TRANSPORT IN PLANTS -I
ort) various types of substances over short (within the cell, across the membranes, and from in the tissue), as well as very long distances. Water taken up by the roots has to reach all parts of the to the very tip of the growing stem. The photosynthates or food synthesized by the leaves have also to be Plants need to move (transp cell to cell withi plant, up
oved to all parts, including the root tips, embedded deep inside the soi. However, plants lack both interstitial fluid as
well as regular circulation system.
Substances move over short distances mainly by difusion and active transport, supplemented by cytoplasmic streaming
Long distance transport occurs through vascular systems, xylem and phloem. This transport of substances over longer Short distance movenent distances through the vascular tissue, ie, xylem and phloem,
is called translocation. The direction of translocation is essentially unidirectional, in case of water (from root to stem, Active transport leaves, flowers and fruits) and multi-directional in case of minerals and organic solutes.
Organic compounds synthesized in the photosynthetic leaves are exported to all other parts of the plant including storage organs. From the storage organs they are later re-exported. The mineral nutrients are taken up by the roots and transported upwards into the stem, leaves and the growing regions. Hormones or plant growth regulators and othe Movement of substances Long distance movement
occurs by occurs by Diffusion Mass or bulk flow Translocation.
