SPOROPOLLENIN ACCUMULATION IN NICOTIANA TABACUM L. MICROSPORE WALL
DURING ITS DEVELOPMENT
N.P. Matveyeva,1,* S.V. Polevova,2 A.V. Smirnova,1 I.P. Yermakov 1
1 Plant Physiology Department and 2 Higher Plant Department of Biology Faculty,
M.V. Lomonosov Moscow State University;
* e-mail: n.matveyeva@yandex.ru
Accumulation of sporopollenin components in microspore wall, its polymerization dynamics and possible
participation of reactive oxygen species (ROS) in this process has been studied. For this purpose fluorescent and
electron microscopy (TEM) was used. It has been determined that phenylpropanoid components of sporopollenin
that form the exine accumulate in the microspore cell wall at the middle and late tetrad stages. At the late tetrad
stage, they fully cover the microspore surface and accumulate abundantly in aperture areas. In accordance
with this, numerous thick sporopollenin lamellae, electron-dense and acetolysis-resistant, emerge in aperture
areas. Exine in the areas between apertures includes both acetolysis-resistant sporopollenin and washout components.
These particular parts of the wall are intensively stained with fluorescent dye MitoSOX, which detects the
presence of ROS. The staining disappeared after the treatment of microspore with superoxide dismutase, demonstrating
the presence of superoxide in the exine. Superoxide easily converts to hydrogen peroxide, which
can cause oxidative polymerization of sporopollenin components, leading to the formation of chemically stable
biopolymer. The data obtained favor the hypothesis of ROS involvement in the formation of sporopollenin.
Key words: exine, microspore tetrad, sporopollenin, ROS
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