a comparative study on the petiolar histology of selected plants in capparidaceae and sterculiaceae
DESCRIPTION
A Comparative Study on the Petiolar Histology of Selected Plants in Capparidaceae and Sterculiaceae .TRANSCRIPT
A Comparative Study on the Petiolar Histology of Selected Plants in
Capparidaceae and Sterculiaceae
Dissertation submitted to the Mahathma Gandhi University, Kottayam, in partial fulfillment for the Degree of Bachelor in
Science.
By,
ANUMOD.I.S
Reg No: 351105
Department Of Botany,
Sacred Heart College,
Thevara,
Kochi-682013.
2006-2009
CERTIFICATE
This is to certify that the dissertation entitled “A COMPARATIVE STUDY ON THE PETIOLAR HISTOLOGY OF SELECTED PLANTS IN CAPPARIDACEAE AND STERCULIACEAE” submitted in partial fulfillment of the requirement for the award of degree of Bachelor of Science in Botany to the M G University, Kottayam is a record of bonafide research work carried out by ANUMOD I S (Reg No: 351105) Under my guidance and supervision.
Date: 24/02/2009 Dr. George Joseph,
Thevara Supervising Teacher,
Department of Botany,
Sacred Heart College,
Thevara.
Acknowledgement
I am thankful to Dr George Joseph lecturer in the Department of Botany, S H College, Thevara, for his guidance and encouragement throughout the course of this project.
I extant my grateful to Dr. V.J. Dominic, Head of the Department of Botany, S.H. College, Thevara, for providing all the facilities necessary for this work. I wish to acknowledge the authorities of Library of college facilities and timely help.
I wish to acknowledge the authorities of the library of our college faculty for their timely help. I also sincerely thank all the teaching and non-teaching staff of the Department of Botany who helped me during different stages of this work. My Sincere thanks to my parents, my brother and all my friends who helped me in this attempt in one way or other.
March 2009 Anumod I S
Thevara Reg No: 351105
Contents
Chapter Pg No
Introduction
1.1 Angiosperms : 01
1.2 Anatomy in relation to Taxonomy : 03
1.3 Anatomy of dicotyledonous stem : 09
1.4 Anatomy of dicotyledonous leaf : 11
1.5 General anatomy of angiosperm petiole : 12
1.6 Tissues in the petioles of dicots : 14
1.7 Family: Capparidaceae : 17
1.8 Family Sterculiaceae : 20
Materials and Methods : 22
Objectives : 22
Observation
Petiole anatomy of selected family members : 23
Discussion : 27
Summary : 28
Reference : 29
Annexure
8.1 Figures and Plates :
Plants selected
CLEOME VISCOSA.L CLEOME BURMANNI.W & A THEOBROMA CACAO.L GUAZUMA TOMENTOSA.H. B. K
Chapter: 1
INTRODUCTION AND REVIEW OF LITERATURE
ANGIOSPERMS
Angiosperms, the flowering plants form the largest group of plant kingdom, including about 300 families (411 Families, Hutchinson), 8,000 genera and 300,000 species(B P Pandey). They are considered to be the highest evolved plants on the surface of the earth. From cretaceous age, the angiosperms eclipsed all other vegetations and now they are dominant. They are found almost everywhere in each possible type of habitat and climate. They occur in deep lake, deserts, in beds of seas and even on high peaks of mountains. The species of Opuntia can survive without water in acute desert conditions, where as on the other hand the species of Hydrilla are extremely sensitive to draught conditions some species found on rocks, some in waterfalls and also some are marine. The species of Rhizophora, popularly known as ‘Mangrove vegetation’ are found near the water of the sea. The epiphytes, parasites, saprophytes, Symbionts and even insectivorous plants are also not uncommon.
They may be annual, biennial as perennial, herbs, trees, shrubs, climbers, and twiners. On the other hand the angiosperms may be as minutes unsize as a pin head,
eg : Wolffia miroscopica. On the other hand, extremity like eculeptiles of Australia may reach up to 300 feet in height.
Following Are The Salient Feature Of Angiosperms
The sporophyte, which is the dominant plant in the life cycle, is differentiated into roots stem and leaves.
The highest degree of perfection of the vascular system wit true vessels in the xylem and companion cells in the phloem.
The organization of the microsporophylls [stamens] and megasporosphylls [carpels] into a structure called the flower, which is typical only of the angiosperms.
The presence of four microsporangia [pollen sacs] per microsporophyll [stamen].
The ovules are always enclosed in an ovary, which is the basal region of the megasporophyll.
Production of two kinds of spores, microspores [pollen grains] and megaspores. Angiosperms thus are heterosporous.
Presence if a single functional megaspore which is permanently retained within the nucellus or megasporangium.
Adaptation f flowers to insect pollination.
Pollination consists of the transference of pollen grains from anther to stigma.
Spore dimorphism having resulted in the production of gametophytes, male and female.
Extreme reduction in size, duration of existence and complexity of the gametophytes, which are extremely parasitic.
The male gametophyte has reached the limits of reduction. It consists only of the pollen grain and the pollen tube contains the tube nucleus and two male gametes or nuclei.
The male cells (gametes) are non-ciliated.
The female gametophyte lacks any extensive development of vegetative tissues. It consists of three egg apparatus calls, three antipodal cells and two polar nuclei in the centre of the embriosac.
The non-motile male cells or nuclei are carried bodily to the neighborhood of egg apparatus by the pollen tube.
The seed or seeds remain closed in the ripened ovary called the fruit.
The phenomenon of double fertilization or fusion is the characteristic of the angiosperms.
The endosperm develops after fertilization, it is tripod.
The angiosperms are completely adapted to life on land.
Anatomy in relation to taxonomy:-
Anatomy provides evidence concerning the inter relationships of larger groups such as families, or in helping to establish the real affinities of genera of uncertain taxonomic status. Anatomy sometimes proves very helpful individual identifications. The anatomical methods are of great value in identifying the herbarium specimens, which do not bear flower or fruits (Sivarajan, 1984).
The most important anatomical characters of which the taxonomic value has become well established. These characters are as follows:-
HAIRS
These are glandular and non-glandular categories, each of which may be sub-divided according to the number of component cells. Smaller variations in size and density should be treated as a basis for the separation of closely related genera and species.
STOMATA
The term stomata mean the pair of guard cells together with the aperture between them. The cells surrounding a stoma differing from the remaining epidermal cells are known as subsidiary cells. There are four main types of stomata found in the dicotyledons. These are – Ranunculaceous, Cruciferous, Caryophyllaceous and Rubiaceous.
EPIDERMAL CELLS AND HYPODERM
Epidermal cells differ considerably in size, shape and outline in different plants. Characters such as a party or wholly crystalliferous epidermis or the cells with specific chemical contents.
VEINS
The comparative structure of the veins of two leaves and in particular in structure of the vascular bundles and their relationship to the surrounding tissues.
PETIOLE
The petiole is of considerable taxonomic importance. Since its structures is little affected by environmental change.
MICROCHEMISTRY
Several types of chemical deposits occur in plants tissues. These deposits are supposed to be particularly valuable as indicators of taxonomic affinity. The chief types of secretory product are as follows: -
a. Crystals
The most common crystals consist of variously shaped deposits of calcium oxalate. The crystalline secretions such as raphides and crystals sand are more restricted in distribution and therefore of greater taxonomic interest.
b. Starch
The size, shape and other characters of starch grains are highly distinctive and of considerable taxonomic value.
c. Cystoliths
The presence of calcium carbonate crystals the cystoliths is highly characteristic of certain families.
d. Laticiferous tissue.
There is a well-developed system of tubes or cells in which variously coloured colloidal fluid known as latex are secreted.
e. Secretory elements
Several secretory elements such as resins, oils, mucilage, tannins, etc. are of considerable taxonomic value.
CORK
In an individual species. the first cork to be formed is often more superficial than that which arises later on. The position of origin of the cork seems to be more constant.
ENDODERMIS
In most dicotyledons stems the endodermis is inconspicuous. In some the endodermis consist of distinct layer of cells, which are differentiated from the neighboring cells in containing starch. In another groups the endodermis consist of cells with well – marked casparian thickenings.
SCLERENCHYMA OF PERICYCLE
The presence or absence and nature of the sclerenchyma of pericycle are of great diagnostic and taxonomic value. The most common types seen in the transverse section of the stem are – (i) an interrupted ring of fibres (ii) a continuous ring of fibres. (iii) an interrupted ring of mixed fibres and stone cells (iv) a continuous ring of mixed fibres and stone cells, which is continuously known as composite, continuous ring of sclerenchyma. (v) stone cells present, but no fibres (vi) Sclerenchymatous elements entirely lacking. The nature of pericycle sclerenchyma plays an important role in separating Species. or genera in some families, but in a few instances the arrangement may be typical of a whole family. For example, the pericyclic sclerenchyma is
not found in all investigated members of Pittosporaceae, where as a ring of sclerenchyma of a very characteristic type is found in near about all the members of Geraniaceeae.
WIDTH OF MEDULLARY RAYS
The T.S. of the internodes of young stems of many plant sow the widely separated vascular bundles by means of broad parenchymatous tissue, the medullary rays. In Ranuculaceae these medullary rays are quite broad. In extreme cases the V.Bs. are scattered. In the T.S. of plants, the xylem appears as a closed ring transversed by very narrow medullary rays.
BICOLLATERAL BUNDLES
The occurance of bicollateral V.Bs. in the axis of Cucurbitaceae is of much taxonomic value. In certain families Eg:- Solanaceae, Asclepiadaceae the presence of internal phloem makes a good diagnostic features.
CORTICAL AND MEDULLARY BUNDLES AND ANOMALOUS SECONDARY THICKENING.
Occurrence of cortical and medullary vascular bundles in various families, genera and Species. is of diagnostic value on account of their restricted appearance, but the families in which they are found are not closely related to one another.
WOOD
The characteristics of the wood that posses greatest taxonomic value and diagnostic features are categorized as follows:-
a. Vessels.
The distribution, pattern, diameter and frequency as seen in T.S., type of perforation and thickening of vessels are of diagnostic value. The presence of tyloses and the diameter or vessels is of much taxonomic value.
b. Wood Parenchyma
The types of wood parenchyma, ie., apotracheal and paratracheal are of much diagnostic value. In apotrcheal type the distribution is independent of the vessels where as in paratracheal type the distribution is determined primarily by the vessels.
The distribution of wood parenchyma in angiosperms is of two main types ie.,
(1) Apotracheal type and (2) Paratracheal type.
Apotracheal type
In such case the parenchyma cells are not in contact with vessels. This type many be sub divided into three sub types.
a. Diffuse apotracheal type
In this case the parenchyma cells occur singly among the fibres and trachieds.
b. Banded apotracheal type
In this case the parenchyma cells occur in bands.
c. Terminal apotracheal type
In this case the bands of parenchyma cells are confined to the ends of the growth rings.
Paratracheal type
In such cases the parenchyma cells remain associated with the vessels.
This type may be divided into two sub types:-
a. Abaxial type
Here the parenchyma cells are found in contact with abaxial surfaces of the vessels.
b. Vasicentric type
Here the parenchyma cells completely surrounds the vessels. In certain cases, the surrounding parenchyma cells make wing like appendages.
c. Rays
The width and hight or rays are of taxonomic value. Exclusively uniseriate rays is another feature of great value for identification.
d. Fibres
The presence of libriform fibres with simple pits and fibre trachieds with ordered pits is great taxonomic value.
e. Storied structure.
This consists of arrangement of the cells or tissue in horizontal series as seen in tangential section.
f. Growth rings
This presence of included phloem in the T.S. of the axis of plant is of diagnostic value.
h. Intercellular canals
The presence of radial and vertical intercellular canals is of great taxonomic value.
Anatomy Of Dicotyledonous Angiosperm Stem
In young dicotyledonous stem there are 3 distinct regions
1. Epidermis
2. Cortex
3. Stele
Epidermis
This is the outermost layer of the stem. It consists of the stem. It consist a single layer. Of cells it contains stomata and produces various types of trichomes. The outer walls are greatly thickened and heavily cutinized. The cells are compactly arranged and do not posses intercellular spaces. It serves mainly for restricting the rate for transpiration and for protecting the underlying tissues from mechanical injury and from diseases-producing organisms.
Cortex
The region that lies next to the epidermis is the cortex. The inner most layer of cortex is the endodermis known also as the starch sheath. It consists of a single layer of cells which surrounds the stele and contains numerous starch grains. The region between epidermis and endodermis s generally divided into
1. Outer zone of parenchyma cells
2. Inner zone of parenchyma cells.
Outer zone of Parenchyma:
The cells of the collenchymas are modified parenchyma cells with cellulose walls thickened at the angle where 3 or more cells are in contact. Chief function of collenchymas cells is to serve as strengthening material in succulent organs.
Inner zone of Parenchyma:
They are regular in size, shape, have comparatively thin walls. They are living cells contain protoplasm. This is the special storage tissue of plants. It serves as a slow conduction of water and food. When they are exposed to light, they produce chloroplast and are known as Chlorenchyma.
Endodermis
The innermost layer of cortex is known as endodermis consists of barrel-shaped, elongated, compact cells having no intercellular space. Therefore of the presence of suberin on radial walls, the lateral conduction becomes impossible.
Stele
The part of the stem inside the cortex is known as stele. It consists of 3 parts
1. Pericycle
2. Vascular Bundles
3. Pith
Pericycle:
This is the region below endodermis. Generally composed of parenchyma cells and sclerenchyma cells. The sclerenchyma may occur as a separate patch or as a continuous rising in the outer part of Pericycle.
Vascular Bundles:
They are arranged in the form of broken rings of vascular bundles. Each vascular bundles consists of 3 parts -1) Xylem, 2) Phloem, 3) Cambium
Vascular bundles are collateral, endarch and open.
Xylem
They are thick walled cells. The xylem formed 1st is nearest. The centre of the stem is called Protoxylem. The peripheral part of the primary xylem is known as the Metaxylem. Xylem is composed of 3 different types of cells- 1)Tracheous cells. 2) Wood fibers. 3) Wood parenchyma.
Trachids are elongated dead cells; Function is conduction and strengthening of cells. Wood fibers are long, slender pointed dead cells. They are strengthening cells.
Phloem
They are composed of sieve tubes, companion cells, phloem parenchyma. Some sieve tubes consist of thin walled, elongated cells arranged in vertical rows. They contain sieve plates. Companion cells are small cells that are attached to the sieve tubes.
Cambium
Cambium lies between Xylem and Phloem; these are the meristematic cells of single layer. It produces xylem cells towards outside.
Pith Rays
The thin-walled parenchyma cells at central portion are known as pith.
Function: Storage of Food
Anatomy of Dicotyledonous Leaf
Upper Epidermis
The upper epidermis is a compactly arranged parenchyma cell. Thick cuticle is present on the outer surface. Outer walls of epidermis are thick and cutinized. Water doesn’t pass through them rapidly and transpiration from the surface of the epidermis is greatly reduced. Stomata are few as absent in upper epidermis.
Mesophyll tissues
The tissue of the leaf that lays between the upper and lower epidermis. It is differentiated into an upper palisade parenchyma and lower spongy parenchyma. Palisade parenchyma is formed of elongated parenchyma cells which are compactly arranged. It contains abundant chloroplasts. Spongy parenchyma consist loosely arranged irregularly shaped parenchyma cells with intercellular spaces.
Function: Diffusion of gases through the intercellular spaces.
Vascular Bundles :-
Vascular bundles seen on the veins. In the dicot leaves there is a big central median vein called midrib with a large number of branches called ’vein– let’s’, which forms a reticulate venation. V.B is collateral consisting of xylem and phloem in the same bundle. Xylem is seen towards upper epidermis and phloem towards the lower epidermis. Cambium is absent. So it is a closed bundle.
The xylem composed of the tracheids, vessels and xylem parenchyma. Smaller veins, vessels may not be present. Phloem consists of sieve tubes, companion cells and phloem parenchyma. The ultimate fine vein-lets lack phloem. Each VB is surrounded by a parenchymatous bundle sheath. In large veins the plates of parenchyma cells extended from the bundle sheath extension. They give mechanical support to leaves.
Lower Epidermis:-
Below spongy parenchyma, there is a single layered parenchymatous layer which is compactly arranged. A large number of stomata are seen in lower epidermis. Cuticle is thin here.
General Anatomy of Angiosperm Petiole
The tissue of the petiole may easily be compared with the primary tissues of the stem. There is a close similarity between petiole and stem with regard to the structure of epidermis. The ground parenchyma of the petiole is like the stem cortex in arrangement of cells and in number of chloroplasts. The supporting tissues is collenchyma or scelerenchyma in relation to the arrangement of vascular tissues in the stem, the vascular bundles of the petiole may be collateral (e.g Syringa), bicollateral (eg. Cucurbitaceae, solananaceae) or concentric. The primary phloem fibers are differentiated in both the stem petiole. The chief anatomical characteristics of the petiole are as follows:
Epidermis:
It consists of single layer of barrel–shaped, elongated or radially elongated compact cells having no intercellular spaces among them. The outer walls of the epidermal cells are generally cuticularised.
Hypodermis:
Usually in multilayered hypodermis of collenchyma cells is found immediately beneath the epidermis. The schlerenchymatous patches may also be found below the epidermis. Both collenchyma and schlerenchyma make the supporting tissue of the petiole.
Ground Tissue:
Just beneath the hypodermis ground tissue is found. It consists of thin walled parenchyma cells having well defined intercellular spaces among them. Usually the vascular bundles are found either arranged in a complete on half ring or scattered in ground tissue.
Vascular bundles:
The vascular bundles are of various sizes in the same petiole. In most of the cases, the biggest vascular bundle is found towards lower surface, whereas lateral bundles are
comparatively smaller in size. Each bundle consists of xylem & phloem. In petiole, the xylem is always found toward upper side where as phloem towards lower side (as in leaf), generally the central biggest bundle remains surrounded by single – layered endodermal sheath which may or may not be followed by a multilayered pericycle.
Features of special interest.
1) Usually a groove is present towards upper side.
2) Mostly the vascular bundles are arranged in a semicircle in ground tissues.
3) Mostly the central bundle is biggest and remains encircled by endodermal sheath.
4) The xylem is always found towards upper side and phloem towards lower side.
Tissues In The Petiole Of Dicots
Permanent Tissue:
The permanent tissues are those in which growth has stopped either completely or for the time being. They may be two types.
1) Simple 2) complex tissue.
Simple Tissue:
Simple tissue made up of one type of cells. Forming a uniform of homogenous system of cell. The common simple tissues are (1) Parenchyma (2) collenchyma (3) sclerenchyma
Parenchyma:
The parenchyma tissue is composed of living cells, which are variable in their morphology or physiology, but generally having thin walls and a polyhedral shape, and concerned with vegetative activities of the plant. They are oval, rounded or polygonal in shape. Tissues are living, contain cytoplasm usually contain one or more nuclei in each cell. Parenchyma cells seen in part, mesophyll leaves the pulp of fruits endosperm of seeds, cortex of stem of root, also occur in xylem and phloem.
In aquatic plants, parenchyma cells in the cortex posses well-developed air spaces known as Aerenchyma. When parenchyma cell exposed to light they develop chloroplasts in them, and such tissue known as Chlorenchyma.
Collenchyma:
Collenchyma is a living tissue composed of somewhat elongated cells with thick primary non-lignified walls. Chiefly occurs in the peripheral regions of the stem and leaves commonly found just beneath the epidermis.
According to mode of cell arrangement they are of 3 types
1) Angular 2) Lamellar 3) Tubular
Sclerenchyma
It consists of thick walled cells, often lignified. These are dead tissues, main function is mechanical. Schlerenchyma cells are grouped into fibers and schlerids.
Fibers: Fibers are elongated schlerenchyma cells with pointed ends. Walls are lignified.
Schlerids: They are broad they are isodiametric, but some are elongated commonly found in cortex and pith they are lignified. They are categorized into 4 groups.
1. Branchyschlerds.
2. Macro
3. Osteoschlerids
4. Astroschlerids
Complex Tissue:
A complex tissue is made up of more than one type of cells.
Eg: Xylem, Phloem.
Xylem:
Xylem is a conducting tissue, which conducts water and mineral nutrients upward from the root to the leaves. Xylem composed of.
1) Fibers 2) Vessels 3) Wood Fibers 3) Parenchyma
Tracheids:
It is an elongated tube like cell having tapering, rounded or oval ends, and hard lignified walls, various thickening like annular, spiral, scalariform, reticulate, pitted, trachieds etc.
Fibres:
Their walls are highly lignified and no chloroplast. Xylem fibres are also known as wood fibres.
Tracheae or Vessels:
It is formed by the end-to-end attachment of row of cylindrical walls whose partition walls become perforated. The walls known as perforation plates. They have also thickening.
Xylem Parenchyma:
In secondary xylem, they are of two types
1) Wood Parenchyma and 2) Ray Parenchyma.
Phloem:
It is composed of sieve tubes, companion cells, phloem parenchyma, fibers.
Sieve Tube:
It is formed by the end-to-end attachment of a number of elongated sieve elements. The cross walls of these elements are called sieve plates.
Companion cells
Companion cells are narrow, elongated, and thin walled, parenchymatous, specialized cells found associated with the sieve tubes.
Phloem parenchyma
They are living with cellulose and containing primary pith fields.
Phloem Fibres:-
They are elongated cells with their ends interlocked. Their walls are lignified with simple pits. They give mechanical support.
Family – CAPPARIDACEAE- An Overview
Type: 1. Cleome viscosa.L - Fig: 1,2,a,b
2. Cleome burmanni.W & A - Fig: 4,5,c,d
Class : Dicotyledons
Sub class : Polypetalae
Series : Thalamiflorae
Cohort : Parietales
Family : Capparidaceae
Distribution:
The members of the family are mainly distributed in the warmer (tropical) parts of the world, the plants occur mostly in dry regions. Several shrubby species of capparis occur in the Mediterranean region. Several genera, such as Cpparis, Gynandropsis, Cleome, Crataiva etc. are found in our country.
Habit:
They may be herbs, shrubs or trees, Gynandropsis pentaphylla is an annual rainy season herb, Capparis decidua (caphylla) is a xerophytic shrub, Eratheva nurvala (C.religiosa) as a tree.
Root:
Tap and branched.
Stem:
Erect, branched, woody or herbaceous, solid, cylindrical etc.
Leaves:
The leaves may be simple or palmately compound; the stipules may or may not be present. In Capparis spinosa the stipules are modified into spines. In certain species,
Eg:- Capparis decidua (ie C.amphylla). The leaves are altogether absent.
Inflorescence:
Usually the inflorescence is of recemose type. The flowers of Cleome, Gynandropsis etc. arearranged in recemes; in Maerua and Capparis deciduas, they are arranged in corymbs, In Capparis sepiaria, the flowers are found to be arranged in umbels; in Crataiva nurvala they are found to be arranged in corymbose clusters. Rarely the flowrs are soltary eg. Nlemburia.
Flowers:
The flowers are pedicellate and bracteates. The bracteoles are absent from the point of view of the structures of the flower; the family occupies an intermediate position between Papaveraceae and Cruciferae. The flowers are Hermaphrodite, actinomorphic (sometimes zygomosphic; eg. Capparis decidua), complete regular or irregular and hypogynous.
Calyx
It consists of four sepals, arranged in two whorls; each whorl consists of two sepals similar to that of Cruciferae. The sepals are free (polysepalous) the sepals of Capparis decidua are unequal in size. In this case the posterior sepals form a hood like structure. The aestivation is either valvate or imbricate
Corolla:
It consists of 4 petals, polypetalous, the petals are arranged diagonally similar to that of cruciferae, usually regular but sometimes irregular, e.g, Capparis decidua. The aestivation may be imbricate (In Cleome) or valvate (in Crativa.)
Androecium:
The number of stamens varies much in different species. In different species of cleome the number of stamens ranges from four to indefinite. The most reduced type of flower is Cleome tetrandra, where there are only four stamens; in Cleome spinosa, there are six stamens, in C.viscosa, the number of stamens varies from 12 to 24 and in C.chelidonii, the number of stamens is indefinite, in Grynandropsis, the number of stamens is 6, in Capparis, Macrua and Crativa, the stamens are indefinite.
This way, the number of stamen ranges from 4 to indefinite in the different species of the family. The stamens are never tetradynamous on Capperidacea.
The characteristic of this family is the development of an internodes between petals and stamens ie, androphore or between stamens and pistil, i.e gynophores. The androphore and gynophore are known together as gynandrophore. In Gynandropsis pentaphylla, both the gynophore and andrephore are well developed. In Capparis, Crataeva only gynophere is present the filaments are filiform, the anthers are basifixed and dithcous.
Gynoecium:
It is situated on a gynophore. It consists of two carpels (bicarpellary) syncarpous; rarely the numbers of carpels are more than two. The ovary is superior and unilocular sometimes it becomes multilocular by the ingrowth of parietal placentation. The placentation is pariatal. The ovules are many and camphylotropus. The style is either very short or absent.
Fruit.:
In Come it is siliqua with Replum , in Capparis it is berry, in Rogdsia, it is drupe and in Emblingia it is a nut. In majority of cases the fruit is siliqua
Floral fomula
Family- STERCULIACEAE- An Overview
Type: 1. Theobroma cacao.L – Fig: 6,7,g,h
2. Guazuma tomentosa.H. B. K-Fig: 8,9,e,f
Class : Dicotyledons
Sub class : Polypetalae
Series : Thalamiflorae
Cohort : Malvales
Family : Sterculiaceae
There are about 50 genera and 750 species in this family.
Distribution
The members of the family are found to be distributed in the tropical and sub-tropical regions. The most important genus is Theobroma cacao, a native of tropical America.
Habit
Most of the plants are trees (sometimes cauliflorous) shrubs or herbs, sometimes climbers.
Leaves
The leaves are simple, entire, palmately compound, alternate, and stipulate with generally caduceus stipules.
Inflorescence
The flowers are found to be arranged in complicated inflorescences.
Flower
Generally the flowers are hermaphrodite but sometimes they are unisexual by abortion; Mostly actinomorphic but sometimes Zygomorphic pentamerous and hypogynous.
Calyx
It consists of 3 to 5 sepals. The sepals are somewhat connate at their base. The aestivation is valvate.
Corolla
Very often the petals are reduced in size. However, the petals are not found in Sterculia and Cola.
Androecium
Typically the stamens are found to be arranged in two whorls. The stamens of the outer whorl which are found opposite to the sepals (Antisepalous) are represented by staminoids or altogether absent, where as the stamens of the inner whorls that are found opposite to the petals (Antipetalous) are fertile. The filaments re more or less united to form a tube (monodelphous).
Gynoecium
It consists of 4 to 5 carpels, syncarpous; the ovary is superior and is 4-5 loculed; the carpels are generally antipetalous and contain two to numerous antropous ovules; the placentation is axile; sometimes the ovary is found carried up along the stamens above the petals by the development of Androgynophore, the styles are as many as the number of carpels which are either free or united together.
Fruits
Generally the fruits are dry, which very often separate into coci.
Seeds
They are endospermic. Each seed contains an embryo with two folded, leaf-like cotyledons.
Pollination
Pollination usually takes place through the agency of insects.
Floral Formula
Chapter: 2
Materials and Methods
Materials
Compound Microscope, Glass slides, Collection bottles, FAA, Blade, Glycerin, Saffranin stain, Staining brush, Needle, Specimen pieces.
Method
First the investigator selected the plants and collected them. Immediately after collection the plat materials were put in a plastic bag. The specimens were cut into pieces of convenient size and put in injection bottles containing FAA. The data of collection such as name of the plant, Family, Data and Time of collection, Plant size, Flower characters, Ecological conditions, Morphological characters and Anatomical characters were noted.
The sections taken from the plant, it is washed well. The section are stained in aqueous Saffranin and mounted in glycerin. The preparations were observed under the compound microscope.
From a proper section all the peculiarities were noticed. Along with place, date, binomial of concerned plant, family, growth and anatomical features. A comparison was made between the two species regarding the histology of the primary and secondary anatomical structures. Then the similarities and contracts between the two plants were noted.
Objectives of present study
1. To study the anatomical details of dicot leaf petioles.
2. To compare the petiolar histology of selected members of Capparidaceae and Sterculiaceae.
3. To practice the method of hand sectioning the selected specimens and to make the micro preparations.
4. To draw and label the parts of anatomical diagrams
5. To practice the pattern of investigation into the anatomy of selected dicots.
Chapter: 3
OBSERVATIONS
Cleome viscosa.L
(Fig.1, 2; Plate- I, II)
Anatomy:
Epidermis:
Single layered epidermis, Barrel shaped. Epidermal hairs are present.
Epidermal cells are thin walled. Cuticle is absent.
Hypodermis:
Hypodermis is collenchymatous and multilayered. Chlorophyll is present in the Hypodermis.
Cortex:
Cortex is divided into outer, inner and middle. Outer cortex and inner cortex are parenchymatous. Outer cortex contains aerenchyma cells.
Vascular bundle:
7 Vascular bundles are present and it is various in sizes. The biggest vascular bundle is found to the lower surface; where as lateral bundles are comparatively smaller in sizes. Each vascular bundle is covered by sclerenchyma cells. Vascular bundles contain xylem and phloem. Xylem is found towards the inner side and the phloem towards the outer side.
Pith:
Pith is absent.
Cleome burmanni.W & A
(Fig.4, 5; Plate- III, IV)
Anatomy:
Epidermis:
Single layer of epidermis is present and is thin walled cells. The cells are barrel shaped. Epidermal hairs are absent. Cuticle is absent.
Hypodermis:
Sclerenchymatous hypodermis is present. It is multilayered. Chlorophyll is present in the hypodermis.
Cortex:
Cortex is divided into outer and inner cortex. The outer cortex contains parenchyma cells. Outer cortex contains aerenchyma cells.
Vascular bundles:
5 Vascular bundles are present and is various in sizes. The biggest vascular bundle is found towards the inner surface; where as the lateral bundles are comparatively smaller in size. Bicollateral vascular bundles are present. Outer and inner side contains phloem and middle layer contain xylem.
Pith:
Pith is absent.
Theobroma cacao.L
(Fig.6, 7; Plate- V, VI)
Anatomy:
Epidermis:
Epidermis is single layered. Cells are barrel shaped and is covered by cuticle. Epidermal hairs are present. The cells are thick walled.
Hypodermis:
Sclerenchymatous hypodermis is present and is multilayered. Chlorophyll is absent in hypodermis.
Cortex:
Cortex is divided into outer and inner. Cortex contains parenchymatous cells. Outer cortexes contain vacuoles and inner cortexes contain mucilaginous canals.
Endodermis:
Below the cortex endodermis is present. Endodermis is single layered and it contains thin walled cells.
Pericycle:
Below the endodermis Pericycle is present. Pericycle is multilayered and it contains thin walled cells.
Modularly ray:
It contains uniseriate modularly rays arising from the cortex.
Vascular Bundle:
4 Vascular bundles are present. Two vascular bundles are large and two are small. Xylem and phloem is present. Xylem is found towards the outer side and Phloem towards the inner side. Xylem is endarch. Metaxylem towards the inner side.
Pith:
Pith is present and is smaller in size. Pith contains vacuoles and it is composed of parenchymatous cells.
Guazuma tomentosa
(Fig.8, 9; Plate- VII, VIII)
Anatomy:
Epidermis:
Epidermis is single layered and the cells are thin walled and barrel shaped. Epidermal hairs are present. Epidermis is covered by thick cuticle.
Hypodermis:
Hypodermis is sclerenchymatous and it is multilayered. Chlorophyll is absent in the hypodermis.
Cortex:
Cortex is differentiated into outer and inner cortexes. Cortex is composed of parenchymatous cells. Outer cortex contains vacuoles and the inner cortex contains mucilage cells.
Endodermis:
Endodermis is single layered and it contains thin walled cells.
Pericycle:
It is multilayered and is of parenchymatous cells. And it contains thin walled cells
Vascular bundle:
4 Vascular bundles are present. The biggest vascular bundle is formed towards the lower surface; where as lateral bundles are comparatively smaller in size. Each bundle consists of xylem and phloem. Xylem is found towards outer side and phloem is found towards the inner side. Between the xylem groups mucilage cells are seen,
Pith:
Parenchymatous pith. It contains vacuoles.
Chapter: 4
Discussion
Petiolar histological observation between the family Capparidaceae and Sterculiaceae show both similarities and dissimilarities. Main difference between these two families is the presence of mucilage in Sterculiaceae, which is absent in Capparidaceae.
In Capparidaceae, epidermis is single layered and it contains thin walled barrel shaped cells and cuticle is absent. Where as in Sterculiaceae, epidermis is single layered and it contain thin walled barrel shaped cells and cuticle is present.
In Capparidaceae, epidermal hairs may or may not be present. Hairs are unicellular and multicellular, where as in Sterculiaceae epidermal hairs are present and hairs are unicellular.
In Capparidaceae, hypodermis is collenchymatous or sclerenchymatous and it is multilayered. Chlorophyll is present. Where as in Sterculiaceae, hypodermis is sclerenchymatous and it is multilayered. Chlorophyll is absent.
In Capparidaceae, Cortex is made up of parenchyma cells and the cortex is differentiated into outer and inner cortex. Outer cortex contains vacuoles and inner cortex contains mucilage.
In Capparidaceae, endodermis is absent but in Sterculiaceae, endodermis is present. It is single layered and it contains thin walled cells.
In Capparidaceae, Pericycle is absent were as in Sterculiaceae, Pericycle is present and it is multilayered and it contains thin walled cells.
In Capparidaceae, medullary rays are absent, where as in Sterculiaceae, medullary rays are present and it is uniseriate.
In Capparidaceae, numerous numbers of vascular bundles are present and are various in sizes and it is covered by sclerenchyma cells were as in Sterculiaceae, 4 vascular bundles are present- two large and two small. And is not covered by sclerenchyma cells.
In Capparidaceae, xylem is present in the outer side and it is endarch. Between the xylem groups mucilage cells are absent; Phloem is present in the inner side. Where as in
Sterculiaceae, xylem is present in the outer side and it is endarch. Between the xylem groups, mucilage is present. Phloem is present in the inner side.
In Capparidaceae, pith is absent. Where as in Sterculiaceae, pith is present and it is small and it is made up of parenchyma cells. Vacuoles are present.
Chapter: 5
SUMMARY
The aim of my project was to compare the petiolar histology of selected plants in Capparidaceae and Sterculiaceae. I took the petiolar section of Cleome viscosa and Cleome burmanni from the family Capparidaceae and those of Theobroma cacao and Guazuma tomentosa from the family Sterculiaceae.
In Capparidaceae family the outer most layers are epidermis. It is single layered and it contains barrel shaped cells. Hypodermis is collenchymatous or sclerenchymatous and multilayered. It contains chlorophyll. Inner cortex contains aerenchyma. Endodermis and Pericycle are absent. Many vascular bundles are present and it is covered by sclerenchyma cells. Xylem and phloem are present. Xylem is found towards the outer side. Pith is absent. In the case of Sterculiaceae family the outer most layer is single layered epidermis and it contains barrel shaped cells. Epidermis is sclerenchymatous and it is multilayered. Outer cortex contains vacuoles and inner cortex contains mucilage. Endodermis is present and it is single layered. Pericycle is multilayered. 4 vascular bands are present. Xylem and phloem is present in the inner side. Between xylem groups mucilage cells are present. Pith is present and it contains vacuoles.
Chapter: 6
References
1. Abraham P C (2006) Anatomy, Embryology and Microtechnique , Changanachery:
St Mary’s press and Book Depot, Page no: 134-149, 242-267.
2. Alfred Gunderson (1950) Family of Dicotyledons, Leyden: Chronica Botanica co.
3. Charles Russell Metcalf and Laurence Chalk (1950) Anatomy of dicotledons: Leaves, Stem and Wood in relation to Taxonomy, Michigan: Clarendon press item notes: v.1
4. Davis P H & Heywood V H (1967) Principles of Angiosperm Taxonomy, Edinburg: Olibo & Boyl.
5. Eames A J (1961) Morphology of Angiosperms, New York: Mc Grow Hill.
6. Gurcharan Singh (2004) Plant Systematics: An Integrated Approach, Science Publishers.
7. Heywood V H (1976) Plant Taxonamy, London: Edward Arnold.
8. Immanuel Pfleiderer (2000) Glimpses into the Life of Indian Plants: An Elementary Indian Botany, Asian Educational Services.
9. James Sykes Gamble, Stephen Troyte Dunn & Cecil Ernest Claude Fisher (1967) Flora of the Prsidency of Madras, Nichigan: Botanical Survey of India
10. Kublizki K, Kramer K U, Green P S, Robwer J G, Bittrich V, Hubber H, Kadereit J W & Jeffrey C, The Families And Genera of Vascular Plants, Springer
11. Pandey B P (2001) Taxonomy of Angiosperms, New Delhi: s Chand & Company Ltd.
12. Pandey B P & Pandey S N (2001) Text Book of Botany: Taxonomy, Anatomy, Embryology (Including Tissue Culture) and Economic Botany, New Delhi: S Chand & Company Ltd, Page no: 122-129, 146-149
13. http://en.wikipedia.org/wiki/Angiosperms
14. http://en.wikipedia.org/wiki/Capparaceae
15. http://en.wikipedia.org/wiki/Cleomaceae
16. http://en.wikipedia.org/wiki/Sterculiaceae
17. http://en.wikipedia.org/wiki/Cleome
18. http://en.wikipedia.org/wiki/Theobroma
19. http://en.wikipedia.org/wiki/Guazuma
20. http://en.wikipedia.org/wiki/Dicotyledons
ABSTRACT
The aim of my project was to compare the petiolar histology of selected plants in Capparidaceae and Sterculiaceae. The Investigator took the petiolar section of Cleome viscosa and Cleome burmanni from the family Capparidaceae and those of Theobroma cacao and Guazuma tomentosa from the family Sterculiaceae.
In Capparidaceae family the outer most layers are epidermis. It is single layered and it contains barrel shaped cells. Hypodermis is collenchymatous or sclerenchymatous and multylayered. It contains chlorophyll. Inner cortex contains aerenchyma. Endodermis and Pericycle are absent. Many vascular bundles are present and it is covered by sclerenchyma cells. Xylem and phloem are present. Xylem is found towards the outer side. Pith is absent. In the case of Sterculiaceae family the outer most layer is single layered epidermis and it contains barrel shaped cells. Epidermis is sclerenchymatous and it is multilayered. Outer cortex contains vacuoles and inner cortex contains mucilage. Endodermis is present and it is single layered. Pericycle is multilayered. 4 vascular bands are present. Xylem and phloem is present in the inner side. Between xylem groups mucilage cells are present. Pith is present and it contains vacuoles.
