Chubar. Ontogenesis and morphogenesis of the Far Eastern species of genus Deutzia. In: The East Asian Flora: and its role in the formation of the world’s vegetation

Ontogenesis and morphogenesis of the Far Eastern species of genus Deutzia

Elena A. CHUBAR
Far Eastern Marine Biosphere Reserve FEB RAS, Vladivostok, Russia

The species of the genus Deutzia Thunb. are widely used in landscaping and gardening as relatively tolerant decorative cultures. The experience of introduction of some of these species accounts for about 100 years. However, beside the brief report on the biomorphological features of the Deutzia species by Mazurenko and Khokhrjakov (1977), we have a shortage of information on the development of these species in situ. This study focuses at biology and morphology of D. glabrata Kom. and D. parviflora Bunge in situ, in the islands and on the coast of the Peter the Great Bay, Sea of Japan. The typical habitats of these species are stony sites and rock outcrops, with different light conditions, located at altitudes between 25 and 300 m a.s.l. within the belt of nemoral mixed broadleaved-conifer (Abies holophylla, Pinus koraiensis) forests. Both species form 2 different ecobiomorphs depending on substrate type.

1) The vegetatively-fixed geoxyle shrubs 2.5 (3) m high with regular changes of skeletal orthotropic axes (shoot forming systems) and crown shoots is developed mainly on well-drained rocky slopes covered with developed brown mountain-forest soils with deep humic horizon in conditions of a moderate shade. The life span of such plants lasts for about 25-35 years (up to 50 years in best conditions).

2) Vegetatively-mobile epi- and hypogeogeneus xylorhizomes geoxyle shrubs 0.9-2.5 (3) m high, with above-ground and underground heterotropic shoots grow on the stony and rocky sites and form clumps and clones from dozens and sometimes hundreds of individuals (partial bushes). They may be developed in both open areas (at the forest margins) and under the forest canopy, in conditions of moderate to strong shading. The formation of vegetatively-mobile ecobiomorph is caused by root sprawling and prostrated shoots and the development of surface and underground rhizomes producing subsidiary axes and partial bushes. The life span of such clones is comparable to the functioning time of community dominants.

D. glabrata and D. parviflora have 2 variants of the ontogenesis: simple and complex. The latter is characterized by the formation of clumps and clones caused by the prostrated branch rooting and by the xylorhizome formation.