Plants

Plants

       Plants have a great deal of diversity.It is estimated that there are more than 390,000 plants species which are described.Discovery of plants are increasing day by day. Systematic of plants needs some organizational framework.Plants systematics provide his system of organization. It is fourm which provide knowledge about plants. 

    Plants varieties  different varieties of plants are present in all over the world like angiosperms,gymnosperms. Angiosperms are flowering plants. their seeds are covered by fruits. Their fertile leaves bear ovules. The fertile leaves are folded and joined to form ovaries. the ovary is changed in to fruit after fertilization. There are more than 23,500 species of angiosperms.Angiosperms are metamorphic  plant.these are most successful plants of the earth . These plants produce flower fruit and seeds. Gymnosperms  are one of the most successful groups of seeds plants.  They have world wide distribution. the term gymnosperms   mean naked seeds. The ovules in these plants are not enclosed. the ovules are borne on the exposed surface of fertile leaves.the gymnosperms are hetrospours plants.they show regular hetromorphic alternation of generation.

Parts Of Plants

  Plants is divide in to to part 

(1) Root 

(2)Shoot

Root is cylindrical plant organ without chlorophyll,growing toward gravity.Root is present under land.It absorb water for plant.Roots has different forms.

Tap Root, Adventitious Roots are those roots which are present in plants.tap root are directly arised from seed.The roots arised from the stem or sometime leaves are called adventitious roots.

The first root which is formed by elongation of radicle is called primary tap root.It give rise to secondary and tertiary roots.The deep feeder plants have long net work of tap root system . The surface feeder have short tap root.Tap roots has some types.These types are.Fibrous tap root The long slender tap root with slender branches is called fibrous tap root.In some leguminous plants it form nodules.Tuberous tap roots the thick or swollen tap roots with reserve food are called tuberous tap root  These roots are present in carrot,turnip,reddish etc.they store food which is used un second season.

 Adventitious roots have different forms. underground adventitious roots these roots arise from some part of stem which is contact with soil.They may be tuberous or fibrous.Example grasses,potato,asparagus. Partly subterranean adventitious roots are swollen fleshy roots.These  roots may be slit roots and aerating roots. Example bamboo,cane,banyan,rubber tree.Aerial roots are entirely exposed in air.  These roots perform special functions . These are two types  climbing roots and absorbing roots.parasitic roots are developed in parasitic plants like Cuscuta. Stem develop these roots for absorption of food from host. Aquatic roots, these roots, are developed in water plants.These roots form stem and spread in water. Example Hydrilla.

Function of roots

Root play very important role for plant.It provide sport to the plant.Some other function of root is given below.

*  Roots anchor the plant to the soil     They absorb water and minerals for plants

*  They store reserve food.roots of turnip radish and carrot are used for storing of food.

*  Some roots are used for clinging. Ex props and haustoria .

*  Some roots are used for vegetative growth. 

 the roots of leguminous plants develop nodules. Bactria lie in these nodules. they fix the   atmospheric nitrogen and increase the fertility of soil. 

Stem

                                                Stem

    The portion of the primary axis of plant plant which develops from which plumule is called main stem. The axis with leaves is called shoot.Stem has node and internodes. The part of stem from leave arise is  called node. the part of stem between two nodes is called ineternode.Stem shows positive geotrompism and is always try to grow upward.Some stem are under ground these stem are called underground stem. They are often thick and swollen with a larger amount if stored food. Underground stems resemble with roots.They always arise from the axils of leaves. There are different types of under ground stem. These are rhizome,corm,bulb and stem tuber. Different type of terms are used for plants. These terms are Herbaceous stem Soft and green stem that can be easily bent is called Herbaceous stem. 

         woody stem hard woody stem which cannot easily bent is called stem. fistular if the inter node of the plant  are hollow ,then the stem is called fistular. solid if stem is not hollow at inter node then it called solid. Joined the stem swollen at internode are called joined. Example stem of grasses. Cylindrical straight and round stem is called cylindrical. Example rose. Angular the stem with alternate ridges and furrows is called angular. Example ocimum. Flattened flat and plant like stem is called flattend. Example opuntia. Succulent  thick and fleshy stem is called succulent. Example euphorbia. Hairy the stem having hair on is surface is called hairy. Example sunflower.Spiny With spines or thorns on the surface is called spiny. Example Acacia (kikar).Prickly Stem with prickles on the surface .Example rose.Some plants have weak and slender stem.Such plant cannot grow erect.Therefore they adopt different method to get  support. They climb the support. They develop different structures for climbing. These structures help them to attach with different supports.

Types of stem 

   Different types of plant stem are present.Stems have following forms Aerial stems and under ground stem  Aerial stem The stem which grows above the ground in the exposed air is called aerial stem.It may be Reduced aerial stem In this case stem is very reduced and present in the form of green structure above the thick roots.These stem ate so small that the leaves appear to be arised from root directly . Example stem of radish turnip etc. Erect  stem In this case stem is thick and strong It grow upward. Such  stems are present in trees Weak stem these stem are much weak. They are unable to grow erect. Therefore they become climber or spread on the ground. Plants are divided into different group on the basis on structure of their weak stem.Climbing plants or climber these plants have weak and slender stem. Such stem cannot grow erect. Therefore, they grow adopt different method to get support.They develop different structures for climbing. These structure help to attach with different support. The plants whose stem are twin or coil around some support are 

called twiners.They do not have any special organ. They have long slender stem with long inter nodes.Thus their long stem coils around host plant. The direction twining may be clock wise or anticlockwise Example Cuscuta. Tendril climber these plants develop long slender long tendrils for climbing up in the support . The tendril may be modified stem or leaves. It is very sensitive to support. As soon as it touch some support. It coil. Ex melons cucumber etc.Root climber These plants are attach to the support by means of small advantitious roots.These are arise form the sides of stem. such roots are very sensitive to touch . they twin around the support. They penetrate into gap in stem of host plant and firmly attach the plant with it. They also produce sticky fluid. It adhere the plant with host plant.Example pepper. Hook Climber these plant develop hooks to attach with support. The hooks are uncurved Example Bougainvillea. Leaf Climber  The leaves of some climber become elongated. They grip the support and help the plant to remain erect. Example is pitcher plant.

Under ground Stem  These are grow underground. They often thick and swollen with a large amount of stored food. They are formed by perennial herbs. Underground stem resemble with roots. But stem have node and inter node or scale leaves. They always arise from axils of leaves. Rhizome The elongated thick, horizontal,thick and fleshy underground stem.Store large amount of food. It has node and inter node.There are different form of of node and inter node.Straggling Rhizome  The elongated thick less branched rhizome which grows horizontally.Example grasses (typha).Monopodial Rhizome  they are arranged like racemose. They have single axis which give rise to lateral branch.They are present in many wood sorrel. Sobole Rhizome are long slender and has long inter node found in grasses. Corm Thick solid rounded under ground stem with few inter node is called corm.It covered with number of loose of sheathing scale leaf. One or more bud is present in axil of each leaf. Each bud form new corm. Example Colocasia. Bulb specialized much reduced short under ground stem composed of broadly conical disc is called bulb.Large fleshy leaves are burn on the surface. These leaves are small scale leaf like onion.Bulb  different form like Tunicated bulb, Scaly bulb.

Function of stem

•  Stem  bear leaves  flower  and fruits. Stem expose to them to sunlight.
•  Stem conduct water and dissolved substances to different part of plant
•  In some cases they serve the function of leaves like Phylloclades and cladodes.
•  Succulents     are   used  storing   of     water   in   arid   areas. In  some   cases   stem           are  used  for   climbing  like   tendrils.                                                         
•   Stems in the form of thorns protect the plants from grazing animals.
•   Stems   are    used   for   vegetative    propagation.

Flower

                            Flower and symmetry of flower   

Parts  of flower 

1  Calyx

2  Corolla

3  Stamen

4  Carpel 

  Flower 

         The highly specialized shoot which is responsible for the production of fruits and seeds is called flower.Flower is concerned with the sexual reproduction.Mostly flower have four series of floral leaves.They form four whorls. In some cases floral leaves are arranged in more than one whorl. Therefore they have more than 4 whorl.It is arranged in twos.threes, fours or fives in each whorl.Thus flower is called dimerous  teramerous and pentaamerous. Some flower have more than ten floral leaves in each whorl.These flower are also identify.

         Flower is known as modified shoot. Flower is arise on the axil of leaf like shoot. Flower is central axis like vegetative shoot. Thalamus has very short internodes. Floral leaves is covered by it.On thalamus some flower like passion flower with elongated inter node are arranged.

        The internal structure of thalamus is resemble with internal structure of stem The floral leaves is show cyclic or whorled phyllotaxis like ordinary leaves. Arrangement of the floral leaves is flower bud. Which similar to the arrangement of floral leaves in leaf bud. Stamens are petal like in some flower.Like rose and canna. The carpal are regarded as leaves This has become folded along its margin to from closed structures.

    Flower as modified shoot 
  It is consider that flower is modified shoot. Flower is supported many facts.These are given 
Flower is arises in the axil of leaf,bract like vegetative shoot.Thalamus has very short internode. Floral leaves are crowed on it. The thalamus of some flower like passion flower has elongated upward and bears other foliage leaves.So it behaves as ordinary shoot.
The internal structure of thalamus resemble the internal structure of stem.They have internal anatomy. Floral leaves show cyclic or whorled phyllotaxis like ordinary leaves.
The forms and structure of sepal and petal is resample with the foliage leaves.The sepal are mostly green in cloure which resample with leaves.In some cases petal are also green it called seples . Carpal is regarded as leaves.This leaves is become folded along its margin and form closed structure.
        Symmetry of flower if flower has capacity to divide  into to equal halves in one or more tan one plane it called symmetry of flower. Flower has three type on the basis of their symmetry.These are

  Actinomorphic or regular flower is cut into two equal halves by more than one plane.Example poppy.
Zygomorphic  If flower can be cut in to two equal halves by only one plane it is called zygomorphic. Example Ocimum.

Asymmetrical Flower which can be cut not into two equal halves in any of the plane.Example is opuntia  Zygomorphic and asymmetric flower called irregular.

Thalamus
        The terminal swollen part of the flower which bears sepals, petals,stamens and carpels is called thalamus.It is very short in most flower.But sometime it become long. Inter node between calyx and corolla is called anthophore. The internode between corolla androcium is called androphore. The internode between androecium and gynocium is known as gynophore.
       Thalamus has different forms. In some cases thalamus is convex or conical.The gynocium develops on the top of thalamus.But stamens and petal and sepal are bore on the side of gynocium. Ovary is superior but all other parts are inferior. Like Brasssica, poppy. This condition is known as Hypogynous.  But in other cases thalamus is falttend or disc like.The gynocium is present in the center of disc. Carpel is develop on the bottom of the cup. Example is Spiraea. Epigynous In this condition  overy is surrounds by thalamus overy. Gynocium is inferior but all other parts are superior.Its example is apple,peer etc.

Flower Parts

                     Floral Parts and its Function 

Calyx

     The outer whorl of flower is called calyx.It consists of sepal.Calyx is usually green.It is present in most of flower.It is protective sheath of flower.Their are flowing descriptive terms of calyx.

Caducous: If the sepals are fall as soon as flower is open it is called cadocous. Example poppy.

Deciduous:Sepal which are fall when the flower is withers this condition is known as deciduous.Example buttercup. 
Persistant: If the sepal is remain in place even after fruit is formed.Example pea , roses and cotton.This contention is persistant in these plants 

Petaloid: If the sepal is coloured like petal this is called petaloid. Its example is Larkspur.sepal have 
Polysepalous: In this condition all the sepal are free from each other. Example of polysepalous is Brassica. Gamosepalous: All sepal is united. They have different structure .Tubular which is long and tube like. Globose which have glob shape.  Hooded one or more sepal forms hood like structure.

  Corolla 

     Corolla is second whorl of the flower.It contain petal.The collective name of petal is called corolla.It is attract the insect to word it self.Insect help the flower for pollination. They  bring pollen grain from one flower to an other.In the corolla foll following terms are used.

     Caducous: Condition in which petal falls as soon as flower open.Its example is Buttercup. 
Sepaloid: If the corolla is sepal like.Corolla colour is similar with the sepal. 
Polypetalous: The petal are free form each other.Example is brassica. Different terms are used  Clawed petals are narrow at base of expanded  at the tip. The tip of petals are short and narrow on the tip. Different terms of polypetalous is used. These terms are 
     Cruciform(کراس): The corolla is consists of four clawed petals. These petals are arranged in the form of cross.  They look like cross shape.  Example  of  cross form is Musterd family.

Rosaceous: Petals are five in number. They have very short claws.Rose is the example of rosaceous. Carylophallaceous: In this case calyx are form long tube It contain five petal. These petals are spread

Gymopetalous :The petals are united with each other.The petal are not similar. They are found in pea

Arrangement of Sepals and Petals 

Aestivation The arrangement of  sepals and petals with respect to one an other is called Aestivation. It has many types..Open The sepal and petals are not meet with each other at any end. Valvate Sepal and petals are merely touch each other at their edge.It is attach on some point with with one another. Twisted In this case margin of petals overlaps the margin of next petal.The next overlap with third one. Quincunicial This is imbricate aestivation with five petals.Two are exterior and two is interior.The fifth has one margin exterior and other is interior. Vexillary Imbericate with five petal. The posterior petal is largest. It covers the  two lateral petals. The lateral petal or wings overlap the interior and smallest petals (keels). Its present in Papilionacae.

Corona

In some flower small outgrowth or ligules are developed in a circle on the corolla.Such outgrowth are called corona.The corona may be free.

Reproductive parts

                              Main Parts of Flower 

    Androcium and Gynoecium which are collective name of stamen and carpel.They are reproductive parts of flower.

Andoecium It is collective name of stamens.It forms third whorl of flower.Stamen has two parts First part is Filament and second part is anther.Anther consist of anther lobes.These lobes are joined by a band convective chamber called pollen sacs.Pollen grains are produced in side the pollen sacs.The ripened anther burst and releases pollen grains. The side of anther containing connectives is called back and other side is called face. 

Terms for Androcium 

     Different terms are used for androcium. The terms which are used for androcium are.

Polyandrous:The stamen are free from each other. These stamen may be di, tri and tetra or petandrous. Stamens are present in different numbers in it.

      Didynamous:  Stamens are four four in number. Four of these stamen two is short and two is long.All is present in single whorl .Example of didynamous is ocium. All stamen are free form each other. Tetradynamous:  Stamens are six in number.Four long and two is short. Example is  Brassica,  Radish Epipetalous:  The term in which stamen fused with petal.It is present in in fused.Its example is potato

   Antipetalous:  Stamens are opposite to petals .Stamen present on opposite side of petals.Example zizyphys. Antiseplous: Stamens are opposite to the sepal. Gynandrous: Stamens are fused with the gynocium.  Adelphous:  Stamens are united by their filament. It may be monocotyledonous,  diadelphous or polyadelphous. Example Cirus, castor oil.

 

Attachment anther on filament 

    Anther are attach with filament. In the anther pollen grain are produced. In is part of male reproductive organ.It is present on the tip. There are four type of attachment of filament to anther.   Basfixed or Innate:  The filament is is attach to the base of anther. It example is Brassica.  

Adnate:  In this case no joint is present between the filament and the base of anther. Filament runs along the whole length of the anther from base to apex. Example of adnate is butter cup.     

  Dorsifixed: Filament is attached to the back of anther.The anther become immovable.Example Passion.Versatile: Filament is attached to the back of anther. It can swing on it.Example is grass.

Gyonecium or pistil

      Gynoecium forms fourth whorl of the flower.It occupies the center of the thalamus. It may consist of one or more carpel. These carpel may be remain free or combined. Or they fuse to form compound pistils. Each carpel has three parts Ovary, Style and Stigma. 

     Ovary It is basal swollen portion of the carpel. It enclose one or more chamber or loculi. The chamber has one and ovules.It is main part of the carpel. It is present near the anther on the flower. 
   Style Slender and stalk structure. It arise from top of ovary. It contain styler tissues.Sometime hallow.  Stigma  It is top of the style. It receive the pollen grain which are come form the pollentube. 

Evolution of Carpel

    It believed that carpel is modified leaf. The leaf is folded. Its two edges are fused and meet together. This line of union is called ventral structure. The opposite side is called dorsal structure. The borad lower portion of the folded leaf forms ovary. The elongated apex from style. The style is swells slightly to form stigma. Placenta develop along the ventral structure on the inner surface of wall of the ovary. Ovules are attached to the placenta is two rows. 

    Descriptive terms In the gynoecium different are used for it. Some of these terms are Monocarpellary   Gynoecium consists of single carpel. Example is pea. They have only one carpel. Biscarpellary  The gynoecium consists of two carpel. These carpel may be free or fused. Example potato. Polycarpillary  Gynoecium has more than one free carpel. Example of pollycarpillary is Butter cup. Apocarpous.

    The cushion like ridges inside the ovary on which ovule are attached is called placenta. Arrangement of placentas in the ovary is called placentation. They have special arrangment of it. Their arrangment have different cases. In some cases placenta is formed along fused margins of ovary. The gynoecium is monocarpellary or polycarpillary and apocarpous. Example is Cassia and etc In the other cases ovary is compound and uni ocular. The fused margins of the carpel swell up to form placentas. Ovules attach on it. Sometime fused margins of the carpel grow inward to form incomplete septa. It divides each ovary into number of incomplete compartments. The ovules are borne on the surface of septa like chamber. The chamber was given its number.

       In Brassica the placentation is partial. It has bicarpellary ovary. This compound ovary become bicoular due to the formation of false septum. Some of these cases gynoecium is polycarpillary and syncarpous. The fused margins of carpels grow inward in the center of ovary. The marginal placenta of all the carpels fuses in the center to form a central axis.Ovules are attached on this central axis .Example of this case is Potato Eu phobia. Sometime a number of fall septa is formed on it.   

Inflorescence

Inflorescence

The method of arrangment of group of flower is called inflorescence. Most of flower develop inflorescence. Small flower are inconspicuous. They collect together to form inflorescence to attract insects. The main axis of inflorescence is called peduncle. A long unbranched leafless peduncle arising form the ground level is called scape.It has 2 types. Inflorescence may be terminal or axillary. 

       Terminal inflorescence:  In this case the inflorescence is form at  apex of main branch. Main  axis continues  in to inflorescence.  Example of  terminal  inflorescence is Foxglove 

Axillary: During this case inflorescence forms branch.Flower born on the branches.Example is Oxalis

Types of Inflorescence

Inflorescence has different types. These types are given below.

Simple raceme is racemose in which main axis is elongated and bears lateral pedicillate flower is called simple raceme. Example Linaria.

The first type of inflorescence is Raceme .It is present in two forms raceme and compound raceme. Different flower show raceme and compound raceme.

It is type of  inflorescence. Flower are grow on the branches. Flower are developed in to the fruit.

        The spike with unisexual flowers is called catkin. The male catkin falls off as whole after flowering. But female catkin drops off after fruiting. Example Mulberry ( شہتوت)  and Willow.

    In this case of inflorescence main axis is short and pedicles of the the older flower are longer and pedicles of the younger flowers are short. Therefore  all the flower are look as come on the same level. Example of  corymb type flower is candy tuft (چاندنی).

       In the simple umbel main axis above the first flower is much shorter and flower appears to be arised from same point.The younger flower grow to ward the center and older flower are present away from the center. It may be  bractiate or  ebractiate.  Example  of  simple  umbel is cherry and  Hydrocotyle.

        The inflorescence in which main axis is elongated and bears sessile lateral flower is called spike. In the flower bract may be present or absent.Their example are Bottle, Brush and Ginger etc.

It is known as head. In this case of inflorescence main axis is flattend to form receptacle and flower are crowed on the capitulum. The flower are small and sessile. They are called flortes. The young florets are present at the centerand older are present toward the periphery. 

Flower may be bracteate or ebracteate. The captitula is homogamous or hetrogamous. Homogamous  In this case all flower are of same kind. Example Sonchus. Herterogamous Two type of flower are present in the captiula in this case. Example Sunflower. Hypanthodium  It is modified from of capitulum. In this case the receptacle grows upward along its margin and form hollow pear shaped structure. It has apical opening guarded by scales. Unisexual flowers are developed on the inner surface of the hollow receptacle. The male flower are developed at apex near the opening.Example is Banyan and peepal.          

Fruit

Fruit 

 The ripened ovary is containing seeds is called fruits. Some fruits are without seed .Example banana, pineapples etc. These fruits are called parthenocarpic. The fruit which is only formed from the overy is called true fruit.Some other parts of plant also take part in the formation of fruit. These parts are thalamus,  calyx.These form  some type of fruits like apple. Such fruits are called psesudocarp.

  The outer wall of the fruit is called pericarp.  It may be fleshy and juicy or some time dry and hard.  It is dived  into  other three  layer  endocarp,  mesocarp  and  exocarp.  Fruits  have  different forms.  

Dispersal of seeds and formation of fruits 
    Seeds consists of embryo and stored food material. It covered by protective covering. The embryo grows into plant by using stored food. This food supply energy for there growth. Most seeds have some means of dispersal. Dispersal mechanism carries them to favorable location. Then they germinate there. There are different method and kinds of dispersal of seeds and formation of fruits.

   Dispersal by wind   Whole fruit or individual seeds  may disperse by wind. Such seeds are light weight. Seeds of following types on the dispersal with wing. These are minute seeds, flattened fruits there wing are like a out growth. Minute seed are orchids and very small. They have light weight and infalted outer  covering. These  fruits  are  dust like  seeds and  blown  by wind to great distance Wings In some cases seeds  and other whole fruit are flattend. Some may have  both flattend and wings. The structure help the fruit for dispersal. Its example are ash, maple and linades. Feathery appendages Seeds or fruits of some plants may have feathry  appendages. These appendages greatly increase the buoncy. These are frequently carried by wind to long distances. Censor mechanism The capsules of many plants open in different ways. Thus the seeds escape when the capsule is violently shaken by wind.It occur in different  fruits like poppy. This mechanism scatter the seeds. Some seeds have flat or wings like out growth.

   Dispersal by water Many seashore and aquatic plants disperse by water. They adapt different adaptation for their dispersal. Whole fruit or seeds may be adapted the floating method. The pericarp of a fruit may be composed of light tissue. In some cases fruit may be inflated. In the lotus fruit the torus is greatly enlarged mass o loose air filled tissue. They float readily. Thus fruits travel for long distance.
    Dispersal by animals  The seeds of  plants also dispersed with animals. So animals and insects like honeybee, ant and butter fly come on the flower to get nectar then the pollen grain on the flower is attach with the legs of these insects. When they move to another flower these pollen grain    are reach on other flower.  Here  in  germinate and produce fruits.Example flower. 

     There are two ways of the dispersal of seeds by animals. Some fruits are fleshy fruits. Some portion of such fruits are eaten by animals.Dry fruits adhere to animals. Fleshy fruits  are used by animals as their food. Some part of these fruits are eaten by animals without any injury to seed. In many cases of sees it coat is hard. Stony seeds  seeds are  protected by stony endocarp in drupes. A seed is protected by stony endocarp. Thus seeds pass without any injury through the digestive tract of animal. Birds are  particularly prominent in dispersing the seeds of fleshy fruits.Some time they eat fleshy portion and throw the seeds away. Dry fruits are often carried by the animals for food by seeds eating animals. They loose them in one or tow ways and leave them to grow. Adhesive fruits Many dry and hook like appendages e.g Cosmos and Bidens etc . It is  fitted for grasping the hair of the animals. Animals carry them and distribute seeds. The fruits is adhere to clothing and dispersed by man. Some seeds and fruits have sticky covering. It adhere to hair of animals and attached with their body. Feathery appendages are capable for adhering the fur. They may fly through wind.