* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Photosynthesis
Plant tolerance to herbivory wikipedia , lookup
Ecology of Banksia wikipedia , lookup
Plant secondary metabolism wikipedia , lookup
Gartons Agricultural Plant Breeders wikipedia , lookup
Plant nutrition wikipedia , lookup
Plant defense against herbivory wikipedia , lookup
Plant use of endophytic fungi in defense wikipedia , lookup
Plant breeding wikipedia , lookup
Plant morphology wikipedia , lookup
History of botany wikipedia , lookup
Plant physiology wikipedia , lookup
History of herbalism wikipedia , lookup
Plant ecology wikipedia , lookup
Evolutionary history of plants wikipedia , lookup
Pollination wikipedia , lookup
Historia Plantarum (Theophrastus) wikipedia , lookup
Plant evolutionary developmental biology wikipedia , lookup
Ornamental bulbous plant wikipedia , lookup
Perovskia atriplicifolia wikipedia , lookup
Flowering plant wikipedia , lookup
Chapter 28 Reproduction in Plants Outline Reproductive Strategies Alternation of generations Adaptation to a land environment Flowers - Pollination - Fertilization Seed Development Fruit Seed Germination Asexual Reproduction Tissue Culture Reproduction in Plants 2 Reproductive Strategies Reproduction in Plants All plants have a two-stage, alternating life cycle Sporophyte produces haploid spores by meiosis Spores divide mitotically to become haploid gametophytes Gametophytes produce gametes Gametes fuse to produce zygote Zygote divides mitotically to become diploid sporophyte 3 Alternation of Generations in Flowering Plants 4 Reproductive Strategies Reproduction in Plants Flower produces two types of spores Microspore - Male gametophyte - Undergoes mitosis - Becomes pollen grain Megaspore - Female gametophyte - Undergoes mitosis - Becomes embryo sac within an ovary, within an ovule - Ovule becomes seed 5 Flowers Reproduction in Plants Flower develops in response to environmental signals such as day length In monocots, flower parts occur in threes and multiples of three In eudicots, flower parts occur in fours or fives and multiples of four or five 6 Anatomy of a Flower 7 Monocot vs. Eudicot Flowers 8 Flowers Reproduction in Plants Leaf-like sepals protect the bud Open flower has whorl of petals Four whorls of modified leaves attached to a receptacle at the end of a flower stalk - Receptacle with a single flower is a peduncle - Receptacle with several flowers is a pedicle 9 Flowers Reproduction in Plants Leaf-like sepals protect the bud Open flower has whorl of petals Four whorls of modified leaves attached to a receptacle at the end of a flower stalk - Receptacle with a single flower is a peduncle - Receptacle with several flowers is a pedicle 10 Flowers Reproduction in Plants Stamens are male portion of flower Anther - Saclike container Filament - Slender stalk Carpel is female portion of flower Stigma - Enlarged sticky knob Style - Slender stalk Ovary - Enlarged base enclosing ovules 11 Flowers Reproduction in Plants Complete vs. incomplete flowers: 12 Complete flowers have sepals, petals, stamens, and a carpel Incomplete flowers missing one or more of above Bisexual vs. unisexual flowers: Bisexual flowers have both stamens and carpel Unisexual flowers have one but not the other Monoecious vs. dioecious plants Monoecious plants have staminate flowers and carpellate flowers on the same plant Dioecious plants have all staminate or all carpellate flowers Corn Plants are Monoecious 13 Life Cycle of Flowering Plants 14 From Spores to Fertilization Reproduction in Plants Male Gametophytes Microspores are produced in anthers Each anther has four pollen sacs, each with many microsporocytes - Undergoes meiosis to produce microspores - Mitosis produces pollen grains 15 Pollination Reproduction in Plants 16 Pollination is the transfer of pollen from an anther to the stigma of a carpel Self-pollination occurs if the pollen is from the same plant Cross-pollination occurs if the pollen is from a different plant Pollination 17 Reproduction in Plants 18 Production of Female Gametophyte Ovary contains one or more ovules Ovule has mass of parenchyma cells One cell enlarges to become megasporocyte - Undergoes meiois and becomes four haploid megaspores - Functional megaspore divides mitotically until there are eight nuclei of a female gametophyte Fertilization Reproduction in Plants 19 When pollen grain lands on stigma, it germinates forming a pollen tube Passes between the stigma and style to reach the micropyle of the ovule Double fertilization occurs One sperm nucleus unites with the egg nucleus, producing a zygote Other sperm nucleus unites with the polar nuclei, forming a 3n endosperm cell Seed Development Reproduction in Plants Development of eudicot embryo After double fertilization, endosperm nucleus begins to divide asymmetrically Small cell is destined to become the embryo Larger cell divides repeatedly to become a suspensor 20 Development of a Eudicot Embryo 21 Monocot vs. Eudicot 22 Reproduction in Plants 23 Development of Eudicot Embryo During globular stage, prembryo is ball of cells Outermost cells will become dermal tissue Embryo is heart shaped when cotyledons appear Epicotyl is portion between cotyledons contributing to shoot development Hypocotyl is portion below that contributes to stem development Radicle contributes to root development Reproduction in Plants 24 Fruit Types and Seed Dispersal Simple Fruits Simple fruits are derived from single or several united carpels - Legumes are fruits that split along two sides when mature Dehiscent - Split open Indehiscent - Fail to split open Pea Flower and Pea Pod 25 Reproduction in Plants Simple Fruits Dry Fleshy Follicle Drupe Legume Berry Capsule Pome Achene Nut Grain 26 Simple Fruits Reproduction in Plants 27 Dispersal - Many seeds are dispersed by wind Woolly hairs, plumes, wings Fleshy fruits - Attract animals and provide them with food - Peaches, cherries, tomatoes Accessory fruit - Bulk of fruit is not from ovary, but from receptacle - Apples Structure and Function of Fruits 28 Compound Fruits Reproduction in Plants 29 Compound fruits develop from several individual ovaries Aggregate Fruits - Ovaries are from a single flower - Blackberry Multiple Fruits - Ovaries are from separate flowers clustered together Seed Germination Reproduction in Plants 30 When seed germination occurs, the embryo resumes growth and metabolic activity Length of time seeds retain their viability is quite variable Some seeds do not germinate until they have been through a dormant period - Temperate zones - Cold Weather - Deserts - Rain Seed Germination Reproduction in Plants 31 Environmental requirements for seed germination Availability of oxygen for metabolic needs Adequate temperature for enzyme activity Adequate moisture for hydration of cells Light (in some cases) Respiration and metabolism continue throughout dormancy, but at a reduced level Seed Structure and Germination in the Common Garden Bean 32 Corn Kernel Structure and Germination 33 Reproduction in Plants 34 Asexual Reproduction in Plants Plants contain nondifferentiated meristem tissue Allows them to reproduce asexually by vegetative propagation Plant hormone auxin: Can be used to cause roots to develop Expands the list of plants that can be propagated from cuttings Asexual Reproduction in Plants 35 Tissue Culture of Plants Reproduction in Plants 36 Tissue culture is the growth of a tissue in an artificial liquid or solid culture medium Plant cells are totipotent Meristem culture Auxins and cytokinins allow many new shoots to develop from a single shoot tip - Virus-free clonal plants Suspension Culture Rapidly growing calluses are cut into small pieces and shaken into a liquid nutrient medium - Single cells or small clumps break off and form a suspension Tissue Culture in Plants 37 Genetic Engineering Reproduction in Plants 38 Traditionally, hybridization was used to produce plants with desirable traits Crossing different varieties of plants Transgenic plants can now be produced by placing foreign genes into a plant Agricultural plants with improved traits - Pest or insecticide resistant Commercial Products - Human hormones, antibodies Maize 39 Genetically Engineered Plants 40 Review Reproductive Strategies Alternation of generations Adaptation to a land environment Flowers - Pollination - Fertilization Seed Development Fruit Seed Germination Asexual Reproduction Tissue Culture Reproduction in Plants 41 Ending Slide Chapter 28 Reproduction in Plants