Labs 2 & 3 Flashcards
what functions do stems provide for a plant?
- support: stems provide the axis upon which leaves, buds, and flowers form. This elevates the leaves for photosynthesis, flowers for pollen release, and fruits for seed release.
- transport: stems are a pathway for the movement of water and mineral nutrients from roots to leaves and the transport of sugar, hormones, and other metabolites from one area of the plant body to the other
- growth: new cells are produced by mitosis occurring primarily in the shoot apical meristem, housed in the shoot tips of the plant
- storage: stems store water, food, and other plant products that may be required in different areas of the plant body at different times during the year
what is the purpose of many stem modifications?
asexual reproduction
what is a rhizome? what are its functions?
a rhizome is a stem that runs horizontally under the ground. they allow the plant to survive extreme conditions such as drought or winter temperatures when the ariel part of the plant dies.
what is a tuber?
the tip of a rhizome that has become enlarged with food
what are corms?
short underground stems filled with food that are enclosed by papery leaves.
what are tendrils? what is their purpose?
tendrils are modified stems that twine around other plants or structures to help support the plant
what are thorns? what is their function?
sharp branches that protect the plant from herbivores
what are cladodes?
flattened, leaf-like stems modified to store water and to photosynthesize for the plant (found in some cacti)
what is the purpose of the plant cell wall?
adds considerable support to the plant body
what are the contents of a plant cell collectively known as?
protoplasm
what is the protoplasm surrounded by?
plasma membrane
what takes up most of the volume of a plant cell?
a large central vacuole
what is the fluid inside the central vacuole called?
cell sap
what is the the tonoplast?
the vacuole membrane
what are the three tissue systems in plants?
dermal, vascular, and ground tissue systems
what does the dermal tissue system consist of?
a layer of protective cells known as the epidermis, which covers the outer surface of the entire plant
what is the main function of epidermal cells?
to secrete a cuticle (a non-cellular, waxy layer of cutin) onto their external cell walls to reduce water loss
what are trichomes? what are their functions?
specialized appendages that extend from the epidermis of stems, leaves, and flowers in some plants. they function in protection, chemical signaling, or prevention of water loss
what are trichoblasts? what is their function?
epidermal projections of the roots (root hairs) that increase the surface area for water absorption