Siphonosteles may be of following three types:
- Ectophloic Siphonosteles- In the ectophloic siphonostele, the xylem is in the form of a hollow cylinder surrounding a pith with the phloem occurring only outside the xylem. It is found in Equisetum and some ferns like Osmunda and Schizaea.
- Equistelic Siphonostele- In this type of stele the central is occupied by pith. ...
- Equistelic Siphonostele- ...
What is the stele present in equise?
> The stele present in Equise... Haplostele consist of smooth ore of xylem which is surrounded by a phloem ring.ex- Seleginella Actinostele consist of star shape xylem core with many radiating arms.ex- Lycopodium Plectostele consist of xylem core broken into a number of parallel plates.ex- Lycopodium clavatum
What are the features of Equisetum?
The jointed plant body with intercalary meristem, whorled leaves alternating with the branches, presence of vascular bundles, sporangia being borne on sporangiophores are some of the notable features. Equisetum is remarkable for the curious intermingling of hydrophytic and xerophytic characters.
What is the stelar organisation of equiSetum?
Campbell (1939) believes that the stelar organisation in Equisetum is more akin to forms than to Lycopodineae. He states that the intermodal bundles represent fused leaf traces as in ferns. The fact that the vascular bundles are not as complicated as in ferns is due to the reduced nature of the leaves.
What is the difference between horsetail and Equisetum?
"Horsetail" redirects here. For other uses, see Horse tail (disambiguation). Equisetum ( / ˌɛkwɪˈsiːtəm /; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family of ferns that reproduce by spores rather than seeds.
What type of stele is found in Equisetum?
SiphonosteleSo the correct option is "Siphonostele".
What are the types of stele?
There are several types of stele found in pteridophytes which are:Protostele.Siphonostele.Solenostele.Dictyostele.Polycyclic stele.Eustele.Polystele.
What kind of stele do gymnosperms have?
Additional Information: The gymnosperm and dicotyledonous stem are distinguished by Eustele. Eustele can be characterized as an ectophloic siphonostele type with overlapping gaps in the leaves.
Which metal is present in Equisetum?
Horsetails (equisetum) as indirect indicators of gold mineralization.
What type of stele is present in Lycopodium stem?
In Lycopodium, the stele is protostelic but the nature and arrangement of xylem and phloem differ in different species.
Which type of stele is found in Pinus?
The stele is eustelic or polyfascicular endarch siphonostele. 6. Vascular bundles are conjoint, collateral, open and endarch, and resemble greatly with that of a dicot stem.
Does Equisetum have a siphonostele?
The node cross section of Equisetum looks quite different: the siphonostele is complete and leaf traces emerge from the solid vascular cylinder only at these locations (Figure 6.4). Above the node, the vascular cylinder divides again to form the discrete bundles you observed in the internode section.
Which stele is found in pteridophytes?
Protostele is a non-medullated stele that comprises a central core of the xylem surrounded by a cluster of phloem.
Which is the simplest type of stele in pteridophytes?
Protostele This is the most primitive and simplest type of stele. Pith is absent in protostele i.e. it is non-medullated. Majority of the pteridophytes show protostelic conditions in their rhizome, stem or roots.
What is unique about Equisetum?
Growth form. Horsetails have a unique growth form that distinguishes them amongst all other ferns. Their stems, leaves and roots are all quite unique and makes the Equisetum species a very interesting group of plants.
What are the characteristics of Equisetum?
The stems are erect, hollow, ribbed, and jointed. The leaves are vestigial (scale-like) in whorls at the nodes. Some species have branches in whorls at the nodes. Horsetails are flowerless and reproduce from spore-forming cones at the ends of fertile stems (Figures 2 and 3).
What is the structure of Equisetum?
The plant body of Equisetum has an aerial part and an underground rhizome part. The rhizome is perennial, horizontal, branched and creeping in nature. The aerial part is herbaceous and usually annual. Majority of the species are small with a size range in between 15 and 60 cm in height and 2.0 cm in diameter.
What are steles in plants?
The Stele. The plant stele consists of the primary vascular system of the plant axis (stem) and its associated ground tissues (e.g., pith). The stele consists solely of primary tissues differentiated from procambial strands derived from the apical meristem.
What are the parts of stele?
The stele consists of vascular tissue, ground tissue or pith, and a pericycle. The pericycle mainly forms the outermost boundary of the stele. Therefore, the stele can be explained as the vascular bundle. The stele is composed of mainly three tissues which are the pericycle, the xylem, and the phloem.
What is stele and its types in pteridophytes?
Stele is the central vascular cylinder of the axis taken as a whole. It incudes the primary vascular tissues (Xylen and Pholem) or plus any associated fundamental or ground tissue present ie. pith, pericyele, interfasicular regions, Leaf gap. The concept of stele as fundamental unit of vascular system was put forward.
What is stele and its function?
The stele functions in the transport of water, nutrients, and photosynthates, while the cortical parenchyma fulfills metabolic functions that are not very well characterized. To better understand the molecular functions of these root tissues, protein- and phytohormone-profiling experiments were conducted.
Where is phloem present in protoxylem?
9. Phloem is present in between the angles of protoxylem.
What is the name of the uppermost whorl of sterile leaves?
This is called annulus. Morphological nature of annulus is controversial. According to some it is the uppermost whorl of sterile leaves while others are of the opinion that it is the lowermost sterile sporangiophore (Fig. 246). Botany, Pteridophyta, Equisetum, Anatomy of Equisetum.
Which layer of the cortex contains casparian strips?
Innermost layer of cortex is the endodermis, the cells of which contains casparian strips. But in species like E. sylvaticum, a layer of inner endodermis is also present (Fig. 239 C, D).
Is hollow pith cavity solid?
5. Hollow pith cavity is not well-developed and sometimes it becomes solid.
What is the body of Equisetum?
Morphology of the Plant: The plant body of Equisetum consists of an underground prostrate rhizome from which spring up a number of aerial shoots (Fig.100). The aerial shoots may be perennial or deciduous. There is a great variety in the height of the aerial shoots.
Where is Equisetum found?
They are found mostly in North temperate and tropical zones.
What are the stomata composed of?
The stomatal apparatus is composed of an inner pair of guard cells and a pair of subsidiary cell’s which cover the guard cells. Another characteristic feature of the stomata is the presence of rib like silica thickenings present between the subsidiary cells and guard cells.
What are the leaves of a rhizome?
The leaves are small microphyllous and scaly. They exhibit a whorled phyllotaxy. As in rhizome, the leaves are connate at the base. The number of leaves per whorl ranges from 3-40. The leaves are in line with the longitudinal ribs below and alternate with the grooves.
How big are eucalyptus shoots?
They range from a few centimetres (E. scirpoides) to several metres (E. giganteum). In some instances aerial shoots as long as thirteen metres have been found. In spite of this length, the diameter is very less. Maximum diameter of the stem reaching ten centimetres, is reported in E. schallneri.
Which sub-genus of stomata is on level with the epidermal cells?
In the sub-genus Euequisetum (E. arvense, E. svlvaticum etc.), the stomata are on level with the epidermal cells, and or either scattered or arranged in broad bands. In the sub-genus Hippochaete (E. giganteum, E. hyenale etc.), the stomata are sunken and are arranged in narrow bands.
Who worked on the stomatal development of the equisetum?
Hauke (1963), Pant and Mehra (1964) and Pant and Kidwai (1968) have worked on the stomatal development in Equisetum. The stomatal structure is used as a criterion to classify Equisetum into two sub-genera.
What is the name of the Equisetum plant?
Two Equisetum plants are sold commercially under the names Equisetum japonicum (barred horsetail) and Equisetum camtschatcense (Kamchatka horsetail). These are both types of E. hyemale var. hyemale, although they may also be listed as separate varieties of E. hyemale.
What is Equisetum hyemale?
Equisetum hyemale L. – rough horsetail, rough scouring rush; most of non-tropical northern hemisphere. The North American subspecies Equisetum hyemale affine (Engelm.) A.A.Eat. may be treated as a separate species Equisetum prealtum Raf.
What is the MXE activity in Equisetum?
The crude cell extracts of all Equisetum species tested contain mixed-linkage glucan : Xyloglucan endotransglucosylase (MXE) activity . This is a novel enzyme and is not known to occur in any other plants. In addition, the cell walls of all Equisetum species tested contain mixed-linkage glucan (MLG), a polysaccharide which, until recently, was thought to be confined to the Poales. The evolutionary distance between Equisetum and the Poales suggests that each evolved MLG independently. The presence of MXE activity in Equisetum suggests that they have evolved MLG along with some mechanism of cell wall modification. Non- Equisetum land plants tested lack detectable MXE activity. An observed negative correlation between XET activity and cell age led to the suggestion that XET may be catalysing endotransglycosylation in controlled wall-loosening during cell expansion. The lack of MXE in the Poales suggests that there it must play some other, currently unknown, role. Due to the correlation between MXE activity and cell age, MXE has been proposed to promote the cessation of cell expansion.
What is the name of the subgenus Equisetum?
The living members of the genus Equisetum are divided into three distinct lineages, which are usually treated as subgenera. The name of the type subgenus, Equisetum, means "horse hair" in Latin, while the name of the other large subgenus, Hippochaete, means "horse hair" in Greek. Hybrids are common, but hybridization has only been recorded between members of the same subgenus. While plants of subgenus Equisetum are usually referred to as horsetails, those of subgenus Hippochaete are often called scouring rushes, especially when unbranched.
Where did horsetails originate?
The oldest remains of modern horsetails of the genus Equisetum first appear in the Early Jurassic, represented by Equisetum dimorphum from the Early Jurassic of Patagonia and Equisetum laterale from the Early-Middle Jurassic of Australia.
Why is the horse tail called the horse tail?
The name "horsetail", often used for the entire group, arose because the branched species somewhat resemble a horse 's tail. Similarly, the scientific name Equisetum is derived from the Latin equus ("horse") + seta ("bristle").
Where are equisetums native to?
The genus Equisetum as a whole, while concentrated in the non-tropical northern hemisphere, is near- cosmopolitan, being absent only from Antarctica, though they are not known to be native to Australia, New Zealand nor the islands of the Pacific. They are most common in northern North America (Canada and the northernmost United States), where the genus is represented by nine species ( E. arvense, E. fluviatile, E. hyemale, E. laevigatum, E. palustre, E. pratense, E. scirpoides, E. sylvaticum', and E. variegatum ). Only four ( E. bogotense, E. giganteum, E. myriochaetum, and E. ramosissimum) of the fifteen species are known to be native south of the Equator. They are perennial plants, herbaceous and dying back in winter as most temperate species, or evergreen as most tropical species and the temperate species E. hyemale (rough horsetail), E. ramosissimum (branched horsetail), E. scirpoides (dwarf horsetail) and E. variegatum (variegated horsetail). They typically grow 20 cm–1.5 m (8 in–5 ft) tall, though the "giant horsetails" are recorded to grow as high as 2.5 m (8 ft) ( E. telmateia, northern giant horsetail), 5 m (16 ft) ( E. giganteum, southern giant horsetail) or 8 m (26 ft) ( E. myriochaetum, Mexican giant horsetail), and allegedly even more.
What type of stele is the most complex?
This type of stelar organization is the most complex one amongst all pteridophytes. Such type of steles are siphonostelic in structure. Each such stele possesses an internal vascular system connected with an outer siphonostele. Such connections are always found at the node. A typical polycyclic stele possesses two or more concentric rings of vascular tissue. This may be a solenostele or a dictyostele. Two concentric rings of vascular tissue are found in Pteridium aquilinum and three in Matonia pectinata.
Where did the name "stele" come from?
The name stele has been derived from a Greek word meaning pillar. This way, the stele is defined as a central vascular cylinder, with or without pith and delimited the cortex by the endodermis. Van Tieghem and Douliot (1886) recognized only three types of steles. They also thought that the monostelic shoots were rare in comparison ...
How did siphonosteles evolve?
According to the theory proposed by Boodle (1901), and Gwynne-Vaughan (1903), the siphonostele has been evolved from the protostele by a transformation of the inner vascular tissue into parenchyma. ADVERTISEMENTS: A siphonostele may be of the following types: 1. Ectophloic:
What is the modification of a protostele?
This is the modification of protostele. A stele in which the protostele is medullated is known as siphonostele. Such stele contains a tubular vascular region and a parenchymatous central region. Jeffrey (1898) interpreted that the vascular portion of siphonostele possessing a parenchymatous region is known as a gap immediately above the branch trace only or immediately above leaf and branch trace.
What is the stelar theory?
In protostele, the vascular tissue is a solid mass and the central core of the xylem is completely surrounded by a layer of phloem. This is the most primitive and simplest of steles.
What are the two groups of vascular plants?
The vascular plants have been divided into two groups on the basis of the presence or absence of the leaf gaps. These groups are 1. Pteropsida and 2. Lycopsida. The ferns, gymnosperms and angiosperms are included in Pteropsida, whereas the lycopods, horse tails, etc., are included in Lycopsida.
Which siphonostele is surrounded by vascular tissue?
1. Ectophloic: In this type of siphonostele, the pith is surrounded by concentric xylem cylinder and next to xylem the concentric phloem cylinder. 2. Amphiphloic: In this type of siphonostele the pith is surrounded by the vascular tissue. The concentric inner phloem cylinder surrounds the central pith.
