Seed

A seed serves as the reproductive unit in flowering plants, including cannabis, encapsulating the genetic potential for a new plant. In cannabis cultivation, seeds are critical for breeding various strains, offering a range of characteristics such as potency, flavor, and growth habits. Seeds can be feminized to ensure the growth of female plants, which produce the cannabis flowers used for medicinal and recreational purposes.

Seed Evolution and Development

• First land plants evolved around 468 million years ago
• Gymnosperms appeared during the late Devonian period (416-358 million years ago)
• Seed ferns evolved during the Carboniferous period (359-299 million years ago)
• Seed plants dominate land niches
• Ferns, mosses, and liverworts do not have seeds
• Angiosperm seeds are enclosed in fruits for protection
• Gymnosperms develop seeds naked on bracts of cones
• Angiosperm seeds consist of embryo, endosperm, and seed coat
• Double fertilization initiates seed development in angiosperms
• Endosperm provides food for the young plant after germination

Seed Structure – Ovule and Embryo

• Components of an ovule include funicle, nucellus, micropyle, and chalaza
• Ovule shapes affect final seed shape
• Zygote’s first division establishes embryo polarity
• Suspensor absorbs nutrients from endosperm for embryo growth
• Ovules develop into seeds after fertilization
• Components of an embryo include cotyledons, epicotyl, plumule, hypocotyl, and radicle
• Cotyledons are seed leaves and a nutrient source
• Epicotyl becomes the shoot upon germination
• Hypocotyl is the stem-root transition zone
• Monocotyledons have additional structures like coleoptile and coleorhiza

Seed Coat Formation and Characteristics

• Seed coat forms from integuments of the ovule
• Seed coat may have patterns, textures, wings, or tufts of hair
• Monocot and dicot seed coats may be distinct or fused with fruit wall
• Seed coat is derived from tissue of the mother plant
• Testa is the outer layer of the seed coat that protects the seed

Seed Shape and Appearance

• Seeds vary greatly in shape and appearance
• Different terms are used to describe seed shapes (e.g., Reniform, Square, Triangular, Elliptic)
• Seeds can also be described based on color, texture, and form
• Surface textures range from highly polished to considerably roughened

Gymnosperms and Seed Composition

• Gymnosperms do not form ovaries
• Ovules and seeds are exposed in gymnosperms
• Coniferous plants like pine and spruce have cones around the seed
• Double fertilization does not occur in gymnosperms
• Seeds consist of the embryo and tissue from the mother plant
• In coniferous plants, a cone forms around the seed
• Gymnosperm seeds are not enclosed in ovaries

Seed Data Sources