roots Flashcards
- Anchoring the plant firmly to a substrate (soil)
- Absorption of water and minerals
- Production of hormones.
• shoot growth and development depend on the hormones cytokinin and gibberellin
Main Functions of Roots
shoot growth and development depend on the hormones __________ and ______________
cytokinin, gibberellin
cytokinin and gibberellin
Shoot system
3 main tissues
Dermal
Ground
Vascular
• Carbohydrate storage - Fleshy taproots (i.e. carrots, beets, radishes)
• Protection – in Crysophila and Mauritia, roots grow out of the trunk and harden into sharp spines
• Vegetative reproduction – roots spread horizontally and produce shoot buds (i.e. willows, sorrel)
• Parasitic roots - modified roots attack other plants and draw water and nutrients out of them (i.e. mistletoe, dodder)
Additional / Specialized Function
Fleshy taproots (i.e. carrots, beets, radishes)
Carbohydrate storage
SN of carrots
Daucus carota
SN of beets
Beta vulgaris
SN of radishes
Raphanus satidus
in Crysophila and Mauritia, roots grow out of the trunk and harden into sharp spines
Protection
roots spread horizontally and produce shoot buds (i.e. willows, sorrel)
Vegetative reproduction
modified roots attack other plants and draw water and nutrients out of them (i.e. mistletoe, dodder)
Parasitic roots
Three types of root system:
- TapRoot
- FibrousRoot
- Adventitious
• single prominent root (tap root) that is much larger than all the rest and numerous small roots (lateral roots or branch roots) coming out of it
Tap Root
Derived from the radicle (embryonic root)
Tap Root
Derived from the radicle (embryonic root)
Tap Root
Anchorage
Tap Root
Common in dicot and gymnosperm
Tap Root
perennial and woody plants: roots undergo secondary growth
Tap Root
perennial and woody plants: roots undergo secondary growth
Tap Root
carrots, beets, radish, turnips
Fleshy taproots
turnips sn
Brassica rapa
sweet potatoes, cassava
Swollen lateral roots
SN of sweet potatoes
Ipomoea batatas
SN of cassava
Manihot esculenta
taproot is about the carrot same size as the laterals
Sunflower
SN of Sunflower
Helianthus annuus
mass of many similarly sized, delicate and hair-like roots
Fibrous Root
no prominent enlarged primary root
Fibrous Root
Produced after death of radicle
Fibrous Root
Derived from the root primordia found at the end of radicle
Fibrous Root
Common in monocots and some dicots
Fibrous Root
Absorption
Fibrous Root
• mass of many similarly sized, delicate and hair-like roots
• no prominent enlarged primary root
• Produced after death of radicle
• Derived from the root primordia found at the end of radicle
• Common in monocots and some dicots
• Absorption
Fibrous Root
• Do not arise from pre-existing roots
• Present in monocot and dicot
- brace root - arise from main trunk stem
- prop root - arise from the lateral
branches of the main stem.
Adventitious Root
Do not arise from pre-existing roots
Adventitious Root
Present in monocot and dicot
Adventitious Root
arise from main trunk stem
brace root
arise from the lateral branches of the main stem
prop root
Secondary growth = ↑ quantity of healthy, functional wood (xylem) in the roots = ↑ no. of leaves and fine absorptive roots
Dicot Roots
secondary xylem and phloem
Dicot Roots
No secondary growth = stem of an older plant is not wider than young plant, no ↑ conducting capacity, no more leaves or roots than young plant
Monocot Roots
no secondary xylem and phloem
Monocot Roots
• Stolons or rhizomes = ↑ size
Monocot Roots
Stolons
horizontal stem above the ground
rhizomes
horizontal stem below the ground
horizontal shoots branch and then produce adventitious roots
Monocot Roots