Nitrogen deficiencies: 

Chlorosis of the basilar leaves and of the whole crown - Lack of growth or stunted growth - General yellowing of foliage, starting from older leaves - Loss of leaves under severe deficiency - Purplish colouration due to accumulation of anthocyanin pigments.
 

Phosphorous deficiencies: 

Green tissues are darker than usual, taking on a reddish or purple coloration -  Leaves necrosis - Reduced fruit quality.

 

 

Potassium deficiencies: 

Marginal Chlorosis with foliar curling, especially at tips and margins between veins - Roots more susceptible to disease.