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Pine embryo female gametophyte female gametophyte cotyledons

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Capsella embryo seed coat endosperm tissue seed coat (endosperm tissue is in the light area below the seed coat) epicotyl root cap hypocotyl-root axis cotyledons seed coat endosperm tissue

 

Plants are placed into two simple kingdom subsections: nonvascular and vascular plants. The big distinction between the two groups is that vascular plants have vascular_tissues: tissues that conduct water and dissolved food in the plant body. The vascular tissues include xylem, which moves water and minerals upward through the plant and phloem, which moves dissolved food downward in the plant.

Nonvascular plants lack these tubes, and therefore must be small and thin so that each cell can acquire its needed materials via passive_transport from the plant's surface, or from other cells within the plant that are located near the surface.

Regardless of whether a plant is vascular or nonvascular, it has structures that (1) anchor it into the soil, (2) provide physical support for its photosynthetic structures, and (3) specialize in performing photosynthesis.

Highly developed vascular systems allow the production of an effective adult plant body, with sufficient reserves to allow the investment in specialized body structures used for reproduction. Good vascularization also provides for structures used to enhance dispersal of the gametes and/or zygotes (fertilized eggs).

All Gymnosperms are perennial and many live for centuries. Oldest known living organism is the bristlecone_pine (Pinus_aristata) in the mountains of California. It is approximately 5,000 years old. Most Gymnosperms are trees, but a few are shrubs and vines. Their ovules develop within a cone, which is known as a strobilus. Gymnosperms differ from Angiosperms, in part because their ovule (which becomes the seed) is not enclosed by the tissue of the sporophyll.

These pine embryo sectiond show the remains of the megasporangium , as well as a well-developed embryo. Locate the female gametophyte (reproductive tissue), cotyledons (first embryonic leaves), epicotyl (first stem), hypocotyl (first root), apical_meristem (region of rapid stem growth), and root_meristem (area of rapid root growth).

cotyledons (first leaves),

epicotyl (first stem),

endosperm (food storage tissue),

hypocotyl (first root),

root_cap (physical protection for the developing root tip) and

seed_coat (physical protection for entire seed).