Plant Biology and Nutrition: Photosynthesis, Growth Stages, and Fertilization

Phototrophic

Plants are phototrophic: they capture light and perform photosynthesis.

Heterotrophic

Animals are heterotrophic: they obtain energy by consuming organic matter.

Energy loss in trophic levels

Energy is lost at each trophic level.

Carl von Linné

1707-1778: Swedish physician & naturalist; 'father of modern taxonomy'. Created binomial names for plants (genus + species), e.g., Betula pubescens.

Botany

The study of plants: morphology, phenology, and ecology.

Photosynthesis

Conversion of light energy → chemical energy stored in sugars.

Primary metabolites

Primary metabolites: growth and reproduction (e.g., sugars, amino acids, nucleotides).

Secondary metabolites

Secondary metabolites; not directly for growth/reproduction, roles in plant defence and responses to abiotic/biotic stress (e.g., phenolics, alkaloids, terpenoids, carotenoids).

BBCH scale

Classification of growth stages: 0: Germination, sprouting, bud development; 1: Leaf development; 2: Formation of side shoots, tillering; 3: Stem elongation or rosette growth, shoot development; 4: Development of harvestable vegetative plant parts, bolting; 5: Inflorescence emergence, heading; 6: Flowering; 7: Development of fruit; 8: Ripening or maturity of fruit and seed; 9: Senescence, beginning of dormancy.

Vegetative stage

Accumulation of resources (carbohydrates, nutrients) prepares the plant for the reproductive phase.

Generative stage

Primary production (leaf/stem growth) slows; accumulated resources are allocated to flowering and seed set.

Tropisms

Tropism = directional growth response to a stimulus (toward = positive; away = negative).

Morphology

The form and structure of plants.

Phenology

The timing of recurring biological events (budburst, flowering, fruiting, leaf fall) and how these are influenced by climate and weather.

Ecology

The interactions among organisms and between organisms and their environment (abiotic factors like soil, water, climate; biotic factors like pests, pollinators, microbes).

Biotic factors

Living factors.

Abiotic factors

Nonliving factors.

Liebig's law

Macronutrients in soil: Nitrogen, Phosphorus, Sulphur, Potassium, Calcium, Magnesium.

Micronutrients

Boron, Copper, Iron, Manganese, Molybdenum, Zinc, Chlorine.

Soil properties

Differences in soil composition, drainability, variation in pH due to different application rates.

Liming

The need for liming to improve soil properties.

Mineral vs. manure

Differences in workload, investment needs, continuous cost, and control of quality.

Nutrient absorption

Define its absorption in plants, the nutrient bound to soil particles, how a farmer may apply it, how the nutrient limits plant growth, and how pH affects overall plant uptake.