Nutrient Procurement and Processing - Plants

Plant Nutrition

1. The two types of organisms based on mode of nutrition.
     I. Nutrient – refers to any substance required for the growth and maintenance of an organism. The two types of organisms based on the mode of nutrition are:
        A. autotrophs – organisms that obtain energy from sunlight and chemicals to produce their own food. Examples: plants; chemosynthetic bacteria
        B. heterotrophs – organisms that cannot make their own food and obtain their energy from other organisms. Examples: animals, fungi

2. The nutritional requirements of plants:
        A. water
        B. carbon dioxide

Further, note that water and carbon dioxide are the raw materials needed for photosynthesis, the process by which plants convert the energy from sunlight into chemical energy.
      
        C. essential nutrients or elements – which include macronutrients which are normally required in amounts above 0.5% of the plant’s dry weight; and micronutrients which are required in minute or trace amounts;
        D. examples of macronutrients: C, H, O, N, K, Ca, Mg, P, S
        E. examples of micronutrients: Cl, Fe, B, Mn, Zn, Co, Mo

3. The routes for the absorption of water and minerals across plant roots:
        A. symplast route – through plasmodesmata
        B. apoplast route – along cell walls

Note that the water and minerals from the soil need to reach the conducting tissues of plants, specifically the xylem. The two routes mentioned show how this can happen.

4.  Specialized absorptive structures:
        A. root hairs – slender extensions of specialized epidermal cells that greatly increase the
surface area available for absorption.
        B. root nodules – localized swellings in roots of certain plants where bacterial cells exist symbiotically with the plant. The bacteria help the plant fix nitrogen and in turn, the bacteria are able to utilize some organic compounds provided by the plant.

3. mycorrhizae (singular, mycorrhiza) – a symbiotic interaction between a young root and a fungus. The fungus obtains sugars and nitrogen-containing compounds from root cells while the plant is able to get some scarce minerals that the fungus is better able to absorb from the soil.

5. Enumerate nutritional adaptation by plants:
        A. Symbiosis of plants and soil microbes
        B. Symbiosis of plants and fungi
        C. Parasitism
        D. Predation

Nutrient Procurement and Processing Quiz 1