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AnatomyRoot, stem, leaves, flowers and fruits are made up of different kind of tissues to perform different functions. Thus, a tissue may be defined as a group of similar or dissimilar cells that perform a common function and have a common origin.Tissues in plants are of three types1. Meristematic tissues: it includes group or cluster of cells which remains in continuous state of division or retain their power of division.Rounded, oval, polygonal or rectangular in shape and are compactly arranged without intercellular spacesThin, elastic primary wall made up of cellulose, dense protoplasm with many small vacuoles and large nuclei, donot store reserve food materialcrystals are absent, ER poorly developed

2. Permanent tissues: made up of mature cells, originate from Meristematic tissues and become permanent at fixed positions, cells have definite shape, size and functions. Normally these tissues lose their power of division but sometime under some special conditions they may regain their power of division. They are of two typesSimple tissues: similar type of cells have common origin and function. Have three categoriesParenchyma: these tissues consists of thin walled living cells having intracellular spaces, cell wall made up of cellulose, found in epidermis, cortex, pith, pericycle, mesophylls of leaves, pulp of fruits, xylem and phloem.

Functions of parenchymaStorage of reserve food materials.Storage of water.Gaseous exchange in water plants.Provide rigidity to plant body and help to maintain shape of plant body.They perform all vital activities of plants.

Collenchyma: cell wall show localized thickenings due to presence of pectin, hemicelluloses and cellulose. Tissue is plastic, extensible and has capacity to expand and gives a tensile strength to the organ and are living, chiefly occurs in hypodermis of dicotyledonous stems.

Functions:- 1) Chief supporting tissue in young stems. 2) This tissue has capacity to expand and gives a strength to the plant and the cells are compactly arranged and have very little inter-cellular spaces. 3) It provides mechanical support, elasticity, and strength to the plant body. 4) Some cells possess chloroplasts and perform photosynthesis. So, It helps in manufacturing sugar and storing it as starch. 5) It is present in the margin of leaves and resist tearing effect of wind.

Sclerenchyma: consists of thick-walled dead cells, possess hard and extremely thick secondary walls. Cells vary in shape, size and origin.b) Complex tissue: a group of more than one type of cells having common origin and working together as a unit is called complex permanent tissue. E.g. xylem and phloem together called as vascular tissue.Xylem: introduced by Nageli (1858). It is chief conducting tissue of vascular plants responsible for conduction of water and inorganic solutes.Phloem: it is the chief food conducting tissue of vascular plants responsible for translocation of organic solutes.

3. Secretory tissues: the product of the cytoplasm are sometime store inside the cells, glands or ducts. This phenomenon is known as secretion. Sometime these products do not take part in further metabolism of plant body and remove to outside of the body. This movement of product towards outside is called excretion. Both secretion and excretion are performed by special type of cells which are either isolated in various plant organs or aggregated to form definite tissue, called Secretory tissue.Thetissuesthat are concerned with the secretion ofgums,resins, volatile oils,nectarlatex, and other substances in plants are calledsecretory tissues.The cells of secretory tissues usually contain numerous mitochondria. The frequency of other cell organelles varies according to the material secreted.

The tissue systemA group of tissues which perform the same general function, irrespective of their position or continuity in the plant body. There are three tissue systems in plantsEpidermal tissue system: originated from the outermost layer of apical meristem, form outermost covering of various plant organs.EpidermisCuticle and waxStomataTrichomes (hair and scales)2. Ground tissue system: it forms the bulk of body, distinct region of ground tissue are cortex, hypodermis, endodermis, pericycle and pith3. Vascular tissue system: xylem and phloem

Epidermal tissue systemEpidermis: (Greek, Epi= upon; Derma= skin) Single layered but in some cases it may be more than one. They are compactly arranged forming a continuous layer, interrupted only by stomata. It provide protection.Cuticle and Wax: is a fatty substance deposited over the outer surface of epidermal cells in form of a separate layer, absent in young roots. It may be thin or thick and smooth or rough.Usually the cuticle is covered with wax. Other substances deposited may be oil, silicon and salts like calcium carbonate.Stomata: Singular is stoma (Greek, Stoma= mouth). A typical stoma is microscopic and usually consists of two kidney-shaped guard cells. The guard cell walls have special elastic properties, help them to stretch laterally during stomatal opening.Trichomes: These are epidermal outgrowths present temporarily or permanently on almost all the plant parts. They may be unicellular or multicellular. Two types:- Hair and scales.

Ground tissue system This system mainly originates from ground meristem. The distinct regions of ground tissue system are cortex, hypodermis, endodermis, pericycle and pith.Cortex: Region between epidermis and endodermis, Consists of parenchymatous, collenchymatous and sclerenchymatous. Cortex is distinct in dicotlyledons but not in monocotlyledons where there is no demarcation between cortex and pith.Cortex of root is made up of one type of cells but in case of stem the outer few layers of cells may be differentiated into hypodermis, considered as a zone of protecting and supporting tissues.Endodermis: Single layer of compactly arranged parenchymatous cells present between cortex and pericycle.Endodermis of roots forms a water-tight jacket around the vascular cylinder and helps to maintain the root pressure. In case of stem, it serves the function of storage of starch.

Pericycle: Single or multi-layered cylinder of thin or thick-walled cells present between endodermis and vascular tissues.Pith: Central portion of root and stem is occupied by pith. It is usually made up of parenchymatous cells with intercellular spaces. The main function is storage of water and food reserves.Ground tissue of Leaves: Ground tissue of petiole is made up of parenchymatous cells with distinct intercellular spaces. In leaf lamina, bulk of ground tissue is called mesophyll. These cells are thin-walled parenchymatous and possess chloroplasts. The main function of mesophyll is Photosynthesis.

Vascular Tissue SystemThis includes vascular tissues, i.e., Xylem and phloem.Both are usually found in bundles, called vascular bundles.Main function of vascular bundles is conduction of water and minerals, translocation of organic solutes and to give mechanical support to the plant body.

Primary structure of a rootVarious cells and tissues of primary root arise from root apical meristem. Primary body of root shows the following anatomical features.epidermis: single layered but in few cases it may be multilayered , made up of closely packed thin walled living parenchymatous cells. Epidermis provide protective covering and to help in absorption of water and solutes.Cortex: originated from the ground meristem , composed of thin walled paranchymatous cells with prominent air spaces.Exodermis: in case of many monocotyledons and a few dicotyledons, the outer few layers of cotex are made up of thick walled cells called exodermis

4. endodermis: innermost layer of the cortex, single layered made up of compactly arranged barrel shaped cells. Provide air tight mechanical protective layer which helps to maintain root pressure, prevent leakage of nutrients from vascular tissues and regulate the movement of water and mineral salts5. Pericycle: outer boundary of vascular cylinder, single layer made of thin walled living cells of parenchyma. It forms lateral roots as acting as site of their origin, develop part of vascular cambium and develop cork cambium6. Vascular system: consist of alternative xylem and phloem. In case of dicot root number of xylem strands are less than eight where as in monocot roots they are more than eight7. Pith: central part of root is occupied by pith. It is very small and absent in dicot roots.

Internal structure of typical Dicot rootEpidermis:- is theouter layerof the cells of the young root. The cells areclosely- packed,thin-walled parenchyma cellswithno cuticle, chloroplasts or stomata.Root hairsarise from some of the epidermal cells. Due to the presence of root hairs the epidermis is called as epiblema or hypodermis.Functions:- 1)The epidermisprotectsthe underlying tissues of the root. 2) The epidermal cells and the root hairsabsorb water and dissolved ions.Cortex: It is simple, multi-layered and consists of thin-walled living parenchymatous cells with numerous intercellular spaces. On theinner sideof the epidermis is the cortex and in many plant types it can be subdivided into anexodermis, a central cortex and endodermis. Functions:- 1) The cortex allows for thediffusion of water, mineral salts and oxygenfrom the root hairs inwards. 2) The cortexstores foods reserve, especially starch. 3)The cortex also serves totransport water and saltsfrom the root hairs to the center of the root.Exodermis: in case of many monocotyledons and a few dicotyledons, the outer few layers of cortex are made up of thick walled cells called exodermis.

Endodermis: innermost layer of the cortex, single layered made up of compactly arranged barrel shaped cells. Provide air tight mechanical protective layer which helps to maintain root pressure, prevent leakage of nutrients from vascular tissues and regulate the movement of water and mineral salts.A single layer of cells in a root that separates the cortex tissues from the pericycle.Vascular Cylinder or Stele:- Thevascular cylindercomprises all the tissues enclosed by the endodermis. It consists of thepericycleandvascular tissues(xylem and phloem). Thepericycleis asingle layer of thick-walled, tightly-packed cellswithoutintercellular spaces.Lateral rootsarise from the pericycle. The vascular tissue isconducting tissuein the root. It consists ofxylem and phloem, which are separated from each other by parenchyma. Onlyprimary xylemis present in young roots, which differentiated intoprotoxylem, which lies against the pericycle, and themetaxylemlying towards the inside. Functions:- 1) Branch or lateral rootsoriginate in the pericycle. 2) The xylemtransports water and dissolved substancesfrom the roots to the stem and leaves. 3) The xylem is themain strengthening tissueof the root. 4) The phloemtransports organic substances such as carbohydratesfrom the leaves to the root.Pith: central part of root is occupied by pith. It is very small and absent in dicot roots.

Internal structure of typical monocot rootEpiblema/Epidermis: It is single layered, consists of thin-walled cells. A few tubular root hair arise as unicellular elongation of epiblema cells. Externally covered by a waxy layer called cuticle. It consists of minute pores called stomata. The cuticle check the evaporation of water and protect the stem from high temperatures.Cortex: It is massive, consists of thin-walled parenchymatous cells with intercellular spaces.Found beneath the epidermis composed of thin walled spherical of oval parenchymatous cells. It is concerned with assimilation and storage of food materials.

Exodermis: In old root, a few outer layers of cortex become thick-walled. This zone is called exodermis and acts as protective layer when the epiblema is disorganised. Endodermis: is single layered consists of thick-walled cells with casparian strips. The cells of endodermis, opposite to protoxylem, are thin-walled and called passage cells.Pericycle: is single layered consisting of thin-walled cells. A few cells may become sclerenchymatous.Vascular bundles: They are radial. Large number of xylem and phloem groups alternate with each other.Pith: is large made up of parenchymatous cells.

Difference between Dicot and monocot Root

Structure of StemStem usually consist of three tissues,dermal tissue,ground tissueandvascular tissue.The dermal tissue covers the outer surface of the stem and usually functions to waterproof, protect and control gas exchange. The ground tissue usually consists mainly of parenchyma cells and fills in around the vascular tissue. It sometimes functions in photosynthesis. Vascular tissue provides long distance transport and structural support. Most or all ground tissue may be lost in woody stems. The arrangement of the vascular tissues varies widely among plant species.

Structure of Dicot StemEpidermis: is outermost single layered protective covering made up of compactly arranged parenchymatous cells. The outer walls of cells are highly cutinised or coated with wax. Stomata may be present in young stem and epidermal out growths include hairs, usually multicellular.Functions:- 1) The epidermisprotects the underlying tissues. 2) The cuticleprevents the desiccation of inner tissuesand thusprevents water loss. 3) The stomata allowsgaseous exchangefor the processes of respiration and photosynthesis.Cortex: epidermis is followed by a few to several layered thick distinct zone, called Cortex, made up of parenchymatous cells or differentiated into two parts- Hypodermis and Cortex.Endodermis: innermost layer of cortex, consists of single layer of barrel-shaped cells.

Vascular Cylinder or Stele:- This region comprises thepericycle, vascular bundles and pith (medulla).Pericycle:- The pericycle is made up ofsclerenchyma cellswhich arelignified, dead fibre cells. These cells havethick, woody wallsandtapering ends.Functions:- 1) Itstrengthensthe stem. 2) It providesprotectionfor the vascular bundles.Vascular Bundles:- are situated in aring on the insideof the pericycle of the plant. A mature vascular bundle consists of three main tissues -xylem, phloem and cambium. Thephloemis located towards theoutsideof the bundle and thexylemtowards thecenter. Thecambium separatesthe xylem and phloem which bring aboutsecondary thickening.Functions:- 1) The xylem provides apassage for water and dissolved ionsfrom the root system to the leaves.2) The xylem alsostrengthens and supportsthe stem.3) The phloemtransports synthesized organic foodfrom the leaves to other parts of the plant.

Pith (Medulla):- The pith occupies thelarge central partof the stem. It consists ofthin-walled parenchyma cellswithintercellular air spaces. Between each vascular bundle is aband of parenchyma, the medullary rays, continuous with the cortex and the pith.Functions:- 1) The cells of the pithstore water and starch.2) Theyallow for the exchange of gasesthrough the intercellular air spaces.3) The medullary raystransport substancesfrom the xylem and phloem to the inner and outer parts of the stem.

Structure of Monocot StemThe tissues of dicots and monocots are basically the same. However, there are essential differences in the arrangement of theepidermis, ground tissue and vascular tissue.Epidermis:- The structure and functions of this tissue are the same as those of the epidermis of the stem of a dicotyledonous plant. The epidermis consists of asingle layer of living cellswhich are closely packed. The walls arethickenedand covered with athin waterproof layercalled thecuticle.Stomataare found in the epidermis. In some stems eitherunicellular or multicellular hair appear from the epidermis.Functions:- 1) The epidermisprotects the underlying tissues. 2) The cuticleprevents the desiccation of inner tissuesand thusprevents water loss. 3) The stomata allowsgaseous exchangefor the processes of respiration and photosynthesis.Ground Tissue:- This region is composed ofsmall, thick-walled sclerenchymaon the inside of the epidermis. These layers of cells are followed by larger thin-walled parenchyma cells. Intercellular air spaces are found in the parenchyma.A cortex or pithis absent.Functions:-1) Sclerenchyma tissuestrengthensthe stem. 2) Parenchyma tissuestores synthesised organic foodsuch as starch. 3) Intercellular air spaces allow theexchange of gases.

Vascular Bundles:-The vascular bundlesoccurring nearer the ring of the stemare smaller and arecloser to one another. The vascular bundles containno cambiumand consequentlysecondary thickening does not occur. The vascular bundle is composed of thefollowing parts:Sclerenchyma sheath:- Thick-walled sclerenchyma fibres surround the vascular bundle.Function:- Sclerenchyma sheathsprotect the vascularbundles and givestrengthto the stem.Xylem:- Large xylem vessels are found within an irregular intercellular air space. This space is surrounded by thin-walled parenchyma cells.Functions:-Xylemtransports water and dissolved ionsfrom the root system to the stem.The lignified thick-walled xylem cellsstrengthenthe stem.Phloem:- Phloem is composed of thin-walled cells, viz. sieve tubes and companion cells.Function:- The phloemtransports synthesized organicfood such as carbohydrates from the leaves to other parts of the plant.

Difference between Dicot and monocot Stem

Structure of LeavesThefoliage leavesare probably the most noticeable organs of a flowering plant. Leaves are adapted to perform certain importantfunctions:photosynthesis, respirationandtranspiration.A typical foliage leaf consists of a large, flatleaf blade (lamina), apetiole (leaf stalk)and aleaf basewith which the leaf is attached to the stem. Theveinsare clearly visible on the leaf blade. The way in which the veins are arranged is known asvenation of the leaf. The leaf blades of some plants show indentations or clefts. If these indentations reach all the way to the midrib so that the leaf blade isdivided into a number of smaller pinnae (leaflets), the leaf is called acompound leaf.If the leaf blade isnot divided into leaflets, the leaf is termed asimple leaf. Most monocots have simple leaves, while dicots can have simple or compound leaves.

Internal Structure of Dicot LeafInternally they show three tissue systems:- Epidermis, mesophyll( Ground tissue) and vascular system.Epidermis:- Each leaf has upper as well as lower epidermis made up of single layer of compactly arranged parenchymatous cells. A few plant possess multi-layered epidermis.Outer walls of epidermal cells are coated with cuticle of variable thickness. Sometimes, has a extra layer of wax. Usually the stomata are present more in lower as compared to upper epidermis.Mesophyll:- Bulk of tissue lying between upper and lower epidermis is called mesophyll. It consist of parenchymatous cells containing chloroplasts and separated by lots of intercellular spaces. These spaces are interconnected and open into sub-stomatal chambers to maintain gaseous exchange through stomata.Vascular system:- vascular supply of leaves is maintained by leaf traces arising from the vascular cylinder of stem. The mid-rib of leaf receives the main supply which is then distributed to veinlets.Mid-rib of leaves either consists of single or many vascular bundles( e.g. Sunflower). Phloem lies towards lower side and xylem towards upper side.

Internal structure of Monocot LeafLeaves usually show parallel venation.Like dicotyledonous leaves, monocotyledonous leaves also possess three tissue systems:- Epidermis, Mesophyll and vascular system.Epidermis:- Each leaf has upper and lower epidermis made up of single layer of compactly arranged cells are coated with thick or thin cuticle. Stomata found on both upper and lower epidermis.Mesophyll:- bulk of tissues lying between upper and lower epidermis. All the cells of mesophyll contain chloroplasts and perform photosynthesis.Vascular system:- monocot leaves are characterized by possessing parallel venation. Each vein comprises of single vascular bundle. Each bundle is surrounded by bundle sheath.

Difference between Dicot and Monocot leaf

Dicot leafMonocot leaf

Digestion

Digestion: breakdown of food molecules by enzymatic action into smaller componentsGeneral StepsIngestion = food is taken in (eating )Digestion = Food is broken down into smaller pieces /molecules Absorption = Nutrient molecules are absorbed into body cells Egestion = undigested material exits the body

Intracellular DigestionIn the animal kingdom, only sponges (Phyla Porifera) do this exclusively. Steps:Cells engulf food via phagocytosis or pinocytosis, forming food vacuole. Lysosomes fuse with food vacuoles; hydrolytic enzymes break down food.

Extracellular DigestionAll animals (except sponges) perform this mode of digestion Extracellular digestion: digestion (with in a cavity) in lumen, stomach, intestines vertebrates, arthropods, many others

Complete Digestive TractsComplete digestive tract = digestive tube running throughout body (alimentary canal)Organisms with a complete digestive tract have both a mouth and an anus

Human DigestionIngestion = mouthDigestion = mouth, Stomach, Small IntestinesAbsorption = Small Intestines, Large IntestinesElimination = End of large intestines

Oral Cavity, Pharynx, EsophagusParticipate in ingestion and digestionMechanical Digestion By teeth and tongue (chewing)Forms mass of food = bolusChemical Digestion Salivary amylase begins digestion of carbohydrates (starch)

Oral Cavity, Pharynx, EsophagusEpiglottis moves during swallowing to cover the trachea, so food travels down right pipe to the esophagusPeristalsis (muscle contractions) will continue movement of the bolus

StomachImportant in storage & digestion The stomach is a big muscular pouch which churns the bolus (Physical Digestion) and mixes it with gastric juice, a mixture of stomach acid, mucus and enzymes.

StomachGastric glands produce gastric juice from a combination of 3 cells: Mucus Cells secrete mucus (protects stomach lining) Chief Cells secrete pepsinogen (inactive enzyme)Parietal Cells secrete HCl

StomachGastric juice is churned with bolus to break down food and kill bacteriaHCl converts pepsinogen into pepsin (active enzyme)Pepsin hydrolyzes (breaks down) protein. Halfway done!

Small IntestineParticipates in digestion and absorption Peristalsis allows for movement of chyme and digestive juices down the small intestine.

Digestion in the Small IntestineDigestion is usually completed in the duodenum (first section) with the help of digestive juices

Digestive JuicesDigestive juices come from 4 sources, entering the duodenum: Pancreas produces digestive enzymes produce basic bicarbonate solution (buffer)

Digestive JuicesLining of duodenum produces digestive enzymes Liver Produces bileGallbladderStores bile

Bilecontains bile saltsbreaks up fat droplets into very small pieces called micelles micelles are then absorbed and taken up by the lymph vessel (lacteal)

Absorption of NutrientsOccurs in the jejunum (mid-small intestine) and ileum (end-small intestine) The surface area in these regions is very large because of the villi and microvilli. Villi and microvilli are projections of the lining

Absorption of NutrientsSome nutrients are absorbed into the lymph vessel.

Absorption of NutrientsMost nutrients are absorbed into the blood vessels capillaries hepatic portal vessel liver the liver converts many nutrients and regulates blood sugar and other nutrient levelsWater is also absorbed here.

Digestion SummaryBiomoleculeWhere DigestedKey EnzymesCarbohydrates Mouth, Small IntestineAmylase, Maltase, Lactase, SucraseLipids Small IntestineBile, LipaseProteins Stomach, Small IntestinePepsin, Peptidases, Trypsin Nucleic Acids Small IntestineNucleases

carbohydrasesStarches Glucose

proteasesProteins Amino acids

lipasesFats Fatty Acids + Glycerol

nucleasesNucleic Acids Nitrogenous bases + pentose sugars + inorganic phosphates

Large Intestineresponsible for water recovery from digested material Feces = Waste of digestive tract Bacteria live here (including E. coli) that live on feces and produce vitamins B and K and stinky gases

Large IntestineEnd of colon = rectum End of rectum = anus

PHOTOSYNTHESIS

Photosynthesis is an enzyme regulated anabolic process of manufacture of organic compounds inside the chlorophyll containing cells from carbon dioxide and water with the help of sunlight as a source of energy. The organisms which perform photosynthesis are called photoautotroph's.

In 1937, Robert Hill discovered that isolated chloroplasts can generate oxygen when they are illuminated in the presence of a suitable electron acceptor, even if no carbon dioxide is present. This finding was a landmark in the study of photosynthesis because it was one of the first indications that the source of electrons in the light reactions is water, and it confirmed that the evolved oxygen comes from water rather than from carbon dioxide. Furthermore, it showed that a significant component of the light reactions can be studied in vitro using isolated chloroplasts. The Hill reaction is formally defined as the reduction of an electron acceptor (A) by electrons and protons from water, with the evolution of oxygen, when chloroplasts are exposed to light:lightH2O + A ----------------> AH2 + 1/2 O2chloroplasts

Importance of photosynthesisWith the help of photosynthesis autotrophic plants synthesizes organic food from inorganic raw materialsAll the animals and heterotrophic plants depends on the phototrophs for their organic foodPhotosynthetic products provide energy to all organisms to carry out their life activitiesAll useful plant products are derived from the process of photosynthesis such as timber, rubber, resins, drugs, oils, fibers. Fossil fuels are also products of photosynthetic organisms.Photosynthesis is the only natural process that evolves molecular oxygen for use by other living organismsPhotosynthesis decrease the concentration of carbon dioxideProductivity of agricultural crops directly depends upon the rate of photosynthesis

Raw material for photosynthesisThe raw materials of photosynthesis areWater: water is used as a source of hydrogen in the formation of a glucose molecule.Carbon dioxide: acts as a source of carbon and oxygen for the formation of glucose molecules. Sunlight: Sunlight is used as a source of energy to conduct the process of photosysthesis Chlorophyll: Chlorophyll are the green pigments present in the plants that impart the plants with a green color. Chlorophyll molecules are excited in the presence of light and liberate electrons, that split water into hydrogen and oxygen. The hydrogen combines with carbon dioxide through various complex processes to form glucose, and the oxygen is liberated out into the atmosphere.

The site of photosynthesis in a plant

Leaves are the major organs of photosynthesis in plants.

Gas exchange between the mesophyll and the atmosphere occurs through microscopic pores called stomata.

An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle.Photosynthesis occurs in two stages: the light reactions and dark reaction (the Calvin cycle).

Light reactions in photosynthesis, the reactions that convert light energy to chemical bond energy in ATP and NADPH. These reactions:Occur in the thylakoid membranes of chloroplastsReduce NADP+ to NADPH

Light absorbed by chlorophyll provides the energy to reduce NADP+ to NAPDH,

Dark reaction (Calvin cycle) the carbon-fixation reactions that assimilate atmospheric CO2 and then reduce it to a carbohydrate. These reactions:

Occur in the stroma of the chloroplast

First incorporate atmospheric CO2 into existing organic molecules by a process called carbon fixation, and then reduce fixed carbon to carbohydrate

Carbon fixation the process of incorporating CO2 into organic molecules.

The Calvin cycle reactions do not require light directly, but reduction of CO2 to sugar requires the products of the light reactions:

NADPH provides the reducing power.

ATP provided the chemical energy.

The light reactions use solar energy to make ATP (chemical energy) and NADPH (power reduction). ATP produced in the light reactions of photosynthesis is only dedicated to drive the Calvin cycle. thylacoidsstroma

The Calvin cycle incorporates CO2 into organic molecules, which are converted to sugar.

Thylakoid membranes are the sites of the light reactions,

the Calvin cycle occurs in the stroma. thylacoidsstroma

Factors affecting photosynthesisExternal factorsLightLight intensity: under low light intensity usually the rate of photosynthesis is lowLight quality: photosynthetic pigments absorb visible part of radiationsDuration of light: longer duration of light favors photosynthesis2. Carbon dioxide: if the CO2 conc. Increase it increases the rate of photosynthesis. But very high conc. Become toxic and inhibit photosynthesis.3. Temperature: increase in rate of photosynthesis by increasing temp up to 40 C, above it decrease the process

4. Water: essential raw material 5. Oxygen: It is inhibitory6. Mineral: elements deficiency of some minerals decrease photosynthesis such as Mg, Fe, Cu, Cl, Mn, P.INTERNAL FACTORSAge: ChlorophyllHormonesLeaf anatomy

RespirationCellular respiration is an enzyme-controlled process of biological oxidation of food material in a living cells, using molecular oxygen, producing carbon dioxide and water and releasing energy in small steps and storing it in biologically useful forms, generally ATP. Organic compounds catabolised in the living cells to release energy are called respiratory substrates. Any foodstuff- carbohydrate, fat or protein- may be used in cellular respiration.

Respiration which is use proteins is called protoplasmic respiration, where as that which uses carbohydrates or fates is termed floating respiration.

Exergonic Reactions: a chemical reaction which releases energy by splitting a large molecule into smaller ones is called exergonic reaction. the splitting exergonic reaction are also called catabolic reactions.

Endergonic reaction: a chemical reaction which joins smaller molecules into larger one by taking up (storing) energy is termed endergonic reaction also termed as anabolic reaction.

Types of respiration1. Aerobic RespirationThe breaking down of organic food to produce energy where oxygen is present.

Glucose + Oxygen Carbon Dioxide + Water+ Energy

2. Anaerobic Respiration: Refers to the oxidation of molecules in the absence of oxygen to produce energy. It is also known as fermentation.

AEROBIC RESPIRATIONANAEROBIC RESPIRATION1. Occurs in majority of organismsOccur in few organisms (yeast and some bacteria)2. It involves exchange of gases between organisms and environmentExchange of gases does not occur3. Use oxygenDoes not use oxygen4. Produce water Does not produce water 5. Release entire energy available in glucoseRelease only 5 % energy available in glucose6. Yield inorganic end productsYield organic end product7. Occur in cytoplasm and mitochondriaOccur in cytoplasm only8. Involves 3 steps: glycolysis, kreb cycle and terminal oxidation.2 steps: glycolysis and incomplete breakdown of pyruvic acid.

DiffusionThe movement of molecules or ions of a solute or a solvent (be it a solid, liquid or gas) from the region of its higher concentration to that of its lower concentration.

Factors influencing rate of diffusionTemperature: increase in temperature increase the diffusionMedium in which diffusion occurs: diffusion will be slow if the medium is concentratedDiffusion pressure gradient: it implies the applications of conc. differences over a specific distance. Greater the diffusion pressure gradient, more rapid will be the net diffusion of molecules.

Importance of diffusion in plantsExchange of gases like CO2 intake and O2 output in photosynthesis and CO2 output and O2 intake in respiration take place by the principle of independent diffusion.Involved in the transpiration of water vapors Ions are absorbed by the simple diffusion during passive salt uptakeIt is a effective mean of transport of substances over a very short distance and helps in translocation of food materials

Osmosis OSMOSIS is the net diffusion of water molecules from a dilute solution to the concentrated solution when the two are separated by means of a semi permeable membrane

TURGOR PRESSURE: the actual pressure exerted by the protoplasm against the cell wall is the turgor pressure

OSMOTIC PRESSURE: maximum amount of pressure that can be developed in a solution separated from pure water by semi-permeable membrane is termed osmotic pressure.

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Osmosis A Special kind of DiffusionDiffusion of water across a selectively permeable membrane (a barrier that allows some substances to pass but not others). The cell membrane is such a barrier.Small molecules pass through ex: waterLarge molecules cant pass through ex: proteins and complex carbohydrates

Hypotonic The solution on one side of a membrane where the solute concentration is less than on the other side. Hypotonic Solutions contain a low concentration of solute relative to another solution.

Hypertonic The solution on one side of a membrane where the solute concentration is greater than on the other side. Hypertonic Solutions contain a high concentration of solute relative to another solution.

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Over time molecules will move across the membrane until the concentration of solutes is equal on both sides. This type of solution is called ISOTONIC.

Importance of osmosis in plantsImportant in the absorption of water in plantsCell to cell movement of water occurs throughout the plant body due to osmosisShape and form of organisms is maintain through osmosisLeaves become turgid and expand due to their OPgrowing point of root remain turgid because of osmosis and thus able to penetrate the soil particlesThe resistance of plants to drought and frost is due to OPopening and closing of stomata is effected by osmosis

Differences between diffusion and osmosisDIFFUSIONOSMOSISDiffusion is net downward movement of a given substance along the free energy gradient from the place of higher concentration to an area of its lesser concentrationSpecial type of diffusion of solvent molecules from low concentration of solution to higher concentration of solution through semi-permeable membraneMay occur in any medium and the diffusing particles may be solid, liquid or gas.Occur in liquid medium and only the solvent molecules move from one place to another

Presence of semi-permeable membrane is not required semi-permeable membrane in between the two solutions is required

Transpiration

1. DefinitionTranspiration is the loss of water in the from of water vapours from the living tissues of the aerial parts of plants.

Of all the water plant absorbs, over 95-99% is transpired to the air as water vapor.

TYPES OF TRANSPIRATION Most of the transpiration occur through foliar surface or surface of leaf known as foliar transpiration (accounts for over 90 % of total transpiration. Transpiration though stem is called cauline transpirationDepending upon the plant surfaces transpiration is of following type

1. Stomatal transpiration : occurs through stomata

CuticleCuticleMesophyllStomataGuard cellsPrevents water lossSite of photosynthesisOpenings allow gases and water to move in and out of leafOpen and close the stomataStomatal transpiration

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How do the guard cells react to the availability of water?Dry guard cells CLOSElots of H2O guard cells OPEN

Function of Guard Cells

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2. Cuticular transpiration: take place through cuticle or epidermal cells of leaf. The leaf is covered by a layer of cuticle, which is made up of cutin (a wax like substance). 5 to 7% of water is lost through the cuticle of the leaf surface. At night when the stomata are almost closedCuticulartranspiration takes place.

3. Lenticular transpiration : found only in woody branches of tree where lenticels are present, 0.1 %, 4. Bark transpiration : take place through corky covering of the stem

Environmental factors that affect the rate of transpiration Light Plants transpire more rapidly in the light than in the dark. This is largely because light stimulates the opening of the stomata , Light also speeds up transpiration by warming the leaf .

2. Temperature Plants transpire more rapidly at higher temperatures because water evaporates more rapidly as the temperature rises. 3. Humidity When the surrounding air is dry, diffusion of water out of the leaf goes on more rapidly.4. atmospheric pressure low atm. pressure enhance evaporation, produce air currents and increase rate of transpiration

5. Wind When a breeze is present, the humid air is carried away and replaced by drier air, thus movement of air increase the transpiration . 6. Soil waterthe rate of transpiration is depends upon rate of adsorption of water from soil by roots. A decrease in water uptake by the root cause partial dehydration of the leaf cells resulting in closure of stomata and wiltingWilting: loss of turgidity of leaf and other soft aerial parts of a plant causing their drooping, folding and rolling.

Plant factors effect transpirationLeaf areaLeaf structureThickness of cuticleStomataHairMesophyllLeaf modification3. Root/ shoot ratio4. Mucilage and solutes

Significance of transpirationadvantagesAscent of sapRemoval of excess waterCooling effectDistribution of mineral saltsIncreasing concentration of mineral saltsRoot systemQuality of fruit

DisadvantagesWiltingReduce growthReduce yieldAbscisic acidWastage of energymodification

Transpiration helps to remove excess water from the plant body by making the plant body cool and hydrate. But when excess transpiration occures the necessary water is removed from the plant body and the body wilts. Loss of water from the plant results wilting, serious desiccation and often death of a plant if a condition of drought is experienced. There is strong evidence that even mild water stress results in reduced growth rate and in crops to economic losses through reduction of yield.

Despite its apparent inevitability, transpiration is also of great significance for the plant. Water is conducted in most tall plants due to transpiration pull. Minerals dissolved in water are distributed throughout plant body by transpiration stream.

Evaporation of water from the exposed surface of cells of leaves has cooling effect on plant. Wet surface of leaf cells allow gaseous exchange. Transpiration affects indirectly the processes of respiration and photosynthesis. So this process is called necessary evil

NutritionProcesses by which organisms obtain and use the nutrients required for maintaining life

Modes of nutrition

Ways of obtaining and using nutrientsNutritionAutotrophic nutritionHeterotrophic nutritionHolozoic nutritionSaprophytic nutritionParasitic nutrition

Autotrophic nutritionOrganisms make their own food (complex organic substances) using simple inorganic substancesAutotrophs

e.g. Green plantsby photosynthesis

1. Photoautotrophic nutrition:

An organism, typically a plant, obtaining energy from sunlight as its source of energy to convert inorganic materials into organic materials for use in cellular functions such as biosynthesis and respiration.

2. chemoautotrophic nutrition:

An organism, such as a bacterium or protozoan, developed a technique to capture energy released during oxidation of organic chemical substances and prepare organic food with its help.

Heterotrophic nutritionOrganisms which depend on other organisms or dead organic matters as their food sourcesHeterotrophsCannot make their own food and obtain their food in organic form

Holozoic nutritionOrganisms take in solid organic food from other organismsheterotrophsFood needs to be broken down into small molecules before they can be used by the organisms

Types of animals taking holozoic nutritionHerbivoresFeed on plants only

CarnivoresFeed on animals onlyOmnivoresFeed on both plants and animals

Saprophytic nutrition(Saprophytism)Organisms feed on dead organisms or non-living organic matterSaprophytes (e.g. fungi, bacteria)

Parasitic nutrition(Parasitism)Organisms (parasite) obtain organic compounds from another living organism of a different species (host)Parasite is benefitedHost is harmed

Macronutrients and MicronutrientsPlants derive most of their organic mass from the CO2 of air but they also depend on soil nutrients More than 50 chemical elements have been identified among the inorganic substances in plants, but not all of these are essentialA chemical element is considered essential if it is required for a plant to complete a life cycle

Macronutrients and MicronutrientsNine of the essential elements are called macronutrients because plants require them in relatively large amountsC, O, H, N, K, Ca, Mg, P, SThe remaining eight essential elements are known as micronutrients because plants need them in very small amountsCl, Fe, Zn, Mn, B, Cu, N, Mo

Essential elements in plants

Mineral DeficiencyThe most common deficienciesAre those of nitrogen, potassium, and phosphorus

Phosphate-deficientHealthyPotassium-deficientNitrogen-deficientFiringdrying along tips and margins of older leavesReddish-purple margins esp. on young leavesYellowing that starts at the tip and moves along the center of older leaves

PollinationTransfer of pollen grains from the opened anther of the stamen to the receptive stigma of the carpal is called pollination. It is of two typeSelf pollinationCross pollination

Self pollination : transfer of pollen grains from the anthers of a flower to the stigma of the same flower. It is of two typesAutogamy : pollen from the anthers of a flower are transferred to the stigma of the same flowerGeitonogamy: pollen from the anther of one flower are transferred to the stigma of another flower borne on the same plant.

Cross pollination: Transfer of pollen grains from the flower of one plant to the stigma of the flower of another plants also known as xenogamy or allogamy.The agents responsible for the cross pollination are Abiotic : such as wind, gravity waterBiotic: animal pollinators

Anemophily (wind pollination): mode of pollination with the agency of wind. The flowers which are wind pollinated are called anemophilous. Flowers are small colourless, odourless and nectarless.Pollon grains are small, light, dey, dusty and somtime winged so that they are easily blown away to long distance. E.g. grasses, sugarcane, bamboo, maize.

Hydrophily (water pollination): mode of pollination through agency of waterFlowers are small colourless, odourless and nectarlessCalyx, corolla and other floral parts are unwettablePollon grains and stigma are generally wetable e.g. Hydrilla

Ornithophily (pollination by birds): mode of pollination performed by birds. Most common bird pollinators are Sub birds, Humming birds, Crow, Bulbul, Parrot, Mynah etc.Flowers are usually large in size. They have tubular or funnel-shapedFlowers are brightly colouredFlowers produce abundant watery nectar.

Entomophily (insect pollination): mode of pollination with the agency of insects.Flowers are usually large, conspicuous, brightly coloured and showy to attract insect pollinatorsSmall flowers bloom in bunches to attract the insects.Different colours of flowers attract different insects.Blossom at a specific time when particular insect pollinator is available.Usually produce specific odours to attract specific insects.The outer surface of pollon grains may be rough, spiny or sticky.

Chiropterophily (bat pollination): mode of pollination performed by bats.the flower they visit are large in size, dull coloured, have strong scent

Advantages of self pollination chance of pollination are moreIt need not to produce a large number of pollen grainsFlowers not need to produce large showy petals, scent, nectar to attract pollinatorsDisadvantagesProgeny gets weaker after every generationLess chance of produce new varieties

Advantages of cross pollinationBrinds about genetic recombination and production of new varietiesProduce healthy and stronger offspringsVariation caused due to cross pollination may results in production of disease resistant plants Several crop plants give significant higher yield if bees are available and cross pollination is allowed to occur.DisadvantagesCross pollination is not economical. Plant waste a lot of energy and food materials in unnecessary adaptationa and devices to bring about pollinationCross pollination is uncertain because factor of chance is always involved.

Dispersal of fruits and seedsthe seeds and fruits are disseminated to different distances from their parents in order to get sufficient space, light and nutrients for successful propagation and evolution of species. normally they do not possess power for locomotion and therefore they are dependent on some external agencies for dispersal.Based on the agencies involved , the dispersal is of two typesDispersal f seeds and fruits

By plant itself By external agencies(Autochory) 1. Anemochory (wind dispersal)Mechanical dispersal 2. Hydrochory (water dispersal) 3. Zoochory (dispersal by man and animals)

WATER DISPERSAL

Seeds of plants which grow near water may be carried far away by streams & rivers.

How do you think the seeds eventually begin growing in this case?

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EXPLOSIVE DISPERSALSome plants distribute their seeds by violently ejectingthem so that they fall well away from the parent plant.

Gorse is a good example of this. Sitting near Gorse bushes on a hot day in summer you can hear exploding pods sound almost like gun shots.

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ANIMAL DISPERSAL - 1Some species of plant use hooks on theirfruits to attach themselves to the fur ofmammals or feathers of birds or even the clothes of humans!

Animals, including humans, have a big role to play in seed dispersal.

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ANIMAL DISPERSAL - 2

The seeds of many plants are dispersed after passing through the digestive system of animals that have eaten them.

What kind of animals would eat these fruits/seeds?

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ANIMAL DISPERSAL - 3

Hard nuts are usually destroyed if chewed or eaten.

However, animals such as squirrels may store them to eat later and forget to go back to get them, giving them a chance to germinate.

On rare occasions, birds such as blue jays can transport acorns long distances.

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Wind Dispersal Small, hard, dry fruits are often dispersed by wind. Some plants have seeds within fruits acting as kites or propellers that aid in wind dispersal.Seed dispersal from the Common Milkweed (Asclepias syriaca), North America.

Leroy Simon / Visuals Unlimited

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Wind Dispersal contd: Most of these plants produce a large number of seeds, but most of the seeds will not produce mature plants. Their large number and ability to disperse to new habitats ensure that at least some will grow and eventually produce seeds themselves.

www.painetworks.com/pagesrf/ii/ii0822.html Overproduction

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Maple winged fruits

Some plants have seeds within fruits acting as kites or propellers that aid in wind dispersal.www.oplin.lib.oh.us/tree/.../maple_hedge.html Wind Dispersal contd:

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Links

http://ncertbooks.prashanthellina.com/11biology.html http://ncertbooks.prashanthellina.com/12biology. Biology/Bhatia K.N. and Tyagi M.P. 2014. Elementary Biology Vol. 1, Truemans. Bhatia K.N. and Tyagi M.P. 2014. Elementary Biology Vol. 11, Truemans. http://yputu.be/ebQdr-UnV6E (for plant anatomy)http://youtu.be/Q6ucKWllFmg (cell division)http://youtu.be/IA42ujTgCnl (probiotics)