Investigations into Trichomes and Anatomy of Saccocalyx satureioides: A Xeromorphic Shrub Endemic to the Arid Zones of Algeria

Abstract

Saccocalyx satureioides is an endemic sub-shrub that
grows in the wild in a restricted area in Algeria, where it is
protected under national law. It is largely used in folk medicine
and has been the subject of extensive investigation leading to
a comprehensive understanding of its phytochemical traits.
However, its morphological and cytological features remain
poorly understood. The main objective of this work was
to study the morphological, anatomical and karyological
characteristics of S. satureioides and compare them with other
features of the members of Menthinae sub-tribe. All parts of
S. satureioides showed an important indumentum on young
stems, leaves and calyx. Two types of glandular trichomes
were found, the capitate ones and peltate ones, with one
and 12 secretory cells respectively. Additionally, three types
of non-glandular trichomes were observed: unicellular,
bicellular, and pluricellular. Trichome distribution and
density displayed variations among different plant organs. As
well as three types of non-glandular trichomes: unicellular,
bicellular and pluricellular. Trichomes distribution and
density showed variability among organs. Furthermore, the
investigated species showed some adaptive traits to cope with
unpredictive rainfall and the characteristic drought conditions
of its habitat in this region. These traits include the shape of
calyx, which facilitate wind-dispersal of the accrescent fruit,
leaves with a thick cuticle, and myxocarpy of nutlets. In the
course of our research, mitotic metaphase photomicrographs
revealed the presence of 2n=30 chromosomes. To the best of
our knowledge, this chromosome count is reported here for
the first time