2. Plant Nutrition (Ch. 37)

3. Physiological adaptation Dogs pee on trees…Why don’t trees pee on dogs? NH 3 animal waste plant nutrient

4. Nutritional needs Autotrophic does not mean autonomous – plants need… sun as an energy source inorganic compounds as raw materials – water (H 2 O) – CO 2 – minerals

5. Macronutrients Plants require these nutrients in relatively large amounts – C, O, H, N, P, K, Ca, Mg, S

6. For what & from where? C macromolecule synthesisCO 2 O macromolecule synthesisCO 2 H macromolecule synthesis & proton pumpsH2OH2O N protein & nucleic acid synthesissoil P nucleic acids, ATP, phospholipidssoil K stomate control, water balancesoil Ca cell wall & membrane structure, regulationsoil Mg chlorophyllsoil S proteins, enzymessoil

7. Local Long Island soil issues Granite Acid soils bind up mineral ions  pH by adding lime Quartzsilica based soils - low in P - can be acid

8. Micronutrients Plants require in very small amounts – Cl, Fe, Mn, Bo, Zi, Ni, Mb – primarily cofactors for enzyme function

9. Nutrient deficiencies Lack of essential nutrients – exhibit specific symptoms dependent on function of nutrient dependent on solubility of nutrient

10. Magnesium deficiency Symptoms – chlorosis = yellowing of leaves – Why? What is magnesium’s function? Take 2 fertilizer pellets & call me in the morning

11. Chlorophyll Why does magnesium deficiency cause chlorosis? The chlorosis shows up in older leaves first, because plant moves Mg + to newer leaves. Why?

12. The role of soils Plants are dependent on soil quality – texture / structure relative amounts of various sizes of soil particles – composition organic & inorganic chemical components fertility Agronomists really dig dirt!

13. Importance of organic matter Topsoil – most important to plant growth – rich in organic matter humus – decomposing organic material » breakdown of dead organisms, feces, fallen leaves & other organic refuse by bacteria & fungi – improves soil texture – reservoir of minerals – organisms 1 tsp. of topsoil has ~5 billion bacteria living with fungi, algae, protists, insects, earthworms, nematodes So don’t rake your lawn or bag your leaves

14. Soil health as a global issue Not taking care of soil health has far-reaching, damaging consequences – 1920’s Dust Bowl – lack of soil conservation growing the same crop year after year (wheat) grazing by cattle bare ground exposed to wind erosion in winter drought

15. Soil health as a global issue Soil conservation & sustainable agriculture – maintaining healthy environment – sustainable production of food supply – economically viable farming industry contour plowingcrop rotation “A sustainable agriculture does not deplete soils or people.” – Wendell Berry cover crops

17. Fertilizers “Organic” fertilizers – manure, compost, fishmeal “Chemical” fertilizers – commercially manufactured – N-P-K (ex. 15-10-5) 15% nitrogen 10% phosphorus 5% potassium What are the political, economic, environmental issues?

18. Nitrogen uptake Nitrates – plants can only take up nitrate (NO 3 - ) Nitrogen cycle by bacteria – trace path of nitrogen fixation! What will the plant use N for? root

19. Soybean root nodules N fixation by Rhizobium bacteria – symbiotic relationship with bean family (legumes)

20. Increasing soil fertility Cover crops – growing a field of plants just to plow them under usually a legume crop taking care of soil’s health – puts nitrogen back in soil erosion control, too A farmer… outstanding in his field? Plow it under? Why would you that?

21. 2006-2007 Some plant oddities…

22. Parasitic plants tap into host plant vascular system Indian pipe Mistletoe

23. Plants of peat bogs High acid environment – most minerals & nutrients bound up & are not available to plants must find alternative sources of nutrients

24. Carnivorous plants Are they really carnivores? Pitcher plantVenus fly trap Sundew

25. Pitcher plant

26. Uses of peat

27. Any Questions??

28. Review Questions

29. 1. The inorganic compound that contributes most of the mass to a plant’s organic matter is * A.H 2 O. B.CO 2. C.NO 3 2. D.O 2. E.C 6 H 12 O 6.

30. 2. You are conducting an experiment on plant growth. You take a plant fresh from the soil and it weighs 5 kg. Then you dry the plant overnight and determine the dry weight to be 1 kg. Of this dry weight, how much would you expect to be made up of inorganic minerals? A.50 grams B.500 grams C.1 kg D.4 kg E.5 kg

31. This figure shows the results of a study to determine the effect of soil air spaces on plant growth. Use these data to answer the following question.

32. 3. The best explanation for the shape of this growth response curve is that A.the plant requires air in the soil for photosynthesis. B.the roots are able to absorb more nitrogen (N 2 ) in high levels of air. C.most of the decrease in weight at low air levels is due to transpiration from the leaves. D.increased soil air produces more root mass in the soil but does not affect the top stems and leaves. E.the roots require oxygen for respiration and growth.

33. 4. Carnivorous plants have evolved mechanisms that trap and digest small animals. The products of this digestion are used to supplement the plant's supply of A.energy. B.carbohydrates. C.lipids and steroids. D.minerals. E.water.