Plant Function: Growth, Nutrients, Seeds Flashcards
What does primary growth do for plants?
Lengthen roots and shoots
What are the two type of growth?
Determinate and indeterminate growth
what is determinate growth?
stopping after a certain size is reached (animals)
What is indeterminate growth?
continues throughout an organisms life (plants)
How are plants categrozied?
how long they live
What are annuals?
complete their life cycle in one year
What are biennials?
complete their life cycle in two years?
What are perennials?
live for many years
What are meristems?
specialized tissues for growth
*Consist of undifferentiated cells that divide when conditions permit
* Apical meristems – found at the tips of roots and shoots
What is primary growth?
*occurs at apical meristems
* allows roots to push downward through the soil
* allows shoots to grow upward toward the sun
What are root caps?
A protective structure at the tip of the root that prevents damage as the root pushes through the soil.
What are the three zones in which root growth occurs behind the root cap?
- Zone of cell division – the apical meristem and cells derived from
it - Zone of cell elongation – cells lengthen by as much as 10 times
- Zone of differentiation – cells differentiate into dermal, vascular,
and ground tissues (including primary xylem and phloem)
What is secondary growth?
- increase in thickness of stems and roots
- occurs at lateral meristems
What is lateral meristems?
areas of active cell division that exist in two cylinders that
extend along the length of roots and shoots
1. Vascular cambium – lateral meristem that lies between primary xylem and primary
phloem
2. Cork cambium – lateral meristem that lies at the outer edge of the stem cortex
What are the two types of cambium’s?
Vascular and Cork
what is vascular cambium?
produces cells in two directions
1. Secondary xylem produces wood toward the interior of the stem
2. Secondary phloem produces the inner bark toward the exterior of the stem
What is cork cambium?
produces cells in one direction
* outer bark – composed of cork cells
What are wood rings?
show layers of secondary xylem
* In temperate regions, periods of dormancy stop growth of secondary
xylem
* Rings occur in areas when new growth starts each year
* “Bark” (secondary phloem and cork)
* sloughed off over time
What is the cycle of reproducation of flower plants?
- mature plant with flowers, where fertilization occurs
- Fruit, containing seed
- Seed
- Germinating seed
- seedling
What is the ovule/seed
Embryonic development
produces a mature seed
What are the seed characteristics?
- an endosperm
- one or two cotyledons
- a root
- a shoot
- a tough seed coat
What is seed dormancy?
– Period when embryonic growth and development are suspended
– Allows for germination when conditions are favorable
What are the two types of seeds?
Eudicot (dicot) and monocot
What are eudicot (dicot) seeds?
- two cotyledons
- apical meristems that lack protective sheaths
- no endosperm because the fleshy cotyledons absorbed the endosperm
nutrients as the seed formed
