BOTANY WITH BASICS OF HYDROBOTANY (AQUATIC PLANTS OF UKRAINE) - B.Ye. Yakubenko - 2011

VII. PLANT TISSUES

Vascular Tissues

In higher terrestrial plants, one part of the vegetative body is located in the soil (roots), while the other is in the air (shoots and their derivatives). Roots extract Water and soil nutrients from the ground. Leaves absorb carbon dioxide from the air and perform Photosynthesis using light energy.

Substances absorbed and produced by different PARTS OF THE plant are redistributed throughout its body via vascular tissue (Fig. 51).

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Fig. 51. Vascular Tissues and vascular bundles:

A - vascular tissues (1 - sieve tube with companion Cell, 2 - annular vessel, 3 - spiral vessel, 4 - scalariform vessel, 5 - pitted vessel, 6 - reticulate vessel, 7 - tracheids); B - closed collateral vascular bundle in a corn stem (1 - phloem, 2 - xylem); C - open collateral vascular bundle in a buttercup stem (1 - phloem, 2 - cambium, 3 - xylem); D - diagrams of various types of vascular bundles: 1 - collateral, 2 - bicollateral, 3,4 - concentric, 5 - radial.

The upward transport of water and substances originates in the roots, carried out through tracheids and vessels (tracheae). The downward transport of predominantly organic substances from the leaves to the roots and Generative Organs occurs through sieve tubes or sieve Cells. It is worth noting that water transport in plants is conducted by dead vascular tissues, whereas The transport of organic substances is carried out by living ones.