Morphology and germination characteristics of seeds with underdeveloped embryo
Svetlana V. NESTEROVA
Botanical Garden-Institute FEB RAS, Vladivostok, Russia
Species with an undeveloped embryo account for ca. 1820 % of the flora of the
Far East. Embryo formation in seed at the maternal plant can stop at different
embryogenesis stages. The embryo remains small in comparison with endosperm
and mature seeds dont germinate. Seeds of 15 herbaceous spring-blooming species
from 5 plant families were studied. Seed linear dimensions varied greatly
between the species. Caltha silvestris (2.2 x 1.1 mm) and Hylomecon vernalis
(2.4 x 1.6 mm) have the smallest seeds. Adonis amurensis (3.6 x 2.5 mm) has
somewhat larger seeds and the largest seeds were observed in Arsenjevia
glabrata (7.1 x 4.7 mm). Embryo lengths and its development stages are speciesspecific.
In mature seeds of Enemion raddeanum and Ranunculus franchetii
embryo is pyriform 0.10.2 mm long. In cordate embryos of Adonis amurensis and
Hylomecon vernalis the primordial cotyledon is clearly visible. The embryo length
is 0.20.3 mm. Embryo of Anemonoides reflexa is 0.30.4 mm long, cotyledons
compose ca. 30 % of its length. In hypocotyl and cotyledon vascular bundles are
evident. After seed dissemination, the embryos are developing during summer and
autumn. Postembryonic embryo development lasts from 4055 days in Hepatica
asiatica and Asarum sieboldii to 110120 days in Epimedium macrosepalum
and Eranthis stellata. It was found that seeds of Anemonoides reflexa, Gagea
nakaiana and Lloydia triflora need morphological endogenic dormancy and have
summer or autumn germination. Seeds of Arsenjevia rossii, Plagiorhegma dubia
and Caltha silvestris having morpho-physiological type of endogenic dormancy
germinate next spring after natural stratification by low winter temperatures. It
was revealed that most species produce recalcitrant seeds containing 5070 % of
moisture necessary for embryo's development. After 23 months storage seeds
lose germination ability.
© 2012 Organizing Committee
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