From clockwise, upper left: Halberd-leaf Hibiscus (Hibiscus laevis) and Purple Coneflower (Echinacea purpurea) by Joseph A. Marcus; Buttonbush

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1 From clockwise, upper left: Halberd-leaf Hibiscus (Hibiscus laevis) and Purple Coneflower (Echinacea purpurea) by Joseph A. Marcus; Buttonbush (Cephalanthus occidentalis) by Campbell and Lynn Loughmiller; Purple Leatherflower (Clematis pitcher) by Joseph A. Marcus. All images courtesy of Lady Bird Johnson Wildflower Center. 1

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5 Photosynthesis = process by which plants convert carbon dioxide into their food (photosynthates = sugars, starches, carbohydrates and proteins), by using the energy derived from the Sun. Essential elements = sunlight, water, carbon dioxide, and chlorophyll. The leaves and stem of a plant have microscopic holes, known as stomata, through which the carbon dioxide enters the plant. While carbon dioxide is absorbed by leaves, water enters the plant through its roots. After being absorbed by the roots, water travels all the way through the stem to reach the leaves where the actual process takes place. Illustration of photosynthetic process at: 5

6 Plant leaves are where the entire process occurs. Within tissue of the plant leaf and some stem tissue = sub-cellular structures (chloroplasts) containing green-colored photosynthetic pigment called chlorophyll; captures energy from sunlight and storing for further use. The energy, which is captured, is eventually used to convert water into hydrogen and oxygen. While hydrogen is combined with carbon dioxide and used by the plant to produce its food, oxygen being a by-product of the entire process is released into the atmosphere through the stomata. The entire process can be put forth in the form on an equation: 6CO2 + 6H2O + Light energy C6H12O6 + 6O2 Illustration of stoma function: University of California Museum of Paleontology's Understanding Evolution ( 6

7 Image: Texas Prickly Pear Cactus (Opuntia engelmannii var. lindheimeri) by Joseph A. Marcus. Image courtesy of Lady Bird Johnson Wildflower Center. 7

8 Transpiration water loss from plant tissue; evaporation of water from leaves results in a suction force pulling water up the xylem vessels and out through stomata. This force due to transpiration is main factor in lifting dissolved mineral salts up the plant from the roots to the leaves 8

9 Respiration process whereby plant obtain energy by oxidation of food (sugars, glucose) utilized for cellular activities. Breathing is different from transpiration as it involves gaseous exchange from the atmospheric air. 9

10 The circulatory system and the vascular system transport nutrients and water to different parts of an organism. A plants vascular system consist of vascular tissues that allows the flow of water and nutrients through plants. Vascular tissues consists of xylem and phloem vessels. Illustration: Elizabeth Morales 10

11 Vascular tissues consists of xylem and phloem vessels. The xylem main function is to transport inorganic nutrients and water through a plant and is found closely to the center of a plant. A good example of a xylem is wood which consists of dead cells with a tube like structure. 11

12 The phloem consist of living cells and is located closely to the outside of a plant. The phloem transport organic nutrients to the upper part of the plant. The phloem also consists of living cells called sieve-tube members, between the sieve-tube members are sieve plates, which have pores that allow molecules to pass through. Illustration: Elizabeth Morales 12

13 Cambium - a layer of actively dividing cells between xylem (fluid-conducting) and phloem (food-conducting) tissues that is responsible for the secondary growth of stems and roots, resulting in an increase in thickness. A cambium may also form within callus tissues. Illustration: Elizabeth Morales 13

14 Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates ( and WH Freeman ( used with permission. From website: 14

15 Illustration: Elizabeth Morales. Girdled tree image: "AnnelageAnnélationGirdling1LilleLamiot3" by Lamiot - Own work. Licensed under CC BY 3.0 via Wikimedia Commons - amiot3.jpg#/media/file:annelageann%c3%a9lationgirdling1lillelamiot3.jpg 15

16 Illustration from Ohio State University: 16

17 Two main types of plant roots = tap roots (dicots) and fibrous roots (monocots). Taproot system = deep-rooted. The taproot system enables the plant to anchor better to the soil and obtain water from deeper sources. In all plants, the primary root develops from the embryonic root (radicle). Lateral roots develop from taproot which may initially grow horizontally then turn downward. These roots form finer roots which terminate in a root tip with a minute, domeshaped, protective root cap at the tip-most part. As the root grows, it pushes its root cap forward, probing the soil and absorbing water and nutrients mainly through fine root hairs. These root hairs are short-lived and constantly replaced. To enhance the development of more lateral roots in taproot plants, pruning of the taproot is practiced (bonsai trees). In contrast, shallow-rooted plants are more susceptible to drought but they have the ability to respond quickly to fertilizer application. Illustration of fibrous and taproot plants Thomson Higher Education; from: Illustration of plant embryo to first true leave; from: 17

18 The primary root which develops from a radicle and becomes dominant is called a taproot (carrot). Roots that develop from other roots are generally = lateral roots; those that arise from other plant organs rather than the root (stems or leaves) = adventitious roots. 18

19 Illustration of photosynthetic process at: 19

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22 Fluorescent or cool-white light is high in the blue range of light quality and is used to encourage leafy growth. These lights are excellent for starting seedlings. Incandescent light is high in the red or orange range but generally produces too much heat to be a valuable light source. Fluorescent "grow" lights have a mixture of red and blue colors that attempts to imitate sunlight as closely as possible. They are costly and generally not of any greater value than regular fluorescent lights. 22

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24 Short-day = form flowers when day length < 12 hours (spring and fall flowering: chrysanthemum and poinsettia) Long-day = form flowers when day length > 12 hours (summer) 24

25 Illustration of photosynthetic process at: 25

26 From left to right: Little Bluestem (Schizachyrium scoparium) by Carolyn Fannon; and Inland Sea Oats (Chasmanthium latifolium) by Sally and Andy Wasowski. All images this page courtesy of Lady Bird Johnson Wildflower Center. 26

27 Comparing warm-season and cool-season grasses USDA NRCS: Native Cool Season Grasses in Missouri USDA Forest Service: 27

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31 Plants can be classified as either hardy or non-hardy depending upon their ability to withstand cold temperatures. Winter injury can occur to non-hardy plants if temperatures are too low or if unseasonably low temperatures occur late in the spring or early in the fall. Winter injury may also occur because of desiccation (drying out). 31

32 Illustration of photosynthetic process at: 32

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34 For example, if a kilogram of air at 75 F could hold 4 grams of water vapor and there are only 3 grams of water in the air, then the relative humidity (RH) is: RH = 3/4 =.75 expressed as a % = 75% From: 34

35 For example, if a kilogram of air at 75 F could hold 4 grams of water vapor and there are only 3 grams of water in the air, then the relative humidity (RH) is: RH = 3/4 =.75 expressed as a % = 75% From: 35

36 Illustration of photosynthetic process at: 36

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38 All 18 elements, both macronutrients and micronutrients are essential for plant growth. 38

39 Calcium is used by plants in cell membranes, at their growing points and to neutralize toxic materials. In addition, calcium improves soil structure and helps bind organic and inorganic particles together. Magnesium is the only metallic component of chlorophyll. Without it, plants can't process sunlight. Sulfur is a component of many proteins. 39

40 Calcium is used by plants in cell membranes, at their growing points and to neutralize toxic materials. In addition, calcium improves soil structure and helps bind organic and inorganic particles together. Magnesium is the only metallic component of chlorophyll. Without it, plants can't process sunlight. Sulfur is a component of many proteins. 40

41 Image from University of Miami, Department of Biology: 41

42 Illustration of photosynthetic process at: 42

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