Roots Flashcards
What is a root
- multicellular, contains vasculature
What is the root responsible for
anchorage to the ground
absorption and conductance of water and minerals
storage
symbioses
What are the 3 groups of roots
primary root
lateral root
adventitious root
What is a primary root
roots that are the first tissue to emerge from a germinating seed
What is a lateral root
subsequent roots emerging from the primary root
What is an adventitious root
root emerging from anywhere where we don’t expect them to emerge
what is a root system
variety of forms which result from different combinations of root types
what are the most common types of root systems
taproot
fibrous roots
prop & stilt roots
pneumatophores
What is a taproot system
- primary root remains the largest root, central to the rest of the root
- root system is found in all plant groups except monocots
what is a fibrous root system
- primary root emerges from the seed but dies shortly after
- lateral roots are very small and dense (web)
- typical monocots
What is the advantage in a fibrous root system
increases the overall surface are –> increases area for absorption and water
What is a stilt and prop root system
- specialized in providing additional support for the plant
- mainly adventitious roots
- mainly aerial roots
what are aerial roots
roots that form aboveground
- all aerial roots are adventitious but not all adventitious roots are aerial
What is a pneumatophore system
- usually adventitious and aerial
- can form a lateral root
- specialized in gas exchange
- only type of root that can grow upwards
What are the 3 cell types of root organization
dermal tissues, ground tissues, vascular tissues
What are the 3 most common patterns of cellular organization
woody, monocot, dicot
What is a monocot pattern
- xylem and phloem both in a ring shape (xylem inner, phloem outer)
- center of the vasculature has a group of parenchyma cells
What is the pith
a group of parenchyma cells
What is a dicot pattern
- xylem is center of vasculature tissue surrounded by phloem
- xylem often visually forming a cross shape
What is a woody pattern
- central cross xylem surrounded by phloem
- additional layers of xylem and phloem produced by vascular cambium –> one layer per growing cycle
What are the characteristics of dermal tissues
- tissue layer b/w external environment and interior of plant –> SKIN
- controls passage of minerals and water to the plant –> gate keeper
- mainly limited to the epidermis
- in woody plants, single-layered epidermis can be replaced by periderm
What is the epidermis
single cell layer b/w the ground tissue and the external environment
What is the periderm
- multiple cell layers
- outer cell layers are often dead
What is the cork
protective layer
