ABOVE. BELOW or UNDER

Transcription

1

2 Learning objective Plant structure of the main parts of a typical flowering plant Describe the function of roots and stem Label the parts of a flower on a diagram, and describe the functions of each part What is the difference between pollination and fertilization?

3 The Shoot System is found ABOVE ground and the Root System is found BELOW or UNDER ground.

4 Plant Body Organization A plant consists of: 1. Root system, which is underground -Anchors the plant, is used to absorb water and minerals, conduction and storage 2. Shoot system, which is above ground -Consists of supporting stems, photosynthetic leaves and reproductive flowers Each has an apex that extends growth

5 Both systems depend on the other. Lacking chloroplasts and living in the dark, roots would starve without the sugar and other organic nutrients imported from the photosynthetic tissues of the shoot system. Conversely, the shoot system (and its reproductive tissues, flowers) depends on water and minerals absorbed from the soil by the roots.

6 AXILLARY BUD TERMINAL BUD FLOWER FRUIT NODE NODE SHOOT SYSTEM INTER- NODE STEM NODE LEAF MAIN ROOT LATERAL OR SIDE ROOT ROOT SYSTEM

7 The Root Structure of root Types of Root Systems Functions of the Root System

8 Structure of root Roots have several structures, such as root caps and root hairs that stems lack.

9 Root cap Each root tip is covered by a root cap. The function of the root cap is to cover and protect the delicate growing tip from injury and damage as the root pushes its way through the soil.

10 Root hairs Root hairs are tiny projections and outgrowths on the outermost layer of the root epidermis. The root hairs increase absorption of water and minerals near the root tip.

11 Looks like a tangled mass of roots Examples of plants With this root system are Rice Corn Sugar Cane

12 Fibrous root A fibrous root system - to many roots of the same size developing from the end of the stem, with smaller lateral roots branching off these roots. Fibrous root systems, which are located relatively close to the surface of the soil, are adapted to obtain rainwater from a larger area as it drains into the soil. Monocots most often have fibrous roots.

13 Have a large main central root Have many branching roots Go deep in the soil Examples of plants : Large trees e.g. mango, avocado Shrubs e.g. tomato, peppers

14 A taproot system - one main root with many smaller lateral roots. Lateral roots often initially occur in regular rows along the length of the main root. Taproot systems often extend down into the soil to obtain water located deep underground

15 Roots : - anchor plants firmly in the ground - absorb water and minerals from the soil - Storage - some plants, can store starch - of some plants can be used to grow a new plant

16 Question Name the two organ systems and three basic organs found in all plants. What are root hairs and what is the function of root hairs? Briefly explain the fibrous root. Describe the functions of roots.

17 Summary The root system is generally underground and obtains water and dissolved nutrient minerals for the plant. Root also anchor the plant firmly in place. A tap root system has one main root from which many smaller lateral roots extend. A fibrous root system has several to many oots of the same size developing from the end of the stem.

18 The shoot system above ground portion The shoot system consists of stems, leaves, flowers and fruits that contain seeds. And the growth occurs at apex. Some stems grow underground Bulbs and rhizomes etc. They may be swollen to store food e.g. potatoes.

19 Woody Plant Stem The stems support the leaves and flowers. In the case of a tree, the stems are the trunk and all the branches, including the smallest twigs.

20 External stem structure Stems all have buds, which are undeveloped embryonic shoots. A terminal bud (apical) is the embryonic shoot located at the tip of a stem. Axillary buds, also called lateral buds, are located in the axils of a plant s leaves.

21 External stem structure When terminal and Axillary buds grow, they form stems that bear leaves and/or flowers. The area on a stem where each leaf is attached is called a node, and the region between two successive nodes is an internode.

22 External Stem Structure Terminal bud = Extends the shoot system during the growing season Axillary bud = Develops into branches with leaves or may form flowers Node = Point of attachment of leaf to stem Internode = Area of stem between two nodes

23 Support Functions of plant stems Conduction Production

24 Annual complete their life cycle in a single year or less (grains, legumes) Biennials - (such as carrot, cabbage) take two years to complete their life cycles before dying. In the first season they produce extra carbohydrates, which they store and use during their second year when they typically form flowers and reproduce. Perennials plants that live and reproduce for more than two years. They include trees, shrubs, but herbs can also be perennial.

25

26 Leaves External Anatomy Leaf Types Function

27 Leaves Tendrils Mayapple Leaves may be round, needle-like, scale like, heart-shaped, fan-shaped, or thin and narrow. They vary in size, colour, texture.

28 EXTERNAL ANATOMY Leaves possess a blade or lamina, an edge called the margin of the leaf, the veins (vascular bundles), a petiole, and two appendages at the base of the petiole called the stipules. margin

29 Structure The petiole, which joins the leaf to a stem node. Some leaf blades are attached directly to the stem and lack a petiole or stipules. These are termed sessile leaves.

30 Structure In the absence of petioles in grasses and many other monocots, the base of the leaf forms a sheath that envelops the stem. Some monocots, including palm trees, do have petioles.

31 Structure The arrangement of veins, differ in monocots and dicots. Most monocots have parallel major veins that run the length of the blade, while dicot leaves have a multibranched network of major veins. veins

32 Structure: Leaf Types

33 Structure: Leaf Arrangement

34 Function of leaves Photosynthesis Transpiration - 99% of water absorbed by plant is lost by transpiration Exchange of gases oxygen and carbon dioxide

35 What is the difference between deciduous and evergreen? Deciduous - they shed all their leaves at the same time and produce new leaves the following rainy season. Evergreen - shed their leaves over a long time period, so that some leaves are always present.

36 Summary The shoot system is generally aerial and obtains sunlight and exchanges gases such as carbon dioxide and oxygen The shoot system consists of a vertical stem that bears leaves (the main organs of photosynthesis) and reproductive structures (in flowering plants, flowers and fruits). Buds (undeveloped embryonic shoots) develop on stems.

37 Summary Buds are undeveloped embryonic shoots. A terminal bud is located at the tip of a stem, whereas axillary buds (lateral buds) are located in leaf axils. The area on a stem where each leaf is attached is called a node, and the region of a stem between two successive nodes is an internode.

38 Summary Leaves exhibit variation in shape and form. Leaves typically consist of a broad, flat blade and a stalk-like petiole. Some leaves also possess small, leaf like outgrowths from the base called stipules. Leaves may be simple or compound Leaf arrangement on a stem may be alternate, opposite or whorled Leaves may have parallel or netted (either pinnately netted or palmately netted) venation.

39 Summary Monocot and dicot leaves can be distinguished based on their external structure. Monocot leaves have parallel venation, whereas dicot leaves have netted venation. The main function of stems is support, conduction and production of new living tissues.

40 Basic Flower Structure

41 The Parts of a Flower Most flowers have four parts: sepals, petals, stamens, Pistil or carpel.

42 Complete flowers Complete flowers usually have four parts-sepals, petals, stamens and pistilwhich are usually borne on a receptacle.

43 Incomplete flower Incomplete flowers lack one or more of the four part: sepals, petals, stamens, or pistil.

44 The parts of a flower Sepals protect the bud until it opens. Petals attract insects. Stamens make pollen. Carpels grow into fruits which contain the seeds.

45 Parts of the Flower Sepals Outer covering of the flower bud. Protects the stamens and pistils when flower is in bud stage. Collectively known as the calyx.

46 Petals Parts of the Flower Brightly colored Protects stamen & pistils. Attracts pollinating insects. Collectively called the corolla. Collectively sepals (calyx) and petals (corolla) are called the perianth.

47 Parts of the Flower (Stamen) Male reproductive part Anther Produces pollen Filament Supports the anther Collectively or a group of stamens is the androecium.

48 Pistil (female) Stigma Style Carpel (ovary) Ovules (eggs) Collectively or a group of pistil or carpel is known as Gynoecium

49 Parts of the Flower (Pistil) Female reproductive part Ovary Enlarged portion at base of pistil Produces ovules which develop into seeds Stigma Holds the pollen grains - Style Connects the stigma with the ovary. Where pollen tube grows down to female sex cells. Supports the stigma so that it can be pollinated. Ovules (eggs)

50 The stamens and pistils are considered the essential parts of the complete flower for sexual reproduction. The sepal (calyx) and the petals (corolla) are accessory flower parts. A flower with both stamen and pistil (carpel) are considered as perfect flower. Imperfect flower has either one but not both.

51 Carpel female parts Style Stigma Petals Stamen male parts Ovary Ovules Sepals Anther Filament Nectaries Collect a cut-out flower, colour it in and put it together.

52 What do the parts do? Sepalsprotect the flower when it is a bud Petalscolourful to attract the insects Nectariesgive out sugary liquid to attract insects Stamen- anther produces male sex cells (pollen) stigma traps pollen Style is where pollen tube grows down to female sex cells. ovary produces female sex cells (ovules)

53 Flowers Function Contain the sexual organs for the plant. Produces fruit, which protects, nourishes and carries seeds. Attracts insects for pollination.

54 Learn About Plants - Different Parts.flv

55 Quick Test 1. Name the parts of a flower that attract insects. 2. Name the male part of a flower. 3. Which part of the flower contains ovules? 4. Which part of the flower produces pollen? 5. Which part of a flower catches pollen grains?

56 Label the parts of a flower

57 SUMMARY A flower may contain sepals, petals, stamens, and carpel (pistils). Sepals cover and protect the flower parts when the flower is a bud. Petals play an important role in attracting animal pollinators to the flower. Stamens produce pollen grains. Each pistil has three sections: a stigma, on which the pollen grains land; a style, through which the pollen tube grows; and an ovary that contains one or more ovules.

58 Pollination and Fertilisation

59 Pollination Pollination involves the transfer of pollen (male gamete) from the anther to the stigma (outermost female part) Plants are pollinated by insects or the wind.

60 Pollination Self-pollination Pollen from the anther is transferred to the stigma in the same flower or a different flower on the same plant

61 Cross Pollination Pollen from the anther of one plant is transferred to the stigma of a different plant of the same species

62 Learn About Plants - Life Cycle.flv

63 Mode of Pollination 1. Insect-pollinated flowers may have: Brightly coloured petals- blue or yellow petals. Strong sweet fragrance Nectar producing glands Guidelines to lead insects to Nectar Stamen are inside Stigma and pollen are sticky 2. Wind-pollinated flowers may have: Large stigmas outside the flower Little or no fragrance Light non-sticky pollen Lack showy petals

64 Insect Pollinated Plants

65 Wind Pollinated Plants

66 Wind/Insect Pollination

67 Mode of Pollination (Continued) 3. Bird-pollinated flowers may have: Long tube shaped flowers Bright red and yellow flowers No odour 4. Mammal-pollinated flowers may have: White flowers Strong fruity odour Flowers opening at night 5. Water-pollinated flowers may have: Pollen which floats on water (this form of pollination is rare)

68

69 Wind Pollinated Flowers Feature small petals, often brown or dull green no scent no nectar pollen produced in great quantities pollen very light and smooth anthers loosely attached and dangle out stigma hangs outside the flower Reason no need to attract insects no need to attract insects no need to attract insects because most does not reach another flower so it can be blown in the wind to release pollen into the wind to catch the drifting pollen stigma feathery or net like to catch the drifting pollen

70 Insect Pollinated Flowers Feature large, brightly coloured petals Reason to attract insects often sweetly scented to attract insects usually contain nectar moderate quantity of pollen pollen often sticky or spiky anthers firm and inside flower stigma inside the flower stigma has sticky coating to attract insects less wastage than with wind pollination to stick to insects to brush against insects so that the insect brushes against it pollen sticks to it

71 Pollination Summary Structure Petals Pollen Stamen Stigma nectar Wind Pollinated dull light dangling feathery none Insect Pollinated bright colour sticky inside flower sticky makes sugar

72 Fertilisation Fertilisation involves the fusion of the nucleus of the male gamete (in the pollen) with the nucleus of the female gamete (in the ovules).

73 Pollen grains germinate on the stigma, growing down the style to reach an ovule. Fertilised ovules develop into seeds. The ovary enlarges to form the flesh of the fruit and to protect the ovary. Fertilisation

74 *The ovule forms the seed and the ovary forms the fruit. A fruit is a ripened ovary

75 Pollination of flowers.flv

76 Seed dispersal Seeds are dispersed in many different ways: Wind Explosion Water Animals Birds Scatter

77 Seed Dispersal- why? Seeds must be carried away (dispersed / scattered) from the parent plant to: Reduce overcrowding Reduce competition for: - Water - Light - Nutrients

78 What is a benefit of a seed being dispersed far away from parent plant? This helps to raise the offsprings chance of survival, at the same time ensuring the parent plants survival. If the seeds land close to the parent plant competition for resources such as water, sunlight, and nutrients will take place, weakening both the offspring plants as well as the parent plant.

79 How birds and animals help seed dispersal Some seeds are hidden in the ground as a winter store. Some fruits have hooks on them and cling to fur or clothes.

80 How birds and animals help seed dispersal Birds and animals eat the fruits and excrete the seeds away from the parent plant.

81 Seed Dispersal Dispersal method Wind Description Seeds are designed to travel as far as possible. May have extensions which act as parachutes or wings. Fruits may be shaken like a pepper pot. Seeds/ Fruits

82 Learn About Plants - Seed Dispersal.flv

83 Quick Test-A 1. What term is used to describe male and female gametes? 2. What is pollination? 3. Name the two types of pollination. 4. Describe the differences in the pollen between insect and wind pollinated plants. 5. Explain why the stigmas of wind pollinated flowers hang outside the flowers.

84 Quick test-b 1. Why do wind pollinated flowers not produce nectar? 2. How does the male gamete reach the female gamete? 3. What is a fruit? 4. Name three ways in which fruits and seeds are dispersed. 5. Why is it important that fruits and seeds are carried away from the parent plant?

85 Parts Of A Flowering Plant.flv

86 Summary Pollination is the transfer of pollen grains from anther to stigma. Flowers pollinated by insects are often yellow or blue and possess a scent. Bird-pollinated flowers are often yellow, orange or red and do not have a strong scent. Bat-pollinated flowers often have dusky white petals and possess a scent. Plants pollinated by wind often have smaller petals or lack petals altogether and do not produce a scent or nectar; wind-pollinated flowers make copious amounts of pollen.

87 Summary Fertilised ovules develop into seeds. Seeds are enclosed within fruits, which are mature, ripened ovaries. Seeds and fruits are adapted for various means of dispersal, including animals, wind, water and explosive dehiscence.