GHOSH, NABARUN1*, A. CHATTERJEE2, and DON W. SMITH3. 1Department of Life, Earth and Environmental Sciences, West Texas A& M University, Canyon, TX 79016 USA; 2CAS, Department of Botany, University of Calcutta, Calcutta, 700019 India; 3Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA. - Acacia, Albizia, Cassia and Dalbergia : seed anatomy with Light and Scanning Electron Microscopy.
Acacia, Albizia, Cassia and Dalbergia are four genera
of Leguminosae comprising trees that produce valuable forest products.
Ultrastructural features obtained from SEM often constitute a valuable
source of information in diagnosing already circumscribed taxa and/or
in phylogenetic inference. We carried out micromorphological studies
on seeds using a light microscope and SEM. We cut transverse and
longitudinal sections of the seeds and observed the sections from
different regions of seeds: midseed, near the hilum and two distal
ends. SEM study on the seed sections revealed the size, shape, and
number of tiers and cellular organization of the epidermis,
hypodermis, endosperm and internal structural details. We observed the
distinctive anatomical features of each species by which they could be
differentiated from the other species with SEM (Ghosh et.al, 1997). We
observed epidermal cells that were round, columnar, cuboidal or
sometimes elliptical. The characteristic presence of "hour glass
cells" was noted in the hypodermis of some species of
Caesalpiniae. Two species of Cassia (siamia and
spectabilis)contained hourglass cells with variation in number and
orientations. We observed a multiseriate epidermis with double
palisade layer in three species of Cassia (glauca, siamia and
spectabilis). In 3 species of Dalbergia the epidermal layer
was but the hypodermal layer was broad having a pattern characteristic
to each species. Stomata were evenly distributed in the storage tissue
of seeds of A. falcataria and D. sissoo. Cross sections
of these seeds appeared green under a dissecting scope indicating
possible photosynthetic activities in the storage tissue. Endosperm
pattern was different in Albizia falcataria and A. lebbeck,
D. assamica, and D. latifolia. Again, in the two species
of Cassia, (siamia, spectabilis) the endosperm pattern was
species specific. We also studied the seed coat pattern that added new
diagnostic information on the tree species.
Key words: Acacia, Albizia, Cassia and Dalbergia, Leguminous trees, Seed anatomy, SEM