How do plant roots grow?
Root grows in length by the activity of root apical meristem and obtains food for nourishment for growth from the green leaves and minerals and water from soil.
Root is underground and non-green. It * obtains food from green part of the plant, mainly leaves which carry on photosynthesis . It obtains water and minerals, needed for growth, from the soil directly through root hairs present in terminal growing region of root.
The growth of root in longitudinal direction is termed primary growth ,that occurs by the activity of meristematic tissue in root apex. Apical meristem is primary meristem . Monocot roots have only primary growth.
Roots in dicots grow in girth or diameter also . This is termed secondary growth . It occurs by the activity of secondary meristems termed vascular cambium and cork cambium or phellogen.