Plant Nutrition and Growth

Vocabulary based on Chapter 36 lecture notes regarding plant nutrients, soil profiles, nutrient uptake mechanisms, and symbiotic or parasitic relationships.

Jean-Baptiste von Helmont

A scientist in the early 1600's who conducted a 5-year experiment with a willow sapling and soil to determine that plant mass does not come from soil.

Major Components of Dry Mass

Carbon ($45\%$), Oxygen ($45\%$), and Hydrogen ($6\%$), which together make up $96\%$ of a plant's dry mass.

Essential Macronutrients

Six elements required in amounts between $0.1\%$ and $1.5\%$ of a plant's dry mass: Nitrogen, Potassium, Calcium, Phosphorus, Magnesium, and Sulfur.

Chlorophyll

A molecule critical for photosynthesis that requires Nitrogen and Magnesium as part of its structure.

Potassium ($K^+$)

A macronutrient required for protein synthesis and the regulation of opening and closing stomata.

Nitrogen Deficiency

A condition resulting in generally stunted, yellow plants, as Nitrogen is key for amino acid, nucleic acid, and chlorophyll production.

Phosphorus Deficiency

A condition resulting in developmentally slow and stunted plants, as Phosphorus is key for nucleic acids, ATP, and phospholipids.

Potassium Deficiency

A condition resulting in curled, necrotic leaves, as Potassium acts as an enzyme coactivator and is necessary for protein synthesis.

Essential Micronutrients

Eight elements required in very small amounts ($<0.01\%$ dry weight): Chlorine, Iron, Manganese, Zinc, Boron, Copper, Nickel, and Molybdenum.

Clay

The smallest soil particle size, categorized as being less than $0.002\,mm$.

Humus

Organic matter in the topsoil combined with animals, fungi, protists, and bacteria.

Leaching

The process where negatively charged ions, which do not bind to clay or organic matter, stay in solution and are easily washed away.

Symporter

A type of cotransporter used in active transport to bring ions into or out of a plant cell against a concentration gradient.

Active Exclusion

The use of active transport, such as $H^+/Na^+$ antiporters, to remove toxins or sequester them in vacuoles.

Nitrogen Fixation

A symbiotic relationship between legumes and bacteria that converts atmospheric $N_2$ into ammonia ($NH_3$) for amino acid building.

Arbuscular Mycorrhizae

A mutualistic symbiotic relationship where fungal hyphae penetrate the outer cells of the plant root; found in approximately $85\%$ of plant families.

Ectomycorrhizae

A symbiotic relationship where fungal hyphae surround and go between plant cells but do not penetrate the cell walls; usually associated with trees.

Indian Pipe

A non-photosynthetic parasitic plant that obtains its carbon by parasitizing nearby plants via their mycorrhizae.

Haustoria

Structures in parasitic plants like mistletoe that penetrate the host plant's xylem to obtain nutrients.

Carnivorous Plants

Plants that live in nutrient-poor, Nitrogen-limited environments and trap insects using tubular traps (pitcher plants) or sticky secretions (sundews).