Plant ReproductionPropagation Learning Objectives 3 Plant ReproductionPropagation a

Plant Reproduction/Propagation

Learning Objectives 3) Plant Reproduction/Propagation a) Develop an understanding of plant genetics b) Contrast mitosis and meiosis and explain the significance of each c) Explain the importance of plant breeding d) Hypothesize the future influence of biotechnology on the plant industry e) Evaluate the significance of sexual propagation of plants f) Assess the effectiveness of various types of asexual propagation of plants g) Defend the need for Germplasm

Develop an Understanding of Plant Genetics • Genes control plant traits – Phenotype refers to physical characteristics – Genotype refers to genetic makeup • Chromosomes and genes separate during meiosis and resulting gamete contains one gene for each characteristic (haploid) – Genes are recombined after pollination (become diploid)

Contrast Mitosis and Meiosis and Explain the Significance of Each Mitosis • • Makes more genetically identical cells Nucleus divides once – 2 diploid cells (2 n) – Number of chromosomes remains the same • Four Phases – – • • • Prophase Metaphase Anaphase Telophase Occurs only during asexual reproduction The basic process of vegetative growth Plants resulting are genetically identical to parents Meiosis • Makes gametes • Nucleus divides twice – 4 haploid cells (1 n) – Reduces the number of chromosomes by half – Nucleus divides twice – Homologous pairs of chromosomes separate once while the cell divides twice • Two major phases – Meiosis II • Occurs during sexual reproduction and only in flowers

Contrast Mitosis and Meiosis and Explain the Significance of Each • Compare Mitosis and Meiosis – http: //highered. mheducation. com/sites/0072495 855/student_view 0/chapter 2/animation__compa rison_of_meiosis_and_mitosis__quiz_1_. html • Contrast Mitosis and Meiosis – http: //highered. mheducation. com/sites/0072495 855/student_view 0/chapter 2/animation__compa rison_of_meiosis_and_mitosis__quiz_2_. html

Explain the Importance of Plant Breeding • Plant Breeding – When reproduction is deliberately controlled and manipulated, it becomes plant propagation • Plants can be bred to have certain desired characteristics

Evaluate the Significance of Sexual Propagation of Plants • Sexual Reproduction – Requires the fusion of two sex cells (gametes) • Forms a cell with two sets of chromosomes, one from each parent – Advantages • • Less expensive than asexual propagation techniques Many plants can be produced quickly Genetic crosses result in hybrid vigor Avoids passing on some diseases

Assess the Effectiveness of Various Types of Asexual Propagation of Plants • Asexual Reproduction – Uses a part or parts of plants of only one parent plant – Resulting plant is genetically identical to the parent plant – Also known as vegetative propagation – Advantages • Less time is required to produce a salable plant • Plants are genetically identical • The only way to reproduce some plant varieties

Assess the Effectiveness of Various Types of Asexual Propagation of Plants • Runners – Stems that grow along the ground and form new plants at their nodes • Stolons – Aerial shoots that take root after coming into contact with the soil • Layering – Roots develop on a stem that is still attached to the parent plant • Grafting – Joining the upper portion of a plant with the lower portion of another plant and fusing them together to become a single plant • Cuttings – Pieces of root, leaves, or stems that are removed from parent plant and placed in an environment that promotes development into total plants • Tissue Culturing – Repro of plants from tiny pieces of plant organs; newest propagation technique

Defend the Need for Germplasm • Plant Germplasm – Living tissue from which new plants can be grown • Seed, leaf, piece of stem, a few cells • Contains the genetic information for the plants hereditary makeup – Needed to preserve the genetic diversity of plants