ROOTS (OTHER TYPES OF ROOTS AND ROOTS MODIFICATION (CONTRACTILE ROOTS…
FUNCTIONS OF ROOTS
anchoring the plant body to the ground and supporting it.
storage of food and nutrients.
absorption of water and inorganic nutrients.
vegetative reproduction and competition with other plants.
STRUCTURE OF ROOTS
EXTERNAL STRUCTURES OF ROOT
ORGANIZATION OF ROOT SYSTEM
MOSTLY MONOCOTYLEDONOUS, SOME EUDICOTS, ARISE AFTER THE DEAD OF RADICLE, BASE OF RADICLE GROWS OUT AND FORMS FIRST STAGE
NOT RADICLES, INCREASE THE ABSORPTIVE AND TRANSPORT CAPACITY OF THE ROOT SYSTEM
SMALL BRANCH ROOTS COMING OUT OF TAP ROOTS
MOSTLY DICOTYLEDONOUS, PRIMARY ROOT, FORMS FROM EMBRYONIC ROOT CALLED RADICLE
STRUCTURE OF INDIVIDUAL ROOTS
FAIRLY SIMPLE, NO LEAVES OR LEAF SCARS, NEITHER LEAF AXILS NOR AUXILIARY BUDS ARE PRESENT
INTERNAL STRUCTURE OF ROOTS
ZONE OF ELONGATION
it is where the newly-formed cells increase in length, thereby lengthening the root.
ZONE OF MATURATION
root hair grows outward, graetly increasing absorption of water and minerals, minerals donot have free access to the vascular tissue, casparian stripes are presented
ROOT APICAL MERISTEM
the region within the growing root containing meristematic cells. At the heart of the root apical meristem are the cells of the quiescent centre.
MATURE PORTIONS OF THE ROOT
a section of tissue at the tip of a plant root, also called calyptra contain statocytes which are involved in gravity perception in plants, protects the growing tip in plants.
ORIGIN AND DEVELOPMENT OF LATERAL ROOTS
arises at the exterior of the vascular cycliner, extend horizontally from the primary root (radicle) and serve to anchor the plant securely into the soil.
OTHER TYPES OF ROOTS AND ROOTS MODIFICATION
They have a wrinkled surface, a thickened specialized root at the base
a symbiotic association between a fungus and the roots of a vascular host plant, refers to role of fungi in plants
AERIAL ROOTS OF ORCHIDS
help to climb other plants and compete for light, absorb moisture directly from the atmosphere
ROOTS NODULES AND NITROGEN FIXATION
Root nodules occur on the roots of plants that associate with symbiotic nitrogen-fixing bacteria
modified roots that arise from the stem of certain plants and provide extra support, .These roots go down in the soil and branch further
ROOTS OF STRANGLER FIGS
grow in the host tree, have no contact with soil for several months, finally reach to soil and penetrate rapidly and branched profusely. upper portion become woody.
usually grow underground as protection from plant-eating animals, specially modified for storage of starch and water