study of psilotum plant, Slides of Botany and Agronomy

Download study of psilotum plant and more Slides Botany and Agronomy in PDF only on Docsity! Psilotum ZAINAB KHALID morpholog VA — * Immature Sporangiun ~ Plant Body: It issporophyte and contains following parts 1. Rhizome 2. Aerial branch 3. Sporangia Rhizome Rhizome The horizontal portion is rhizome Buried in soil or humus. Dichotomously branched 2 celled rhizoids are present near the apices of the younger branches These rhizoids absorb water and nutrients fram soil for aerial branches Stem Anatomy It is circular in outline from base, pentagonal near the first dichotamy and triangular between successive dichotomies . It has following parts. 1. Epidermis 2, Cortex 3, Steler system © Cutaie Epiderrnis —» Outer carter (Chisranchymatous| ® Undedermin » © Parieyale » Phisam oMatanylerm 1: Epidermis * There is a single layer of epidermis present outside * [tis heavily cutinized * Stomata are also present on epidermis , situated at the grooves c) Parenchymatous 5 = a a Ez 2 =a c a z 2 & + 2 “ a a = a — = a & They form the major portion of the stem. SLEIET salen The stele of Psilotum consists of following parts a, while pericycle and pith are usually absent. 1 Endodermis There is well developed endodermis between the stele and the corte. These cells has casparian bands on their radial walls The xylem is actinostelic and radial in outside in 6 rays, the protoxylem is located at the tip of the rays. In the center the metaxylem xore is present The cells of xylem are thick walled and their main function is transport of nutrients Sclorotic pith Fig. 21, Poilotwn : T.5. of Acrial Shoot (a sector enlarged) 4: Phloem Between the endodermis and the xylem thereis phloem. tt is of thin walled cells tt consist of sieve cells and sieve areas in their oblique end walls. Nuclei disintegrate at maturity Sclorotic pith Fig. 21. Psilotwm : T.S, of Aerial Shoot (a sector enlarged) Reproduction lt ischaracterized by altemationof generation Both spore producing and gamete producing regeneration are independent Sporophyte reproduces by asexual reproduction ‘Gametophyte reproduces by sexual reproduction Asexual reproduction ( the sporophyte ) Sporophytes reproduces by formation of asexual reproductive units, Called as spores , produced in complex trilobed structure synangium Structure of synangium Each synangium is trilobed , stalked structure borne at the apexof short lateral branch . Abilobed appendage is present at the base of each synangium that curve and surround the stalk of synangium Pat 1, Padotam, T.5. of Mature Symangium wit Sexual reproduction ( Ser gametophyte } The gametophyte lives underground as a saprophyte, sometimes in a mycorrhizal association. When the gametophyte is mature, it produces both egg and sperm cells. ... The gametophyte of Psilotum is unusual in thatit branches dichotomously, lives underground and possesses vascular tissue. Antheridium The gametophyte of Psilotum is called as Prothallus . It contains parenchyma cells and there is a strand of tracheids extending back fromthe Fig: A mature prothellus apex. Aevargarial coll Fig: A-B: Development of antheridium, C: Mature antheridium, 0 Antherozoid -¢ as ea tell * camttons (ar a) GENERATION SPOROPHTTIC (in) GENTRATION Fig. 7.22 : Lila cycle of Psviotuer