10 May 2021

6.3. Mineral requirements of plants


Nitrate ion and magnesium are essential minerals for plant growth.

Plants need:

  • nitrate ions (NO3−) for making amino acids
  • magnesium ions (Mg2+) for making chlorophyll

Nitrate ions (NO3−)

Nitrate ion deficiency

  • Function
    • needed for making amino acids (building blocks of protein)
    • amino acids are formed by sugars + nitrate
    • all proteins contain N
    • proteins are used to make cytoplasm and enzymes
  • Deficiency:
    • plant can't synthesize (make) amino acids and proteins
    • --> slows down growth
    • symptoms
      • stems --> weak
      • lower leaves --> yellowing --> die
      • upper leaves --> pale green

Nitrate ion deficiency in tomato leaf

Magnesium ions (Mg2+)

Magnesium deficiency

  • Function:
    • needed for making chlorophyll
    • each chlorophyll molecule contains one Mg ion
    • plants need chlorophyll to trap light to provide energy during photosynthesis
  • Deficiency:
    • can't synthesize chlorophyll
    • reduced photosynthesis
    • symptoms
      • leaves turn yellow (chlorosis) from the bottom of the stem upwards
      • plant growth suffers

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  1. Please give notes of O level syllabus. Please please.

  2. Could you please make a combined biology notes pdf??

    1. You can find them here! http://igbiologyy.blogspot.com/2014/04/biology-notes-all-in-one.html