REPRODUCTION OF FLOWERING PLANTS Many flowering plants are pollinated by insects. Picture is that of a honeybee (Apis mellifera) about to land on a flower.

Figure 29.04

Terminology Haploid Diploid Meiosis Mitosis Nerve with 1 set of chromosomes (n) Diploid Nerve with 2 sets of chromosomes (2n) Meiosis Nerve division 2n mother cell  Four n daughter cells, NOT identical Mitosis 2n mother cell  TWO 2n daughter cells, identical

A. Asexual Reproduction Parent plant produces progeny that are genetically identical to it and to each other (clones). Clones can develop from portions of stems, leaves or roots. Strawberry plants produce clones from nodes on horizontal stems (stolons). The “maternity plant” produces clones by growing plantlets on edges of its leaves. Cherry, pear, apple, blackberry, black locust & aspen trees produce clones from buds on their roots. Buds produce aerial shoots called “suckers” that can become new individuals.

Asexual reproduction is advantageous when environmental conditions are stable. Commercially, rooted cuttings and grafting are important forms of asexual reproduction.

Objectives Describe the major processes in the development of a seed plant from a seed through a mature plant to the production of new seed Explain the differences between plants & animals in the processes that are homeostatically controlled Briefly explain the mechanism of action of auxin Name the sites of auxin production in the plant and give the means by which they reach their site of action Describe the role of cytokinins in plant growth

Parent plants produce progeny that are genetically diverse. B. Sexual Reproduction Parent plants produce progeny that are genetically diverse. Involves alternation of generations. Refer to chapter 22. Sporophyte (diploid plant) produces haploid spores by meiosis. Spores develop into gameophytes (haploid plants). male gametophyte is called a microgametophyte; produces sperm by mitosis. female gametophyte is called a macrogametophyte; produces eggs by mitosis. Haploid gametes fuse (fertilization) forming a diploid zygote, which divides by mitosis to form a new sporophyte.