Lab on Roots Flashcards
What percentage of plants form mutualistic realtionships with fungi?
90%
What are mycorrhizae?
mutualistic fungi that line in or around plant roots (means fungus root)
What does the fungi gain from the mutualistic realtionship with roots?
products of photosynthesis
What does the root gain from the mutualistic relationship with fungi?
phosphorus and other minerals.
Why are most species of orchid difficult to cultivate?
the corresponding fungus is hard to obtain.
What is present in fungal walls that corresponds to the cellulose in plant walls?
Chitin (stains blue)
Fungal hyphae that are endomycorrhizae enter…
the cells of the cortex.
hyphae in ectocorrhizae grow only…
between the cells of the cortex.
In terrestrial systems, the nutrient that most commonly limits plant growth is….
nitrogen (triple bonded and hard to break.)
With what can a plant form a mutualistic relationship that allows the plant to receive nitrogen in a usable form?
bacteria (prokaryotes)
What are the small bulges of prokaryotes on the outside of roots called?
root nodules
What are the functions of roots?
most importantly anchorage and absorption, with other functions like storage, hormone production, and can be modified for purposes including support, aeration, propagation and parasitism.
What is the primary root?
the first root that emerges from the seed in germination.
In most plats, the primary root develops into what?
the taproot, which becomes central in the plant’s root system and continues to be most prominent throughout the life of the plant.
Taproot systems are common in which class of species?
dicots
What replaces the primary root in monocots?
adventitious roots develop into a fibrous root system where no one root is dominant.
What are adventitious roots?
roots that develop from a structure other than another root (ex: from the stem)
All roots on grasses are…
adventitious.
What are aerial roots?
adventitious roots that originate from above ground structures.
What are epiphytes?
plants that grow on other plants.
What is the velamen?
the white, spongy material which is a multiple epidermis that helps the root retain water in epiphytes.
What are pneumatophores?
negatively gravitropic roots that provide ventilation to a submerged root system.
pneumatophores are often referred to as…
knees.
What are lenticels?
areas of periderm that facilitate gas exchange.
The parasitic plant dodder is incapable of photosynthesis. How does it gather those nutrients?
it sinks a haustorium into the stem of another plant where it taps into the xylem and phloem.
What is a haustorium?
a modified root of a parasitic plant used to reach the xylem and phloem for nutrient absorption.
What are the three regions of growth in a root called?
- region of cell division
- region of elongation
- region of maturation
The region of cell division is located where?
at the end of the root (where cells are still dividing) and where patterns of root growth are being established.