Page 134 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six

Biology for Secondary Schools

Functions of macroelements in plants

Task 6.6
Read from reliable online sources and books about the functions of macro and
microelements in plants
FOR ONLINE READING ONLY

Each mineral element has a specific function in the plant body. Some are used
in the formation of building materials for proteins and carbohydrates in plants
while others play important roles in other metabolic activities of the plant. The
deficiency of such elements will eventually affect plant growth and metabolic
activities. Table 6.2 shows the functions, signs of deficiency, and effects of excess
macroelements in plants.

Table 6.2: Functions, signs of deficiency, and effects of excess macroelements
in plants
Macroelement Functions Signs of deficiency Effects of excess

Nitrogen (i) Synthesis of (i) Slow growth (i) Very dark
proteins and (ii) Yellowish or green
transfer of light green succulent
energy leaves, as leaves
(ii) Formation of shown in (ii) Break down of
chlorophyll Figure 6.14(b) vascular tissue
and restricted
(iii) Increases (iii) Reduced yield
seed and fruit of fruits and transport of
production seeds water
(iii) Easily
(iv) Speeds up (iv) Poorly
growth rate developed damaged
leaves stems because
of excess sap
Phosphorus (v) Germination (i) Reduced plant Reduces the
and growth of growth plant’s ability to
seeds (ii) Delayed take up required

(vi) Production of development micronutrients,
flowers and (iii) Small leaves particularly iron and
fruits zinc
that drop early
(vii) Growth of
roots

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