Plant Nutrition Powerpoint adopted from: Powerpoint%2520files/35Ch37PlantNutrition2005a.pdf+ap+biology+plant+nutrition&hl=en&ct=clnk&c d=2&gl=us&lr=lang_en&client=safari Powerpoint%2520files/35Ch37PlantNutrition2005a.pdf+ap+biology+plant+nutrition&hl=en&ct=clnk&c d=2&gl=us&lr=lang_en&client=safari

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

Essential Elements  Macro nutrients (needed in relatively large amounts)  Carbon (C)  Oxygen (O)  Hydrogen (H)  Nitrogen (N )  Phosphorous (P)  Sulfur (S)  Potassium (K)  Calcium (Ca)  Magnesium (Mg)  Micro nutrients (needed in very small amounts)  Chlorine  Iron  Manganese  Boron  Zinc  Copper  Nickel  Molybdenum

Nutrient Deficiency  Lack of essential nutrients  Exhibit specific symptoms  Dependent on function of nutrient  Dependent on solubility of nutrient

Water and mineral uptake  Water uptake  Plants cannot extract all water from soil, only free water  osmosis  Cation uptake  Cation uptake is aided by H+ secreation by root cells (proton pump)  Active transport

The Role of Soils  Plants are dependent on soil quality  Texture/structure  Relative amounts of various sizes of soil particles  Composition  Organic and inorganic chemical component  Fertility

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 and fungi  Improves soil texture  Reservoir of minerals

Importance of organic matter, cont.  Topsoil, cont.  Organisms  1 teaspoon of topsoil has 5 billion bacteria living with fungi, algae, protists, insects, earthworms, and nematodes

Soil health as a global issue  Lack of soil conservation  Growing wheat  Raising cattle  Land exposed to wind erosion  Drought  Soil conservation and sustainable agriculture  Maintaining healthy environment  Production of food supply  Economically viable farming industry

Global Issues  Fertility  Erosion  Irrigation  Forestry destruction

Fertilizer  “Organic” fertilizers  Manure, compost, fishmeal  “Chemical” fertilizers  Commercially manufactured  N-P-K ratio

Irrigation  Most often the limiting factor in plant growth  Issues  US rivers reduced to trickles by diversions of water  Soil becomes salty and infertile

Erosion  Topsoil - lost to water and wind erosion  Precautions  Trees as windbreaks  Hillside crops  Contour pattern  Sustainable Agriculture

Soil Reclamation  Removal and storage of contaminated soils  New method: phytoremediation  Biological, nondestructive  cheap

Nitrogen Fixation Atmosphere Soil N 2 (gas) Nitrogen-Fixing Bacteria NH3 (ammonia) Organic material (humus) Ammonifying Bacteria NH4+ (ammonium) H+ (from soil) Root Nitrifying bacteria Denitrifying bacteria NO3- (nitrate) NH4+

Soybean Root Nodule  N fixation by Rhizobium bacteria  Symbiotic relationship between nitrogen-fixing bacteria and legumes  Bacteroids inside nodules form

Mycorrhizae and Plant Nutrition  Symbiotic relationship  Mycorrhizal fungus gets sugars from the plant  In return, mycorrhizal fungus provides better absorption of water and minerals for the plant  Ectomycorrhizae versus Endomycorrhizae

Unusual Adaptations  Epiphytes  Grows on branches and trunks of trees  Staghorn ferns, orchids  Parasitic Plants  Absorbs sugars and minerals from living hosts  Mistletoe, dodder, and Indian pipes

 Carnivorous Plants Carnivorous Plants  Photosynthetic, but obtain minerals and nutrients by killing insects and other small animals  Venus’ flytraps, pitcher plants, sundews