Chapter 37: Plant nutrition

Humus

Humus

Remains of dead organisms and other organic material

Topsoil

Mixture of derived materials from humus and inorganic materials

Soil horizons

Soil layers with characteristics that differ from those above it

Soil horizons A

Topsoil

Soil horizons B

Less organic material

Soil horizons C

Broken down rock

Organic chemicals

Chemical compounds containing carbon

Inorganic chemicals

Chemical compounds that don’t contain carbon

Leaching

Slow movement of water through pores in the soil or permeable rock

Anion

Negatively charged atom

Cation

Positively charged atom

Streptomyces

Found in soil, used to develop antibiotics; gram positive

Fertilization

Addition of minerals and nutrients in the soil, allows for soil renewal

Crop rotation

Growing an array of crops in the same area across different seasons in order to prevent soil destruction

Sustainable agriculture

Long-term farming practices that are environmentally friendly

Nitrifying bacteria

Bacteria that oxidize ammonium to nitrite and then nitrite to nitrate which is absorbed by plants

Denitrifying bacteria

Bacteria that reduce nitrate to nitrite

Inorganic fertilizers

Contain the direct minerals needed

N-P-K ratio

the ratio of nitrogen, phosphorous, and potassium in fertilizers, written on bag

Organic fertilizers

Contain biological waste or products that contain the minerals needed, must be broken down first

pH

The concentration of protons in a solution

Citrate synthase

An enzyme that synthesizes citric acid which increases aluminum resistance

Phytoremediation

A type of bioremediation that relies on the ability of select plants to remove pollutant from the soil

Bioremediation

introduction of microorganisms or other organisms to break down pollutants in soil

Thlaspi caeruescens

Plant that can accumulate zinc 300x higher than most plants can tolerate

Essential elements

CHNOPS

Hydroponic cultures

Plants grown in water infused with vital minerals and nutrients instead of soil, can be used to test which nutrients are essential

Macronutrients

Nutrients that are required in large amounts

Micronutrients

Nutrients that are required in small amounts

Enzyme cofactors

A substance that helps enzymes in their functions

Mutualism

relationship in which both parties benefit

Rhizobacteria

Bacteria that live in or near plant roots

Rhizosphere

Area close to plant roots where bacteria live

Mycorrhizae

Symbiotic relationship of a fungus and plant roots; different kinds

Nitrogen cycling

Series of steps where nitrogen containing compounds are cycled through the soil, organisms, and the air

Ammonia

NH3

Ammonium

NH4+

Nitrate

NO3

Nitrite

NO2

Nitrogen gas

N2

Nitrogen fixing-bacteria

Bacteria that capture Nitrogen from the air and reduce it to ammonia

Nitrogen fixation

The conversion of atmospheric nitrogen to a form of nitrogen usable by plants

Nitrogenase

Enzyme responsible for nitrogen fixation

Ammonifying bacteria

Bacteria that convert amino acids in the soil into ammonium

Rhizobium

Root living bacteria found in legumes

Nodules

Swellings in the roots of legumes where rhizobium live

Epiphytes

Plants that grow on other plants, do not tap into vascular system, produces own nutrients

Parasitic plants

Plants that absorb nutrients from other plants

Carnivorous plants

Plants that a photosynthetic and supplement their diet with insects and other small organisms

How does the nitrogen cycle work

Nitrogen (N2) is oxidized to NH3 by nitrogen fixing bacteria. NH3 is then taken up by nitrifying bacteria to produce NO3 which is absorbed by plants. NO3 is then taken up by denitrifying bacteria that release it back into the air as N2