MODULE 3: ROOTS AND PLANT PROCESSES Flashcards
A part of the embryo (immature plantlet) within it, grows out and develops into first root.
EMBRYONIC ROOT or RADICLE
Generally grows straight down from the stem. It is a heavy, thick root that does not have many branches.
TAP ROOT SYSTEM
Number of large, equal-sized
taproots.
TAPROOT EVEN/EQUAL
Large taproot extending from stem
TAPROOT SWOLLEN
Larger than average root going deeper
into the soil.
TAPROOT PRIMARY
Advantage of Taproots:
- Anchors plant deeply, helping to prevent the wind from blowing them over
- Food storage
- Drought tolerance
Thin, somewhat hair- like, and numerous.
FIBROUS ROOT SYSTEM
Advantage of fibrous root
- Absorbs water and nutrients quickly
- Helps prevent soil erosion as they anchor plants to the top layers of soil.
It is often used for human or animal consumption. COMMON IN DICOTS
TAP ROOT SYSTEM
Dry out quicker, thus cannot tolerate drought. COMMON IN MONOCOTS
FIBROUS ROOT SYSTEM
Thimble-shaped mass of parenchyma cells at the tip of each root.
ROOT CAP
Golgi bodies release_______ lasts less than a week, then these die – slough cells.
MUCILAGINOUS LUBRICANT (mucigel)
Accumulate at the bottom of cells;Important in perception of gravity.
AMYLOPLASTS
Regions of plant cell:
- ROOT CAP
- REGION OF CELL DIVISION/ MERISMATIC REGION
- REGION OF ELONGATION
- REGION OF MATURATION/DIFFERENTIATION
Divide once or twice per day.
APICAL MERISTEM
Forms the epidermis
PROTODERM
Ground tissue and produces parenchyma cells of the cortex.
GROUND MERISTEM
Forms the vascular tissues, the primary xylem and phloem.
PROCAMBIUM
Protoderm, Ground meristem, Procambium
REGION OF CELL DIVISION/ MERISMATIC REGION
Cells become longer and wider.
REGION OF ELONGATION
Aka Root hair zone, Root hairs develop as protuberances from epidermal cells.
REGION OF MATURATION/DIFFERENTIATION
Increase the surface area for the absorption of water
REGION OF MATURATION/ DIFFERENTIATION
Originated from the root of the seedling.
PRIMARY ROOTS
(Lateral) roots originate from the primary roots
SECONDARY ROOTS
Originate on stems, except the radicles/roots.
ADVENTITIOUS ROOTS
3 Meristematic Tissues
- PROTODERM
- GROUND MERISTEM
- PROCAMBIUM
The growth of the tips of roots and stems in length with the help of apical meristem.
PRIMARY GROWTH
The growth that results from cell division in the cambia or lateral meristems causing the roots and stems to thicken; Doesn’t occur in monocots Mostly occur in seed plants
SECONDARY GROWTH
TYPES OF MODIFIED ROOTS
- FOOD STORAGE
- WATER STORAGE
- PROPAGATIVE ROOTS
- PNEUMATOPHORES
- AERIAL ROOTS AND PHOTOSYNTHETIC ROOTS
- CONTRACTILE ROOTS
- BUTTRESS ROOTS
- PARASITIC ROOTS
- SYMBIOTIC ROOTS
MODIFIED ROOTS
Roots are enlarged and store large quantities of starch and other carbohydrates, which may later be used for extensive growth.
FOOD STORAGE
MODIFIED ROOTS
Ex.: Carrots, beets, turnips, sweet potatoes, yams, hemlocks, dandelions, radish
FOOD STORAGE
MODIFIED ROOTS
Plants that grow in arid regions are known for growing structures used to retain water & used these water supply when the supply in the soil is inadequate.
WATER STORAGE ROOTS
MODIFIED ROOTS
Ex.: pumpkin, manroots, calabazilla, watermelon
WATER STORAGE ROOTS
MODIFIED ROOTS
Produces adventitious buds along the roots that grow near the surface of the ground. The buds develop into aerial stems (suckers). The rooted suckers can be separated from the original root & grow individually.
PROPAGATIVE ROOTS
MODIFIED ROOTS
Ex.: cherries, apple, pear, rice-paper plant, tree-of-heaven, weeds such as hoarseradish, Canada thistle
PROPAGATIVE ROOTS
MODIFIED ROOTS
Breathing roots to help plants that grow in very wet areas like swamps get enough oxygen. These roots act like snorkel tubes for plants, rising up above the surface of the water so that the plant can get oxygen.
PNEUMATOPHORES
MODIFIED ROOTS
Ex.: Mangrove trees
PNEUMATOPHORES
MODIFIED ROOTS
Orchids produce velamen roots, corn plants have prop roots, ivies have adventitious roots and vanilla orchids even have photosynthetic roots. They can facilitate climbing and support to the plant.
AERIAL AND PHOTOSYNTHETIC ROOTS
MODIFIED ROOTS
Ex.: Orchids, corn, ivies, vanilla orchids
AERIAL AND PHOTOSYNTHETIC ROOTS
MODIFIED ROOTS
It pulls the plant deeper into the soil by expanding radially and contracting longitudinally. The contractile part of the root may lose as much as 2/3 of its length within a few weeks as stored food is used and the cortex collapses.
CONTRACTILE ROOTS
MODIFIED ROOTS
Ex.: Lily, dandelion, hyacinth
CONTRACTILE ROOTS
MODIFIED ROOTS
Large roots on all sides of a tall or shallowly rooted tree. It provides support and stability to a tree.
BUTTRESS ROOTS
MODIFIED ROOTS
Ex.: Fig tree and other tropical trees
BUTTRESS ROOTS
MODIFIED ROOTS
Plants without chlorophyll become dependent on chlorophyll-bearing plants for nutrition. They parasitize their host plants via peglike projections called haustoria, which develop along the stem in contact with the host.
PARASITIC ROOTS
MODIFIED ROOTS
Ex.: Mistletoe, orchids
PARASITIC ROOTS
MODIFIED ROOTS
Mycorrhizae form a mutualistic association with plant roots.
SYMBIOTIC ROOTS
MODIFIED ROOTS
Ex.: Peanuts, pea, beans, legumes
SYMBIOTIC ROOTS
MODIFIED ROOTS
Root+ fungi = __________
(better absorption of phosphorus from the soil)
MYCHORRHIZA
MODIFIED ROOTS
Root + bacteria = ___________
(nitrogen fixation, convert n2 to nh3 to use by plant for protein synthesis)
RHIZOBIA
They parasitize their host plants via peglike projections called
HAUSTORIA
