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SEEDS AND FRUIT. Fruit and Seed Dispersal A. Need for Dispersal B. Dispersal by Wind 1.Curved wings maple samara 2.Inflated sacs hop hornbeam 3.Plumes.

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Presentation on theme: "SEEDS AND FRUIT. Fruit and Seed Dispersal A. Need for Dispersal B. Dispersal by Wind 1.Curved wings maple samara 2.Inflated sacs hop hornbeam 3.Plumes."— Presentation transcript:

1 SEEDS AND FRUIT

2 Fruit and Seed Dispersal A. Need for Dispersal B. Dispersal by Wind 1.Curved wings maple samara 2.Inflated sacs hop hornbeam 3.Plumes Buttercup and Sunflower Families 4.Cottony or woolly hairs Willow Family 5.Minute (Tiny) seeds orchids and heaths

3 Dispersal

4 hop hornbeam

5 Buttercup and Sunflower Families

6 (a) Black Cottonwood, (b) Fremont Cottonwood, (c) Quaking Aspen, (d) Willow

7 Minute (Tiny) seeds orchids and heaths

8 Wolffia

9 Fruit and Seed Dispersal cont. C.Dispersal by Animals 1.Pass through digestive tracks of birds and mammals 2.Hooks and barbs, stick to fur of animals D.Dispersal by Water 1.Inflated buoyant sacs, Hydrophytes sedges 2.Waxy coverings E.Other Dispersal Mechanisms and Agents 1.Mechanical, splitting action touch-me-nots, dwarf mistletoes 2.Humans act as dispersal agents

10 stick to fur of animals

11 Sedges

12 touch me not and its seeds

13 Seeds A.Structure 1.Hilum 2.Micropyle 3.Seed Coat 4.Embryo a.Cotyledons = seed leaves b.Embryo axis 1)Epicotyl (stem axis above cotyledon attachment) 2)Hypocotyl (stem axis below cotyledon attachment) 3)Radicle (embryonic root) 4)Plumule (embryonic shoot with immature leaves) c.Additional structures (e.g., corn seeds) coleoptile and coleorhiza

14

15 B.Germination 1.Dormancy 2.Breaking of dormancy a.Scarification nicking or breaking seed coat b.After-ripening embryo needs further development c.Stratification cold temperature treatment d.Environmental regulation 1)Water and oxygen 2)Role of light phytochrome pigment

16 C.Longevity 1.Viability certain seeds retain capacity to germinate for many years 2.Professor Beal's viability experiment page 142

17 Asexual Plant Propagation Leaf Cuttings

18 Splitting plants

19 Tip layering

20 Air layering

21 Other ways of propagation

22 Seeds and germination 1. annuals – grow from seed each year 2. bi-annuals – takes two years to mature to flower and seed out. 3. seeds are resistant to environmental changes can last a long time 4. genetic variance (recombination)

23 Seed coat 1. seed – a structure formed by the maturation of the ovule of seed plants following fertilization. Protects and nourishes developing plant. 2. fruit – a mature, ripened ovary or group of ovaries, contains the seeds and sometimes includes other parts Seed from ovule Fruit from ovary

24 Some seed anatomy and physiology 1. seed coat (testa) – outer layer of seed. Develops from the integuments of the ovules 2. raphe – ridge on the seed formed by the stalk of the ovule 3. hilum – scar left on the seed after separation from the stalk of the ovule (fanicullus) 4. micropyle – opening of the ovule through which the pollen tube grew 5. aril – an extra seed covering which is formed by an outgrowth at the base of the ovary (yew)

25 Japanese yew

26 Endosperm formation (double fertilization) 1. endosperm – nutritive material in the seed for the embryo 2. formed from – polar nuclei and male nucleus union of the central cell (seen only in angiosperms) 3. endosperm formation (pea plant) – Anther meiosis – Ovule meiosis

27 Anther meiosis Your drawing goes here

28 Ovule meiosis Your drawing goes here

29 Double fertilization Drawing goes here

30 Zygote –mitosis-> embryo

31 Embryo 2n 1. Young plant inside the seed 2. Epicotyls - part above the cotyledons, but below the next set of leaves 3. Cotyledons – seed leaves – Monocots – absorbs food – Dicot – stores food 4. Hypocotyls – portion of the embryo below the cotyledons. But above the radical 5. Radical – embryonic root

32 Steps in germination 1. favorable environment – Water – Oxygen – Temperature – light 2. imbibition – seed takes in HOH 3. anaerobic decreased O 2 conditions Aerobic conditions increased oxygen 4. temperature constraints – Minimum 0-5 o C, maximum o C, optimal o C 5. light – day length (photoperiod) tell time of year by the day length – Negative photoblastic seed is one that is inhibited by light


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