CRSCI 3300 PART II

Plant Nutrition (Plant symptoms and toxicity)

Cannot complete life cycle without it
Function is non-replaceable
Direct role in metabolism

What are the three criteria of essentiality for a mineral element?

Arnon and Stout (1939).

Who proposed the criteria of essentiality for plant nutrients?

Carbon = 45%, Oxygen = 45%.

What percentage of plant dry matter is Carbon and Oxygen each?

CO₂, H₂O, O₂.

What are the three basic requirements for plant growth besides minerals?

Hydrogen (H⁺).

Which nutrient forms part of cell wall acidification for cell enlargement?

Needed to synthesize leucine, isoleucine, and valine via ALS gene.

What is nitrogen’s role in amino acid synthesis?

General chlorosis starting in older leaves.

What are symptoms of nitrogen deficiency?

Excessive vegetative growth, delayed flowering.

What symptoms appear with nitrogen toxicity?

The backbone (sugar-phosphate).

What compound contains phosphorus in DNA?

Purple discoloration of leaves, poor root development, stunted growth, poor fruit/seed set.

What are symptoms of phosphorus deficiency?

Delays maturity.

How does phosphorus deficiency affect plant maturity?

Translocation and stomatal regulation.

What two major functions does potassium serve?

Over 40 enzymes.

Potassium acts as a co-factor for how many enzymes?

Leaf edge necrosis, weak stems, poor drought resistance.

What are symptoms of potassium deficiency?

Serine, cysteine, methionine.

Which amino acids contain sulfur?

Uniform chlorosis of young leaves, stunted growth.

What are signs of sulfur deficiency?

Chlorophyll.

What molecule is magnesium central to

Interveinal chlorosis in older leaves.

What symptom indicates magnesium deficiency?

Cell wall.

Calcium is a component of which plant structure?

Acts as a secondary messenger under stress.

What is calcium’s signaling role?

Tip burn in young leaves, blossom end rot in fruits, root death.

What are symptoms of calcium deficiency?

Involved in chlorophyll synthesis.

What is iron’s role in photosynthesis?

Essential for electron transport in mitochondria.

What is iron’s role in ATP synthesis?

Young leaves (interveinal chlorosis).

Where does iron deficiency show symptoms?

Brown spots from leaf tip to base.

What does iron toxicity look like in rice?

Nitrogen assimilation.

Molybdenum is critical for what process?

Older leaves.

Where do molybdenum deficiency symptoms appear first?

Cell wall formation and reproduction.

What are boron’s primary functions?

Poor flower and fruit development.

Boron deficiency leads to what reproductive symptom?

Growth reduction, chlorosis in mature leaves, wilting, root damage.

What are signs of copper toxicity?

Dieback of stems and twigs, leaf deformation.

What are symptoms of copper deficiency?

Important for enzyme activity and growth hormones.

What is zinc’s role in plant development?

Zinc deficiency symptoms

Short internodes (rosetting), distorted leaves, interveinal chlorosis.

Enzyme activation and photosynthesis.

What is manganese’s function?

Manganese deficiency

Interveinal chlorosis and necrotic spots.

Osmotic and ionic balance.

chlorine’s role?

Wilting, leaf bronzing, and reduced growth.

Deficiency of chlorine leads to?

Mobile nutrients (N, P, K, Mg, Mo).

Which deficiencies show first in older leaves?

Immobile nutrients (Ca, S, Fe, B, Cu, Mn, Zn).

Which deficiencies appear first in young leaves?

Phosphorus deficiency.

Purple leaves + poor roots = ?

Iron or manganese deficiency.

Interveinal chlorosis in young leaves

Nitrogen or magnesium deficiency.

Chlorosis in older leaves = ?

Potassium deficiency.

Leaf tip necrosis = ?

Boron deficiency.

Poor fruit development = ?

Calcium deficiency.

Blossom-end rot = ?

Zinc deficiency.

Leaf rosetting (short internodes) = ?

Solvent, transport, photosynthesis substrate.

What does water contribute to in plant metabolism?

Reduced ATP, anaerobic respiration.

What happens under low O₂ availability?

Copper toxicity.

What causes whitening between leaf veins in toxicity?

C, H, O.

What are the 3 most abundant elements in plants?

Carbon, Hydrogen, Oxygen.

What nutrients make up over 90% of plant dry matter?

Nitrogen

What is the most limiting nutrient in most soils?

Molybdenum.

What micronutrient has the smallest required concentration?

Deficiency.

Which is more common: nutrient deficiency or toxicity?

Over-fertilization or poor drainage.

What typically causes nutrient toxicity?

Iron.

Which nutrient aids ATP synthesis?

Sulfur.

What nutrient is needed for protein synthesis?

K, Mn, Zn, Mg.

Which nutrients are involved in enzyme activation?

Phosphorus.

What nutrient is required for DNA synthesis?

Sulfur.

Nutrient associated with Ferredoxin?

Potassium.

Nutrient linked to stomatal control?

Magnesium, Iron.

Nutrient needed for chlorophyll synthesis?

Calcium.

Nutrient that triggers stress signaling?

General chlorosis.

What symptom does Mo deficiency share with N deficiency?

Hydrogen.

What nutrient helps in sucrose-proton co-transport?

Phosphorus.

What element causes DNA mutations if deficient?

Molybdenum.

Which element’s deficiency can impair nodulation in legumes?

Leaf burn and necrosis.

What indicates Cl toxicity?

Interveinal chlorosis.

What is the common early symptom of multiple micronutrient deficiencies?