Seed: Tomato seeds are small, flat and disk shaped and about 1/8 inch wide. They contain two energy storage organs called cotyledons and an embryo encased in a hard outer shell called the seed coat. The seed is the dormant or resting stage of the plant life cycle. When young tomato plants are damaged, they tend to go into a dormant, survival stage in which plant growth is delayed for a while. Frost damage is something to look out for when planting tomatoes early on in the season. Frost damage is marked by tender, dark green spots on the leaves. Although they won't kill the plant, frostbites will make them dormant for a while, delaying plant growth. During the germination process, the seed absorbs moisture and nutrients from the soil and begins to form the plant. When the seed coating reaches full capacity, it breaks open and reveals the root, also known as the radicle, which emerges deep into the soil. As the radicle grows downward, the cotyledons form the plumule, which contains the stem and first leaves of the tomato plant. Tomatoes respond well to warm temperatures. The minimum temperature for seed germination is 10°C with a maximum temperature of 35°C and an optimum range of 17°C to 20°C.
a) Primary Root: to anchor the plant to a substrate, to absorb water and dissolved minerals, and to store food reserves. b) Lateral Root: Lateral roots extend horizontally from the primary root and serve to anchor the plant securely into the soil. This branching of roots also contributes to water uptake, and facilitates the extraction of nutrients required for the growth and development of the plant. c) Root Hairs: a fine growth from the outer cells of a plant root that resembles a hair and absorbs nutrients. Root hairs are elongated epidermal cells that increase the surface area of roots to improve absorption of water and minerals. d) Root Tip: Part of the plant which grows in the opposite direction from the...
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