Plants ❮ 175
❯ Answers and Explanations
❯ Rapid Review
The following terms and topics are important in this chapter:
Anatomy of plants:tissue systems are divided into ground, vascular,anddermal.
Ground tissue:the body of the plant is divided into three cell types:
- Collenchyma cells:provide flexible and mechanical support; found in stems and leaves.
- Parenchyma cells:play a role in storage, secretion, and photosynthesis in cells.
- Sclerenchyma cells:protect seeds and support the plant.
Vascular tissue: xylem(transports water and minerals) and phloem(transports sugar).
Dermal tissue: protective outer coating for plants:epidermis.
Roots
Types:taproot system(dicots)—system that divides into lateral roots that anchor the
plant;fibrous root system(monocots)—anchoring system that does not go deep down
into soil.
Structure:epidermis →endodermis (casparian strip) → vascular cylinder → xylem/
phloem.
Growth:occurs for lifetime of the plant thanks to meristemcells:
- Primary growth:increasedlengthof a plant (occurs in region of apical meristems).
- Secondary growth:increasedwidthof a plant (occurs in region of lateral meristems,
limited in monocots).
- Three main growth regions: zone of cell division(cells divide), zone of elongation(cells
elongate), zone of maturation(cells mature to specialized form).
- C—When the concentration of water inside the
plant is low, the stomata close in an effort to
minimize transpiration.
- C
- D
- A
- E
- C—Thigmotropism is a plant’s growth in response
to touch. Phototropism is growth in response to
light, and gravitropism is growth in response to
gravitational force. Photoperiodism is the response
by a plant to the change in the length of days, and
phototaxis is the sad phenomenon whereby moths
fly kamikaze-style into burning hot lights at night.
- C
- D
- B
- E
- B—Phototropism, a plant’s growth response to
light, is controlled by auxin. This hormone is
produced in the apical meristem and sent to the
zone of elongation to initiate growth toward the
sun.
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