Colorado AgriScience Plant Science Unit 4: Plant Reproduction & Genetics Lesson 2: Sexual Reproduction in Plants

Sexual Reproduction Involves flowers, fruit, & seed Sperm from male flower fuses w/the ovum of the female plant Results in recombination of DNA Results in genetically unique individual Allows plants to adapt & evolve to environmental change

Pollination Transfer of pollen from the male to the female part of the plant(s) How pollination occurs Self-Pollination Pollen from a plant pollinates a flower on the same plant Cross-Pollination Pollen from a plant pollinates a flower on a different plant

Fertilization Necessary in flowering plants in order for a seed to develop Double Fertilization Unique to plants Two sperm nuclei involved in fertilization 1st fertilization occurs when one sperm fuses with the egg creating a zygote 2nd fertilization occurs when the 2nd sperm nucleolus fuses with the two nuclei in the embryo sac Results in the formation of the endosperm

Fertilization Hybrid Fertilization occurring from parents that are genetically different Advantages Best traits of each parent is expressed Results in Hybrid Vigor Increased growth, drought resistance, or insect resistance is possible

Fertilization & Genetics Genetic information is stored in every cell of the plant in DNA Segments of DNA, called genes, establish the code for plant appearance and traits Genes are arranged into a set of chromosomes

Fertilization & Genetics Diploid Normal sets of cells containing two chromosomes Haploid Sex cells contain one chromosome When fertilization occurs, the single sets of chromosomes are combined into the double set, one from each parent Results in traits from each parent to be passed on to offspring.