Currants are important berry crops cultivated for medicinal purposes. Most currant cultivars are crossings between Ribes nigrum varieties, while many Ribes species are not used in hybridisation. Recent research on Ribes crossbreeding is scarce. Hybridisation of wild species can improve reproductive success and the taste of fruit. However, hybrids of certain currant species cannot produce fully formed berries. Crossbreeding of currant species was performed in Northwest Russia (Saint Petersburg Botanical Garden). The research included both introduced (R. sachalinense, R. sanguineum, R. rubrum, R. hispidulum, R. mandschuricum, R. spicatum, R. latifolium) and native species (R. aureum, R. alpinum, R. nigrum). The research aimed to identify the hybridisation system, pollination mechanisms and hybrids with the highest percentage of fruit and seed set. Pollen fertility and viability were assessed. Pollen is fertile (acetocarmin staining: 80.3% for R. alpinum and 96.0% for R. mandschuricum); germination is active on nutrient medium and in situ, especially in R. sachalinense, R. aureum and R. spicatum (54.2–41.8%). Pollen germination can be irregular. Flowers were castrated before pollination. Optimal hybrids with a high percentage of fruit set were identified: R. alpinum x R. mandschuricum, R. alpinum x R. aureum, R. sachalinense x R. sanguineum, R. rubrum, R. hispidulum.
ОСОБЕННОСТИ СТРОЕНИЯ ГИНЕЦЕЯ И СЕМЯЗАЧАТКА У ПРЕДСТАВИТЕЛЕЙ РОДОВ CERASUS, MICROCERASUS И AMYGDALUS (ROSACEAE)Изучен морфогенез гинецея и семязачатка у представителей родов Cerasus, Microcerasus и Amygdalus (Rosaceae). Псевдомономерный гинецей представлен двумя плодолистиками: фер-тильным (в нем формируются 4 семязачатка, из которых 2 останавливаются в развитии на стадии примордия) и стерильным, в котором семязачатки не образуются. Гинецей синкарп-ный. Семязачаток геми-анатропный, крассинуцеллятный, унитегмальный, мезохалазальный, с коротким фуникулусом, массивным рафе и гипостазой. Интегумент имеет дермально-суб-дермальное происхождение. Впервые в нуцеллусе изученных видов выявлены постамент и подиум. Моноспорический зародышевый мешок формируется по Polygonum-типу.
PECULIARITIES OF GYNOECIUM AND OVULE STRUCTURE IN REPRESENTATIVES OF GENERA CERASUS, MICROCERASUS AND AMYGDALUS (ROSACEAE)Herzen State Pedagogical University of Russia, 48, Moika nab., St. Petersburg, 191186, Russian Federation; yandovkatgu@mail.ru; ivan.shamrov@gmail.com Th e gynoecium and ovule morphogenesis in Cerasus, Microcerasus and Amygdalus was studied. Pseudomonomerous gynoecium consists of two carpels: a large carpel is fertile (4 ovules are formed in it, two ovules only develop, whereas the others stay at primordial stage) and a small sterile carpel (the ovules do not arise). Th e gynoecium in Cerasus, Microcerasus and Amygdalus may be determined as syncarpous. Th e ovule is hemi-anatropous, crassinucellate, unitegmic, characterized by short funiculus, massive raphe, mesochalase and hypostase. Th e integument is of dermal-subdermal origin. Th e postament and podium in the nucellus in species were studied for a fi rst time. Embryo sac develops by Polygonum-type. Refs 26. Figs 3.
The paper studies the anatomic and morphological peculiarities of fruits and seeds of 17 species of Sorbus introduced in the Saint Petersburg Botanical Garden, including one species of local flora, S. aucuparia L. f. rosea. The fruits and seed of Sorbus species are diverse, which can be used as taxonomy criteria in discussion of arguable issues arising during the systematization of the plant genus. The species differ in the external color of a fruit and morphology of seeds in them which can be dissimilar within one fruit or even one dissepiment. Seeds differ the most by shape and dimensions, structure and number of cell layers in the testa. In primitive and archaic species, the number of cell layers in the testa, especially parenchyma layers, is large (6–7 layers in S. cashmiriana and S. roopiana). The smallest number of parenchyma layers (2–4) is typical for more evolutionary advanced species S. sambucifolia, S. ‘Joseph Rock’, S. alnifolia, S. commixta and S. luristanica.
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