Presentation on theme: "Level 1 Horticulture Science"— Presentation transcript:
1Level 1 Horticulture Science AS 90923Plant Propagation
2Plant PropagationThe following PowerPoint notes are to support students towards the assessment for:AS Demonstrate knowledge of basic plant propagation techniquesLevel credits Internal AssessmentAchievementAchievement with MeritAchievement with ExcellenceDemonstrate knowledge of basic plant propagation techniques.Demonstrate in-depth knowledge of basic plant propagation techniques.Demonstrate comprehensive knowledge of basic plant propagation techniques.
3Contents The difference between asexual and sexual Types of sexual propagationTypes of asexual propagationSeed SowingCuttingsDivisionGround Layering
4The difference between asexual and sexual DefinitionsAsexual Involves only one parent to make a new individual that is a clone of the parent (genetically identical). In plants there are heaps of ways of doing this.Sexual Involves 2 (or 1) parent plants mixing their genes to produce offspring. In plants the parents have ‘sex’ using flowers and the offspring are seeds
5Examples of Propagation AsexualSexualCuttingsHardwood /Semi-Hardwood/ Soft-woodGraftingWhip and tounge / cleft / budding etcDivisionTubers/ runners/ rhizomes/ crown/ stolons/ bulbs/ cormsLayeringGround/ airPropagation using SeedNote:Always involves flowersexcept in gymnosperms (pine trees) ferns and mossesSexual propagation always results in a seed
6Seed sowing To understand seed sowing technique we will be looking at: Seed structureGerminationRespirationSeed requirementsSeed DormancySeed Sowing Menu
7Seed sowing – seed structure Three parts to a seedSeed coatEndospermEmbryo‘A seed is a plant in a box with it’s lunch’Seed Sowing Menu
8Seed sowing – seed structure Seed coat -the outer covering of a seed helps protect the embryo from injury and drying out. Seed coats can be thin and soft as in beans or thick and hard as in walnuts or coconut seeds.Endosperm, a temporary food supply, is packed around the embryo in the form of special leaves called cotyledons or seed leaves. These are often the first parts visible when the seed germinates.Embryo – the ‘baby’ plant.Seed Sowing Menu
9Two different situations: Cotyledon(s) appear above ground as first leaves (seed leaves)Cotyledon(s) remain below the ground
10Seed sowing – Seed Structure There are two types of plants that produce seeds:Monocotyledonsand DicotyledonsSeed Sowing Menu
12Germination Starts when the seed begins to absorb water Ends when the new plant is able to get all its’ energy from photosynthesis.
13Germination – the process The seed absorbs water until it swells and smoothens its exterior wrinkles.Swelling continues until the coat of the seed bursts open.Food stored in cotyledons or endosperm soaks up water and soluble substances dissolve in it.Respiration begins thus energy and raw materials are supplied by food for cell division and growth.A radical appears first and then a pumule.
14RespirationDuring respiration (in plants and animals) energy is released from sugar (glucose) by a series of chemical reactions. The sugar is broken down into carbon dioxide and water in a process which uses oxygen.
16Seed requirements List the inputs all seed require to germinate Match your list to the following.Allows seed to swell and break seed coatRequired for respirationSpeeds up the various chemical processes
17Seed dormancyDormant seeds are seeds that are still alive but when the seed is supplied all that it needs to germinate, - it doesn't.The seed is asleep, waiting for the proper time to awaken.Seed dormancy aids a species' survival by delaying germination so that 'overall germination' is dispersed over time.
18Seed Storage Germination needs water. warmth and oxygen Seed storage needs (the opposite)Cool and dry!Why can we not store seeds in a oxygen free environment?
19Seed Sowing SummarySeeds don’t get re-assessment opportunities. Once they begin to germinate they either survive or die.Seeds need the WOW factor to survive (water oxygen, warmth). Soil, light, CO2 are only for ‘grown-up’ seedsA seed is a plant in a box with it’s lunch – but no dinner – if a seed is in the packet too long it will run out of lunch and die.
20Sexual Propagation – Exercise Which of the following statements are true T/FIf we collected 1000 seeds from one kowhai tree, it is unlikely that any one seed will have the same genetic materialA sunflower produces 800 seeds. The genetic material in each seed has come form two parentsSeed is made after a pollen grain and an egg (ovum) have joined together in a flowerSeed is spread by bees and other insects in a process known as pollinationA Flower contains both the male and female sexual organs of a plant.