co26 - CHAPTER 26 NUTRITION AND TRANSPORT IN PLANTS Chapter...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
C HAPTER 26 N UTRITION AND T RANSPORT IN P LANTS Chapter Outline 26.1 Plant Nutrition and Soil A. Early Views 1. Ancient Greeks considered plants “soil-eaters” that converted soil into plant tissue. 2. The 17 th Century Dutchman Jean-Baptiste Van Helmont conducted an experiment. a. He planted a five pound young willow tree in a pot with 200 pounds of soil. b. After five years of watering, the tree weighed 170 pounds but only a few ounces of soil was missing. c. He concluded the increase in tree weight came from water; he was unaware of substances in air. B. Essential Inorganic Nutrients 1. Essential inorganic nutrients (e.g., carbon, hydrogen, oxygen) comprise 96% of plant dry weight. a. Carbon dioxide is the source of carbon for a plant. b. Water is the source of hydrogen. c. Oxygen can come from either atmospheric oxygen, carbon dioxide, or water. 2. Essential nutrient s must fulfill the following criteria. a. They have an identifiable nutritional role. b. No other element can substitute and fulfill the same role. c. A deficiency of the element causes the plant to die. 3. These elements are divided into macronutrients and micronutrients by concentration in plant tissue. 4. Beneficial nutrients are elements required for or improving growth of a particular plant. a. Horsetails require silicon as a mineral nutrient. b. Sugar beets show better growth in the presence of sodium. c. Soybeans use nickel when root nodules are present. C. Determination of Essential Nutrients 1. When a plant is burned, most mineral elements (except for nitrogen) remain in the ash. 2. Hydroponics is the preferred method for determining plant mineral requirements. a. Hydroponics is cultivation of plants in water. b. Nutrient requirements of plants are determined by omitting a mineral and observing the effects. c. If plant growth suffers, it can be concluded that the omitted mineral is a required nutrient. d. This works for macronutrients but impurities make micronutrient measurement difficult. D. Soil Formation 1. Soil formation begins with weathering of rock by freezing, glacier flow, stream flow, and chemicals. 2. Lichens and mosses grow on barren rock and trap particles and leave decaying tissues. 3. Decayed organic matter (humus) takes time to accumulate; its acidity leaches minerals from rocks. 4. Depending on parent material and weathering, a centimeter of soil may develop within 15 years. E. The Nutritional Function of Soil 1. Soil consists of soil particles, decaying organic matter, living organisms, air and water. 2. The best soil includes particles of different sizes; this provides critical air spaces. 3. Soil Particles a. Particles vary by size. 1) Sand particles are larger: 0.05–2.0 mm in diameter. 2) Sand particles are medium sized: 0.002–0.05 mm in diameter. 3) Clay particles are smallest: below 0.002 mm in diameter.
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern