Sunday, 17 July 2016

Leaf structure and histochemistry of the hardy evergreen Euphorbia characias L. (Mediterranean spurge)

Published Date

January 2015, Vol.210:13–18, doi:10.1016/j.flora.2014.10.008

Title

Leaf structure and histochemistry of the hardy evergreen Euphorbia characias L. (Mediterranean spurge)

Author

Nikolaos S. Christodoulakis^a,^,

Stavroula Mamoucha^a

Aikaterini Termentzi^b

Nikolas Fokialakis^b

aDepartment of Botany, Faculty of Biology, University of Athens, Athens 15701, Greece
bDepartment of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, University of Athens, Athens 15771, Greece

Received 21 April 2014. Revised 1 September 2014. Accepted 25 October 2014. Available online 3 December 2014. Edited by Shahin Zarre

Highlights

•
A rather xerophyte with not prominent xeromorphic structural leaf characteristics.
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Unique curly trichomes and a peculiar light scattering epidermal surface.
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Latex translocated within an elaborated, “two-storey” network of laticifers.
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First report to focus on the nonpolar secondary metabolites of the latex.

Abstract

The dorsiventral, hypostomatic leaf of Euphorbia characias is investigated to disclose its structural features and the chemical nature of the secondary metabolites produced. Light and scanning electron microscopy along with histochemical tests were employed to investigate the leaf of this well known perennial dwarf Mediterranean shrub. The compact leaf is characterized by numerous, rather uniform, curly, unicellular hairs on both surfaces, vaulty protrusions of the outer periclinal walls of the epidermal cells, prominent on the lower epidermis in particular, and a network of latex producing ducts (laticifers) extending in two layers within the mesophyll. Histochemical reactions proved positive only for alkaloids within the laticifers and phenolic compounds, especially for the condensed tannins accumulated within the vacuole of the epidermal cells. GC–MS and GC-FID analyses of the latex revealed the presence of several secondary metabolites, mainly belonging to the class of triterpenes. Lanosterol, butyrospermol, cycloartenol and lupeol were the major constituents in the extract examined.