Seedless Plants Mosses & ferns (ferns are vascular plants) make spores, not seeds Embryo from sexual reproduction develops within archegonium in parent plant Embryo does not need to await favorable conditions to develop Seed Plants Embryo from sexualreproduction develops in seed Seeds dispersed, await favorable conditions to germinate Seeds formed in cone (gymnosperm) or fruit (angiosperm) Classification - Seeds
Flowering Plants:Angiosperms/Anthophyta Seeds enclosed in a fruit Flowers make gametes (eggs & sperm) Fertilized flower fruit Naked Seed Plants: Gymnosperms/Coniferophyta Seeds in cone No flowers Male & female cones make gametes (egg & sperm) Conifers: pines, firs, spruces, cypresses, redwoods Classification - Flowers
Sexual Reproduction in Seed Plants (ch. 30)Life Cycle of Coniferophyta/Gymnosperms Male gametophyte (n) No more spores… (n) In pollen cone and ovule of female cone: Meiosis to produce gametophytes (n)Mitosis to produce gametes (n) Pollination *Water not needed* Female gametophyte (2n) (2n)
Life Cycle of Anthophyta/Angiosperms In anther and ovule: Meiosis to produce gametophytes (n)Mitosis to produce gametes (n) Male gametophyte Pollination *Water not needed* Fertilization Female gametophyte No more spores… Mitosis
Your Textbook picture Double fertilization: 2 sperm cell + egg + polar nuclei Zygote (2n) Endosperm (3n)
Seed Germination • Germination – embryo in seed starts to grow (usually triggered by water absorption) • Radicle – first shoot/part of embryo to appear outside seed; develops into root • Cotyledons – seed “leaves,” not real leaves, do not photosynthesize • Monocot one coteledongrains: rice, corn, wheat, etc. • Dicot two coteledonslegumes: beans, peas, etc.
If April showers bring May flowers,what do May flowers bring?Pilgrims. Botanists have developed a vegetable that eliminates the need to brush your teeth.Bristle sprouts.
Seed Structure & Development in Flowering Plants Double fertilization seeds containing embryo and endosperm(one sperm for egg, one for endosperm) Endosperm – contains starch/oil/protein -- energy for developing embryo Each ovule develops into a seed. The micropile is the small opening where sperm came into ovule for fertilization.
Seed Development Hypocotyl = embryo shoot under cotyledons develops into first stem Epicotyl = embryo shoot above cotyledons develops into first leaves Cotyledons (seed leaves) eventually fall off Brassica, our lab plant
Bean Seed Hilum Scar where ovule attached to ovary Micropile Scar where pollen tube entered ovule Radicle emerges here,becomes root
Development of Bean Plant cotyledons epicotyl hypocotyl
Corn Kernel / Seed / Fruit Silk Scar (pollen tube entered ovule here) Embryo Point of attachment
Flowers • Sexual reproductive structures (contain gametophytes) • Attract pollinators • Make gametes by mitosis • Anther makes pollen containing sperm • Ovary makes ovules eggs • Seeds/fruits develop from flower ovary • Pollination – stigma receives pollen, pollen tube forms • Double fertilization in ovary: 2 sperm cells + egg --> embryo & endosperm (endosperm = food for embryo)
Flower Structure • Perfect/complete Flowers • have both male & female parts • Imperfect Flowers • have either male or female parts
Formation of Female Gametophyte -- Terms you need to know/ID: Ovary, ovule, female gametophyte, meiosis, egg & polar nuclei, endosperm, double fertilization
Formation of Male Gametophyte -- Terms you need to know/ID: Anther, male gametophyte (pollen), meiosis, sperm (2, for double fertilization)
Fleshy Fruits High moisture content Apples, cherries, grapes, strawberries, tomatoes, cucumbers, etc. Dry Fruits Low moisture Walnuts, acorns, wheat kernels, dandelion “parachutes” Fruits
Fleshy Fruits Berry Pome Drupe Aggregate http://www.csdl.tamu.edu/FLORA/201Manhart/repro/fleshyfruits/fleshyfruits.html Multiple Accessory
Dry Fruits Policidal capsule Nut Silique Follicle http://www.csdl.tamu.edu/FLORA/201Manhart/repro/dryfruits/dryfruits.html
Dry Fruits Samara Legume Winged schizocarp
Asexual Reproduction in Plants • Vegetative reproduction – occurs naturally, very fast, via modified ground surface/underground stems that make buds: • Stolons/runners – close to ground surface; ex.: aspen groves (clones), water hyacinths • Rhizomes – underground; ex.: bamboo plants • Tubers – swollen tips of rhizomes; modified for food storage;ex: potatoes • Corms and bulbs – modified for food storage; ex.: tulips, onions • Artificial propagation – people do it: cutting, grafting, tissue culture • faster than seeds, produces genetically identical crop – plant regenerates parts Ex: bananas, apples, grapefruits, grapes, potatoes, pears are often grown by artificial propagation