There are two types of complex permanent tissues; they are the xylem and phloem which constitute the major part of vascular bundle. The vascular bundle forms the continous and inter connected system through the different organs of the plant. The xylem and phloem forms the vascular or the conducting tissue in the plants.
I. Xylem:
The xylem consists of different types of cells including both the living and non living cells. The higher plants have four elements; i. Tracheids, ii. Vessels, iii. Xylem fibres, iv. Xylem parenchyma. The xylem is responsible for the conduction of mineral salt and water to all parts of the plant. It also gives a mechanical support to the plant body.
II. Phloem:
The phloem is another type of vascular tissue present in the vascular bundle. It consists of i. Sieve elements, ii. Companion cells, iii. Phloem parenchyma, iv. Phloem fibres. The phloem helps in the transport of the photosynthate to all the parts of the plant.
