plant structure.pptx

8/10/2019 plant structure.pptx

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PLANT STRUCTURE


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The Root System


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Refers to the over all mass of undergroundroots of plant.


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FUNCTIONS OF ROOT Anchor the plant in soil Absorb water and dissolved minerals from the soil. Storage of food Conduction transport water and dissolved nutrients to and

from the shoot.


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PRIMARY ROOT

Underground extension of the stem resulting fromgrowth of the radicle.


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SECONDARY ROOT

Offshoot growing out of theprimary root.


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ROOT HAIRS

Root cell extensions that ensure the provision ofwater and mineral salts; they increase the surfacearea available for absorbing nutrients.


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TYPES OF ROOTS TAPROOT SYSTEM characteristic of dicotyledonous plants. - the primary root continuous to grow and

send out lateral smaller roots. FIBROUS DIFFUSE ROOT SYSTEM - characteristic of

monocotyledonous plants. - the primary root stops

growing and numerous adventitious roots grow and developfrom the base of the stem and take the place of primary roots.

-


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TYPES OF SPECIALIZED OR MODIFIEDROOTS


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Aerial roots are short roots above the ground.


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Prop roots roots arising from the lower parts of corn stalks.


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CONTRACTILE ROOT

th ickened special ized roo t a t the base o fa co rm , bu lb ,roset te o r o ther organ wh ich i sdes igned to shr ink ver t ical ly under cond i t ions of seasonal d r o u g h t tha t he lps pos i t ion th i s p lan t par t

at an app rop r iate level in the g r o u n d .
http://www.cactus-art.biz/note-book/Dictionary/Dictionary_C/dictionary_contraction_contractile.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_R/dictionary_root.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_S/dictionary_specialized.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_B/dictionary_base.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_C/dictionary_corm.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_B/dictionary_bulb.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_R/dictionary_rosette.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_O/dictionary_organ.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_S/dictionary_season.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_S/dictionary_season.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_D/dictionary_drought.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_G/dictionary_ground.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_G/dictionary_ground.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_D/dictionary_drought.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_S/dictionary_season.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_S/dictionary_season.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_O/dictionary_organ.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_R/dictionary_rosette.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_B/dictionary_bulb.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_C/dictionary_corm.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_B/dictionary_base.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_S/dictionary_specialized.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_R/dictionary_root.htmhttp://www.cactus-art.biz/note-book/Dictionary/Dictionary_C/dictionary_contraction_contractile.htm


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STORAGE ROOTS

Root which stores plant food in the form of starchycarbohydrate.


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Shoot System


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Refers to the stem ,leaves, flower and fruits


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Stem


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FUNCTIONS OF STEM Store minerals

Support leaves

Transport water and solutes between roots and leaves.

Produce carbohydrates.


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EXTERNAL STRUCTURE nodes- slightly enlarged portion where leaves and buds arise. internodes - region between two successive nodes bud - contains apical meristem and newly-forming leaves axillary bud - bud that appears where an older leaf attaches to

the stem; a twig will grow out of it. Lenticel tiny raised pores on the surface of matured dicot

stem for gas exchange.


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Types of stems stolons (runners)- horizontal, aboveground- strawberries rhizomes - horizontal, underground; responsible for rapid

spread of many weeds tubers - enlarged tips of rhizomes; food storage- potato corms - underground, short, thick, vertical; food storage-

gladiolus bulbs - underground with thick, fleshy leaves- onion


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Leaves function in photosynthesis


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MODIFICATION OF LEAVES Tendrils

Modified leaves that curl around more rigid objects helping the plant to climb or support weak stems.

Spines, Thorns, and Prickles Spines - Modified leaves designed to reduce water loss and

protect from herbivory. Thorns - Modified stems arising in the axils of leaves of woody

plants. Prickles - Outgrowths from the epidermis or cortex.


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Bracts are floral leaves that form at the base of a flower or flowerstalk. They are usually small and scalelike, and protectdeveloping flowers.

Storage leaves-flowerpot leaves are typically of rosette plants,and such epiphytes. They are packed tightly into a flower potlikestructure that catches falling water and debris.


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TENDRILS


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Spines, Thorns andPrickles


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Water and Mineral Trapping Leaves


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Storage Leaves


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Leaves as Agents of Reproduction


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FLOWERS

reproductive part of most plants


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Bracts grow just below the blossoms of certain plants. Mostbracts are smaller and simpler in shape than a plant's regularleaves. Many members of the daisy family-including daisies,goldenrods, marigolds, and sunflowers-have bracts. Thesebracts form a cup beneath the plant's cluster of flowers. A few

kinds of plants, such as the flowering dogwood and poinsettia,have large, showy bracts. These bracts look like part of theflower, but they are not.


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Insect-capturing leaves. Carnivorous (meat-eating) plants, such as the butterwort,pitcher plant, sundew, and Venus's-flytrap, have leaves that capture insects. Theseleaves, like other leaves, can make food using sunlight. But they also have featuresthat attract, trap, and then digest insects. Plants with insect-capturing leaves grow inwetlands, where the soil contains little nitrogen. They obtain this necessary nutrientfrom the captured insects. For a description of these plants and their leaves. >>
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Storage leaves. Most plants store food in their roots or stems.However, some plants have special leaves that hold extra food.Onion and tulip bulbs, for example, consist mainly of short, fatstorage leaves called bulb scales. These leaves cannot make food.Their job is to store food underground during the winter months.

BULB. Many plants that grow in dry places have thick leaves thatstore water. The mosslike stonecrop plants that grow on rocky cliffsin the Southwestern United States have such leaves.


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Protective leaves include bud scales, prickles, and spines. Asdescribed earlier, bud scales are specialized leaves that protectthe young, undeveloped tissues of the bud. Bud scales are shortand broad, and they overlap like roof shingles. In many plants, thebud scales have an outer layer of waterproof cells. Prickles andspines are sharp leaf structures that protect the plant from beingeaten. For instance, prickles cover the leaves of the Canadathistle. The prickles protect the plant from grazing animals. Manycactuses have clusters of spines. In many species of cactuses,the pointed spines replace the leaves on the mature plants. Inthese plants, the green stem has the job of photosynthesis.


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Some leaves have special functions along with or insteadof food making. Such specialized leaves include (1)protective leaves, (2) storage leaves, (3) tendrils, (4)bracts, and (5) insect-capturing leaves.


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External Features Leaf blade Flattened part of the leaf Petiole Leaf stalk Stipules Leaf-like appendages at the base of the leaf.


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plant structure.pptx

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