Vascular System of the Stem of the Wheat Plant .II. Development

1972 ◽  
Vol 20 (1) ◽  
pp. 65 ◽  
Author(s):  
JW Patrick
Keyword(s):  
Vascular System ◽  
Wheat Plant ◽  
Sieve Tube ◽  
Triticum Aestivum L ◽  
Leaf Primordia ◽  
Vascular Differentiation ◽  
Vascular Elements ◽  
A Site ◽  
Further Development ◽  
Main Tiller

The sequence of vascular differentiation in the shoot of the main tiller of Triticum aestivum L. was reconstructed from seriai transverse sections of shoot apices made at various stages of development. The pattern of initiation and development of the pro- cambial strands was confirmed. The provascular bundles of the pith plexus arose independently and developed acropetally from the base of the future node. Early dif- ferentiation of proto-phloem and -xylem in the main procambial strands proceeded bidirectionally up the leaf primordia and down the stem from a site of initiation isolated from other differentiated vascular elements. Further development was basipetal from the tip of the primordia, and the rate of differentiation of the sieve elements was sufficient to maintain phloem continuity across the intercalary meristems of the laminae, sheaths, and internodes. Within the developing nodes sieve tube differentiation in the cross-linking strands lagged behind that of the leaf traces they interconnected, and this may influence the movement of photoassimilate from a recently expanded leaf to the apex.

Vascular System of the Stem of the Wheat Plant. I. Mature State

1972 ◽  
Vol 20 (1) ◽  
pp. 49 ◽  
Author(s):  
JW Patrick
Keyword(s):  
Triticum Aestivum ◽  
Vascular System ◽  
Wheat Plant ◽  
Triticum Aestivum L ◽  
Vascular Bundles ◽  
Vascular Connections ◽  
Main Tiller

The courses of the various vascular bundles in the nodes of the main tiller of Triticum aestivum L. have been reconstructed from anatomical observations of con- secutive serial transverse sections. Of the bundles entering a node (n) from its attached leaf, the first-formed and largest, the median, passes directly through the node to the second node below (n-2), where it bifurcates and fuses with other strands. These continue to node n- 3 before fusing completely with the nodal plexus. The next six bundles to form (laterals) establish some links with bundles from higher leaves in the node of entry, much more extensive connections in node n- 1, and fuse completely with the nodal plexus in node n-2. The next four lateral bundles to differentiate are more extensively linked in node n and fuse completely with the nodal plexus in node n - I . The remaining 16-20 bundles from the leaf (intermediates) follow much the same course but develop more extensive connections with other bundles. The extensive plexus which develops in each node ensures vascular connections between most bundles. The significance of these in transport is briefly discussed.

scholarly journals Sieve tube structural variation in Austrobaileya scandens and its significance for lianescence

2021 ◽  
Author(s):  
Juan M Losada ◽  
Zhe He ◽  
Noel Michele Holbrook
Keyword(s):  
Structural Variation ◽  
Vascular System ◽  
Light And Electron Microscopy ◽  
Sieve Tube ◽  
Phloem Transport ◽  
Sieve Plate ◽  
Geometrical Properties ◽  
Mechanical Constraints ◽  
Vascular Elements ◽  
Sieve Plates

Lianas are characterized by large leaf areas and slender stems, a combination of features that require an efficient vascular system. The only extant member of the Austrobaileyaceae, is an endemic twining liana of the tropical Australian forests with well-known xylem hydraulic traits. However, the vascular phloem continuum through aerial organs remains understudied. We analyzed the structure of phloem conduits across leaf veins and stems of A. scandens, combining topological data obtained through light and electron microscopy, with current models of phloem transport. Leaves displayed a low xylem to phloem ratio compared with leaves of other angiosperms, with vascular elements invariant in diameter along the midrib, but tapered across vein hierarchies. Sieve plate pore radii were extremely small: 0.08μm in minor veins, increasing to 0.12μm in the petiole and only to 0.20μm at the base of the stem, tens of meters away. Searcher branches contained tube shaped phloem conduits with a pectin-rich wall, whereas twining stems displayed sieve elements with tangential connections that displayed a greater fraction of the tubes populated with an astonishing number of sieve plates. Hydraulic segmentation of the leaves in Austrobaileyaceae correlate with vesseless leaves that benefit photoassimilate export through volumetric scaling of the sieve tube elements. Yet, compared with canopy dominant trees, the geometrical properties of the sieve tube in twining stems, restrict considerably energy distribution in the sub-canopy layers, potentially favoring the allocation of assimilates toward the elongating branches. Thus, the conductive xylem of twining stems contrasts with a poorly conductive phloem that meets the mechanical constraints of lianescence.

scholarly journals The Transverse Veins of the Wheat Leaf

1972 ◽  
Vol 25 (4) ◽  
pp. 721 ◽  
Author(s):  
J Kuo ◽  
TP O'brien ◽  
S-Y Zee
Keyword(s):  
Vessel Wall ◽  
Sieve Tube ◽  
Triticum Aestivum L ◽  
Wall Thickening ◽  
Tracheary Elements ◽  
Mestome Sheath ◽  
Vascular Elements ◽  
Parenchyma Cells ◽  
Wheat Leaf ◽  
Vascular Parenchyma

The histology and fine structure of the transverse veins that connect the longitudinal veins in the leaf of wheat (Triticum aestivum L. cv. Heron) are illustrated and discussed. The transverse veins consist of a single sieve tube and vessel, and two files of vascular parenchyma cells. They lack the mestome sheath and parenchyma sheath that is present around longitudinal veins except where they make connection with longitudinal veins. The vascular elements of the transverse veins are connected to metaxylem and metaphloem of the longitudinal veins and these connections are illustrated in sections. The tracheary elements have an unusual pattern of wall thickening. Experiments with ferric chloride solutions reveal that the vessel wall may severely restrict passage of solutes from the transpiration stream to the free space of the mesophyll.

scholarly journals Sieve tube structural variation in Austrobaileya scandens and its significance for lianescence

2021 ◽  
Author(s):  
Juan Losada ◽  
Zhe He ◽  
Noel Holbrook
Keyword(s):  
Resource Allocation ◽  
Hydraulic Resistance ◽  
Structural Variation ◽  
Vascular System ◽  
Sieve Tube ◽  
Sink Strength ◽  
Sieve Plate ◽  
Vascular Elements ◽  
Microscopy Analysis ◽  
Sieve Plates

Lianas combine large leaf areas with slender stems, features that require an efficient vascular system. The only extant member of the Austrobaileyaceae is an endemic twining liana of the tropical Australian forests with well-known xylem hydraulics, but the vascular phloem continuum aboveground remains understudied. Microscopy analysis across leaf veins and stems of A. scandens revealed a low foliar xylem to phloem ratio, with isodiametric vascular elements along the midrib, but tapered across vein orders. Small sieve plate pore radii increased from 0.08 µm in minor veins to 0.12 µm in the petiole, but only to 0.20 µm at the stem base, tens of meters away. In searcher branches, phloem conduits contained a pectin-rich wall and simple plates, whereas in twinning stems, conduits connected through highly-angled-densely populated sieve plates. Twisted and elongated stems of A. scandens display a high hydraulic resistance of phloem conduits, which decreases from leaves to stems, efficiently delivering photoassimilate from sources under Münch predictions. Sink strength of a continuously growing canopy might be stronger than in self-supporting understory plants, favoring resource allocation to aerial organs in angiosperms that colonized the vertical niche.

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 EFFECT OF EMS ON ANTIOXIDANT ENZYME ACTIVITY AND OXIDATIVE STRESS OF TRITICUM AESTIVUM L. VAR HD-2894

2018 ◽  
Vol 10 (1) ◽  
pp. 33
Author(s):  
Shailja Dubey ◽  
Renu Bist ◽  
Shrilekha Misra
Keyword(s):  
Lipid Peroxidation ◽  
Triticum Aestivum ◽  
Data Analysis ◽  
Treatment Time ◽  
Lethal Dose ◽  
Wheat Plant ◽  
Biochemical Parameter ◽  
Triticum Aestivum L ◽  
Enzymatic Antioxidants ◽  
Functional Variation

Objective: Ethyl methano sulphonate (Ems), a chemical mutagen is widely used to induce a large number of functional variation in wheat plant. The objective of present study was to determine the activity of enzymatic antioxidants and Lipid peroxidation (LPO) after EMS exposure in a wheat plant in M1, M2 and M3 generation of Triticum aestivum L. var. HD 2894.Methods: Presoaked seeds were treated with EMS for 6 hour with different concentration like 0%, 0.1%, 0.2%, 0.3%, 0.4% and 0.5%. Some biochemical parameter such as Catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR) and Lipid peroxidation (LPO) were studied.Results: Our result showed that EMS affects enzymatic and oxidative parameters in all generation. CAT, GR, APX and LPO activity was found to be reduced in m1 generation as compared to control. A simultaneous elevation was recorded in the concentration of ems compared to control treated plants after given the exposure of ems in m2 and m3 generation. Data analysis of antioxidant and LPO during the m2 generation showed that the effect of the mutagen on the activity of antioxidant and LPO did not cease in the m1 but continued to affect the m2 generation. Analysis of m3 generation showed stability in the activity of antioxidant and LPO from m2 to m3 generation.Conclusion: Lethal dose of ems was determined by the activity of antioxidant under laboratory condition. In this experiment, quantitative determination was applied as a regular procedure. The data analysis showed the activity of antioxidant, LPO and doses of ems concentration in m1, m2 and m3 generation. Variability observed on the basis of mean and standard deviation. On the whole, differences between concentrations and treatment time of Ems significantly affect the activity of antioxidant and LPO in all generation. 

Primary vascular patterns in root meristems of Pontederia cordata and their relevance to studies of root development

1980 ◽  
Vol 58 (12) ◽  
pp. 1351-1369 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Apical Meristem ◽  
Vascular System ◽  
Root Apex ◽  
Root Apical Meristem ◽  
Vascular Pattern ◽  
Quiescent Centre ◽  
Vascular Differentiation ◽  
Pontederia Cordata ◽  
Distribution Of Components ◽  
Root Apices

There are several files of metaxylem cells in root apices of Pontederia cordata L., each considered to consist of a series of prospective vessels with their ends in contact. Two longitudinally adjacent vessels may be in the same file of cells produced by the root apex or in adjacent files. As the root grows, successive prospective vessels are added to the apical ends of most of the files but not all files are continued. Addition of prospective vessels appears to take place within the "quiescent centre" of the root apical meristem. Where files are not continued there is no immediate readjustment of remaining files. The longitudinal and transverse distribution of components of the vascular system (including protophloem and protoxylem) is discussed in relation to the means by which the pattern of development may be controlled. Rates of production of vessels and the final lengths of the vessels are estimated. The observations and deductions are discussed in relation to other studies of root growth, vascular differentiation, and vascular pattern formation and maintenance.

DEVELOPMENTAL MORPHOLOGY OF THE INFLORESCENCE IN HEXAPLOID WHEAT CULTIVARS WITH AND WITHOUT THE CULTIVAR NORIN 10 IN THEIR ANCESTRY

1973 ◽  
Vol 53 (1) ◽  
pp. 7-15 ◽  
Author(s):  
JOHN E. FISHER
Keyword(s):  
Triticum Aestivum ◽  
Apical Dominance ◽  
Triticum Aestivum L ◽  
Leaf Primordia ◽  
Developmental Pattern ◽  
Morphological Development ◽  
Wheat Cultivars ◽  
Developmental Morphology ◽  
Secale Cereale L ◽  
The Individual

The morphological development of the spike in short-statured hexaploid wheats (Triticum aestivum L.) derived from the cultivar Norin 10, and in Norin 10 as well, was markedly different from that in standard hexaploid wheats. In Norin 10 and its derivatives, the single ridges (slowly growing leaf primordia) on the elongating apex were considerably larger and spikelet primordia initiation and expansion were markedly delayed, resulting in a long apex with many single ridges. When spikelet development commenced, it was much more synchronous and hence gave rise to longer heads than in standard wheat in which spikelet development began soon after the start of the elongation of the apex. In most Norin 10 derivatives, more spikelets were initiated than in standard wheat. Apical dominance in the spike appeared to be stronger than in standard wheats. Also, apical dominance within the individual spikelets appeared to be greater, the net result being more fertile florets per spikelet. The developmental pattern of the spike of Norin 10 and its derivatives resembled, to a marked degree, the developmental pattern of rye (Secale cereale L.).

scholarly journals Straw competition and wheat root endophytism of Trichoderma gamsii T6085 as useful traits in the biocontrol of Fusarium head blight

2020 ◽  
Author(s):  
Sabrina Sarrocco ◽  
Pilar Esteban ◽  
Isabel Vicente ◽  
Rodolfo Bernardi ◽  
Tracy Plainchamp ◽  
...  
Keyword(s):  
Fusarium Head Blight ◽  
Competitive Ability ◽  
Vascular System ◽  
Wheat Plant ◽  
Wheat Root ◽  
Limited Attention ◽  
Plant Residues ◽  
Head Blight ◽  
Wheat Roots ◽  
Cortex Area

Trichoderma gamsii T6085 has been investigated for many years as a beneficial isolate for use in the biocontrol of Fusarium head blight (FHB) of wheat caused primarily by Fusarium graminearum. Previous work focused on application of T6085 to wheat spikes at anthesis, whereas application to soil before and/or at sowing has received limited attention. In the present study, the competitive ability of T6085 on plant residues against F. graminearum was investigated. Results showed a significant reduction of wheat straw colonization by the pathogen and of the development of perithecia, not only when T6085 was applied alone but also in the presence of a Fusarium oxysporum isolate (7121), well known as a natural competitor on wheat plant residues. T6085 was able to endophytically colonize wheat roots, resulting in internal colonization of the radical cortex area, without reaching the vascular system, as confirmed by confocal microscopy. This intimate interaction with the plant resulted in a significant increase of the expression of the plant defense-related genes PAL1 and PR1. Taken together, competitive ability, endophytic behavior, and host resistance induction represent three important traits that can be of great use in the application of T6085 against FHB, not only on spikes at anthesis but potentially also in soil before and/or at sowing.

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