Nutrition in Plants

3 min read

Nutrients - components of food - necessary for our body NUTRITION - mode of taking food by an organism and its utilisation MODE OF NUTRITION IN PLANTS: AUTO TROPHS - self - nourishment HETEROTROPHS - other for nourishments SAPROPHYTES - feed on dead and decayed

AUTO TROPHS

PHOTOSYNTHESIS: light - combine leaves - food factories of plants Water & Minerals - absorbed from soil by roots - transported to leaves by vessels CO2 - from air - by tiny pores called Stomata - guarded by Guard Cells Chlorophyll - green pigment - capture sunlight Energy to synthesise food from co2 and water and minerals o2 is produced

co2 + water ----> sunlight + chlorophyll —> carbohydrate + o2

carbohydrates converted into starch

sun - ultimate source of energy for all living organisms

all living org depend directly or indirectly on plants

  • leaves other than green also have chlorophyll
  • red, brown, other pigment - mask green
  • photosynthesis takes place here also

ALGAE: green in colour - chlorophyll found in water bodies

Synthesis of other plant food

  • Carbohydrates - made of o2, H, C

    • used to synthesis other than protein and fats

  • Proteins - nitrogenous substances

  • nitrogen present in air - in abundance - more than 70%

    • plants cannot absorb it
    • soil - bacteria - RHIZOBIUM - convert gas nitrogen into usable form and release into soil - plants absorb this nitrogen
    • fertilisers are also used
HETEROTROPHIC NUTRITION

yellow tubular structures around stem and branches - CUSCUTTA (AMARBEL) not have chlorophyll - takes readymade food

  • host
  • parasite - deprives the host

insectivorous plants but it is green then why does it feed on insects when it can prepare its own food plants traps insects and digest them pitcher like structure - modified leaf - apex lid digested by digestive juices

SAPROTROPHS - SAPROPHYTIC NUTRITION

Mushrooms Fungi - secrete digestive juices on the dead and decaying matter - convert into a solution - absorb nutrients from it Fungi grow on humid and hot weather

wheat field spoiled by fungus

but fungi like yeast and mushrooms are helpful some are dangerous

fungal spores present in air land on wet and warm things

SYMBIOTIC RELATIONSHIPS:

live together and share shelter and nutrients

fungi - live in roots of plants plant gives nutrients fungi helps in taking water and nutrients from soil

lichens - fungi + algae fungi gives shelter, water and minerals algae - provides food as it has chlorophyll

NUTRIENTS REPLENISHED IN SOIL:

fertilisers, manures added - nitrogen, phosphorus, potassium crops need more nitrogen to make proteins

Rhizobium - fix atmospheric nitrogen and convert it into soluble form it cant make its own food so it lives in the roots of leguminious plants like beans, peas, gram, etc

no need to add nitrogen fertiliser to soil where leguminous plants are grown

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