Factors Influencing Growth

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Germination Noun

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[jur-mi-nay-shun]

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Germination

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The process where a seed activates, the root emerges, and then the shoot emerges to begin its growth cycle.

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Example: This diagram shows the stages of germination, where a seed sprouts a root (radicle) and shoot (plumule) to grow into a new plant.

Front

Dry mass Noun

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[dry mass]

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Dry mass

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The mass of a plant after all water has been removed, used for consistent and accurate growth comparisons.

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Example: This image shows that a plant, like alfalfa, is made of water and dry matter, which contains all the nutrients like protein and fiber.

Front

Gene Noun

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[jeen]

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Gene

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A specific section of DNA that contains the instructions for building a protein or controlling a particular trait.

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Example: This image shows that a gene is a specific section of a DNA molecule, which is found inside a chromosome within a cell's nucleus.

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Allele Noun

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[uh-leel]

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Allele

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A specific version or alternative form of a gene, which can result in different observable traits in an organism.

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Example: This image shows an allele is a specific version of a gene, like 'A' or 'a', located at the same spot on a chromosome.

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Polygenic Adjective

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[pol-ee-jen-ik]

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Polygenic

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Describing a trait that is influenced by the combined effect of multiple genes rather than just a single gene.

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Example: This graph shows how a polygenic trait like height creates a continuous range, where most people are average height and fewer are very short or very tall.

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Dominance Noun

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[dom-i-nans]

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Dominance

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A genetic principle where one allele for a specific trait masks the observable effect of another allele.

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Example: A dominant allele (A) on one chromosome determines a trait, masking the effect of a recessive allele (a) on the other chromosome.

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Photoperiod Noun

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[foh-toh-peer-ee-ud]

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Photoperiod

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The duration of an organism's daily exposure to light, which influences growth rhythms and the timing of flowering.

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Example: This diagram shows that a short-day plant flowers only when the period of uninterrupted darkness is longer than a critical length (16 hours).

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Phototropism Noun

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[foh-toh-troh-piz-um]

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Phototropism

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The directional growth of a plant in response to a light source, typically causing the shoot to bend towards it.

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Example: This image shows a plant bending its stem and leaves toward a light source, which is the definition of phototropism.

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Transpiration Noun

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[tran-spuh-ray-shun]

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Transpiration

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The process of water movement through a plant and its evaporation from leaves, aiding in cooling and nutrient transport.

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Example: This diagram shows water being pulled up from the roots, through the stem, and evaporating as water vapor from the leaves into the air.

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Macronutrients Noun

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[mak-roh-noo-tree-ents]

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Macronutrients

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Essential chemical elements required in large amounts for plant growth, such as nitrogen, phosphorus, and potassium.

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Example: This image shows the three types of macronutrients—carbohydrates, proteins, and fats—and gives examples of common foods that are primary sources for each.