Presentation on theme: "Weed Biology and Identification-202 Target students: M.Sc. Students in Weed Science Lecture: Dr. Majid AghaAlikhani (Ph.D.) Academic position : Associate."— Presentation transcript:
Weed Biology and Identification-202 Target students: M.Sc. Students in Weed Science Lecture: Dr. Majid AghaAlikhani (Ph.D.) Academic position : Associate Prof. of Tarbiat Modares University 1
Basic Parts of the Plant Roots Stems Leaves Flower
Shoot system Root system
Taproot Lateral roots Shoot system Root system
Taproot Lateral roots Leaves Stem Shoot system Root system
Taproot Lateral roots Branch Leaves Stem Shoot system Root system
Taproot Lateral roots Apical bud Branch Leaves Stem Shoot system Root system Lateral bud
Taproot Lateral roots Apical bud Branch Node Internode Leaves Lateral bud Stem Node Shoot system Root system
Roots 1. Anchor Plant 2. Absorb water and minerals 3. Translocate water and minerals to stem 4. Store Food
Anchorage and support
Stems 1. Translocate water, minerals and food to the leaves 2. Support the leaves and display them to light 3. Store Food
Woody Dicot Stem Morphology
Transport and support.
Cactus stems store water, photosynthesize.
Stolons produce new individuals at nodes above ground.
Rhizomes produce new individuals at nodes below ground.
Tubers store carbohydrates.
Thorns provide protection.
Leaves 1. Make food through photosynthesis 2. Provide site of gas exchange 3. Store food
Transport of water, sugar, and nutrients through vascular tissue CO 2 Sunlight Water Nutrients (such as N, P, K) Shoot system Root system
Make food through photosynthesis
Vascular tissue (b) Close-up of root tip Ground tissue Epidermal tissue Apical mersitem Sloughed-off root cap cells Root cap Root hair Zone of Cellular Maturation Zone of Cellular Elongation Zone of Cellular Division Lateral root (a) Longitudinal section of root segment mucilage Primary Growth
Flowers 1. Contain organs for specialized sexual production 2. Produce seeds and fruit
Different type of Roots A. Tap Root –Continuation of the primary root –Ideal for anchorage –Penetration is greater for water –Storage area for food made by photosynthesis
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Different type of Roots B. Fibrous Roots –Many finely branched secondary roots –Shallow roots cover a large area More effective absorption of water and minerals Roots hold the soil to prevent erosion
Different type of Roots C. Aerial roots –Clinging air roots Short roots that grow horizontally from the stems Roots that fasten the plant to a support –Absorptive air roots
Different type of Roots Adventitious Roots –Develop in places other than nodes –Can form on cuttings and rhizomes
Roots Root hairs: –Tiny one celled hair like extensions of the epidermal cells located near the tips of the roots where vascular tissues have formed. –Increase surface area –Absorb water and minerals from soil
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Specialized Stems B. Bulb (tulips, lillies, onions) –Layers of fleshy scales that overlap each other –Underground stem
Specialized Stems C. Tuber (potato, caladium) –Food storage area –Short, thick underground stem
Specialized Stems D. Crown (African Violets, fern) –Closely grouped stems or plantlets –Just above ground or just below
Specialized Stems E. Spurs (pear and apple trees) –Short sems found on woody plant limbs adapted for increased production of fruits
Specialized Stems F. Rhizomes (iris, lily of the valley) –Underground stems that produce roots on the lower surface and extend leaves and flower shoots above the ground
Specialized Stems G. Stolon (Strawberry, airplane plant) –Stem that grows horizontally above the soil surface
Principal Tissues of the Leaf Epidermis –Cuticle Waxy substance covers the leaves and stems Waterproof layer that keeps water in plants
Principal Tissues of the Leaf Epidermis (cont) –Stomata Openings in the epidermis mainly located on underside of leaves Exchange of gases
Principal Tissues of the Leaf Epidermis (cont) –Guard Cells Two cells located on each side of stomata Open and closes stomata
Principal Tissues of the Leaf Mesophyll layer –Palisade mesophyll Primary site of photosynthesis –Spongy mesophyll Contains air and chloroplasts Site of photosynthesis and gas exchange
Principal Tissues of the Leaf Veins or vascular bundles –In spongy mesophyll –Phloem tissues conduct food from photosynthesis to rest of plant –Xylem tissues conduct water and minerals up to cells in leaves and stems
Parts of the Flower Sepals –Outer covering of the flower bud –Protects the stamens and pistills when flower is in bud stage
Parts of the Flower Petals –Brightly colored –Protects stamen and pistills –Attracts pollinating insects
Parts of the Flower Stamens –Male Reproductive part –Anther-produces pollen –Filament-supports the anther
Parts of the Flower Pistil –Female reproductive part –Ovary Enlarged portion at base of pistill Produces ovules which develop into seeds –Stigma Holds the pollen grains
Parts of the Flower Style –Connects the stigma with ovary –Supports the stigma so that it can be pollinated
Complete and Incomplete Flowers Complete: have all four main parts –Sepals –Petals –Stamens –Pistils