Transcript PLANT NUTRITION - Falmouth Schools

Plant Nutrition
Chapter 37
• Uptake of nutrients happens in
roots and leaves.
• Roots, through mycorrhizae and
root hairs, absorb water and
minerals from soil.
• Essential nutrient required for
plant to grow from seed and
complete life cycle.
• Macronutrients needed in large
numbers; micronutrients are not.
• Texture, pH, composition of soil
determines types of plants that
grow in area.
• Soil may be acidic or basic because
of minerals that absorb in soil.
http://eppftpserver.ag.utk.edu/profiles/tobacco/diseases/tob-pH-2.jpg
• Soil made of topsoil - mixture of
rock, living organisms, and humus
(residue of partially decayed
organic material)
• Can be washed away by water,
robbing soil of important nutrients.
• Plants cannot use nitrogen in form
of N2.
• Bacteria, nitrogen-fixing bacteria,
convert N2 to NH3 (ammonia), via
nitrogen fixation.
• Roots also form symbioses with
organisms; relationships that are
helpful to both species.
• Legume’s roots have swellings called
nodules - plant cells that contain
nitrogen-fixing bacteria.
• Crop rotation increases amount of
nitrogen in soil.
• Farmers do this so nitrogen-rich
plants (legumes) can add nitrogen to
different soil areas.
• Mycorrhizae - modified roots, made
of symbiotic relationships between
fungi and roots.
• Fungus increases surface area for
water uptake, secretes growth
factors that stimulate roots to
grow and branch, and produces
antibiotics.
• Mycorrhizae - hyphae - help
increase surface area; also invade
cells by digesting cell wall.
http://www.plantpath.wisc.edu/tddl/tddl/disimg/bp/hyphae.jpg
• Some plants - parasites - will not
photosynthesize.
• Tap into other plants that do.
• Epiphytes (orchids) - not parasitic;
grow on other plants.
• Some plants evolved modified
leaves that trap insects.