Ch27 Lecture-Reproduction of Flowering Plants

72 Pages·2014·4.87 MB·English

Reproduction
of Flowering Plants
Chapter 27 Reproduction of Flowering Plants
Key Concepts
• 27.1 Most Angiosperms Reproduce Sexually
• 27.2 Hormones and Signaling Determine the
Transition from the Vegetative to the
Reproductive State
• 27.3 Angiosperms Can Reproduce Asexually
Chapter 27 Opening Question
How did an understanding of angiosperm
reproduction allow floriculturists to
develop a commercially successful
poinsettia?
Concept 27.1 Most Angiosperms Reproduce Sexually
Most angiosperms reproduce sexually—this
strategy results in the genetic diversity that is
the raw material for evolution.
Concept 27.1 Most Angiosperms Reproduce Sexually
Differences between sexual reproduction in
angiosperms and in vertebrate animals:
• Meiosis in plants produces spores, after which
mitosis produces gametes.
• Most plants have alternation of generations.
• In plants, cells that will form gametes are
determined in the adult organism.
Concept 27.1 Most Angiosperms Reproduce Sexually
Male and female gametophytes are contained in
flowers.
A complete flower consists of four concentric
groups of organs arising from modified leaves:
Concept 27.1 Most Angiosperms Reproduce Sexually
• Carpels—female sex organs that contain the
developing female gametophytes
• Stamens—male sex organs that contain the
developing male gametophytes
Perfect flowers have both carpels and stamens
Imperfect flowers have only male or only female
organs
Figure 27.1 Perfect and Imperfect Flowers (Part 1)
Concept 27.1 Most Angiosperms Reproduce Sexually
Imperfect flowers:
Monoecious—male and female flowers on the
same plant
Dioecious—individual plants have only male or
only female flowers
Figure 27.1 Perfect and Imperfect Flowers (Part 2)