Biology Plant Morphology-1- PDF Material for SSC & RRB Exams
1. Morphology is the branch of biology of that deals with the study and forms of various parts of plants and their specific special features.
2. The roots, stems and leaves are vegetative parts , while flowers constitute the reproductive part.
3. Annuals –Complete their life cycle in one year or single growing season or few weeks to a few months. They pass the unfavourable period in the form of seeds eg. Mustard, Pea.
4. Biennials –Complete their life cycle in two years growing, vegetative and storing food in the first year, flowering and fruiting in the second year. They die off after producing flowers and fruits eg. Radish, turnip, carrot are biennial in colder areas. They become annual in warmer places.
5. Perennials – Survives for several years. eg. Mango, Banana, Guava
6. Roots are non-green, underground, (+) geotropic, (–) phototropic and (+)
7. Buds present for vegetative propagation in sweet potato (Ipomea) and Indian red wood (Dalbergia)
8. Roots do not bear nodes and internodes. Roots have unicellular root hairs
9. Root Cap: It is a cap like structure that covers the apex of the root. The main function of the root cap is to protect the root apex.
10. Meristematic Zone or Zone of cell division: This is the growing tip of the root. It lies a little beyond the root cap. The cells of this region are actively dividing and continuously increase in number.
11. Zone of elongation: It is a region that lies just above the meristematic zone. The cells of this zone increase in size. This zone helps in the growth in length of the plant root.
12. Zone of cell differentiation: (Cell maturation) This is a zone that lies above the zone of elongation. They form the tissues like the
epidermis, cortex and vascular bundles. In this region a number of root hairs are also present.
13. The root hairs are responsible for absorbing water and minerals from the soil.
14. Tap root: It develops from radicle and made up of one main branch and other sub branches. The primary roots and its branches constitute tap root system. e. g. Dicot roots.
15. Root developing from any part of the plant other than the radicle is called adventitious root
16. Fusiform roots: These root are thicker in the middle and tapered on both ends. In this type of roots both hypocotyl and root help in storage of food. eg. Radish.
17. Conical roots: These roots are thicker at their upper side and tapering at basal end. eg. Carrot.
18. Napiform: These roots become swollen and spherical at upper end and tapered like a thread at their lower end. eg. Turnip (Brassica rapa) Sugar beet.
19. Tuberous root: Such roots do not have regular shape and get swollen & fleshy at any portion of roots. eg. Mirabilis
20. Nodulated root: Nodules are formed on branches of roots by nitrogen fixing bacteria, (Rhizobium). Plants of leguminosae family (Papilionatae) – Pea.
21. Respiratory roots: Halophyte or mangrove grow in oxygen deficient marshy area. Some branches of tap root in these plants grow vertically & comes out from soil. These roots are called pneumatophores through which air entered inside the plant. eg.Rhizophora, Heritiera, Sonaratia and another mangrove plant.
22. Stilt roots: These adventitious roots arise from the first few nodes of the stem. These penetrate obliquely down in to the soil and give support to the plant. eg. Maize, sugarcane and pandanus
23. Prop roots: These roots give mechanical support to the aerial branches as in banyan tree
24. Epiphytic roots: These are adventitious roots found in some orchids that grow as epiphytes upon the branches of other trees. These epiphytes develop special kinds of aerial roots which hang freely in the air. Eg . Vanda
25. Parasitic roots or haustoria: These roots are found in non-green parasitic plants. Parasitic plants are those plants which cannot make their own food and they have to obtain its food from the host
26. The plumule of the embryo grows into the stem which forms the main axis of the plant.
27. Lateral branches of the stem are exogenous in origin i. e they arise from the tissues which are in the periphery of the main axis (cortex)
28. Caudex: It is unbranched, erect, cylindrical stout stem and marked with scars of fallen leaves. Crown of leaves are present at the top of plant. eg.: Palm
29. Culm: Stem is jointed with solid nodes & hollow internodes. eg. Bamboo (Gramineae)
30. Excurrent: The branches arise from the main stem in acropetal succession and the tree assumes a cone like appearance e. g. Pinus, Eucalyptus, Casuarina.
31. Decurrent (Deliquescent): The lateral branches grow more vigorously and outcompetes the main trunk, giving a dome-shaped appearance, e. g. , mango (Mangifera indica), shishem (Dalbergia sissoo) and banyan (Ficus bengalensis)
32. Reduced stem – Stem reduced to a disc. eg. , Radish, Carrot, Turnip.
33. Erect stem – It is strong and upright e. g. , maize, wheat, mango.
34. Weak stems –These are thin, soft and weak and need support. They can be upright or prostrate.
35. Runner – When stem grows and spread on the surface of soil. Roots are developed at lower side and leaves from upper side from node eg. Cynodon dactylon (Doob grass), Oxalis.
36. Stolon – In its branches are small and stem condensed and grow in all direction. After some time, of growing, their apical region comes out from the soil. eg. Fragaria(Wild strawberry), Jasmine Peppermint.
37. Sucker – In it the main stem grows in the soil horizontally and branches develop obliquely from nodes above the soil, eg. Mint, Pineapple, Chrysanthemum
38. Offset– A lateral branch with short internode and each node bearing a rossette of leaves and tuft of roots at base. eg. Pistia, Eichhornea.
39. Tuber – The tips of underground branches become swollen in the soil. Eyes are found on then which are axillary buds and covered with scaly leaves. eg. Potato, Helianthus tuberosus
40. Rhizome – It is fleshy and horizontally stem found below in soil. Small nodes and internodes are found which are covered by scaly leaves. eg. Ginger, Turmeric, Canna, Water lily, Banana.
41. Corm – It is condensed structure which grow vertically under the soil surface. They are having spherical node and inter node eg. Colocasia, Alocasia, Zaminkand, Saffron, Gladiolus, Colchicum
42. Bulb– This stem is reduced and has disc like structure and surrounds with numerous fleshly scaly leaves. Many roots arise from its base. Food is stored in flashy leaves. They show apical growth eg.Onion, Garlic.
43. Phylloclade – It is green photosynthetic flattened or rounded succulent stem with leaves either feebly developed or modified into spines e. g. , Opuntia, Casuarina, Euphorbia, Cactus.
44. Thorn – It is modification of axillary bud, e. g. , Bougainvillea, Duranta, Carissa. Thorns of Alhagi possess flowers, while thorns of Duranta bears leaves.
45. Cladode – Phylloclade usually having one or two inter node long & succulent is called cladode, e. g. , Asparagus, Ruscus.
46. Stem tendrill– it is a leafless, spirally coiled structure found in climbers. It may be a modification of Axillary bud, e. g. Passiflora or terminal bud e. g. , Vitis
47. A condensed , axillary fleshy bud is called bulbils. It helps in vegetative reproduction. eg. , Dioscorea, Globba, Agave, Oxalis
48. Leaf base (Hypopodoium): The part of the leaf which is attached to the stem or a branch is called leaf base.
49. In some plants the leaf has a swollen leaf base. It is known as pulvinus. Eg . Fabaceae
50. In monocots the leaf base is very broad and flat, and it clasps a part of the node of the stem as in maize and in banana. It is called sheathing leaf base.
51. In most of the dicotyledonous plants, the leaf-base bears two lateral appendages called the stipules. The main function of the stipule is to protect the leaf in the bud
52. Leaves which have the stipules are called stipulate. The leaves without stipules are called exstipulate.
53. Petiole connects the lamina with the stem or the branch.
54. A leaf is said to be petiolate when it has a petiole
55. A leaf is said to be sessile when it does not have a petiole
56. Leaf blade or Lamina is the most important, green part of the leaf which is mainly concerned with the manufacture of food.
57. The arrangement of veins in the leaf blade or lamina is called venation.
58. Reticulate Venation: This type of venation is common all dicot leaves. In this type of venation there is a prominent vein called the midrib from which arise many small veins which finally form a net like structure in the lamina.
59. Parallel Venation: In this type of venation all the veins run parallel to each other. Most of the monocot leaves have parallel venation.
60. Simple Leaf – A leaf which may be incised to any depth, but not down to the midrib or petiole, then this type of leaf called simple leaf. eg. Mango, Chinarose, Ficus.
61. Compound leaf –A leaf in which the leaf blade is incised up to the midrib or petiole, thus dividing it into several small parts, known as leaflets. This type of leaf is known as compound leaf eg. Neem
62. innately compound leaf – In this type of leaf mid rib is known as rachis. Leaflets are arranged on both sides of rachis. eg. Neem
63. Unipinnate – In this type of leaf, division occurs only once, and leaflets are directly attached on both sides of rachis.
64. If the number of leaflets is even, then leaf is known as paripinnate. eg. Cassia fistula, Sesbania
65. If the number of leaflets is odd, it is known as imparipinnate. eg. Rose, Neem.
66. Bipinnate – A twice pinnate compound leaf eg. Acacia, Gulmohar, Mimosa.
67. Tripinnate – A thrice pinnate compound leaf eg. Moringa.
68. Decompound – A compound leaf, which is more than thrice pinnate. eg. Carrot, Coriander.
69. Palmate compound leaf – In this type incision of leaf are directed from leaf margin to apex of petiole and all leaflets are attached on the upper end of petiole.
70. Unifoliate – When single leaflet is found. eg. Lemon
71. Bifoliate – When two leaflets are present. eg. Bauhinia, Regnelidium, Bignonia.
72. Trifoliate – When three leaflets are attached. eg. Oxalis, Aegle, Trifolium
73. Tetrafoliate –When four leaflets are attached to the petiole. eg. Marsilea
74. Multifoliate – when more than four leaflets are found, then leaf is called multifoliate palmate compound leaf. eg. Silkcotton
75. The arrangement of leaves on the stem or the branches is known as phyllotaxy.
76. Alternate phyllotaxy: In this type the leaves are arranged alternatively in the nodes. There is only one leaf at each node. eg. Polyalthia
77. Opposite Phyllotaxy: In this type of arrangement two leaves are present at each node, lying opposite to each other Eg: Guava
78. Ternate Phyllotaxy: In this type there are three leaves attached at each node eg. Nerium
79. Whorled: In this type, more than three leaves are present in a whorl at each node eg. Alamanda.
80. Leaf tendril – In it, whole leaf is modified into thin thread like structure which is called leaf tendril eg. Lathyrus aphaca(wild pea).
81. Leaflet tendril – When leaflet is modified into tendril like structure than it is called leaflet tendril. eg. Pisum sativum (Garden pea), Lathyrus odoratus (sweet pea).
82. Leaf spine – Leaves or any part of leaflet are modified into pointed spine. eg. Asparagus, Opuntia, Aloe, Argemone.
83. Leaf scale – In it, leaves become thin, dry and form a membrane or paper like structure and serve to protect axillary buds as in Ficus and Tamarix, Ruscus, Casurina.
84. Leaf pitcher – Leaves of some plants are modified to pitcher shape. eg. Nepenthes, Dischidia.
85. Leaf bladder – In some plant , leaves are modified into bladder like structure eg. Utricularia.
86. Leaf Hooks – In some plants terminal leaflets are modified into curved hooks for helping the plant in climbing. eg. Argemone, Opuntia, Aloe, Cat’s nail (Bignonia unguis – cati)
87. Phyllode – In its, petiole becomes flat structure and function as normal leaf. eg. Australian acacia.
88. Flashy leaves – In onion and garlic food storing flashy leaves are present
89. Arrangement of flower on floral axis is called inflorescence.
90. In plants like Callistemon the inflorescence is found in between the stem. This is called intercalary inflorescence.
91. Raceme –When peduncle (main axis) is elongated and flowers are pedicellate. eg. Radish, characteristic feature of Cruciferae family
92. Spike –In its peduncle is elongated but flowers are bisexual and sessile. eg. Achyranthes
93. Catkin –In its peduncle is thin, long and weak, and flowers are sessile and unisexual. Peduncle is pendulus. eg. mulberry, betula, oak.
94. Spadix –In its peduncle is thick, long and fleshy and have small sessile and unisexual male and female flowers covered with one or more green or colourfull bracts known as spathe. eg. Colocasia, Maize, Aroids, Palms.
95. Corymb –In its peduncle is short and all flowers are present at same level because the lower flower has much long pedicel than the upper one eg. Candytuft (Iberis amara).
96. In mustard corymbose raceme type of inflorescence is present
97. Umbel –An inflorescence in which the flower stalks of different flowers are of more or less equal length, arise from the same point. At the base of flowers stalks, there is whorl of bracts forming the involucre. eg. Centella
98. Scapigerous umbel is found in onion
99. CYMOSE: In this type of inflorescence, the peduncle terminate in a flower.
100. Thyrsus: The main axis of the inflorescence shows a number of simple dichasial cymes arranged in a racemose manner eg. Ocimum.
101. Verticillaster: A pair of dichasial cymes arise from the axils of opposite flowers. Later this grow as monochasial scorpioid cymes around the stem eg. Leucas.
102. Mixed Spadix: In Musa several cymose clusters are arranged on the swollen inflorescence axis from base to apex. Each cymose cluster is surrounded by a large bract called spathe.
103. Cyathium– The bracts or the involucre become fused to form a cup shaped structure on the margin. In the central part of cup shaped structure, a single female flowers is found, which mature earlier.
104. Coenanthium: In Dorsitenia, the receptacle becomes saucer shaped and its margins are slightly curved.
105. Hypanthodium – In its peduncle is modified in narrow cup like structure. At the base of cup female flowers develop while towards mouth male flower develops. All three types of flowers are present in this inflorescence. eg. Banyan, Peepal, Ficus species.
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