Interconnection between the transport and reinforcing functions of the leaf venation is studied. It is shown by detailed computer assisted image analysis of the leaf blades the principles of design of conducting systems are the same as were found in circulatory and respiratory systems of mammals and fluid transport systems in some animals. The obtained regularities correspond to a model of the optimal pipeline that provides liquid delivery at minimal total energy costs. Solution of the optimization problem of the liquid transport in the branching pipeline with permeable walls into a round plate has been obtained at different branching angles between the main veins and branching patterns of the minor veins. The same patterns have been used in the model of the plant leaf as a fiber-reinforced horizontal round plate. The best patterns are found by numerical computations and proposed as Nature inspired solutions for novel artificial fiber-reinforced materials when the fibers are composed by tubes that provide fluid or gas flow for heating or cooling in technique.