I doubt , any such empirical equation is available , where we can derive the shoot nutrient concentration from leaf nutrient concentration . But , nice question.....

Thank you @Anoop Kumar Srivastava sir

Soil and leaf nutrient analysis are widely used as effective methods of diagnosing nutrient deficiency in fruit trees, the results of which are used to properly manage fertilizer application.

Have a look to this article

https://doi.org/10.1016/j.hpj.2018.03.009