Plant Vocabulary & Bryophytes

Plant Vocabulary and Definitions

• Vasculum: A vessel or duct.
• Trachea: The windpipe.
• Phyton: Refers to a plant.
• Bryton: Refers to moss.
• Sporophyte: The structure that produces haploid spores through meiosis.
• Extant: Currently living.
• Phloem: Plant tissue that conducts food manufactured by leaves.
• Xylem: Plant tissue that conducts water and minerals.
• Gametophyte: Produces haploid gametes through mitosis.
• Archegonia: Female gametangia that produce egg cells.
• Zygote: A fertilized egg, which is diploid.
• Thalli: Flattened, leaf-like photosynthetic structures.
• Antheridia: Male gametangia that produce sperm cells.
• Rhizoids: Root-like structures that anchor the plant.
• Bryophytes: Plants lacking vascular tissue.
• Tracheophytes: Plants possessing vascular tissue.

Bryophytes

• Marchantia, a liverwort, belongs to the Bryophytes/non-vascular plant division.
• In bryophytes, the gametophyte generation is conspicuous and dominant, while the sporophyte generation is nutritionally dependent on the gametophyte.
• The developing zygote of a bryophyte will develop into the mature diploid sporophyte generation.

Gymnosperms

• Most conifers are monoecious, producing both micro and megasporangiate cones on the same tree.
• Pinecones become woody and brown in late summer or fall.
• Completion of the conifer life cycle requires two growing seasons.
• Gymnosperms are primarily distinguished by naked seeds.
• Living genera of non-coniferous gymnosperms are often referred to as living fossils.
• Microsporangium produce pollen, and megasporangium produce female gametophytes.
• Strobili are the reproductive structures in gymnosperms, often referred to as cones.
• An ovule is considered an immature seed.
• The seed provides protection, water, food, and a means for dispersal.

Roots

• In a dicot root, the vascular cambium layer lies between xylem and phloem.
• The meristematic region of the root tip has small undifferentiated cells.
• The elongation region of the root tip has large undifferentiated cells.
• The maturation region of the root tip has differentiated cells.
• Root hairs are extensions of mature epidermal cells, increasing the surface area for water uptake.
• Monocot roots do not possess a vascular cambium layer and generally do not increase in diameter annually.
• Vascular tissue is located directly in the center of a dicot root.
• The root cap is a protective sheath over the end of a rootlet.
• The apical meristem produces the root cap as it generates unorganized cells in the direction of root growth.
• The cortex, the largest region of a root, is made up of parenchyma tissue.
• The endodermis limits the pathway used by minerals and nutrients into the vascular tissues.
• The stele is the central vascular cylinder of a root cross-section.
• The pericycle, the outermost layer of the stele, produces secondary lateral roots.
• Most dicot roots possess xylem in the center of the stele with radiating arms projecting from the center.
• Pith is located directly in the center of a monocot root.

Stems

• A vascular bundle is a group of xylem and phloem in a ring.
• Phloem conducts food (glucose).
• Xylem conducts water and minerals.
• Ground is the central region of a monocot stem.
• Ground tissue is composed of parenchyma tissue.
• The bundle sheath is composed of sclerenchyma/parenchyma tissue.
• In herbaceous dicot stems, the vascular bundles are arranged in a ring.
• The vascular cambium layer separates the xylem and phloem in herbaceous and woody dicot stems.
• There is no vascular cambium layer in monocot stems.
• The central region of a dicot stem is the pith.
• The region of a dicot stem away from the central pith is the cortex.
• The vascular tissues of woody dicot stems are arranged in cylinders.
• Lenticels are areas of tissue in a stem that allow gas exchange between the atmosphere and stem tissues.
• The pith region of a woody stem continually gets smaller as new xylem and phloem are formed each year.
• As a woody dicot stem matures, xylem hardens and becomes wood.

Leaves

• Xylem cells transport water and minerals.
• Phloem cells transport food produced by leaves.
• The cells of the upper epidermis are covered by a waxy non-cellular layer that is cut in.
• The mesophyll region consists of the palisade and spongy layers of photosynthetic parenchyma.
• The palisade and spongy layers are composed of parenchyma tissue.
• The palisade layer lies just below the upper epidermis.
• Pairs of small specialized epidermal cells called guard cells flank either side of openings called stomata.
• Stomata allow gas exchange between the leaf and the external environment.
• When guard cells are turgid, the stomata is open.
• Dicot leaves generally possess stomata only on the lower epidermis.

Flowers

• Perianth is the collective term for all sepals and petals.
• Stamens are the male organs of the flower.
• Carpels are the female organs of the flower.
• Pollen is found within the anther at the top of the stamen.
• The ovary is the swollen base of a carpel.
• Pollen sticks to the stigma at the top of a carpel.
• The unfertilized seeds within the ovary are called ovules.
• The sepals collectively make up the calyx.
• The petals are collectively called the corolla.
• The part of the ovary to which the ovules attach is the funiculus.
• The space where ovules are found is known as the locule.
• The pollen tube grows down through the microphyle, the neck of the carpel
• The generative cell and tube nucleus are found in a pollen grain.
• The function of the corolla is to attract pollinators.
• Pistil refers to the female sex organ composed of carpels, while carpels are sections within the pistil.
• Double fertilization is when two sperms fertilize in the seed, one fertilizes the egg to form the embryo, and the other provides nutrients for the embryo.