Plants and their Organs LEAVES STEM ROOTS FLOWERS I. LEAVES I. Leaves-Functions a. Trap light energy Photosynthesis b. Producing sugar (Glucose) c. Breathing-Exchange of gases: O2 and CO2 PHOTOSYNTHESIS Sunlight + Carbon Dioxide + Water go into the plant. Glucose (sugar) and Oxygen are produced. PHOTOSYNTHESIS Leaves- Structure Wide Helps to catch more light energy Thin Help get carbon dioxide from bottom to top of leaf for photosynthesis Leaf structure Greener on top a. Top-catch sunlight and contain chloroplasts/ chlorophyll b. Bottom-exchange gases through stoma. CO2 gets in here Leaves-Gas exchange c. Stomata-Small holes on bottom of leaf that allow CO2 in and O2 out. d. Guard Cells-Open and Close each stomata hole based on stimuli (light, temp, etc). e. Leaves are designed to allow carbon dioxide to get to the main chlorophyll layer at the top of the leaf and release oxygen. See HMH page Page 72 for more details Leaf diagram – stoma and guard cells Stoma function is for gas exchange in the leaf Guard oxygen cell Carbon dioxide Stomata open and close at different times of the day When it is light the plant needs CO2 for photosynthesis so the stoma open At night (darkness) they close II. STEMS II. STEMS -Functions a. A stem is a plant organ which: Moves water and food between the roots and the leaves. b. Helps support leaves and flowers. Stems-Types -There are two kinds of stems: a. Green stems-flexible, soft, allow for photosynthesis to take place.(flowers). b. Woody stems-hard (trees). **Bark is made out of phloem cells. **The growth rings in a tree are made out of xylem cells. Stem Types GREEN STEM WOODY STEMS STEM STRUCTURE- XYLEM AND PHLOEM a. Vascular tissues of the plant are known as Xylem and Phloem b. Xylem: carries water from the roots to rest of the plant. c. Phloem: carries sugar from the leaves to rest of the plant. Lets compare structure to function in plants and animals III.ROOTS ROOTS-FUNCTIONS a) Hold-plant in position b) Absorb-water and minerals from the soil c) for more information please see HMH page 70 Root Hairs Fragile parts of cells that grow from the main root c. Root Hairs-increase surface area for water intake d. They massively increase the surface area for absorption Root ‘B’ has had the hairs damaged Across section of a root IV. Flowers Flowers-Functions a) Help with reproduction. b) Attract ‘Pollinators’ Bees, etc c) Protect/Hold/Spread seeds Flowers-Structure and Parts a. Petals-protect and attract pollinators b. Stamen-produces pollen (male) c. Pistil-produces the eggs and becomes seed. d. Ovary-bottom of pistil/stores the eggs. e. Seed-pollinated egg. Becomes new plant. Pollination Process of getting pollen from one plant in contact with egg from another plant. Pollinators are used such as bees and birds. Plant response to stimuli: Phototropism the growth response of plant parts to the stimulus of light, producing a bending towards the light source Carnivorous Plants Carnivorous plants still go through photosynthesis. They eat bugs etc. to get nutrients such as Nitrogen. Usually in harsh environments with poor soil..