What is vessel elements

Ask the Editors 'Everyday' vs. What Is 'Semantic Bleaching'? How 'literally' can mean "figuratively". Literally How to use a word that literally drives some pe Is Singular 'They' a Better Choice?

The awkward case of 'his or her'. Take the quiz. Our Favorite New Words How many do you know? Spell It Can you spell these 10 commonly misspelled words? Two cylinders, each 2 cm long, were taken from each sample. These sections were stained with safranin-fast green Ruzin, and mounted in synthetic resin. Iresine latifolia samples collected. We added hydrochloric acid and phloroglucinol Ruzin, to the transverse plane of the second stem cylinder to highlight the lignified tissue.

Once the surface acquired a reddish color, we counted the number of secondary xylem rings and measured their width with the help of an American Optical stereoscopic microscope. Next, secondary xylem was separated from each of the vascular rings using a disposable microtome knife.

Macerations were washed with tap water, and temporary slides were prepared for measurements of 50 fibers and vessel elements for each vascular ring using Image-Pro Plus version 6.

Variance analyses were performed using the general linear model SAS, to evaluate whether there are significant differences between the rings within each sample. The wood of I.

The wood has growth rings abruptly delimited by vessel and fiber wall thickness. Porosity is diffuse. The vessels are in radial multiples of 2, with 16—22 vessels, sometimes 2—3 parallel radial multiples in each vascular fascicle, and occasional vessels are solitary Fig. The vessel elements are morphologically heterogeneous Fig. The libriform fibers are nucleated and have simple pits, with no helical thickenings or septa Fig. The parenchyma is scanty and vasicentric.

Additionally, it forms concentric unlignified bands conjunctive tissue of more than 3 cells wide and alternating with bands of secondary xylem. Rays are heterocellular, uni- and multiseriate, 4—10 cells wide, with short procumbent, erect and square cells. In the multiseriate rays, there is a center with meristematic activity, where xylem and phloem are differentiated Fig. Wood of Iresine latifolia with successive cambium.

A, Stem showing successive cambia with abundant vascular rings; B, detail of vascular rings, showing the vessels in radial multiples, phloem, and conjunctive unlignified tissue; C, uniseriate ray and vessel elements with simple perforation plates and intervascular alternate bordered pits; D, nucleated libriform fibers; E, multiseriate unlignified ray with meristematic center; F, cambial zone with 2—3 layered cambial cells.

Diversity in morphology and sizes of vessel elements and fibers of Iresine latifolia wood. Additionally, the vascular cambium of each ring is distinctively active and differentiates new derivatives Fig. The secondary phloem is composed of 2 regions: the first is a functional region of parenchyma cells and angular sieve tube elements with simple sieve plates and nucleated companion cells Fig.

Prismatic crystals were observed in ray cells, and sandy and prismatic crystals are present in the pith and the parenchyma cells conjunctive tissue between the vascular rings. The number of concentric secondary xylem rings is highly variable between samples, and the larger the stem diameter, the higher the number of secondary xylem rings Fig.

In the 3 samples, the first 8 secondary xylem rings have a width of at least 1 mm. However, in sample 1, secondary xylem rings of 1 mm in width are present between the intermediate secondary xylem rings Fig. The secondary xylem rings closer to the stem periphery were the narrower ones mm , and the separation between them is minimal, joining a vascular ring to another through parenchyma cells, which anastomose. Widths of xylem rings and lengths of vessel elements and fibers in Iresine latifolia.

A, Widths of xylem rings in sample 1 triangles , sample 2 diamonds , and sample 3 squares ; B—D, lengths of vessel elements open circles and fibers close circles from pith to periphery. B, Sample 1; C, sample 2; D, sample 3. Each point represents the mean of 50 measurements for fibers and for vessel elements. Different letters indicate statistically significant differences. The fibers are almost twice the length of vessel elements, due to intrusive growth. In samples 1 and 2, the length increases from pith toward periphery, and some significant differences were found between some rings p 0.

Variance analyses confirmed significant differences in the length of vessel elements and fibers only for some of the secondary xylem rings from pith to periphery for each of the I. For vessel elements, there are no major differences between the first ring, which was formed from vascular cambium, and those that are closer to the periphery, which come from parenchyma cells that would correspond to rings 13 or This lack of size difference between the first and last vascular rings formed in 2 of the samples Fig.

Moreover, the results in vessel element lengths support the assertion of Robert et al. In fibers, there were significant differences between those differentiated from vascular cambium and those derived from successive cambia, with no clear pattern.

For example, in sample 1, their length increased, but in samples 2 and 3, fiber lengths decreased. In the 3 samples, the fibers became twice the length of vessel elements as a result of intrusive growth, similar to reports for C. The variation in vessel element and fiber lengths in the 3 samples of I. On the other hand, no association between the width of the vascular ring and the size of the vessel elements and fibers was found in any of the 3 samples.

For further comparative studies of the wood in other Amaranthaceae species, we recommend measuring the length of the vessel elements and fibers in any of the 2 most external vascular rings, especially when the complete stem cylinder is not available. Concentric successive cambia may develop complete vascular rings, discontinuous rings or an anastomosing network.

It is confirmed that I. This Iresine species has uniseriate rays with erect, square and short procumbent cells but also multiseriate rays with a meristematic center similar to the multiseriate rays reported for Hebanthe eriantha Poir.

Other Iresine species should be examined to ascertain whether multiseriate rays with a meristematic center are characteristic of the genus or unique to I. Their distribution is observed throughout the different districts of West Bengal to see their habitat and climatic preference. Ampelopteris prolifera were studied from six populations of three places viz. Thelypteris interrupta were found to grow in similar environments everywhere. Studied population of a Ampelopteris prolifera open environment from University Campus , b A.

Tracheary elements of Ampelopteris prolifera showing histochemical differentiation in tissue specific stain. For each population tracheary elements of different plants were studied to see the organ wise variations i. First, the tracheary elements were isolated following the standard maceration technique Johanssen ; measurements were taken from the macerated material. Length and width of protoxylem and metaxylem tracheids, vessels, and endplate of the vessel elements.

For each of the plant parts slides were prepared from different plants. Minimum 15 readings were taken and mean and standard deviations were calculated in MS Excel. Taxa mean was calculated from population mean for each of the plant organ.

The tissue somewhat distal in position from the apical parts and the portion of roots adjacent to the rhizome were taken for study. Hand-razor cut longisections were observed in the light microscope then passed though aqueous alcohol grades and air-dried samples were placed on stub, sputter coated with gold and examined with SEM model Zeiss EVO-MA 10 Carlquist and Schneider Histochemical and optical tests of vessel end-walls were done by using different tissue specific stains like phloroglucinol—hydrochloric acid and Toludine blue O lignified wall , ruthenium red pecto-cellulosic middle lamella , Johanssen ; Yata et al.

The plants invaded undisturbed to highly disturbed habitats by rapid proliferation. Their distribution is observed throughout West Bengal and it was seen that the moist climatic part of the state is congenial for their rapid proliferation because these plants are represented very poor or not at all in the drier parts of the state.

Tracheary elements i. In the Tables 2 , 3 longest and shortest tracheary elements of different organ are shown with bold font double and single superscript respectively by considering the population level variation. Among all three types of tracheary elements in root metaxylem components are longer and wider in all the population of A.

P3S where vessel elements are longer than the metaxylem components. In rhizome of A. P2S whereas in T. In petiole of A. P1S and P2Ss. In the costa of A. Metaxylem tracheids of rhizome are absent in all the populations except one that is in population 4 P2S. Longest metaxylem tracheid i. Longest vessel element was seen in the root of P3S i.

Longest vessel element endplates are seen in petiole of P1O i. Metaxylem tracheid was longest in root of P2DO i. Root vessel element of P2 DO was longest i. In both the taxa protoxylem tracheids are with spiral thickening and metaxylem tracheids are with scalariform thickening of opposite and alternate patterns. End-walls are pointed or tapered. In Table 4 a comparison of mean length—width of two taxa is provided. Taxa mean was calculated from population mean of each organ.

Among vessel elements of all the organ petiole vessel elements are longer in A. Width is similar of all the organ in case of vessel elements of A.

In comparison of two studied taxa tracheary elements of all the types are longer in the different organ of T. The petiole vessel elements of A. Vessels are with inclined and horizontal endplate. Endplates are with simple Fig. In the present observation vessel elements are found to be present in all the plant parts that is in root, rhizome, petiole, rachis and in the primary vein of the pinnae of the genera.

The uniqueness of the endplate is having completely Fig. In the vessel elements of primary vein the secondary thickening of the lateral wall is of reticulate type Fig. In the root-rhizome junction Fig. SEM images of Ampelopteris prolifera -vessel elements. Abbreviations used: ipp intermediate perforation plate, spp simple perforation plate, cpp compound perforation plate, pm pit membrane.

Lignified tissues of phloroglucinol—hydrochloric acid stained sections are showing reddish Fig. Transections of root and petiole showing vessel elements occupy the central part of the stele stained positively with phloroglucinol—hydrochloric acid Fig.

Toludine blue O which stains lignin blue did not stain the end-wall Fig. Walls with pectic substances are stained red with ruthenium red Fig. Very week double refraction in polarized light from the end-wall indicates their cellulosic nature and lignified part is refracted when seen in cross polarized light Fig. Vessels are associated either with xylem parenchyma in both the sides or with metaxylem and protoxylem tracheids in the other end Fig.

Vessel members are joined end to end and form vessel network Fig. Vessel—vessel inter connections and the interruption of the vessel network was observed from a part of tissue in longitudinal sections in white light Fig. Over 60 species of pteridophytes have managed to invade both intact and disturbed ecosystems, often outcompeting and even smothering native angiosperms and conifers Robinson Studied two taxa were also of similar nature always outcompeting the associated components and occupy a continuous large area.

Appearance of vessel characters in distantly related plant group is the result of parallel evolution Baas and Wheeler Phylogenetic distribution of vessel across vascular plants is: gigantopterids-the Permian seed plants only fossil representative of gymnosperm bearing vessel , some extant ferns and lycophyte, extant taxa of gnetales and angiosperms except some genera of basal clades.

The distribution of the vessel element is not apodeictic in seedless vascular plants. Recent method of vessel detection was established by Carlquist and Schneider ; following that, vessel elements are found to be present in the root, rhizome and petiole of Marsilea aquatic , Selaginella , Pteridium aquilinum terrestrial , Astrolepis, Woodsia, Aleuritopteris and Cheilanthes xeric Carlquist and Schneider ; Sen and Mukhopadhyay i.

Present investigation reports vessel elements in A. Presence of vessel elements through entire vascular connections of the studied taxa is established first time by the present study. In monocot secondary xylem vessels are present in the root and absent in leaves and stems later on vessel replaced tracheid in leaf and stem vasculature Cheadle Another important feature noticed in A.

The orientation of endplate gradually changed from root to leaf vasculature, more advanced type is found in root and gradually become primitive to leaf previously mentioned by Cheadle , is not supported by this study. All plant organ studied separately, revealed the presence of more elongated end-walls in the petiole. Series of intermediate characters i.