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Plant Organs


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Plant Organs

  1. 1. By T- 1-855-694-8886Email-
  2. 2. Plant Organs Organs: tissues that act together to serve a specific function. Dermal Vascular Leaves Ground Dermal Vascular Stems Ground Dermal Vascular Roots Ground
  3. 3. Plant Organs
  4. 4. Plant Organs – Organs composed of one or more tissues. – Three major types: • Roots • Stems • leaves – Flowers and fruits evolved from stems and leaves
  5. 5. Function of Plant Organs LEAVES – Function  Photosynthesis STEMS –Function  Suppor  Transport. ROOTS – Function  Anchorage  Absorption  Storage  Conduction
  6. 6. ROOT ROOTS “the hidden half” Functions of roots:  Anchorage  Absorption of water & dissolved minerals  Storage (surplus sugars, starch)  Conduction water/nutrients
  7. 7. Structure of RootsLongitudinal section of roots  Root cap  Zone of cell division  Zone of cell elongation  Zone of maturationCross section of root  Vascular bundle (Stele) contains xylem and phloem  Cortex  Epidermis  Root hairs  Absorb water and minerals
  8. 8. Types of Roots– Fibrous, multibranched roots (e.g. lettuce)– Dominant tap root • Tap roots used to absorb water deep in soil • Some tap roots used to store carbohydrates (e.g. carrots)– Adventitious roots • root-like structures arising from stems or leaves • e.g. prop roots (corn) and holdfasts– Tuberous roots • Swollen structure on fibrous root used to store carbohydrates (e.g. sweet potato)
  9. 9. Types of Roots Fibrous roots Tap rootAdventitious roots Tuberous roots
  10. 10. STEMS  Above-ground organs. (usually)  Support leaves and fruits.  Conduct water and sugars throughout plant.
  11. 11. STEM STRUCTURES Stem Structure  Nodes: location of leaves on stem  Internodes: stem between leaves  Buds: undeveloped leaves or flowers – Terminal (apical) – axillary (lateral) – Apical dominance is growth inhibition caused by apical bud
  12. 12. Function of Stems Support leaves, flowers, fruits. Transport of water (xylem) and products of photosynthesis (phloem). Storage of carbohydrates  Tubers - swollen underground stems that store carbohydrates (e.g. potato).  Corm - swollen base of stem covered in papery leaves.  Bulb - cluster of fleshy leaves attached to short, thick stem with basal roots (e.g. onion).  Bulbils - tiny bulbs arising in leaf axils.  Rhizome - horizontal stem below ground that produces roots and shoots at each node.
  13. 13. Stems Stems used only for asexual reproduction. Stolon (or runner) - horizontal stem that arises from leaf axel and runs above ground (e.g. spider plant)  When tip of solon hits ground a new plant forms
  14. 14. Types of StemsTypes of modified stems  Spur - stem with short internodes growing from a larger branch of woody plant.  Waterspout - stem that arises from latent buds in branches of woody plants.  Sucker - stem arising from root tissue, often from cut woody plant.
  15. 15. Types of StemsTypes of modified stems  Tendrils - twining stems used to secure climbing plants to vertical surfaces (e.g. peas, grapes).  Prickles - tiny, pointed projections of epidermis tissues of stems (e.g. blackberry).  Thorns - long, pointed projections produced in leaf axils (e.g. Hawthorn).  Cladophylls - stems modified for photosynthesis (e.g. cacti, asparagus).
  16. 16. Types of modified stems
  17. 17. Types of modified stems
  18. 18. LEAVES Most leaves are thin and flat  An adaptation that helps them capture sunlight for photosynthesis.  Although this structure may be typical, it is certainly not universal.  Leaves are extremely variable.  This variability represents adaptations to environmental conditions.
  19. 19. Leaves structureLeaf parts  Blade - Flat expanded area  Petiole - stalk that connects leaf blade to stem, and transports materials  Pair of stipules
  20. 20. Leaf epidermis Is transparent – so that sun light can go through. Waxy cuticle protects against drying out Lower epidermis: stomata with guard cells – for gas exchange (CO2, H2O in; O2 out) A. Cuticle B. Upper epidermis C. Palisade layer D. Spongy Layer E. Lower epidermis
  21. 21. Leaves functionsLeaves  Carry out photosynthesis in order to make glucose.  Composed of epidermal, vascular and ground tissue.
  22. 22. Flower A flower is the reproductive organ of angiosperms. Flowering plants reproduce by pollination.
  23. 23. Flower To Fruit
  24. 24. Fruits  A fruit is defined as a ripened ovary that contains angiosperm seeds.  The function of a fruit is to hold and protect the seeds. Each kernel of corn on a cob is actually an individual fruit In peaches, the fruits are soft and fleshy and contain a single, stony seed. Legumes like beans and peas produce a fruit called a pod that contains many seeds.
  25. 25. www.iTutor.comThe End