Completing Photosynthesis Single most important event for the

Completing Photosynthesis • Single most important event for the evolution of life • Geological Formation • Fossil Fuels • Green Energy – Biodiesal – Solar energy – Ethanol • Food and Medicine

Completing Photosynthesis & Respiration • Assembly line economics and production – How can two separate processes be linked and influence each other? • Extend to – Light Independent Reactions & Calvin Cycle – Citric Acid Cycle & Electron Transport

Adaptive Value of Seeds Kindergartners is Disguise • Miniature plant with arrested growth • Resistant to cold, drought, heat, and time • Dispersal structure • Dormant—very slow respiration, 5 -20 %water • Food to begin life

Germination-a controlled event timed to favorable environmental conditions • • BREAKING DORMANCY Cold—temperate zone Acid—animal gut Rain—wash chemical inhibitors for desert seeds • Mechanical abrasion • Fire or really smoke

Germination Sequence • Imbibition of water • Activation of cell machinery (enzymes) • Division and enlargement of root meristematic cells • Emergence of radicle Radicle Cotyledons—seed leaves

Bean—a typical dicot Radicle emergence Hypocotyl protection of meristem Cotyledons-seed leaves

Corn—a typical monocot

Fig. 25. 6

Root-Cap • Protects apical meristem-production of MUCIGEL – Dessication – Abrasion – Microbial protection • Sensory-gravity Fig. 25. 4

Root Development • Region of Root Tip – Cell Division – Elongation – Maturation • Maturation & Differentiation – – Cell Elongation Plastid Development Cell Differentiation Secondary cell wall formation in some cells – Root hair formation

Fig. 25. 9

Fig. 25. 10

Xylem Fig. 25. 10

Mature Root Tissues chalkboard illustrations • Epidermis – Protection & water/mineral uptake – Root hairs • Cortex—storage – Endodermis—innermost layer of cortex – Casparian strip is waxy layer of cell wall in endodermis— controls movement of water into vascular cylinder • Vascular cylinder – Vascular tissues • Phloem—carbohydrate movement • Xylem—water & mineral movement • Broyles-remember 2°CW – Pericycle— dedifferentiation and branch root formation

Branch root formation from pericycle. Figure 25 -18

Branch root formation from pericycle. Figure 25 -18

Some monocot roots have a pith within the vascular cylinder. Fig. 25 -11

Flowering Plant Groups • Monocots – – – Leaves without petiole Leaves with parallel veins Seeds with single cotyledon No woody growth Flower parts in 3’s – Grasses, orchids, lilies, tulip, ginger, sugarcane, pineapple

Flowering Plant Groups • Dicots – – – Leaves with petiole Leaves with net veins Seeds with two cotyledons Some with woody growth Flower parts in 4’s or 5’s – Apple, oak, snapdragon, tomato, beans, eucalyptus

Orchids *tropical epiphytes- attach to bark of tropical trees high in the canopy *bizarre plants with unusual Pollination syndromes *orchid collectingprestige, status symbol

Photosynthetic Roots of Orchids *roots anchor orchid to tree *dry environment in tree tops, so orchid epiphytes are like succulents growing on trees

The Ghost Orchid Polyradicon • “The Orchid Thief” book – by Susan Orlean • “Adaptation”—movie – starring Nicholas Cage & Meryl Streep

The Ghost Orchid Polyradicon • Ghost Orchid of bald cypress hummocks in Everglades does not have photosynthetic leaves • “The Orchid Thief” book by Susan Orlean • “Adaptation”—movie starring Nicholas Cage & Meryl Streep

Buttressed Roots on Tropical Trees *tall tropical forest trees *buttressed roots add mass to anchor tree to shallow tropical soils

Strangler Figs (Ficus) *plants form in tropical forest canopy *roots grow from the canopy to the ground and form a strangling net around the support tree.

Bald Cypress “Knees” or Pneumatophores -adapted to inundated environments -roots require oxygen for respiration; and need to remove carbon dioxide Cypress Knees “breathing” roots? ? ?

Black Mangrove Pneumatophores

Contractile Roots of Plants with Underground Stems Trillium erectum

Yellow Birch Goodnow Mtn-Adirondacks Chris Broyles-2003

Cory Broyles-2003 Hemlock Roots