Dictionary > Secondary phloem

Secondary phloem

The type of phloem derived from the secondary meristems of a vascular plant
The phloem is a vascular tissue that is responsible for translocation. Translocation pertains to the process that transports the photosynthate materials to different parts of a vascular plant. The phloem may be primary or secondary depending on which type of growth it came from or on which type of cambia (i.e. whether procambium or vascular cambium) it came from.
The secondary phloem is a type of phloem that forms from the vascular cambium during the secondary growth. The secondary growth is responsible for the growth in girth in plants, especially trees. The vascular cambium is the meristematic tissue involved in this type of growth. Some of the cells produced by the vascular cambium may differentiate into secondary phloem (others as secondary xylem).
The secondary phloem is located in the stems and roots. It forms inner to the primary phloem. A radial system of phloem rays occurs in the secondary phloem. In terms of cellular components, the secondary phloem has more phloem fibers (occur in bands or patches, and referred to as bast fibers), sieve tubes, phloem parenchyma, and sclereids than the primary phloem. The sieve tubes of secondary phloem are shorter but wider. Thus, there is a rather rapid flow of photosynthate across the sieve tubes of secondary phloem than those of primary phloem.
Also called:

  • bast
  • liber

See also:

  • phloem
  • primary phloem
  • bark

    You will also like...

    Angle Oak Tree
    Seed Plants

    Seed plants are vascular plants. They differ from the other vascular plants in producing seeds that germinate into a new..

    Young plant growing from the soil.

    Nutrients in the soil are essential to the proper growth of a land plant. This tutorial deals with the properties of soi..

    Developmental Biology
    Developmental Biology

    Developmental biology is a biological science that is primarily concerned with how a living thing grows and attains matu..

    Biological Viruses
    Biological Viruses

    Viruses possess both living and non-living characteristics. This unique feature distinguishes them from other organisms...

    Chemical effects on plant growth and development
    Effect of Chemicals on Growth & Development in Organisms

    Plants and animals need elements, such as nitrogen, phosphorus, potassium, and magnesium for proper growth and developme..

    Animal Water Regulation

    Animals adapt to their environment in aspects of anatomy, physiology, and behavior. This tutorial will help you understa..