Morphology of flowering plants
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flowering plants morphology flower : whorls,symmetry,aestivation,placentation Leaf : parts,venation,types,phyllotaxy,modifications.
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Morphology of flowering plants
- 2. Parts of a flowering plant
- 4. Inflorescence • The arrangement of flowers on a floral axis • Depending on whether the apex gets converted into a flower or continues to grow: Recemose Cymose
- 5. Recemose inflorescence • the main axis continues to grow • The flowers are borne laterally in an acropetal succession • Some times in centripetal succession • Eg : Crotalaria
- 9. Cymose inflorescence • the main axis terminates in a flower, hence is limited in growth. • The flowers are borne in a basipetal order • Some times in centrifugal succession • Eg : Jasmine
- 11. FLOWER • The reproductive unit in the angiosperm • A typical flower has four whorls : Calyx Corolla Androecium Gynoecium • If the calyx and corolla are not distinguishable – Perianth (lilly, coconut)
- 12. Calyx and corolla – Accessory organs Androecium and gynoecium- Reproductive organs
- 13. Unit of each whorl • Calyx – Sepal • Corolla –Petal • Androecium – Stamen • Gynoecium – Carpel / Pistil
- 14. When a flower has both androecium and gynoecium – Bisexual flower When a flower has either androecium or gynoecium – Unisexual flower
- 15. In Symmetry… • Actinomorphic (Radial symmetry) • - When a flower can be divided into two equal radial halves in any radial plane passing through the centre • Zygomorphic ( Bilateral symmetry) -When it can be divided into two similar halves only in one particular vertical plane
- 17. A flower may be trimerous,tetramerous or pentamerous when the floral appendages are in multiple of 3, 4 or 5, respectively
- 18. Based on the position of floral parts on thalamus… Flowers are of three types • Hypogynous flower •Perigynous flower •Epigynous flower
- 19. Hypogynous flower • Superior ovary • other parts are situated below to ovary • Mustard,China rose,brinjal
- 20. Perigynous flower • Half inferior/ Half superiour ovary • Other parts are situated on he rim of thalamus ,almost the same level • Rose,peach
- 21. Epigynous fower • Inferior ovary • Other parts of flower arise above the ovary • Guava,cucumber
- 22. Parts of a flower Calyx • Outermost whorl • Unit- Sepals • Sepals are green, leaf like and protect the flower in the bud stage • Gamosepalous- sepals united • Polysepalous- sepals free
- 23. Corolla • Composed of petals • Petals usually bright coloured • Pollination • Gamopetalous – petals fused • Polypetalous – petals free
- 24. Is rose coloured part corolla????
- 25. Aestivation • The arrangement of sepals or petals in the floral bud • Valvate • Twisted • Imbricate • Vexillary
- 27. Valvate • sepals or petals in a whorl just touch • one another at the margin, without overlapping ( calotropis)
- 28. Twisted • one margin of the appendage overlaps that of the next one
- 29. Imbricate • the margins of sepals or petals overlap one another but not in any particular direction • as in Cassia
- 30. Vexillary • there are five petals • the largest (standard) overlaps the two lateral petals (wings) which in turn overlap the two smallest anterior petals (keel)
- 31. 3. Androecium • Male reproductive organ • Composed of stamens • Stamen : anther+ Filament • Anther : Bilobed,each lobe has two chambers – pollen sacs 9where the pollengrains are produced) • Filament : stalk of the stamen • A sterile stamen is called Staminode
- 32. • Epipetalous • Epiphyllous • Polyandrous- stamens are free • May be united • monoadelphous • diadelphous • Polyadelphous
- 33. 4. Gynoecium • female reproductive part of the flower • Made up of one or more carpels. • A carpel consists of three parts : stigma, style and ovary • Ovary is the enlarged basal part, on which lies the elongated tube, the style. • The style connects the ovary to the stigma. • The stigma is usually at the tip of the style and is the receptive surface for pollen grains
- 35. Overy • When more than one carpel is present, Apocarpous (carpels free ) Syncarpous ( carpels fused )
- 36. After fertilisation, the ovules develop into seeds and the ovary matures into a fruit.
- 37. Placentation • The arrangement of ovules within the ovary. • marginal • axile • parietal • basal • free central
- 38. Marginal • Ovary in which the placenta forms a ridge along the ventral suture and the ovules are borne on this ridge forming two rows • Eg. Pea
- 39. Axile • placenta is axial • ovules are attached to placenta in a multilocular ovary • China rose, Lemon, Tomato
- 40. Parietal • the ovules develop on the inner wall of the ovary or on peripheral part • Ovary is one-chambered but it becomes two chambered due to the formation of the false septum • Mustard, Argemone
- 41. Free central • ovules are borne on central axis • septa are absent • Dianthus, Primrose
- 43. Basal • the placenta develops at the base of ovary • a single ovule is attached to it • in sunflower, marigold.
- 46. LEAF • Lateral appendages of stem developing from the nodes. • generally flattened structure • Leaves originate from shoot apical meristems and are arranged in an acropetal order • They are the most important vegetative organs for photosynthesis.
- 47. • A typical leaf consists of three main parts: Leaf base Petiole Lamina
- 48. Leaf base • The leaf is attached to the stem by the leaf base. • It may bear two lateral small leaf like structures called stipules • In monocotyledons, the leaf base expands into a sheath covering the stem partially or wholly. Eg: Paddy
- 49. • In some leguminous plants the leaf base may become swollen, which is called the pulvinus
- 50. Petiole • The petiole help hold the blade to light • Long thin flexible petioles allow leaf blades to flutter in wind, thereby cooling the leaf and bringing fresh air to leaf surface • If petiole is absent - Sessile
- 51. Lamina • The lamina or the leaf blade is the green expanded part of the leaf • veins and veinlets are seen here • The main vein is called midrib • upper side of leaf – Adaxial/ ventral side • Lower side of leaf – Abaxial/ dorsal side • The tip of leaf – leaf apex • The edge of lamina – leaf margin
- 52. • Leaf shape, margin, apex, surface may be of various shapes
- 54. Venation • The arrangement of veins and the veinlets in the lamina of leaf • There are two types of venation : Reticulate venation Parallel venation
- 55. Reticulate venation • When the veinlets form a network, the venation is termed as reticulate • Dicot leaf
- 56. Parallel venation • When the veins run parallel to each other within a lamina, the venation is termed as parallel • Monocot leaf
- 57. Types • Leaves are mainly of two types Simple Compound • Simple leaf : A leaf is said to be simple, when its lamina is entire or when incised, the incisions do not touch the midrib
- 58. Compoud leaf • When the incisions of the lamina reach up to the midrib breaking it into a number of leaflets, the leaf is called compound • The main petiole is called Rachis • A bud is present in the axil of petiole in both simple and compound leaves, but not in the axil of leaflets of the compound leaf.
- 59. • The compound leaves may be of two types • pinnately compound leaf : a number of leaflets are present on the rachis, as in neem. • palmately compound leaves: the leaflets are attached at a common point, i.e., at the tip of petiole, as in silk cotton.
- 60. Phyllotaxy • Phyllotaxy is the pattern of arrangement of leaves on the stem or branch • This is usually of three types – Alternate Opposite Whorled
- 61. Alternate type : • a single leaf arises at each node in alternate manner • china rose, mustard and sun flower plants
- 62. Opposite type : • A pair of leaves arise at each node and lie opposite to each other • Calotropis, guava plants
- 63. Whorled type : • If more than two leaves arise at a node and form a whorl, it is called whorled • Alstonia, Allamanda
- 64. Leaf Modificaton • The normal functions of leaf are Photosynthesis,respirattion and transpiration • Often leaves are modified to perform functions other than the normal function • These modification are called Leaf modification Leaf tendrils Leaf spine Leaf scale Phyllode Pitcher Bladder
- 65. Leaf tendrils • They are converted into tendrils for climbing • Pea plant
- 66. Leaf spine • Modified into a sharp pointed structure • for defence • Cacti ( Opentia)
- 67. Leaf scale • Modified into a thin membraneous structure • In onion and garlic,the scale leaves are fleshy due to storage of food materials
- 68. Leaf of acacia??
- 69. Phyllode • In some plants such as Australian acacia, the leaves are small and short-lived. • The petioles in these plants expand, become green and synthesise food.
- 70. Pitcher • Modified to capture insects • Nepenthes, venus flytrap
- 71. Bladder • To capture small insects • Utricularia
- 72. • The presence of more than one type of leaves on a same plant - Heterophylly
- 73. • In nepenthes, the pitcher is modified a. Leaf tip b. Stem c. leaf lamina d. lower part of petiole • The leaves without petiole is a.Sessile b. petiolate c.rachis d.stipule • Phyllotaxy refers to the arrangement of a.Leaves on a branch b. veins in a leaf c.flowers on a branch d.axillary buds in a plant • Phyllode is a modification of a. Rachis b.stem c. lamina d. stipule • In acacia the leaves are a. Bipinnate b.unipinnate c.tripinnate • Leaves are the common means of vegetative propagation in …………. a. mango b.oxalis c. Bryophyllum d. Chrysanthemum