Seed Propagation PDF

Plant Propagation – Seed Propagation Sexual Propagation (有性繁殖)  The major method of plant reproduction...

Plant Propagation – Seed Propagation Sexual Propagation (有性繁殖)  The major method of plant reproduction  Most efficient / widely used propagation Seed Propagation  Seedling – 實生苗 - Sexual Propagation Filial 1 hybrid  Starting from sowing seeds Homogeneity and predictability Jongyun Kim Higher performances  F1 hybrid – Cultivar breeding Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Seed Development Non-vascular plants  Mosses  Non-vascular  Spore producing plants 400 million 300 million 200 million 100 million 55 million years ago years ago years ago years ago years ago Non-vascular Vascular Mosses Seedless plants Seed plants SEED Ferns Gymnosperms Angiosperms Cycads, Ginkgo, Conifers Dicots, SPORE Monocots Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Life Cycle of Ferns Seedless plants - Ferns frond Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Seed Plant – Gymnosperms Gymnosperm - Ginkgo  Gymnosperms Male 裸子植物  Cycads, Gingko Female  Conifers  Male / Female Flowers Seeds Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Life Cycle of Pine Tree Conifer – Pine tree Male Female Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Seed Plants - Angiosperms Flower Anatomy  Angiosperm (被子植物)  Flowering plants (顯花植物)  Ovule (胚珠) is covered by ovary (子房)  Double fertilization (重複受精)  Monocots (單子葉植物)  Dicots (雙子葉植物) Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Flower Anatomy Life Cycle of Angiosperms Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Seed Plants - Angiosperms Complete vs. Incomplete Flower  Complete/perfect flower  Petal  Stamen  Sepal  Pistil Petal (花瓣) Anthers (葯) Stigma (柱頭) Style (花柱) Ovary (子房) Sepal/calyx (萼) Female flower parts Complete Flower Incomplete Flower Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Imperfect Flower (單性花) Imperfect Flowers  Diclinous flower (雌雄異花)  Monoecious plants (雌雄同株)  Dioecious plants (雌雄異株) Male flower Female flower Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Imperfect flower, Why? Terms homogenous To increase the chance of cross pollination A population of seedlings that are phenotypically similar Cross-Pollination heterogeneous F1 A population of seedlings that are phenotypically dissimilar Increase heterozygosity Evolutionary adaptation within the population homozygous Plant vigor tends to be enhanced A population of seedlings whose genotypes are very similar Inbreeding depression Vigor, size, productive may be reduced by heterozygous homogeneous population A population of seedlings whose genotypes are dissimilar Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Dichogamy (雌雄異熟) Pollination (受粉)  Dichogamy  Genetic trait in which male and female flowers on the same plant bloom at different times  Reduce the ratio of self- to cross-pollinated flowers Generative cell Tube cell Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Pollen (花粉) - microgametophyte Pollen Development – anther Tetrad in Anther (4 sacs) 0 0 Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Pollen Development Gymnosperm Fertilization Tube cell Generative cell Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Angiosperm Egg cell - megagametophyte Angiosperms Egg cell Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Double Fertilization Angiosperm Fertilization Double Fertilization (重複受精) Embryo sac Embryo (2n) Endosperm (3n) Sperm (n) + Egg cell (n) Zygote (2n) Endosperm (3n) Sperm (n) + Polar nuclei (2n) Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Ovary Seed Anatomy  Ovary – 子房  Ovule – 胚珠  Embryo sac – 胚囊  Polar nuclei – 極核  Egg cell – 卵細胞  Integuments – 周皮 Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Seed Anatomy Seed Development STAGE I STAGE II STAGE III Histo- Cell Expansion Maturation differentiation Drying Embryogenesis Food Physiological accumulation maturation Cell enlargement Preparation for germination Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Histodifferentiation - Embryogenesis Embryogenesis Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Stage II - Cell Expansion Seed Development of Lettuce  A stage of rapid cell enlargement  Seed filling  Food reserves  Carbohydrates, proteins, oils  Energy for germination  Seed food crops (e.g., cereal, legumes) Growth and development of the fruit and seed in lettuce showing the relative changes in seed size during the three stages of seed development. P, pericarp; I, integuments; N, nucellus; EN, endosperm; EM, embryo Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Seed Development Stage III – Maturation Drying Histo-  Maximum differentiation dry weight  Decrease in Cell fresh weight Expansion (drying)  ABA Maturation Drying Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Parthenocarpy Parthenocarpy How to make a seedless watermelon  Parthenocarpy is fruit production without seed Colchicine selfing formation Diploid Tetraploid Tetraploid (2n) (4n) (4n)  單爲結果 Induction of parthenocarpy by auxin application 4n flower 3n plant Use of Triploids (3n) 2n pollen 2n pollen Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Seed Germination Phases of Seed Germination Radicle Seedling Imbibition Lag Phase Protrusion Emergence Petunia seed demonstrating Seed morphology related to germination. (a) Lentil two-step germination (lens) is non-endospermic and most of the seed cavity (a) Seed coat cracks. is filled with cotyledon tissue. The seed coat restricts (b) Endosperm stretches over emerging radicle. radicle protrusion. (b) In tomato the embryo is (c) Radicle protrudes from endosperm. embedded in endosperm, the endosperm cap covers (d) Hypocotyl and radicle elongation. the radicle, and is the restraint to radicle protrusion. Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Seed Germination Environment Seed Dormancy Imbibition (吸水) Types of Dormancy Growth driving force Water Enzyme reaction Dormancy (休眠)  Exogenous dormancy Light The condition where  Physical dependent seeds will not  Chemical germination Light Temp germinate even when the  Endogenous dormancy Optimal environment is  Physiological Temperature suitable for  Morphological Oxygen germination  Morphophysiological Respiration Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Breaking Seed Dormancy Measures of Germination Scarification (加傷法) Germination Percentage (發芽率) # of seeds germinated / seeds sown x 100 A treatment that allows water to penetrate seeds with a hard seed coat. Scarification may be physical, chemical (acid), or involve high temperature Stratification (層積法) A period of moist-warm or moist-chilling conditions that satisfies dormancy in seeds with endogenous, physiological dormancy GA and other PGR Treatment Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Measures of Germination Germination Tests Germination Speed (rate, 發芽勢)  ISTA (International Seed Testing Association) Time to reach 50% germination or emergence in those seeds that germinate Plant Propagation – Seed Propagation Plant Propagation – Seed Propagation Enhancing Germination Seed Priming  Coated Seed  A controlled hydration seed treatment that  Pelleted seed induces faster, more uniform germination  Increase sizes for mechanization  To hold seeds in an imbibed condition  Seed Priming  But, preventing germination (radicle emergence)  Seed hydration  Uniform germination  Osmotic priming  Pre-germinated Seed  Matrix priming  Seeds are germinated in a controlled environment  Drum priming  Good germination during poor field conditions