“Basal Angiosperms” Plant Breeding Systems Announcements Herbarium Tour today during lab. Lab Quiz 2 next Monday. Keying practice this Friday, 3-5 pm, HCK 246. Phylogeny of angiosperms Angiosperms “Basal angiosperms” Parallel venation scattered vascular bundles 1 cotyledon Tricolpate pollen ANITA grade •Ambor ella •Nymphaeaceae •Illicium •T rimenia vessels •Austr obaileya (Jansen et al. 2007) Phylogeny of angiosperms Angiosperms “Basal angiosperms” Parallel venation scattered vascular bundles 1 cotyledon Tricolpate pollen Nymphaeales is a monophyletic group including Nymphaeaceae, Barclayaceae, and vessels Cabombaceae (Jansen et al. 2007) Nymphaeaceae (Water lily family) http://botany.csdl.tamu.edu/FLORA/tfplab/lilyp.gif http://www.squidoo.com/VictoriaWaterLily Nymphaeaceae (Water lily family) 8 genera, 70 species (Nymphaea, Nuphar, Victoria) Habit: Ben Legler Textbook DVD WSJ Stems: Leaves: Nymphaeaceae (Water lily family) Inflorescence: Flowers: Sex of plant: Ben Legler Nymphaeaceae (Water lily family) Flower symmetry: Perianth parts: http://www.missouriplants.com/Whitealt/Nymphaea_odorata_calyx.jpg # of stamens: # of pistils/flower: Textbook DVD KRR & DLN # of carpels/pistil: Ovary position: http://sevenhillslake.com/LUTEXPUM_I020720333.jpg Nymphaeaceae (Water lily family) Fruit type: Textbook DVD KRR & DLN Textbook DVD JRA Phylogeny of angiosperms Angiosperms “Basal angiosperms” Parallel venation scattered vascular bundles 1 cotyledon Tricolpate pollen Magnoliids is a monophyletic group including Magnoliaceae, Lauraceae, Piperaceae and vessels several other families (Jansen et al. 2007) Magnoliaceae (Magnolia family) Textbook DVD KRR Magnolia X soulangeana Magnoliaceae (Magnolia family) 2 genera, 220 species (Liriodendron, Magnolia) Habit: Textbook DVD WSJ Magnolia grandiflora Leaves: Textbook DVD WSJ Liriodendron tulipifera Magnoliaceae (Magnolia family) Inflorescence: Flowers: Textbook DVD WSJ Magnolia grandiflora Sex of plant: Textbook DVD WSJ Liriodendron tulipifera Magnoliaceae (Magnolia family) Flower symmetry: Perianth parts: # of stamens: Textbook DVD KRR # of pistils/flower: # of carpels/pistil: Ovary position: Textbook DVD KRR Magnoliaceae (Magnolia family) Fruit type: Textbook DVD SMK & KRR Textbook DVD KRR Early Angiosperm Flower •Insect-pollinated •Radially symmetric •Floral parts numerous, spirally arranged and free •Perianth of tepals Textbook DVD KRR •Perfect flower •Laminar stamens •Gynoecium of simple pistils, and superior ovaries Ben Legler Phylogeny of angiosperms Angiosperms “Basal angiosperms” Parallel venation scattered vascular bundles 1 cotyledon Tricolpate pollen vessels (Jansen et al. 2007) Phylogeny of Eudicots (or Tricolpates) Eudicots (or Tricolpates) “Basal eudicots” Ranunculales is a monophyletic group including Ranunculaceae, Berberidaceae, Papaveraceae, and 4 other families. (Jansen et al. 2007) Ranunculaceae (Buttercup family) Yaowu Yuan Yaowu Yuan Aquilegia Ranunculus Ranunculaceae (Buttercup family) 47 genera, 2000 species (Anemone, Clematis, Delphinium, Helleborus, Ranunculus) Habit: http://commons.wikimedia.org/wiki/File:Helleborus_orientalis2.jpg Leaves: Textbook DVD KRR Ranunculaceae (Buttercup family) Inflorescence: Flowers: Jim Riley Sex of plant: Ranunculaceae (Buttercup family) Flower symmetry: Perianth parts: # of stamens: Yaowu Yuan # of pistils/flower: # of carpels/pistil: Ovary position: Yaowu Yuan Ranunculaceae (Buttercup family) Fruit type: Textbook DVD KRR Textbook DVD KRR & DLN Papaveraceae s.s. (Poppy family) (Hoot et al. 1997) Papaveraceae s.s. (Poppy family) http://www.missouriplants.com/Redalt/Papaver_rhoeas_plant.jpg Textbook DVD CSC Eschscholzia californica California poppy Papaver rhoeas Papaveraceae s.s. (Poppy family) 23 genera, 240 species (Argemone, Eschscholzia, Papaver) Habit: Stems: http://www.missouriplants.com/Yellowalt/Argemone_mexicana_plant.jpg Leaves: Textbook DVD WSJ Papaveraceae s.s. (Poppy family) Inflorescence: Flowers: Sex of plant: Yaowu Yuan Papaveraceae s.s. (Poppy family) Flower symmetry: Perianth parts: # of stamens: Textbook DVD DLN # of pistils/flower: # of carpels/pistil: Ovary position: Yaowu Yuan Papaveraceae s.s. (Poppy family) Fruit type: Yaowu Yuan Textbook DVD KRR http://www.indianetzone.com/photos_gallery/1/274_poppy_seed_fruit.jpg PLANT BREEDING SYSTEMS Diversity and Evolution of Reproduction in Angiosperms Plants vs. Animals • Flowering plants are generally hermaphroditic. • Use intermediary agents. • Can reproduce asexually & sexually. • Less rigidly controlled development. • Alternation of generations. • Plant breeding systems are rarely fixed & static! Asexual Reproduction • Reproduction of genetically identical individuals from a single parent plant. • Main type: vegetative reproduction. • No meiosis, no fertilization, and no recombination. Modes of Vegetative Reproduction • Rhizomes – underground shoots • Tillers – aboveground shoots • Bulblets – “little bulbs” • Bulbils – inflorescence veg buds • Cuttings Advantages of Asexual Reproduction • Parent plants well-adapted to local environment will have offspring with a competitive advantage. • Less reproductive effort. • Colonization with limited dispersal. • Reproductive assurance in limited cross-pollination. Disadvantages of Asexual Reproduction • Little if any new genetic variability. – Genetically uniform populations. • Very narrow population niche width. • No capabilities for travel, dormancy, and establishment that seeds exhibit. Sexual Reproduction • Production of offspring through meiosis and fertilization. – Offspring genetically different from parents due to recombination = genetic diversity. • Plants can be both asexual and sexual, with a variety of forms. SUCCESSFUL POLLINATION ≠ SUCCESSFUL FERTILIZATION Hermaphroditic Flowers • Self-compatible (SC) – Capable of self-fertilization or cross-fertilization • Self-incompatible (SI) – Only capable of cross- fertilization – Inability of hermaphroditic plant to produce zygotes w/ self pollen Self-fertilization • Pollen transfer within or among flowers of same individual • ~20% of angiosperms are habitual selfers • ~40% of angiosperms can self-fertilize Advantages of Self-fertilization • Reproductive assurance. • Selectively advantageous by transmitting both sets of genes to offspring. – Well-adapted genotypes preserved. • Only single colonizing individual needed. • Cost-saving on male expenditure. Disadvantages of Self-fertilization • Decreases genetic variability. • Inability to adapt to changing conditions. • Increases inbreeding depression. – Reduces heterozygosity and increases homozygosity of deleterious alleles. – Loss of vigour in offspring! Loss of Heterozygosity from Selfing Aa x Aa A a A AA Aa 1/4 AA 1/2 Aa a Aa aa 1/4 aa A selfed heterozygote will yield offspring that are 50% heterozygous. Loss of Heterozygosity from Selfing Proportion of heterozygotes is 1/2 in each successive generation. F1: 50% of offspring heterozygous from original parent (Aa). F2: 25% F3: 12.5% F4: 6.2% F5: 3.1% F6: 1.5% Disadvantages of Self-fertilization • Decreases genetic variability. • Inability to adapt to changing conditions. • Increases inbreeding depression. • Reproductive inefficiency. Self-incompatibility (SI) • Inability of a fertile hermaphrodite flower to produce zygotes after self-pollination. • Involves a biochemical reaction in the stigma or style to reject self pollen or prevent pollen tube growth. • Genetically controlled by S-locus. – opposite S alleles attract – like S alleles repel Selfers vs. Outcrossers • SC • SI or SC • Mostly annuals • Mostly woody perennials • Small flowers (few) • Large showy flowers (many) • Unscented flowers • Scented flowers • Nectaries & nectar • Nectaries & nectar guides guides absent present • Similar maturation of • Differential maturation of reproductive parts reproductive parts – Anthers near stigma – Anthers far from stigma – Style included – Stigma well-exserted • All fruits mature • Only some fruits mature • Low pollen:ovule ratio • High pollen:ovule ratio Cleistogamy (CL) • Flowers never open and only capable of self-fertilization in bud. • Inconspicuous, bud-like apetalous flowers that form directly into seed capsules. • 488 species, across 212 genera and 49 families. – Violaceae, Fabaceae, Poaceae Cleistogamy (CL) • Mixed mating systems -can produce both CL and open flowers on an individual. • CL fls are a “back-up” in case pollinators scarce. • CL occur after normal flowering period. – open fls early spring and CL fls later in season. Strategies to Prevent Self-fertilization Physical Separation of Reproductive Parts (Herkogamy) • Within flowers • Among flowers Heterostyly • Flowers in different individuals of the same species having 2 or 3 different style lengths – With stamen lengths varying inversely • 25 families of angiosperms, over 18 orders, and 155 genera. Distyly • 2 floral morphs. • “Thrum” flower – long filaments w/ short styles • “Pin” flower – short filaments w/ long styles • Only pollinations between different floral morphs are successful. • E.g.: Primulaceae, Boraginaceae Tristyly • 3 floral morphs • Style long, stamens short and medium • Style medium, stamens short and long • Style short, stamens medium and long • Only 3 families! Temporal Separation of Reproductive Parts (Dichogamy) • Protandry – Anthers release pollen before stigma receptive – Common in insect- pollinated plants Temporal Separation of Reproductive Parts (Dichogamy) • Protogyny – Stigma receptive before pollen release – Less common than protandry Physical Separation of Reproductive Parts • Unisexual