Chapter 38 and 39 provides knowledge of angiosperm reproduction - Plant responses to internal and external signals. In this chapter, the following content will be discussed: Types of fruit, plant peproduction, experiments with light and the coleoptile, ethylene gas: fruit ripening, plant movement, plant responses to light, plant responses to stress. | Chapter 38 Angiosperm Reproduction Angiosperms have 3 unique Features: Flowers Fruits Double Fertilization (by 2 sperm) REPRODUCTIVE VARIATIONS Pollination: transfer pollen from anther to stigma Some plants are self-pollinated Cross-pollinated plants: Self-incompatibility: plant rejects own pollen or closely related plant Maximize genetic variation Stigma Stigma Pin flower Anther with pollen Thrum flower “Pin” and “thrum” flower types reduce self-fertilization The development of a plant embryo Fruit Egg cell plant embryo Ovules inside ovary seeds Ripe ovary fruit Fruit protects enclosed seed(s) Aids in dispersal by water, wind, or animals Seeds Mature seed dormancy (resting) Low metabolic rate Growth & development suspended Resumes growth when environmental conditions suitable for germination Germination Seed take up water (imbibition) trigger metabolic changes to begin growth Root develops shoot emerges leaves expand & turn green (photosynthesis) Very hazardous for plants due to vulnerability Predators, parasites, wind Sexual Asexual (Vegetative Reproduction) Flower Seeds Runners, bulbs, grafts, cuttings vegetative (grass), fragmentation, test-tube cloning Genetic diversity Clones More complex & hazardous for seedlings Simpler (no pollinator needed) Advantage in unstable environments Suited for stable environments Plant Reproduction Asexual reproduction in aspen trees Test-tube cloning of carrots Humans Modify Crops Artificial selection of plants for breeding Plant Biotechnology: Genetically modified organisms “Golden Rice”: engineered to produce beta-carotene (Vit. A) Bt corn: transgenic – expresses Bt (bacteria) gene produces protein toxic to insects Biofuels – reduce CO2 emissions Biodiesel: vegetable oils Bioethanol: convert cellulose into ethanol Chapter 39 Plant Responses to Internal and External Signals Experiments with Light and the coleoptile Excised tip placed on agar block Growth-promoting chemical diffuses into agar block Agar block . | Chapter 38 Angiosperm Reproduction Angiosperms have 3 unique Features: Flowers Fruits Double Fertilization (by 2 sperm) REPRODUCTIVE VARIATIONS Pollination: transfer pollen from anther to stigma Some plants are self-pollinated Cross-pollinated plants: Self-incompatibility: plant rejects own pollen or closely related plant Maximize genetic variation Stigma Stigma Pin flower Anther with pollen Thrum flower “Pin” and “thrum” flower types reduce self-fertilization The development of a plant embryo Fruit Egg cell plant embryo Ovules inside ovary seeds Ripe ovary fruit Fruit protects enclosed seed(s) Aids in dispersal by water, wind, or animals Seeds Mature seed dormancy (resting) Low metabolic rate Growth & development suspended Resumes growth when environmental conditions suitable for germination Germination Seed take up water (imbibition) trigger metabolic changes to begin growth Root develops shoot emerges leaves expand & turn green (photosynthesis) Very hazardous for .
