Index value Frequency

Soil and mineral nutrition Soil is a complex product of the interaction between living organisms and their terrestrial environment Soils are very heterogeneous Soil texture describes the relative contribution of particle with different sizes that impart different characteristics and affect plant performance

Most plants depend on soil to obtain water and mineral nutrition The pH of soil is an important characteristic that affects nutrient intake Essential nutrients are indispensable for plant growth and reproduction Most plants depend on mycorrhizae (symbiotic relationships with fungi) to increase phosphorus and other minerals from the soil

taproot Fibrous root enlarging radicle, or embryonic root Adventitious roots (develop from stems) Stem x.s. of Lycopersicon (tomato)

Contain suberin, a fatty waterproof material Water enters by osmosis Nutrient minerals enter by passing through carrier proteins in the membranes

Root x.s. of Zea mays (corn) Epidermis Cortex cell Endodermis Pericycle cell Pith cell Xylem vessel element Phloem cell

Soil is composed of Inorganic mineral particles Organic matter Water Air The texture, or structural characteristic of a soil is determined by the percentages (by weight) of the different- sized inorganic mineral particles -sand ( mm), silt ( mm), and clay (<0.002 mm), -

A loam: 40 % sand, 40 % silt, and 20 % clay

Igneous rocks

Metamorphic rocks

Sedimentary rocks

Elements required by plants (macronutrients, >0.05% dry weight) Table 34-2 pp. 744

Elements required by plants (micronutrients, <0.05% dry weight) Chlorine, Iron, Boron, Manganese, Sodium, Zinc, Copper, Nickel, Molybdenum Parts of enzymes and Ionic balance. Table 34-2 pp. 744

Plant proteinsAnimal proteins Nitrogen wastes Ammonium NH 4 Ammonia Loss to Atmosphere Nitrites, NO 2 Nitrates, NO 3 Nitrogen fixing bacteria, Azotobacter (ae) and Clostridium (an) Gain from atmosphere Nitrifying bacteria Denitrifying bacteria e.g. Nitrobacter Denitrifying bacteria e.g. Nitrosomonas Decay bacteria and Fungi The Nitrogen Cycle

Endophytes: Legume/Rhizobium nodules Leghaemoglobin sequesters oxygen and creates a low oxygen environment

Above: Ectomycorrhyzae Below: Endomycorrhyzae MOORE-LANDECKER FUNDAMENTALS OF THE FUNGI. PRENTICE HALL. ENGLEWOOD CLIFFS. Pp. 481, fig. 15-9; 483, fig Occurs in 90 % of all plant families

Total mass (g) of mycorrhyzae present absent Andropogon gerardii Sorghastrum nutans Wilson and Hartnett. American Journal of Botany 84 No, 4, 1997

Arbuscular Mycorrhizae

Cross-section of Ranunculus root (buttercup) immature Mature epidermis stele cortex Notice numerous amyloplasts which store starch

Close up of Cross-section of Ranunculus root immature Mature Cortex cells Endodermis cells Pericycle cells Phloem cells Xylem vessel element Intercellular spaces

Cation exchange

Neutral pH near 7 Acid pH, 4-5