Colorado AgriScienceColorado AgriSciencePlant Science Plant Science
Colorado AgriScienceColorado AgriSciencePlant Science Plant Science
Unit 4: Plant Reproduction & GeneticsUnit 4: Plant Reproduction & Genetics
Lesson 2: Sexual Reproduction in Plants 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.