e3sconf/202129102017 ◽

2021 ◽

Vol 291 ◽

pp. 02017

Author(s):

Pavel Feduraev ◽

Artem Pungin ◽

Anastasiia Riabova ◽

Elina Tokupova ◽

Liubov Skrypnik

Keyword(s):

Triticum Aestivum ◽

Metabolic Pathway ◽

Cell Walls ◽

Phenylalanine Ammonia Lyase ◽

Lignin Content ◽

Triticum Aestivum L ◽

Soft Wheat ◽

Nutrient Media ◽

Key Enzyme ◽

Stimulation Of

The paper demonstrates an approach to increasing the accumulation of lignin in plants of soft wheat (Tríticum aestívum L.) at the early stages of ontogenesis, by means of substrate stimulation of the key enzyme of the synthesis of phenylpropanoids – phenylalanine-ammonia-lyase. It was shown that plants grown on nutrient media containing phenialanine or tyrosine at a concentration of 500 μM significantly increased the lignin content of cell walls compared to controls.

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MESURE DE L’ENDURCISSEMENT AU FROID ET DE LA VIABILITE DES PLANTES EXPOSEES AU GEL PAR LE DOSAGE DES PHOSPHATASES ACIDES LIBRES

Canadian Journal of Plant Science ◽

10.4141/cjps78-154 ◽

1978 ◽

Vol 58 (4) ◽

pp. 1007-1018 ◽

Cited By ~ 3

Author(s):

R. BOLDUC ◽

L. RANCOURT ◽

P. DOLBEC ◽

L. CHOUINARD-LAVOIE

Keyword(s):

Triticum Aestivum ◽

Phosphatase Activity ◽

Cell Walls ◽

Cold Hardiness ◽

External Medium ◽

Freezing Point ◽

Activity Index ◽

Triticum Aestivum L ◽

Freezing Test ◽

The One

Cellular freezing induces leaking of non-specific acid phosphatase enzymes (EC. 3.1.3.2) from the cell walls of wheat crowns into the liquid medium surrounding the plant tissues. Those free enzymes leak both in the disorganized cytoplasm and in the external medium surrounding the tissues. The phosphastase activity index, measured in the external medium of the frozen plants as compared with the one of the non-frozen plants, decreases proportionally with the temperature of the freezing test until a minimum plateau is reached corresponding to the killing temperature of the plants. The determination of this phosphatase activity index can be used therefore as a quantitative method for the estimation of the viability of plants exposed to freezing. The initial drop of the phosphatase activity index precedes the viability loss as measured with the regrowth tests. The solubilization of those acid phosphatases previously bonded to the cell walls is one cause of the plant death rather than its consequence. The differentiating degrees of cold hardiness can be calculated from the changes in the phosphatase activity during a programmed freezing test among cultivars or species, immediately after running the test. Kharkov (Triticum aestivum L.) sampled in the fall shows + 13 °C differential of cold hardiness as compared with the one sampled in summer while Champlein (Triticum aestivum L.) has developed + 5 °C differential of cold hardiness. In the same conditions, another species (Medicago sativa L. cv. Saranac) shows − 9 °C differential of cold hardiness as compared with Kharkov. Temperatures near the freezing point stabilize instantly the attachment of enzymes to cell walls. This molecular rearrangement, at the enzymatic level, is related to the initial metabolism of cold hardening.

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