Deficiency of which mineral element causes the dormancy of lateral buds?

If a plant shows a symptom which could develop due to deficiency of more than one nutrient,how would you find out experimentally,the real deficient mineral element?

Name the deficiency symptoms shown by plants and their causative elements.

Premature leaf fall is caused due to the deficiency of

Less concentration of which mineral causes delay in flowering?

Define the following terms:
$(1)$ Chlorosis
$(2)$ Necrosis