Pollen production can be estimated using for example ether-ethanol method

See Denisow B. Wrzesień M, Bożek M., Jeżak A. Strzałkowska-Abramek M., 2014. Flowering, pollen characteristics and insect foraging on Campanula bononiensis (Campanulaceae), a protected species in Poland. Acta Agrobotanica 67(2); 13-22

Denisow B, Strzałkowska–Abramek M., Bożek M., Jeżak A., 2014. Ornamental representatives of the genus Centaurea L. as a pollen source for bee friendly gardens Journal of Apicultural Science 58 (2): 49-58.

The pollen production in particular flowers can be also established by counting the pollen grains in anthers

See Czarnecka B. Denisow B. 2014. Floral biology of Senecio macrophyllus M. BIEB. (Asteraceae), a rare Central European steppe plant. --- Acta Societatis Botanicorum Poloniae, 83 (1): 29-37. 

the honey is made out of flower nectar. if you measure the total volume and sugar percentage  of a flower, you can calculate the amount of flowers need to make for instance a gram of honey.

The classical paper about qualitative and quantitative pollen analysis of honeys is:

METHODS OF MELISSOPALYNOLOGY

J. LOUVEAUX, ANNA MAURIZIO AND G. VORWOHL

Bee World 51(3): 125-138 (1970)

Do you mean, how can we discriminate between artificial (Sugarcane) and natural (blossom) honey

...using pollen and other structured elements analysis of honey sediments.