b'The actively absorbed nitrate (NO3-) is transported by the wood vessels to the sprouts in the form of nitrate, ammonia and amino acids.The absorption of nitrate causes an increase in the pH and the absorption of K +, Ca2 + or Mg2 + causes a decrease in the pH.Deficiency symptomsThis is reflected in the overall yellowing of the plant.The leaves between the veins discolour (chlorosis). In a very serious stage, the leaf edges will dry out and turn brown.The roots develop less so the absorption of other minerals is also delayed. Hollow fruits can also develop.Lack of nitrogenExcess symptomsExcess of nitrogen leads to larger leaves, more chlorophyl production, strong stretching of stems (weaker plant), longer growth period (susceptibility to frost) and is more attractive to harmful insects and mites. In addition, too much nitrogen can cause the plant to be less generative (less fruit production).109'