Plant Structure, Growth, and Development. Chapter 35

Transcription

1 Plant Structure, Growth, and Development Chapter 35

2 PLANTS developmental plasticity = ability of plant to alter form to respond to environment

3 Biological heirarchy Cell basic unit of life Tissue group of cells perform a common function Organ multiple tissue types with a common function Organ system multiple organs with common function Organism all of above

4 Example Parenchyma cells Plant epidermis Leaf Shoot system Plant

5 PLANTS Moss, ferns, gymnosperms, angiosperms

6 ORGAN SYSTEMS 1. Root System Root (organ) Anchors plant Absorbs minerals and water Stores food

7 Root hairs Absorption of water and minerals Large surface area Renewed continually Extension of root epidermis Radish seedling Extension of epidermis

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9 A. Taproot system Embryonic root Taproot = main vertical root, deep Stores sugar, starch So, harvest carrots before they flower Lateral roots deep

10 Radish, mustard, carrot,

11 B. Fibrous root system (embryonic root dies) Begins with Adventitious roots Roots arise from stems or leaves Shallow mat From stem on bottom of bulb canary island date palm Maize: Prop roots are adventitious Monocots and seedless vascular plants

12 ferns grains, grass, lilies, onions scallion fern grass

13 2. Shoot system Stem (organ) Nodes = points at which leaves are attached Internodes= stem segments between nodes Axillary bud can form a lateral shoot, or branch Apical bud near shoot tip for elongation

14 Apical bud is dominant Pinch off apical bud plant grows laterally

15 Stem adaptations: Rhizome =modified stem (shoot below surface) iris bamboo ginger

16 Onion bulb is an underground shoot Storage leaves Stem

17 Stolon= horizontal shoot or runner Stolons of strawberry plant

18 Tubers = enlarged rhizome ends Eye is cluster of axillary buds (can plant)

19 Leaves (organs) Photosynthesis Blade Petiole stalk joins leaf to node of stem

20 cc Simple =single blade Compound - blade has multiple leaflets Doubly compound = each leaftlet divided into smaller leaflets LEAF MORPHOLOGY (shape)

21 Leaf veins = vascular tissue of leaves parallel veins ex. lily, orchid, grass (monocots) branching veins Ex. apple, maple, dandelion (eudicots) daylily mint Grape (Vitis)

22 Plant tissues 1. Dermal tissue system Protection against: Water loss Disease Damage A. Epidermis (non-woody plants) Waxy cuticle on leaves, stems

23 Specialized epidermis Trichomes Hair-like Reduce water loss Reflect excess sunlight May secrete sticky or toxic fluids May sense prey (carnivorous plants)

24 trichomes

25 B. Periderm (woody plants) from epidermis On older stems and roots (cork, bark)

26 EXPERIMENT Does soybean trichome density relate to beetle damage? Very hairy pod (10 trichomes/ mm 2 ) Slightly hairy pod (2 trichomes/ mm 2 ) Bald pod (no trichomes) Read experiment Chapter 35 RESULTS Very hairy pod: 10% damage Slightly hairy pod: 25% damage Bald pod: 40% damage Cerotoma trifurcata, the bean leaf beetle

27 Fig 35.8 Dermal tissue Ground tissue Vascular tissue

28 2. vascular tissue system long-distance transport from roots to shoots Xylem tissue Transports water, minerals from roots shoots One way transport Older xylem = wood Phloem tissue transports sugars from leaves to where needed (leaves, fruits) 2 way transport

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30 Xylem vessels cells not alive at maturity

31 Phloem cells alive at maturity

32 3. ground tissue system Storage Photosynthesis Support pith tissue internal to vascular tissue cortex tissue external

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34 A transverse section of corn (Zea mays) internode showing ground tissue

35 Plant growth Mature plant contains Embryonic cells Developing organs Mature organs

36 Life cycles Annuals complete life cycle in <year Germinate grow flower seed

37 Biennials require two growing seasons foxglove thistle sweet william

38 Perennials live for many years

39 PLANT GROWTH Determinant growth Some organs grow to certain size Leaves Flowers

40 Indeterminate growth Plant grows throughout life Meristems = embryonic tissue Apical meristems for primary growth Tips of roots, shoots, leaves New cells either remain as meristematic or differentiate

41 Apical meristem in stem with leaf primordium

42 Apical meristem in root

43 Primary Growth of Roots root cap covers root tip protects apical meristem as root pushes through soil

44 Primary Growth of Shoots Leaves from leaf primordia Note: Axillary buds

45 Lateral meristems Secondary growth Roots and stems Increases thickness Woody plants

46 Organization of stems Vascular bundles of tissue Monocot bundles throughout stem Eudicot bundles in outer ring Same tissues different arrangement

47 Monocot ex. corn, grass

48 African violet Eudicot example:

49 Organization of Leaves Stomata In epidermis guard cells regulate stomata opening and closing mesophyll ground tissue of leaf Between upper and lower epidermis

50 Scanning electron microscope image of leaf from a Black Walnut tree. Image shows a crosssection of a cut leaf, its upper epidermal layer, mesophyll layer with palisade cells and vascular bundles, and lower epidermal layer. Dartmouth College

51 RMS

52 Monocot leaf Eudicot leaf Same tissues, different arrangements