Anatomical changes induced by triazoles in wheat seedlings

1988 ◽  
Vol 66 (6) ◽  
pp. 1178-1185 ◽  
Author(s):  
J. Gao ◽  
G. Hofstra ◽  
R. A. Fletcher
Keyword(s):  
Triticum Aestivum L ◽  
Chlorophyll Synthesis ◽  
Epidermal Cells ◽  
Vascular Bundles ◽  
Mesophyll Cells ◽  
Wheat Seedlings ◽  
Anatomical Changes ◽  
Subsidiary Cells ◽  
Wheat Leaves ◽  
Stimulation Of

The triazoles triadimefon and S-3307, applied as seed treatments at two concentrations each (0.1 and 1.0, and 0.001 and 0.01 g active ingredient/kg of seed, respectively), increased epicuticular wax and reduced the length but increased the width and thickness of wheat leaves (Triticum aestivum L. cv. Glenlea). Mesophyll cells of treated leaves were thicker than those of controls and there were more layers of cells around the median and lateral vascular bundles of leaves treated with the higher concentration of S-3307. The length of epidermal cells was reduced and the width was increased by both triazoles; the depth of epidermal cells was increased by the higher concentration of triadimefon only. S-3307 increased the number of vascular bundles, whereas triadimefon at the higher concentration increased their diameter. Both concentrations of S-3307 reduced the length of trichomes. The two triazoles increased chloroplast size along both the long and short axes. Compared with those of controls, the stomata in the triadimefon-treated leaves were constricted and sunken, whereas in S-3307 treated leaves the subsidiary cells were wider. The effects of the triazoles observed in this study may account in part for several plant growth regulatory activities reported earlier, including growth retardation, stimulation of chlorophyll synthesis, and protection against injury from water stress.

Water Relations in Young Growing Wheat Leaves after Application of (2-Chloroethyl)trimethyl- ammoniumchloride (CCC) to the Roots of Wheat Seedlings

1985 ◽  
Vol 40 (9-10) ◽  
pp. 745-747
Author(s):  
Jutta Bode ◽  
Aloysius Wild
Keyword(s):  
Water Relations ◽  
Reducing Sugars ◽  
Triticum Aestivum L ◽  
Water Deficiency ◽  
Pressure Potential ◽  
Tissue Water ◽  
Wheat Seedlings ◽  
Diffusive Resistance ◽  
Wheat Leaves ◽  
Synthetic Growth

Abstract The influence on the water relations of the third developing leaf of (2-chloroethyl)trimethylammoniumchloride, a synthetic growth regulator, applied to the roots of young wheat plants (Triticum aestivum L.) has been investigated. The tissue water potential and the pressure potential were found to be reduced by several bars in comparison to the untreated controls, whereas the osmotic potential remained unchanged. The content of soluble reducing sugars was considerably increased in the cell sap of CCC-treated leaves. With this accumulation, however, the turgor was not maintained. Additionally, CCC-treated leaves showed considerably lower transpiration rates and higher diffusive resistance than the controls. Thus, the application of CCC to the roots causes alterations in the water relations of developing wheat leaves, which resemble those induced by water deficiency.

Histo-anatomical leaf variations related to depth in Posidonia oceanica

2015 ◽  
Vol 42 (4) ◽  
pp. 418 ◽  
Author(s):  
Silvia Nicastro ◽  
Anna M. Innocenti ◽  
Nicodemo G. Passalacqua
Keyword(s):  
Anatomical Variation ◽  
Light Availability ◽  
Posidonia Oceanica ◽  
Absorption Efficiency ◽  
Epidermal Cells ◽  
Vascular Bundles ◽  
Terrestrial Plants ◽  
Mesophyll Cells ◽  
Seagrass Meadows ◽  
Functional Efficiency

The purpose of our study is to explore the acclimation of Neptune seagrass (Posidonia oceanica (L.) Delile) to depth by characterising the histo-anatomical leaf modifications. P. oceanica is the dominant seagrass and main habitat constructor of seagrass meadows in the Mediterranean Sea. Meadows play an important biological and ecological role in marine ecosystems, serving as a habitat for a large diversity of species and an efficient erosion protection system for our coasts. Seagrasses are very sensitive to change in light availability and small changes can have significant effects on growth, abundance and distribution. In this study, we analyse changes in P. oceanica leaves collected at –5 m, –15 m and –25 m depth in the Cirella meadow (Tyrrhenian coast, Southern Italy) in order to determine their depth-related histo-anatomical variation. Two main changes were observed at depth: (1) photosynthetic epidermal cells showed smaller chloroplasts but in the same number; and (2) leaves showed smaller epidermal cells and in greater number. Hence, the photosynthetic surface of P. oceanica leaves remains the same at different depths but pigment absorption efficiency can be significantly enhanced with depth. This response supports the differential photoacclimatory response of seagrasses with respect to terrestrial plants previously documented. Mesophyll cells are smaller with depth and more numerous, with a consequent increase in leaf density. The number of vascular bundles also increases, which allows improved functional efficiency of the transport system and solute exchange. Our study is a new contribution to the morpho-functional implications of the histo-anatomy of P. oceanica.

scholarly journals Stimulant effect of plant activator BION on photosynthesis and its inhibitory effect on pathogenic fungi

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 497-501
Author(s):  
M.K. Solntsev ◽  
V.A. Karavaev ◽  
T.P. Yurina ◽  
E.V. Yurina ◽  
A.M. Kuznetsov ◽  
...  
Keyword(s):  
Photosynthetic Activity ◽  
Pathogenic Fungi ◽  
Inhibitory Effect ◽  
Fluorescence Induction ◽  
Stimulant Effect ◽  
Wheat Seedlings ◽  
Slow Fluorescence Induction ◽  
Wheat Leaves ◽  
Plant Activator ◽  
Stimulation Of

Spraying of wheat seedlings with aqueous preparations of CGA 245704 (BION) caused a slight decrease in chlorophyll content accompanied by the stable increase in the rate of O<sub>2</sub> evolution per chlorophyll. Stimulant effect of BION on photosynthetic activity depended on both the ai concentration and number of treatments. Biophysical methods based on the registration of slow fluorescence induction and thermoluminescence of wheat leaves revealed the stimulation of photosystem II activity and the increase in the rate of electron transport between the photosystems in treated plants. It is also shown that BION itself can show a partial fungitoxic activity because it slowed down the germination of Erysiphe graminis f.sp. tritici fungi. This is obviously the reason for partial protective effect of BION when it was applied after the inoculation of wheat seedlings with the pathogen.

Studies on Graminicolous Species of Phyllachora Fckl. II.. Invasion of the host and development of the fungus

1963 ◽  
Vol 11 (2) ◽  
pp. 131 ◽  
Author(s):  
DG Parbery
Keyword(s):  
Life Cycle ◽  
Close Contact ◽  
Detailed Examination ◽  
Epidermal Cells ◽  
Vascular Bundles ◽  
Mesophyll Cells ◽  
Full Life Cycle ◽  
Full Life ◽  
Made In ◽  
Mechanical Tissue

Infection of grasses by species of Phyllachora Fckl. has been observed, and a detailed examination of the life cycle of two species of this genus has been made on hosts artificially inoculated while growing under glass-house conditions. Gemiiiatiiig ascospores of P. ischaemi and P. parilis prodced appressoria on the leaves of their respective hosts, Ischaemum australe and Paspalurn orbiculare. From each appressorium an infection peg penetrated into the lumen of an epidermal cell and expanded into a normal hypha. Some branches of this hypha invaded adjacent epidermal cells, thus laying the foundations of the clypeus, while other branches invaded the underlying mesophyll cells. At first all hyphae were intracellular and passed from cell to cell by means of fine infection hyphae produced by appressorium-like swellings of the hyphae appressed to the cell wall. Intercellular mycelium was found at a later stage when hyphae were forming perithecium initials. The observation that the clypeus developed independently of the perithecium dispels some existing confusion about its origin. The clypeus developed in the epidermal cells of the host and not as an outgrowth of the ostiolar region of the perithecium. The perithecium initial developed deep in the mesophyll, and in the case of Phyllachora parilis was preceded by the formation of a subclypeal pycnidium containing filiform spores. In each case, the perithecium expanded until its ostiolar region came into close contact with the clypeus. The ostiole then developed right through the ciypeus, and its development is believed to be lysigenous. The mouth of the ostiole remained closed by a membrane which appeared to be the undissolved cuticle. It was noted that asci of all species examined possessed an ascus crown, a structure not previously observed in species of this genus. It has been found that the anatomy of the host can determine the form of some structures of Phyllachora spp. Clypeus thickness is governed by the size of the epidermal cells, while its radial expansion is checked by the mechanical tissue associated with vascular bundles. Similarly, perithecium size and shape are influenced by the amount of mechanical tissue in a leaf. The time for P. ischaemi to complete its life cycle was influenced by seasonal conditions. Colonies arising from infections in April 1961 discharged ascospores in 32 days, whereas infections made 1 month later did not produce sporulating colonies until 54-58 days later. The full life cycle of P. parilis took 62-77 days when inoculations were made in May 196 1.

scholarly journals Anatomical changes on coffee leaves infected by Pseudomonas syringae pv. garcae

2015 ◽  
Vol 41 (4) ◽  
pp. 256-261 ◽  
Author(s):  
Lucas Mateus Rivero Rodrigues ◽  
Rachel Benetti Queiroz-Voltan ◽  
Oliveiro Guerreiro Filho
Keyword(s):  
Pseudomonas Syringae ◽  
Vascular System ◽  
Vascular Bundles ◽  
Mesophyll Cells ◽  
Internal Damage ◽  
Anatomical Changes ◽  
Halo Blight ◽  
Inoculation Site ◽  
Palisade And Spongy Parenchyma ◽  
Colonization Period

ABSTRACTAlthough poorly studied, the bacterial halo blight is an important disease in the major coffee-producing states of Brazil. External damage and anatomical changes on leaves were measured in seedlings of Coffea arabica cv. Mundo Novo, susceptible to Pseudomonas syringae pv. garcae, by using histological sections obtained at 10 and 20 days after inoculation (DAI). The changes on the epidermis were smaller than the lesions measured in the mesophyll, irrespective of the evaluated colonization period, showing that the internal damage caused by the bacterium represent twice the damage observed externally. From the inoculation site, lysis occurred on the epidermal cells and on the palisade and spongy parenchyma cells, with strong staining of their cellular contents, as well as abnormal intercellular spaces in the palisade parenchyma, hypertrophy and hyperplasia of mesophyll cells and partial destruction of chloroplasts. Additionally, this study revealed the presence of inclusion bodies in epidermal and mesophyll cells. Bacterial masses were found in the apoplast between and within mesophyll cells. Bacteria were also observed in the bundle sheath and vascular bundles and were more pronounced at 20 DAI, not only near the inoculation site but also in distant areas, suggesting displacement through the vascular system. These results can be useful to understand this plant-pathogen interaction.

A histological study of interactions between avirulent races of stem rust and wheat containing resistance genes Sr5, Sr6, Sr8, or Sr22

1979 ◽  
Vol 57 (4) ◽  
pp. 324-331 ◽  
Author(s):  
R. Rohringer ◽  
W. K. Kim ◽  
D. J. Samborski
Keyword(s):  
Resistance Genes ◽  
Stem Rust ◽  
Chinese Spring ◽  
Histological Study ◽  
Fungal Growth ◽  
Triticum Aestivum L ◽  
Epidermal Cells ◽  
Host Cells ◽  
Colony Development ◽  
Mesophyll Cells

Primary leaves of wheat (Triticum aestivum L.) with and without resistance genes Sr5, Sr6, Sr8, or Sr22 were inoculated with avirulent races of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn.) and examined by fluorescence microscopy. In leaves containing the Sr5 gene for resistance, both epidermal and mesophyll cells fluoresced when interacting with the fungus, indicating incompatibility. In leaves containing the Sr6 gene, interacting epidermal cells did not fluoresce and incompatibility was expressed only in mesophyll cells.When the effect of the Sr5 gene was studied in leaves with different genetic backgrounds, it was found that most colonies developed only one or two haustorial mother cells in leaves containing this gene in Prelude, Marquis, or Reliance backgrounds, when examined up to 72 h after incubation. Conversely, in leaves with the Chinese Spring background, one-third of the colonies continued to grow and they produced macroscopically visible lesions. Our observations indicated that the Chinese Spring genotype partially altered the expression of the Sr5 gene in mesophyll but not in epidermal cells. In contrast, the Sr6 gene was more effective in the Chinese Spring background than in the Prelude background.Rust development in leaves with or without the Sr8 gene was the same up to 60 h after incubation, when incompatibility in resistant plants was first detected by the appearance of fluorescing host cells. By 72 h, mean colony size in resistant leaves was smaller than that in susceptible leaves, evidently because growth of runner hyphae was inhibited. Apparently, the P8 gene for avirulence was not expressed until colonies had reached considerable size. In leaves containing the Sr22 gene for resistance, the sequence of histological events was similar to that in leaves containing Sr8, but fluorescing host cells appeared later (72 h) and colony growth was inhibited only at 96 h after incubation. In both of these interactions, fluorescing host cells developed at the periphery of colonies when incompatibility was expressed. The host-parasite interaction in cells invaded before that time remained compatible even at later stages of colony development. In leaves containing the Sr5 or the Sr8 gene, but not in those with the Sr6 gene, the growth of some colonies was inhibited although they were not associated with fluorescing host cells. Evidently, host-cell necrosis was closely associated with reduced fungal growth in interactions involving Sr6, but not in interactions involving the resistance genes Sr5 and Sr8.

Functional leaf anatomy and ultrastructure in a marine angiosperm, Syringodium isoetifolium (Aschers.) Dandy (Cymodoceaceae)

1993 ◽  
Vol 44 (1) ◽  
pp. 59 ◽  
Author(s):  
J Kuo
Keyword(s):  
Vascular Bundle ◽  
Leaf Blade ◽  
Small Region ◽  
Total Surface Area ◽  
Epidermal Cells ◽  
Secretory Cells ◽  
Vascular Bundles ◽  
Mesophyll Cells ◽  
Vascular Tissues ◽  
Syringodium Isoetifolium

The terete leaf blade of Syringodium isoetifolium (Aschers.) Dandy from south-western Australia has uniformly small epidermal cells and a few large secretory cells. Mesophyll tissues contain several air lacunae, a central longitudinal vascular bundle, and eight to twelve peripheral longitudinal vascular bundles, but no fibre bundles. The total volume of air lacunae is about 10% that of the leaf blades, but the total surface area of air lacunae is similar to that of leaf blades. The leaf cuticle appears as a thin, electron-transparent layer. Leaf-blade epidermal cells have a large central vacuole and peripheral cytoplasm containing many chloroplasts that lack starch grains. Wall ingrowths are absent. However, the small region between the walls and the plasmalemma could play an important role in nutrient absorption. Plasmodesmata appear to be absent between adjacent epidermal cells, and also between epidermal and mesophyll cells, suggesting that there is only an apoplastic pathway for the transport of photosynthate to the vascular tissues. Each vascular bundle is surrounded by a layer of sheath cells, which are characterized by the presence of suberized lamellae in their walls. These may act to reduce the apoplastic exchange of solutes and water between the mesophyll and vascular tissues. Xylem elements, represented by large lumens and intensely hydrolysed walls, may not be present in all peripheral vascular bundles. Two types of sieve elements occur in S. isoetifolium leaf blades: normal thin-walled ones with large lumens, and thick-walled ones with reduced lumens, representing the photophloem and the metaphloem, respectively.

Effect of 24-epibrassinolide on localization of ABA, AZP, and dehydrins in wheat plant roots during dehydration

Biomics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 329-336
Author(s):  
A.R. Lubyanova ◽  
F.M. Shakirova ◽  
M.V. Bezrukova
Keyword(s):  
Triticum Aestivum ◽  
Wheat Germ ◽  
Wheat Plant ◽  
Triticum Aestivum L ◽  
Immunohistochemical Localization ◽  
Plant Roots ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Apoplastic Barrier ◽  
Protective Proteins

We studied the immunohistochemical localization of abscisic acid (ABA), wheat germ agglutinin (WGA) and dehydrins in the roots of wheat seedlings (Triticum aestivum L.) during 24-epibrassinolide-pretreatment (EB-pretreatment) and PEG-induced dehydration. It was found coimmunolocalization of ABA, WGA and dehydrins in the cells of central cylinder of basal part untreated and EB-pretreated roots of wheat seedlings under normal conditions and under osmotic stress. Such mutual localization ABA and protective proteins, WGA and dehydrins, indicates the possible effect of their distribution in the tissues of EB-pretreated wheat roots during dehydration on the apoplastic barrier functioning, which apparently contributes to decrease the water loss under dehydration. Perhaps, the significant localization of ABA and wheat lectin in the metaxylem region enhances EB-induced transport of ABA and WGA from roots to shoots under stress. It can be assumed that brassinosteroids can serve as intermediates in the realization of the protective effect of WGA and wheat dehydrins during water deficit.

scholarly journals Remodeling of root morphology by CuO and ZnO nanoparticles: effects on drought tolerance for plants colonized by a beneficial pseudomonad

Botany ◽  
2018 ◽  
Vol 96 (3) ◽  
pp. 175-186 ◽  
Author(s):  
Kwang-Yeol Yang ◽  
Stephanie Doxey ◽  
Joan E. McLean ◽  
David Britt ◽  
Andre Watson ◽  
...  
Keyword(s):  
Calcareous Soils ◽  
Root Hairs ◽  
Triticum Aestivum L ◽  
Metal Stress ◽  
Root Tip ◽  
Zno Nps ◽  
Wheat Seedlings ◽  
Cuo Nps ◽  
Expression Of Genes ◽  
Induced Tolerance

Formulations that include nanoparticles of CuO and ZnO are being considered for agricultural applications as fertilizers because they act as sources of Cu or Zn. Currently, few studies of the effects of these nanoparticles (NPs) consider the three-way interactions of NPs with the plant plus its microbiome. At doses that produced root shortening by both nanoparticles (NPs), CuO NPs induced the proliferation of elongated root hairs close to the root tip, and ZnO NPs increased lateral root formation in wheat seedlings (Triticum aestivum L.). These responses occurred with roots colonized by a beneficial bacterium, Pseudomonas chlororaphis O6 (PcO6), originally isolated from roots of wheat grown under dryland farming in calcareous soils. The PcO6-induced tolerance to drought stress in wheat seedlings was not impaired by the NPs. Rather, growth of the PcO6-colonized plants with NPs resulted in systemic increases in the expression of genes associated with tolerance to water stress. Increased expression in the shoots of other genes related to metal stress was consistent with higher levels of Cu and Zn in PcO6-colonized shoots grown with the NPs. This work demonstrates that plants grown with CuO or ZnO NPs showed cross-protection from different challenges such as metal stress and drought.

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