Plant Reproduction & Controls

Chapters 38-39

Simplified overview of angiosperm life cycle

Review of an idealized flower

Lily

Types of Flowers

• Complete – have all four organs (sepals, petals, stamens, carpels)

• Incomplete – Lack one or more organs• Bisexual – has carpels and stamens• Unisexual – has carpels or stamens

• Monoeicous – stamens and carpels located on same plant

• Dioecious – carpels and stamens located on different plants

Pyrethrum, a composite flower

Sunflower

Pollination modes

The development of angiosperm gametophytes (pollen and embryo sacs)

Growth of the pollen tube and double fertilization

Pollen grains have tough, ornate, and distinctive walls

“Pin” and “thrum” flower types reduce self-fertilization

Genetic basis of self-incompatibility

The development of a dicot plant embryo

Seed structure

Mobilization of nutrients during the germination of a barley seed

Seed germination

Controls

Review of a general model for signal-transduction pathways

An example of signal transduction in plants: the role of phytochrome in the greening response

An Overview of Plant Hormones

Early experiments of phototropism

Cell elongation in response to auxin: the acid growth hypothesis

Apical dominance: with apical bud (left), apical bud removed (right)

Treating pea dwarfism with a growth hormone

The effect of gibberellin treatment on seedless grapes

Experimental evidence for a flowering hormone(s)

A corn leaf recruits a parasitoid wasp as a defensive response to an herbivore, an army-worm caterpillar

Structure of a phytochrome

Phytochrome: a molecular switching mechanism

Phytochrome regulation of lettuce seed germination

Biological clocks: Example - sleep movements of a bean plant

Biological clocks

Photoperiodic control of flowering