Plant organs system


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Plant organs system

  1. 1. Plant Organs SystemRoots & StemLeafFlower & Fruits
  2. 2. The plant body consists of two basic parts:the shoot system and the root system.• Shoot System: includes organs such asleaves, buds, stems, flowers, and fruits and usually itdevelops above ground.– The functions of the shoot system includes:• Photosynthesis• Reproduction• Storage• Transport• Hormone production
  3. 3. • Root System: includes roots as well asmodified stem structures such as tubers andrhizomes and usually it develops underground.– The functions of the root system includes:• Anchorage• Absorption• Storage• Transport• Production of certain hormones
  5. 5. Roots• Root– is the organ of a plant that typically lies below thesurface of the soil.– a root can also be aerial (growing above theground) or aerating (growing up above the groundor especially above water).– PARTS OF A ROOT.
  6. 6. PARTS OF A ROOT• Root tip Cambium– Meristem Water Uptake– root cap Mineral Uptake• The Region of Elongation Gas Exchange• The Region of Differentiation– Epidermis– Cortex– Endodermis– Stele• Pericycle• Xylem• Phloem
  7. 7. PARTS OF A ROOT• Root Tip– Meristem- a region of rapid mitosis, whichproduces the new cells for root growth.
  8. 8. PARTS OF A ROOT• Root Cap– a sheath of cells that protects the meristem fromabrasion and damage as the root tip growsthrough the soil.
  9. 9. PARTS OF A ROOT• The Region of Elongation– Here the cells produced by mitosis undergo aperiod of elongation in the direction of the axis ofthe root. It is at this time that they are sensitive togravity and respond with gravitropism.
  10. 10. PARTS OF A ROOT• The Region of Differentiation– Here develop the differentiated tissues of theroot.
  11. 11. PARTS OF A ROOT• Epidermis– A single layer of flattened cells at the surface. When firstformed, epidermal cells have extensions - the root hairs - whichgreatly increase the surface area available for the uptake ofwater from the soil. The photo below shows the root hairs in theregion of differentiation of a germinating radish seed.
  12. 12. PARTS OF A ROOT• Cortex– A band of parenchyma cells that develops beneaththe epidermis. It stores food. Its inner surface isbounded by a single layer of cells, the• Endodermis.
  13. 13. PARTS OF A ROOT• Stele– Pericycle• the outer boundary of the stele. Secondaryroots branch from it.
  14. 14. PARTS OF A ROOT• Xylem– arranged in bundles in a spoke like fashion.– caries water and disolved nutrients from the rootsthroughout the plant.
  15. 15. PARTS OF A ROOT• Phloem– alternates with xylem.– carries/ distributes the products of photosynthesis(mainly from the leaves) to the rest of the plants.
  16. 16. PARTS OF A ROOT• Cambium– In older parts of the root, another meristem formsbetween the xylem and phloem. Mitosis in the cambiumproduces new "secondary xylem" to the insideand secondary phloem to the outside.
  17. 17. PARTS OF A ROOT• Water Uptake– Water enters the root through the root hairs. Theseextensions of epidermal cells have sickly walls and adheretightly to soil particles with their film of moisture.
  18. 18. PARTS OF A ROOT• Mineral Uptake– One might have expected that minerals would enter theroot dissolved in water. But, in fact, minerals enterseparately:Even when no water is beingabsorbed, minerals enter freely.– Minerals can enter against their concentration gradient;that is, by active transport.– Anything that interferes with the metabolism of root cellsinterferes with mineral absorption.
  19. 19. PARTS OF A ROOT• Gas Exchange– The older parts of roots are sheathed in layers of dead corkcells impregnated with a waxy, waterproof (and airproof)substance called suberin. This sheath reduces water lossbut is as impervious to oxygen and carbon dioxide as it isto water.– However, the cork is perforated by nonsuberized porescalled lenticels. These permit the exchange of oxygen andcarbon dioxide between the air and the living cellsbeneath.
  20. 20. Stem• Stem– A stem is one of two main structural axes of a vascularplant.– The stem is normally divided into nodes andinternodes, the nodes hold buds which grow into one ormore leaves, inflorescence (flowers), conifercones, roots, other stems etc.• PARTS OF STEM.
  21. 21. PARTS OF STEMLeaf scar - is the mark left on a stemafter a leaf falls.Terminal bud - is the main area ofgrowth in most plants.Lenticel - it function as apore, providing a medium for the directexchange og gases between the internaltissues and atmosphere.Flower bud – have not yet bloomedinto a full-size flower.Growth rings - also referred to as treerings or annual rings, can be seen in ahorizontal cross section cut through thetrunk of a tree.
  22. 22. Leaf• Leaf– A leaf is an organ of a vascular plant, as definedin botanical terms, and in particular in plant morphology.– Typically a leaf is a thin, flattened organ borne aboveground and specialized for photosynthesis, but many typesof leaves are adapted in ways almost unrecognisable inthose terms: some are not flat (for examplemany succulent leaves and conifers), some are not aboveground (such as bulb scales), and some are without majorphotosynthetic function (consider forexample cataphylls, spines, and cotyledons).– PARTS OF THE LEAF.
  23. 23. Chloroplasts• A chloroplast is a structure in plants that iswhere photosynthesis happens.
  24. 24. Flower• Flower– A flower is the part of the plant that makes theseeds.– A flower, sometimes known as a bloom orblossom, is the reproductive structure foundin flowering plants.– PARTS OF A FLOWER.
  25. 25. Parts of Flower• Pollen• Anther• Filament• Stamen• Stigma• Style• Ovary• Pistil• Seeds• Sepal• Petals• Stem
  26. 26. Parts of Flower• Pollen– sperm of the plant.– is a fine to coarse powder containing the microgametophytes of seed plants, which produce themale gametes (sperm cells).
  27. 27. Parts of Flower• Anther– contains the pollen.
  28. 28. Parts of Flower• Filament– are a series of chain like cells.– stalk on which anther is attached, longer in wind pollinatedplants.
  29. 29. Parts of Flower• Stamen– male part of plant, parts where pollen anther andfilament are combined.
  30. 30. Parts of Flower• Stigma– sticky part to which pollen attaches.
  31. 31. Parts of Flower• Style– simply, a tube through which sperm travel toseeds.
  32. 32. Parts of Flower• Ovary– contains the seeds, later to become the fruit ofthe plant.
  33. 33. Parts of Flower• Pistil– female part of the plant, parts whereStigma, Style and Ovary are combined.
  34. 34. Parts of Flower• Seeds– future plants, contained in the ovary.
  35. 35. Parts of Flower• Sepal– tiny leaf-like structures that protect the flower asa bud.
  36. 36. Parts of Flower• Petals– brightly colored, used to attract pollinators.
  37. 37. Parts of Flower• Stem– supports the flower.
  38. 38. Fruits• Fruits– is a part of a flowering plant that derives fromspecific tissues of the flower, one ormore ovaries, and in some cases accessory tissues.