Chapter 8 Plant Reproduction

Basics of Sexual Reproduction Fertilization occurs Male gamete: Sperm Female gamete: Egg Usually occurs in plant’s flower Produces zygote (fertilized egg) Zygote grows into seed

Flower Basics Develops from stem or branch bud Attached by receptacle Enclosed by calyx Flower opens, corolla emerges Calyx + corolla = perianth Perfect flower: Male + female parts

Female Organs (Carpels) Pistil: Tubelike structure Stigma: Broad top of pistil Style: Tube from stigma to pistil bottom Ovary: Bottom of pistil Ovule: Hollow structure in ovary

Egg Production Begins with meiosis in ovary Mother cell forms four haploid cells Three deteriorate One stays functional Functional cell forms embryo sac Sac divides to form haploid nuclei Some become gametes

Pollen Production Pollen fertilize ovules Stamen produce pollen Arranged around the pistil Attached by filament Anther at filament top makes pollen Mother cells divide, make pollen

Fertilization Pollen contacts stigma Stigma takes in and holds pollen Pollen forms tube to ovary Gametes pass through tube One sperm unites with egg (zygote) One sperm unites with polar nucleus Zygote becomes embryo or seed

Fertilization Terms Complete: With sepals, petals, stamen, and pistil (or carpel) Monoecious: Staminate and pistillate flowers on same plant Dioecious: Staminate and pistillate flowers on separate plants Self-pollinate: Pollinate on one plant

Insects in Pollination Flowers secrete fluid (nectar) Insects crawl or fly into flowers Pollen catches on insects’ bodies Insects fly to next flowers Pollen grains remain

Asexual Propagation Basics Process Grow new plant from part of old plant New plant genetically identical to old Advantages Reproduce superior plants Speed propagation Create seedless plants

Asexual Propagation Basics May occur naturally or by method Methods Separation Division

Methods of Asexual Propagation Specialized plant parts Propagation by cuttings Growth regulators Layering Grafting Tissue culture

Summary Agriculture uses plant reproduction as its basis. Increasing the efficiency of one increases the efficiency of the other. Ag research reproduces plants efficiently to benefit the world.