Pteridophyta III:

Heterosporous Leptosporangi

ate Ferns

Reporter: Desiree B. Singson

Topic Outline

I. Definition of Heterospory and LeptosporangiateII. Heterosporous Order (Salvineales)

A. Family Marsileaceae1. Genera

a. Marsilea b. Regnellidium c. Pilularia

2. Morphology3. Reproduction4. Habitat and Ecological Uses

B. Family Salviniaceae1. Genera

a. Salviniab. Azolla

2. Morphology3. Reproduction4. Habitat and Ecological Uses

III. Studies

Heterospory• A condition in which the life

cycle of a plant contains two types of spores, microspores and megaspores.

• Gives rise to distinct microgametophytes and megagametophytes.

• Necessary precondition for the evolution of seeds.

Leptosporangiate

• From Greek word “Leptos”, fine or small• Type of sporangium ontogeny wherein the

sporangium arises from a single surface cell whose derivatives protrude from the surface of the plant

• Leptosporangiate sporangia are small, produce a definite number of spores and have a wall layer of cells in thickness.

Salviniales

A. Family Marsileaceae- Constituted of three genera: 1. Marsilea (approx. 50-75 spp.)2. Regnellidium (1 spp.)3. Pilularia (approx. 3-6 spp.) (Cuneo et al,

2013)

-Amphibious Ferns (except for 1 species of Marsilea which is xerophytic)

1

2

3

Classification

Kingdom: Plantae Division: Pteridophyta Class: Pteridopsida Order: Salvineales Family: Marsileaceae Genera: Marsilea

Regnellidium Pilularia

MORPHOLOGY

Marsilea sp.

Description: Rhizome : The stem is a long and slender rhizome-Roots: primary root formed on the stem is short-lived and is soon replaced by adventitious roots, which arise gradually at the nodes on the underside of the stem-Leaves: The leaves arise from the upper side of the stem and are arranged intwo alternate rowsSporocarps: nut-like, epipetiola bodies, borne laterally on the petioles

Anatomy of the Rhizome Can perennates- which are

embedded in soil or mud Elongated, branched, stolon-

like stem Branches arise at the base of

the leaves Mature stem- arranged in

amphiphloic siphonostele form Pericycle cells

covers the inner and outer phloem

covered by endodermal layer

Pith may be parenchymatous or sclerotic

Anatomy of Leaf and Petiole

• Leaflet veins- Dichotomously branched

• Sunken stomata- both leaf surface

• Presence of upper epidermis and lower epidermis• Mesophyll layer– Spongy – Palisade

Anatomy of Roots

• Adventitiously branched • Contains monarch and

diarch proto- steles with exarch arrangements• Stele- surrounded by a

single layer of pericycle and an endodermis• Inner cortex is sclerotic,

the outer contains air chambers

Sporocarp Morphology

REPRODUCTION

Sporophyte Reproduction:

SporocarpSori

Spores

Diagram showing stages in the dehiscence of Marsilea sporocarps.

Gametophyte Reproduction

Embryogeny-Development of the embryo is initiated several hours after fertilization by nuclear and cell division of the zygote.1. Cytokinesis2. 2nd cell division resulting to

formation of 4 cells (develops into foot, leaf, stem and root of the embryonic sporophyte.

3. Vegetative cells of gametophyte are stimulated to divide as an embryonic sporophyte develops and forms a sheathing calyptra .

4. Surface cells of the gametophyte tissue develop rhizoids

5. Cells develop chloroplast and growth is rapid

A. Marsilea drummondii (SEM longitudinal radial section)

B. Marsilea drummondii (transverse logitudinal section)C. Marilea drummondii sorusD. Marsilea mutica sporocarpH. Marsilea sporocarp wall

Legend:sw- sporocarp wall S1 and 2-sorophore segenentsVb-vascular bundleSo-sorusMe-magasporangiaMi-microsporangiaIn-indusiumRe-receptacleS-sorophoreLv-lateral veinE-epidermal zonesl- sclerenchymatous zonePa-parenchyma zoneSc-stomatal chamberHb-hair base

Regnellidium diphyllum

Description:-characterized by having highly reduced pinnately compound leaves-having sori and sporangia enclosed in a specialized structure known as a sporocarp that has a sclerenchymatous wall -bearing micro- and megaspores that have a conspicuous proximal, six or seven-lobed ornament or gelatinous extension subtended bya rim (Marsilea) known as an acrolamella

E. Regnellidium diphyllum sporocarpH. Regnellidium diphyllum sporocarp wall

Legend:Sw-sporocarp wallS-sorophoreIn-indusiumMe-megasporangiaMi-microsporangiaRe-receptacleE-epidermal zonesl- sclerenchymatous zonePa-parenchyma zone

Pilularia sp.

Description:- Rhizomes short- to long-creeping, branching, bearing roots at nodes, bearing septate hairs or almost glabrous.- Leaves monomorphic, not articulated to rhizome, arising at nodes, with long stalks

lacking lamina segments, herbaceous, glabrous. - Veins greatly reduced, undivided. - Sporocarps globose, sessile or stalked, hardened, hairy, attached to the rhizome at the base of the leaf stalks, opening with two valves, each containing at least two sori. Each sorus containing both mega- and microsporangia. Megaspores spheroidal toslightly ellipsoidal, plain to slightly undulate; microspores spheroidal, and plain, papillate or rugulate.

F. Pilularia globulifera sporocarp

I. Pilularia globulifera sporocarp wall

Legend:

Sw-sporocarp wallS-sorphoreRe-recptacleMi-microsporeIn-indusiumE-epidermal zonesl- sclerenchymatous zonePa-parenchyma zone

Habitat and Uses

• -Used as vegetation for some animal, cultivated as ornamental and has found to have nerve relaxant nature and curative properties for various other ailments of nervous system and its nutritional value

Studies on MarsileaceaeComparative Morphology of Reproductive Structures in

Heterosporous Water Ferns and a Reevaluation of the Sporocarp Nathalie S. Nagalingum, Harald Schneider,y and Kathleen M. Pryer (2006)

Structure and Function of spores in the Aquatic Heterosporous Fern Family Marsileaceae

Harald Schneider and Kathleen M. Pryer (2002)

Ecophysiological Traits of Leaves of Three Marsilea Species Distributed

in Different Geographical RegionsTai-Chung Wu and Wen-Yuan Kao (2011)

Marsilea quadrifolia linn. - A Valuable Culinary and Remedial Fern in Jaduguda, Jharkhand, India

Prafulla Soni and Lal Singh

Salviniales

B. Family Salviniaceae- Constituted of 2 Genera:1. Salvinia (approx. 12 spp.)2. Azolla (approx. 7 spp.)(Nagalingum et al, 2008)

2

1

VEGETATIVE MORPHOLOGY

Salvinia sp.

Description: - Stems: dichotomously branched rhizomes, protostelic and aerenchymatous- Leaves: simple, dimorphic (fertile different from sterile), aerenchymatous, at

maturity in whorls of three (2 floating, 1 submerged and root-like), blades round to oblong, entire with water repellent trichomes in upper surface

- Sporocarps: sporocarp which is interpreted as modified sorus with the indusium functioning as protective wall is globose, heterosporous, each bearing either one megasporangium or several microsporangia at maturity

Salvinia sp.A. Salvinia

oblongifolia fertile node

B. Salvinia oblongifolia submerged organ

C. Salvinia auriculata sorus

D. Salvinia minima fertile branch

E. Salvinia oblongifolia sorus

F. Salvinia oblongifolia sorus

G. Salvinia auriculata sori

Azolla sp.

Description:-consist of branching stems densely clothed with alternate bilobed leaves-Each leaf is composed of chlorophyllous dorsal lobe and a submerged achlorophyllous ventral lobe.-have true roots that arise endogenously at intervals along the stem-The roots bear root hairs as long as they exist.-Sporocarp: Formed in groups of two or four in the axil of the dorsal lobe of a basal leaf of a branch

SPOROCARP MORPHOLOGY

Azolla sp.

A. Azolla nilotica fertile plantB,C. Azolla nilotica reproductive unitsD. Azolla nilotica reproductive unitsE. Azolla filiculoides megasporangiate sorusF. Azolla filiculoides sorus

Azolla Life Cycle

Schematic drawings of spore-bearing structures of Marsileaceae (A, B) and Salviniaceae (C, D).

Studies on Salvinia and Azolla

Phytoremediation Potential of Aquatic Macrophyte, Azolla

Anjuli Sood, Perm L. Uniyal, Radha Prasanna, Amrik S. Ahluwalia

Heavy metal induced physiological alterations in Salvinia natans

Bhupinder Dhir, P. Sharmila , P. Pardha Saradhi , S. Sharma , R. Kumar , Devinder Mehta