FRUITS, SEEDS & SEED DEVELOPMENT Packet #73 Chapter #30

INTRODUCTION A fruit is a mature ovary Monday, April 24, 2017 Figure 30.8 Page 599 A fruit is a mature ovary As the seed develop, the wall of the ovary thickens The thickened wall becomes the pericarp. As the ovary grows, the other flower parts whither away Fruits protect the seeds and aid in dispersal. Are they any vegetables that should be truly classified as fruits? Yes. What are some examples?

ADAPTATIONS IN FRUIT Figure 30.9 Page 599 Dandelions & Maple Trees Monday, April 24, 2017 Figure 30.9 Page 599 Dandelions & Maple Trees Wind dispersal is observed Fruits are described as kites or propellers. Thistles & Grasses Animal dispersal is observed Fruits are described as hitchhickers or burrs. Animal dispersal often provide resources such as fecal material that fertilize the young sporophyte plant.

CLASSIFICATION OF FRUITS Monday, April 24, 2017 Simple Fruits Single ovary Can be fleshy or dry Cherry Soy bean pod Aggregate Fruits Arise from a single flower with several carpels Blackberry Multiple Fruits Arise from an inflorescence Many flowers As the walls of the many ovaries thicken, they fuse and become one fruit Pineapple

Monday, April 24, 2017 THE SEED PART II Chapter 38

STRUCTURE OF MATURE SEED Monday, April 24, 2017 If a common bean seed, a eudicot, is opened, several structures are observed Hypocotyl Radicle Epicotyl Plumule Seed coat endosperm Know the structure of the seed!

“EVOLUTIONARY” ADAPTATIONS TO SEED DORMANCY & GERMINATION Monday, April 24, 2017 “EVOLUTIONARY” ADAPTATIONS TO SEED DORMANCY & GERMINATION Chapter 38

INTRODUCTION I Monday, April 24, 2017 As the seed matures, it dehydrates until only about 5 – 15% of its weight is water Enters dormancy Period of extremely low metabolic rate and suspended growth and development Increases the chance that germination will occur at a favorable time Species dependent environmental cues break dormancy Fire; light; water; temperature; digestion through animal’s gut Sexual reproduction produces seeds with dispersal and dormancy abilities.

Monday, April 24, 2017 SEED GERMINATION

GERMINATION I Water HAS to be absorbed Monday, April 24, 2017 Water HAS to be absorbed Causes the seed to swell and rupture seed coat Triggers metabolic changes in the embryo promoting growth Radicle (embryonic root) emerges first from the germination seedlings Hypocotyl pushes way up through the soil Protecting fragile shoot apex and large cotyledons Epicotyl spreads “true leaves” and begin photosynthesis

GERMINATION II Cotyledons “seed leaves” whither away. Monday, April 24, 2017 Cotyledons “seed leaves” whither away. Seedling is vulnerable to many hazards and only a small number survive.

REVIEW

REVIEW Students List potential examination questions and/or here, and on following slides, based on the packet.