Roots, stems and leaves are present in all vascular plants: pteridophytes, gymnosperms and angiosperms. Rhizophore are shoots that grow downwards with roots in the apex and that are recognised in living Selaginella and Carboniferous Lepidodendrales.
What is rhizophore pteridophyta?
Rhizophore. In many species long, cylindrical, unbranched and leafless structures arise from the lower side of the stem at the point of dichotomy called rhizophores. They grow vertically downwards and produce tufts of adventitious roots.
Which organ of the Selaginella is?
NEET Question. Rhizophore is an individual structure in Selaginella which is known as “Organ Sui generis” which means it is an intermediate part between root and shoot. According to J.C.Shoute, Organ sui generis is one that has not arisen as result of metamorphosis of any organ.So, the correct answer is “Rhizophore”.
What is the nature of rhizophore of Selaginella?
Explanation: The morphological nature of rhizophore of selaginella is unusual. It is considered a root and stem both. Bower & Gobel considered it a structure intermediate between the root and stem, various theories are given to prove this thing.
Why can the rhizophore of Selaginella be considered as root?
They can be considered as roots because they can give rise to leafy branches. … It is like an assisted structure which may originate from a branching point and branch out in two ways after making a contact with a hard surface or the soil.
Which steel is found in Rhizophore of Selaginella?
Rhizophore of Selaginella has Monoarch stele so the student can conformed and follow for this one to gather right answer in a winning way.
Which type of stele is found in Rhizophore of Selaginella?
Each stele is made up of diarch and exarch xylem in centre. The steles are connected with the cortex by means of many tube-like structures called trabeculae, Monarch which are modified endodermal cells with casparian strips on their lateral walls. The stems contain no pith.
Does Selaginella belong to Pteridophytes?
❇ Selaginella Belongs to the pteridophytes phyllum of Kingdom Plantae. They come under Cryptograms( Non flowering plants). These are also known as Club moss. … ↪ Pteridophytes are also known as Vascular Cryptograms as they have vascular tissues unlike Bryophytes, and Thallophytes which don’t have vascular tissues.
Does Selaginella have Microphylls?
Description. Selaginella species are creeping or ascendant plants with simple, scale-like leaves (microphylls) on branching stems from which roots also arise. … In Selaginella, each microphyll and sporophyll has a small scale-like outgrowth called a ligule at the base of the upper surface.
What is Heterophyllum Selaginella?
In the sub-genus Heterophyllum, the leaves are of two types; small leaves and large leaves, that are arranged in four rows along the stem. There are two rows of small leaves on the dorsal side of the stem and two rows of larger leaves on the ventral side or in a lateral position (Fig. 7.46B).
Is a fern a Pteridophyte?
Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as “cryptogams”, meaning that their means of reproduction is hidden. Ferns, horsetails (often treated as ferns), and lycophytes (clubmosses, spikemosses, and quillworts) are all pteridophytes.
What is Selaginella Strobilus?
The genus Selaginella is classified in the division Lycophyta, which includes the numerous plants commonly known as clubmosses and spike mosses. Similar to their close relatives, Selaginella plants develop strobili, spike-like reproductive organs that form on fertile branches.
Why are Pneumatophores spongy?
The root surface of the pneumatophores is covered with lenticels, i.e. raised pores allowing gas exchange between the atmosphere and the internal tissues. The lenticels take up air into the spongy tissue of the pneumatophore. The oxygen is then spread throughout the plant.
What is Selaginella Trabeculae?
Trabeculae is one of the projections from the cell wall which extend like a cross-bar across the cell cavity of ducts of some plants like moss and Selaginella. … These cells are highly elongated and span an air space which intervenes between the cortex and the stele.
Where Trabeculae are found in Selaginella?
In the shoot apex of Selaginella kraussiana A. Br., air spaces develop between the endodermal cells, isolating the two steles from the cortex. The endodermal cells elongate to form trabeculae connecting the two tissues.
Which type of stele is found in Equisetum?
Stele is of ectophloic siphonostelic type. ADVERTISEMENTS: 15. Each vascular bundle is conjoint, collateral, closed, and consists of xylem, phloem and some parenchyma.
Is Siphonostele modified?
Siphonostele:
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.
What are Ligulate leaves?
Ligulate leaves are also known as club or spike moss. The leaves are generally simple, microphyllous and sessile. The lateral leaves are bigger compared to the dorsal leaves. Every leaf consists of a small scale on the adaxial surface which is known as ligule.
What is organ sui generis?
The term organ sui generis is latin phrase which means unique. When we study the anatomy of the plant Selaginella it is shown that rhizophore is a unique and different structure as compared to root and stem although it presents on the branch opening of stem and gives rise to root.
Which one of the following is absent in Selaginella?
Root hairs are absent (Fig. 215). 3. Presence of a thick-walled hypodermis.
What is the function of Ligule?
Of the three component organs of the grass leaf – blade, sheath and ligule – the ligule is the least studied and the least understood. Traditionally, it has been assumed to act in a passive way in protecting the culm and leaves that it encloses from the entry of water, dust and harmful spores.
What is the modified stem of Selaginella?
Option B: Trabeculae in Selaginella stem are a modified form of endodermal cells.