Biology Seventh Edition Solomon Berg Martin Chapter 31

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Plants • Herbaceous –In temperate climates, aerial parts die back –Annuals, biennials, perennials • Woody –In temperate climates, aerial parts persist –Perennials Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Annuals • Grow, reproduce, and die in one year or less –Corn –Geranium –Marigold Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Duckweeds, with Wolffia on

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Biennials • Take two years to complete their life cycles before dying –Carrot –Queen Anne’s lace Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Perennials • Have the potential to live for more than two years –Asparagus –Oak trees Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Eucalyptus regnans Copyright ©

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Life history strategies • Long-lived trees compete successfully against smaller plants in favorable environments (e. g. , tropical rain forests) • Small, short-lived plants thrive in unfavorable environments (e. g. , deserts after a rainy spell) Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Vascular plant body • Root system –Generally underground –Obtains water and dissolved nutrient minerals –Anchor plant in place Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation The plant body: Arabidopsis

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Vascular plant body, cont. • Shoot system consists of –A vertical stem bearing leaves (organs of photosynthesis) –Reproductive structures (flowers and fruits in flowering plants) –Buds (undeveloped embryonic shoots that develop on stems) Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Vascular plant body, shoot system, cont. • Generally aerial • Obtains sunlight and exchanges gases, such as CO 2, oxygen, and water vapor Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Vascular plant body, cont. • Plant body is composed of –Ground tissue system –Vascular tissue system –Dermal tissue system • Although separate organs exist, tissue systems are integrated throughout plant body Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation The three tissue systems

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Ground tissue system • Parenchyma tissue • Collenchyma tissue • Sclerenchyma tissue Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Parenchyma cells Copyright ©

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Collenchyma cell Schlerenchyma cells

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Parenchyma tissue • Composed of living parenchyma cells with thin primary cell walls • Functions –Photosynthesis –Storage –Secretion Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Collenchyma tissue • Consists of collenchyma cells with unevenly thickened primary cell walls • Function is to provide flexible structural support Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Sclerenchyma tissue • Composed of sclerenchyma cells (sclereids or fibers) with –Primary cell walls –Secondary cell walls • Function is to provide structural support, although Sclerenchyma cells are often dead at maturity Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Parenchyma cell type Sclerenchyma

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Vascular tissue system • Conducts materials throughout plant body • Provides strength and support • Consists of –Xylem –Phloem Copyright © 2005 Brooks/Cole — Thomson Learning

Tracheid (xylem cell Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Sieve tube element Vessel element (xylem cell) Copyright © 2005 Brooks/Cole — Thomson Learning Phloem tissue

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Vascular tissue system, cont. • Xylem –Complex tissue conducting water and dissolved nutrient minerals –Conducting cells are tracheids and vessel elements Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Vascular tissue system, cont. • Phloem –Complex tissue conducting sugar in solution –Conducting cells are sieve tube elements; they are assisted by companion cells Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Tracheid Vessel element Copyright

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Sieve tube element Companion

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Dermal tissue system • Outer protective covering of the plant body • Consists of –Epidermis –Periderm Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Dermal tissue system, cont. • Epidermis –Complex tissue covering herbaceous plant body –Epidermis of aerial parts secretes a waxy cuticle to reduce water loss –Stomata permit gas exchange –Trichomes (outgrowths or hairs) Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Dermal tissue system, cont. • Periderm –Complex tissue covering woody parts of plant body in woody plants Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Epidermal cell Guard cell

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation Trichome Cork cell Copyright

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Growth in plants versus animals • Localized in meristems • Involves –Cell division –Cell elongation –Cell differentiation Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Primary growth • Increase in stem or root length • Occurs in all plants • Secondary growth • Increase in stem or root girth • Localized • Typically occurs in long cylinders of meristematic cells throughout length of older stems and roots Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Apical meristems • Localized –At tips of roots –At tips of shoots –Within buds of stems • Activity herein results in primary growth Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation A root tip Copyright

Biology, Seventh Edition CHAPTER 31 Plant Structure, Growth, and Differentiation • Lateral meristems • Vascular cambium • Cork cambium • Responsible for secondary growth Copyright © 2005 Brooks/Cole — Thomson Learning