Anatomía wreath - Anatomía Kranz

Diagram of the cross section of a leaf with kranz anatomy. E: epidermis , M: mesophilic ; W: vascular bundle ; BS: mestomatic sheath.

In botany , Kranz anatomy or structure refers to the arrangement of two concentric layers of mesophyll and the compacting cells of the vascular sheath around the vascular bundles in the leaves of most C 4 plants . The sheath is made up of parenchymal cells with an abundance of large chloroplasts . [ 1 ] Mesophyll cells also have chloroplasts, but they do not synthesize starch because they do not perform the Calvin cycle ; this is reserved for the chloroplasts in the sheath. [2]

The presence of this anatomy increases the internal cycling of carbon dioxide , which could result in a reduction in the sensitivity of plants to photoinhibition . [ 3 ] This is due to the fact that the layer of cells of the mesophyll, located radially in the outermost part, capture the CO 2 molecules and concentrate them by converting them into molecules of four-carbon sugars, to transfer them to the cells that compose the inner layer or the sheath. [ 4 ]

This pathway to form sugars from the mesophyll is called the Hatch Slack Pathway. In the first step, oxaloacetic acid is formed by attaching carbonic anhydride to phosphoenolpyruvate . Hence there is a transformation that differs in the result depending on the type of plant. The product passes into the cells of the sheath through the plasmodesmata and through a series of transformations the carbon dioxide is released, which enters the Calvin cycle. [ 5 ]

References

  1. ^ Raven, Peter H .; Evert, Ray F .; Eichhorn, Susan E. (1992). «22 - The stem: Primary structure and development» (Digitized book) . Plant Biology, Volume 2 . Reverte. p. 432 |página=and |páginas=redundant ( help ) . ISBN 9788429118421 . Retrieved November 29, 2013 .
  2. Redes Garcia, Rosa; Collazo Ortega, Margarita (2006). Photosynthesis Practices Manual (Digitized Book) . UNAM. p. 61 |página=and |páginas=redundant ( help ) . ISBN 9789703233137 . Retrieved November 30, 2013 .
  3. ^ Baruch, Z .; Fischer, MJ (1991). "Climatic and competition factors that affect the development of the plant in the establishment of a pasture" (Digitized book) . In Carlos E. Lascano, ed. Pasture Establishment and Renovation: Concepts, Experiences, and Research Focus, International Tropical Pasture Assessment Network, Sixth Meeting of the Advisory Committee . CIAT. p. 121 |página=and |páginas=redundant ( help ) . ISBN 9789589183267 . Retrieved November 29, 2013 .
  4. ^ International Center for Tropical Agriculture (April 22, 2008). CIAT report (Digitized book) . University of Texas: International Center for Tropical Agriculture. p. 39 . Retrieved November 30, 2013 .
  5. García Breijo, Francisco José; Roselló Caselles, Josefa; Santamarina Siurana, Pilar (2006). Introduction to the operation of plants (Digitized book) . Ed. Univ. Politéc. Valencia. p. 32 |página=and |páginas=redundant ( help ) . ISBN 9788497059442 . Retrieved November 30, 2013 .