roots
internal structure of roots
external structure
root and root modifications
origin and development of lateral roots
zone of maturation or root hair zone
zone of elongation
root apical meristem #
root cap
mature portion of roots
contains statocytes which is why root grows downwards.
secrects slimy substances that helps roots move though soil.
serves as a protection side that saves the tip of plants.
the very tip of root is loose
mass of parenchyma cells slough off and regenerates with the growth of root system
region at tip of root in which cells are capable of repeated divisions from which primary roots tissues formed.
this type of root is undifferentiated
grow towards and away from the plant.
they divide but loose the ability as a result they form a permanent tissue.
it is singled celled
older cells become parenchyma to store and nutrients.
increase the surface area for roots and absorbs most of the plants water and nutrient.
root hairs needs to be replaced so that it wont produce poison
encloses root vascular tissue.
generates vascular cambium
newly formed cells by the activity of apical meristem start elongating.
obtain water and minerals from soil that are too narrow.
the primary tissues of the root begin to form within or just behind the Zone of Cellular Maturation in the root tip.
The root apical meristem gives rise to three primary meristems: protoderm, ground meristem, and procambium.
Root is an underground part of the plant that absorbs water and minerals from the soil and anchors the plant firmly.
types of roots modifications
aerial roots
storage roots
grows above the ground and provides the structural support
modified for food storage
offers varying function depending upon the growth place.
usually grow underground as a protection from plant eating animals.
examples: banyan tree, screwpine
examples: carrots, beet roots, sweet potatoes.
epiphyte root is type of aerial roots that enable plant to grow on other plant in non- parasitic manner.
aerating roots
rise above the water, especially above water.
commonly seen in mangrove forest that grow along with salt water coast line.
haustorial roots
often seen in parasitic plants such as mistletoe
Their roots allow the plants to absorb water and nutrients from other plants.
start to develop in the pericycle, which is the outermost cell layer in the vascular cylinder
the xylem and phloem make up the vascular cylinder and that it is found in the center of the root. #
in woody roots the vascular cambium originates in the pericycle as well in procambium
the pattern of lateral root production is readily observed with taproot system. #
organization of root system
structure of individual roots
root system includes those parts of the plant below ground, such as the roots, tubers, and rhizomes.
taproot
fibrous root
stretch deep into the soil
spread out close to the surface.
Characterized by having one main root from which smaller branch roots emerge.
when germination occurs the first root to appear is radicle.
important adaptations for searching for water, as those long taproots found in mesquite and poison ivy.
radicle from a germinating seed is short lived and is replaced by adventitious roots.
Characterized by having a mass of similarly sized roots
Adventitious roots are roots that form on plant organs other than roots. Most monocots have fibrous root systems.
Plant cells are formed at meristems, and then develop into cell types which are grouped into tissues
examples: beetroot, carrot
example: maize, sweet potatoes
