* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Section 23.2 Summary – pages 612
Photosynthesis wikipedia , lookup
History of botany wikipedia , lookup
Plant use of endophytic fungi in defense wikipedia , lookup
Ornamental bulbous plant wikipedia , lookup
Evolutionary history of plants wikipedia , lookup
Venus flytrap wikipedia , lookup
Plant reproduction wikipedia , lookup
Plant stress measurement wikipedia , lookup
Plant defense against herbivory wikipedia , lookup
Plant breeding wikipedia , lookup
Plant secondary metabolism wikipedia , lookup
Plant nutrition wikipedia , lookup
Plant ecology wikipedia , lookup
Plant evolutionary developmental biology wikipedia , lookup
Plant physiology wikipedia , lookup
Plant morphology wikipedia , lookup
Sustainable landscaping wikipedia , lookup
1. What are the main parts of this tree? 2. What is the function of each part? REVIEW How do plants obtain energy? In the food chain, they are the producer…. PLANT STRUCTURE AND FUNCTION Roots: Anchors the plant Collects water and nutrients for plant LEAVES Cannot carry out photo. Stem: Above ground Transports nutrients If green, can photosynthesize STEM Leaves: Major Photosynthesis Transpiration ROOTS Remember Capillary Action and Adhesion ROOTS Roots can be short or long Rhizome Roots can be thick and Most massive roots or grow in the soil, thin and thread-like. some do not…. TYPES OF ROOTS 1. TAPROOTS: like carrots and beets single thick structures with smaller branching roots accumulate and store food TYPES OF ROOTS 2. Fibrous Roots: have many small branching roots from a central point example: grass TYPES OF ROOTS 3. PROP ROOTS: originate above ground to help support the plant example: corn Plant Hormones • Plants, like animals, have hormones that regulate growth, help them respond to the environment, and send chemical messengers. • A hormone is a chemical that is produced in one part of an organism and transported to another part, where it causes a physiological change. • The plant’s hormones are produced in the ROOTS. STEMS Stems transport water, dissolved minerals, and sugar to and from roots and leaves. 1. Herbaceous Stems Fleshy, green stems, Can also carry out photosynthesis. 2. Woody stems Grow year after year Have cork tissue for protection A tree trunk is one example of a woody stem. Woody stems are composed primarily of dead xylem cells. Annual growth rings • These annual growth rings can be used to estimate the age of the plant. Cork Phloem Vascular cambium Xylem Besides age, the thickness of a tree can show how much water was available at the time. A thin tree ring indicates a year of drought. LEAVES • The primary function of the leaves is photosynthesis. • Sunlight passes through the transparent cuticle into the photosynthetic tissues just beneath the leaf surface. Cuticle Upper epidermis Palisade Layer (where most chloroplasts are found) LEAVES Size, Shape, and type of leaves vary enormously. Opposite Arrangement LEAVES • Gases can also move in and out of a leaf through the stomata, which are located in the upper and/or lower epidermis. Stomata LEAVES • Guard cells are tiny cells that surround and control the size of a stoma. • The loss of water through the stomata is called transpiration. LEAVES Stoma Transpiration Water • When water enters the guard cells, the pressure causes them to bow out, opening the stoma. Guard cell LEAVES Transpiration • As water leaves the guard cells, the pressure is released and the cells come together, closing the stoma. Water LEAVES One way to distinguish among different groups of plants is to examine the pattern of veins in their leaves. PARALLEL VEINS NET-LIKE VEINS (Monocot) (Dicot) PLANT RESPONSES • Although a plant lacks a nervous system and usually cannot make quick responses to stimuli, it does have mechanisms that enable it to respond to its environment. • Plants can respond to: Gravity Light Temperature PLANT RESPONSES • Tropism is a plant’s response to an external stimulus. • The tropism is called positive if the plant grows toward the stimulus. • The tropism is called negative if the plant grows away from the stimulus. WE WILL LOOK AT THREE TYPES OF TROPISM TROPISM The growth of a plant toward light is called phototropism. • As these cells lengthen, the stem bends toward the light. TROPISM Gravitropism is plant growth in response to gravity. Stems usually exhibit a negative gravitropism. Roots that grow down into the soil are able to anchor the plant and can take in water and dissolved minerals. How do growing seeds exhibit both phototropism and gravitropism? TROPISM Some plants exhibit another tropism called thigmotropism, which is a growth response to touch. • Because tropisms involve growth, they are not reversible. • The position of a stem that has grown several inches in a particular direction cannot be changed. Ivy is a good example of a plant that exhibits all three types of tropism. PLANT RESPONSES • A responsive movement of a plant that is not dependent on the direction of the stimulus is called a nastic movement. • An example of a nastic response is the sudden closing of the hinged leaf of a Venus’s-flytrap. • Naustic movements do not involve growth. • The relative lengths of daylight and darkness each day have a significant effect on the rate of growth and the timing of flower production in many species of flowering plants. • The response of flowering plants to daily daylightdarkness conditions is called photoperiodism. Question 1 Most plants produce their own food in the form of _______. A. cellulose B. proteins C. glucose D. chlorophyll The answer is C. Question 2 Which of the following is NOT a function of most plant roots? A. absorbing water and nutrients B. conducting photosynthesis C. store starch D. anchoring the plant The answer is B. Question 3 Most roots that humans eat are _____ roots. A. taproots B. fibrous roots C. prop roots D. aerial roots The answer is A, taproots. Question 4 If a plant becomes too dry, are the stomata in the leaves more likely to be open or closed? Answer The stomata are more likely to be closed to prevent any more water loss from the plant. Question 5 What is the main difference between tropisms and nastic responses? Answer The main difference between the two is that tropisms are not reversible and nastic responses are reversible. Also, nastic responses do not depend on the direction of the stimulus, tropisms do. Question 6 As you walk through a room, you notice that a plant sitting on a table 2 m from a window is leaning toward the window. What type of response is the plant exhibiting? Answer phototropism. Question 7 Name the two stages of a plant’s life cycle, and describe which each entails. Answer Gametophyte: Haploid stage Sporophyte: Diploid stage