Vascular tissue in plants, which consists of xylem and phloem, is essential for transporting water, minerals, and photosynthetic products throughout the plant. This tissue is organized differently in monocots and dicots, influencing their growth and structure, with dicots having more organized vascular bundles. Functions of vascular tissue include maintaining water and sugar balance, facilitating photosynthesis, and enabling agricultural practices like girdling to optimize fruit size.