MODE OF NUTRITION IN PLANTS
BY
ARNAB BASHISTHA
BOTANY MAJOR
1ST SEM
BAJALI COLLEGE’14
WHAT IS NUTRITION:
• It is the process of taking in of food.
• The energy which is stored within the food materials is used by
the living organisms for various activities.
• Nutrition occurs in several stages like ingestion, digestion,
absorption, assimilation and egestion.
MODE OF NUTRITION IN PLANTS:
• Photosynthesis is a type of plant nutrition carried out by green
plants only.All the plants can not get their nourishment
through the process of photosynthesis. Some plants are
dependent on other plants and animal for their food. Different
plants have different nutritional processes.
CLASSIFICATION OF PLANTS ON THE BASIS OF MODE OF NUTRITION:
• Autotrophs:
Epiphytes
• Chemoautotrophs
• Heterotrophs:
Parasites
Saprophytes
Symbiont
Insectivorous Plants
AUTOTROPHS
• The autotrophic plants are all green plants by virtue of the presence of
chlorophyll in their cells.As they can produce their food from inorganic
materials, they are not dependent on other plants or animals for food.
• According to different habitat and environmental conditions autotrophs
have structural differences.They range from unicellular type (algae e.g.
Chlamydomonas) to large branched trees.
• Epiphytes (e.g. some orchids) are a kind of autotrophs which only live on
other plants but do not take any food from that plant.
CHEMOAUTOTROPHS
• They prepare their own food by the process of chemosynthesis
i.e. the process of carbohydrate formation in which chemical
reaction is used to obtain energy from inorganic compounds.
• Example: Sulphur bacteria like Beggiatoa convert H2S to Sulphur
and releases enegy.
2H2S + O2 2H2O + 2S + energy
HETEROTROPHS
• The heterotrophic plants are incapable of
photosynthesizing.They are non-green i.e. they lack of
chlorophyll.They obtain certain organic compounds (food) from
other autotrophs.
• They may be saprophytes, parasites, symbionts or
insectivorous.
Saprophytes:
• They get their nutrition from dead or decaying organic matter.
• They may be obligate saprophytes (i.e. they can live only on
dead organic matter) or facultative saprophytes (i.e. they are
mainly parasitic organism with the ability to survive for a part
of its life cycle as a saprophyte).
• Examples: Neottia , Monotropa etc.
Parasites:
• They get their nutrition from the host.The parasites maintain their physical contacts with the host plant through haustoria(parasitic roots).
• Parasites may be of two types- Obligate parasite (i.e. they are parasitic organism that can’t completes its life cycle without exploiting a suitable host) and Facultative parasite (i.e. they may resort to parasitic activity but absolutely rely on any host for completion of its life cycle).
• They may live on the stem or on the roots of the host.They may be partially autotrophic and partially parasitic.On this basis parasites are –
a. Total stem parasite
b. Partial stem parasite
c. Total root parasite
a. Total stem parasite: They totally depend
on the host plant as they lack of
chlorophyll.Example: Cuscuta
b. Partial stem parasite: They depend on the
host plants only for water and minerals, but
they bear chlorophyll and get nutrition
through the process of
photosynthesis.Example: Viscum
c. Total root parasite: They live on
the roots the host and get their
nourishment.Example: Raflessia,
Orobanchae
d. Partial Root Parasite: They possess
chlorophyll but for germination of
their seeds they follow parasitism
on roots of the host.Example:
Santalum album
Symbionts:
• It means the close association between two different plants of
different categories.In this association both the plants get
benifited.
• Examples: Lichen(association between algae and fungi),
Mycorrhiza(fungal association with the roots of higher plants)
etc.
Insectivorous Plants:
• They have the mechanism to trap insects and are adapted to
digest the protein matter contained in insects.They depend
only partially on nutrition as they bear normal leaves and roots.
• Examples: Nepenthes, Drossera, Dionea, Utricularia etc.
LET’S SEE HOWTHE HERO KILLS THE VILLAIN
THANK YOU
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