Question

how are nature of roots and venation in leaves of a plant related?

Answer 1

Nature of roots and venation in leaves of a plant is related. If the root is tap root then the plant has reticulated venation.If the root is fibrous root then the plant has parallel venation.so in this way the root and venation in leaves of plant are related. Hope this helps you

Answer 2

The leaf veins consists of vascular bundles that help in the transport of mineral nutrients and water from the roots to the leaf and the materials produced in the leaf to the rest of the plant. the veins branch and unite forming a complicated network 
All the veins are interconnected, like the strands of the net
Leaves of ‘Dicot plants’ generally have reticulate venation,the veins run parallel or nearly parallel to each other and are connected by smaller veins
Leaves of ‘Monocot plants’ generally have parallel venation...