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PLANT NUTRITION You Are What You Eat!.

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Presentation on theme: "PLANT NUTRITION You Are What You Eat!."— Presentation transcript:

1 PLANT NUTRITION You Are What You Eat!

2 Essential Nutrients in Plants

3 Absorption of Nutrients
80-85% of herbaceous plant mass is water. More than 90% of absorbed water is lost through transpiration. The dry mass of plants comes from CO2. Organic substances account for 95% of dry mass: 5% is inorganic. Positively charged ions (cations) stick to soil particles. Roots use cation exchange to obtain cations. Anions are not tightly bound and leach away faster. Root hairs release H+ and CO2 into the soil.

4 Availability of Soil, Water, and Minerals

5 Plants Can’t Acquire N2 Directly
Approx. 80% of the atmosphere is nitrogen. N2 must be converted to NH4+ or NO3-. In ammonification, ammonifying bacteria release NH4- from organic material by decomposition. Nitrogen-fixing bacteria make NH4+ by nitrogen-fixation using nitrogenase complex. Only certain prokaryotes of the genus Rhizobium (root living) can fix nitrogen. Lightning and U.V. radiation can also generate NH4+.

6 Ammonium Production by Bacteria

7 Conversion of Ammonia Ammonia converts to the ammonium ion in soil.
Plants usually absorb nitrate, NO3-. Nitrification is the conversion (oxidation) of NH4+ to NO2- and then to NO3- by nitrifying bacteria. After absorption of by the roots, NO3- is reduced back to ammonium within the plant. NH4+ is converted to protein and other organic compounds. Export of nitrogen is via xylem. Dentrifying bacteria convert soil NO3- back to N2. It takes 8 ATP’s to produce one NH3 molecule.

8 Nitrification Conversion of NH4- to NO3-

9 Assimilation of NO3-

10 The Nitrogen Cycle

11 Rhizobium Live as Symbiotes in Root Nodules as Bacteroids

12 Soybean Root Nodule

13 Another Symbiote - Mycorrhizae Symbiotic Fungi Aid in Water Absorption

14 Parasitic Plants Indian pipe obtain nutrients from the host tree by tapping into the host tree’s micorrhizae. Mistletoe projects haustoria to siphon xylem sap from vascular tissue of the host: Oaks and other trees. They are also photosynthetic. Epiphytes (air plants) are not parasitic. They derive nutrients from the air and rainfall. Examples are: Spanish moss (angiosperm), staghorn fern,

15 Indian Pipe

16 Carnivorous Plants Live in acid bogs where soil conditions are poor.
Have trouble obtaining nitrogen. Supplement their nutrition with animals.

17 Venus Fly Trap Pitcher Plant

18 Sundew


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