Plant Structure Adaptations and Responses - Plant Science - Lecture Slides, Slides of Biology

Download Plant Structure Adaptations and Responses - Plant Science - Lecture Slides and more Slides Biology in PDF only on Docsity! 4 evan? we F ' > —_ Ot =| ' , ess - ve mae y J . o ; oil Th ps eS : u ; i Docsity.com A. Functions of Roots 1. Anchor & support plant in the ground 2. Absorb water & minerals 3. Hold soil in place Fibrous Roots Root Hairs Docsity.com A. Functions of Stems 1.Support system for plant body 2.Transport system carries water & nutrients 3.Holds leaves & branches upright Each light and dark tree ring equals one year of annual growth. Light rings for fast spring growth, dark for slow summer growth. Smaller rings tell of past droughts that have occurred. Looking at the picture to the left: What years had the most rain? What years experienced t e worst drought? Docsity.com A. Functions of Leaves 1. Main photosynthetic organ 2. Broad, flat surface increases surface area for light absorption 3. Have systems to prevent water loss • Stomata open in day but close at night or when hot to conserve water • waxy cuticle on surface 4. System of gas exchange • Allow CO2 in and O2 out of leaf Elephant Ear Plant Docsity.com B. Leaf Structures 1.Cuticle: waxy layer; covers upper surface • Protects leaf against water loss 2.Veins: transports water, nutrients and food • Made of xylem and phloem 3.Mesophyll: contains cells that perform photosynthesis b/c they contain Chloroplasts. 2 Guard Cells Surround each Stoma M e s o p h y ll (Opening) Leaf Cross-Section Veins Cuticle Stoma Stoma- singular Stomata-plural Docsity.com Stoma Open Stoma Closed Guard Cells Function of Guard Cells Guard Cells •These stomata (leaf openings) naturally allow water to evaporate out. •Why would the plant close stomata with guard cells? •Prevent excess water loss through transpiration. (conserve water) •So what is the point of having stomata? •Allow gas exchange for photosynthesis Docsity.com A average size maple tree can transpire 200 liters of water per hour during the summer. Transpiration is the #1 driving force for pulling water up stems from roots. C. Plants find a use for Transpiration 1. Transpiration: loss of excess water from plant leaves 2. Significance: B A a. Transpiration causes enough pressure to help pull water (& required nutrients) up stem from roots. b. As part of the water cycle, trees transpire water back into the atmosphere. c. Transpiration provides much of the daily rain in rainforest. Docsity.com 1.Pistil:female reproductive structure a.Stigma: sticky tip; traps pollen b.Style: slender tube; transports pollen from stigma to ovary c.Ovary: contains ovules; ovary develops into fruit d.Ovule: contains egg cell which develops into a seed when fertilized Filament Anther Stigma Style Ovary Pistil Petal Sepal Ovule Stamen Structure of a Flower Docsity.com Cross Pollination • How does pollination happen? • Pollen from an anther is caught by the stigma, travels through style to the ovules in the ovary. • What is the result of pollination? • A Fruit: An ovary containing seeds. Docsity.com Chapter 25 Plant Responses and Adaptations Docsity.com Hormone- producing cells Target cells Movement of hormone Hormone Action on Plants A. Plant cells can produce hormones: which are chemical messengers that travel throughout the plant causing other cells called target cells to respond. B. In plants, hormones control: 1. Plant growth & development 2. Plant responses to environment Cells in one blooming flower signals other blooms using hormones to open. Docsity.com Plant Tropisms 1. Tropism: the way a plant grows in response to stimuli in the environment. a.Phototropism: growth response to light -Plants bend towards light a.Geotrophism: growth response to gravity -plant roots grow down with gravity, shoots (stems) grow up against gravity and out of the soil. a.Thigmotropism: growth response to touch -vines grow up around trees, venus flytrap closes when leaves are touched Docsity.com What type of tropism is shown in these pictures? Docsity.com