Pollen, seed and fruit morphology of the genus Hesperis L. (Brassicaceae) in Austria and their taxonomic value Padure I.M. 1, S. Šimić. 2, Zernig, K.3 & Heber, G. 4 1
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Universalmuseum Joanneum, Botanik, Weinzöttlstraße 16, 8045 Graz, ioanapadure@yahoo.com, Graz Centre for Electron Microscopy (ZFE), Steyrergasse 17, 8010 Graz, sanja.simic@felmi-zfe.at 4 Universalmuseum Joanneum, Botanik, Weinzöttlstraße 16, 8045 Graz, kurt.zernig@museum-joanneum.at, Universalmuseum Joanneum, Botanik, Weinzöttlstraße 16, 8045 Graz, gerwin.heber@museum-joanneum.at
Introduction Hesperis L. is native to Europe, to Marocco, and to temperate and tropical Asia, but centered to the temperate zones of Eurasia. This genus comprises ± 56 species, 49 of them occurring in Europe and 3 species occur in Austria: H. tristis and H. sylvestris with glandular on stem and pedicels, and the eglandular species H. matronalis ssp. matronalis and ssp.candida (endangered, therefore protected by law in Styria). The species are characterized mainly by white and purplish to violet petals, or yellow-green with brown-purplish veins in H. tristis- an endangered rarity in Austria, growing only in the Pannonian area. c
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Hesperis L.: a. H.m. ssp. matronalis, b. H.m. ssp. candida, c. H. sylvestris, d. H. tristis.
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This study presents macro- and micromorphological characters of pollen, seed and fruit, including type of trichomes, fruiting pedicel hair types and density, seed coat pattern including seed wings, type of pollen, and type of fruit septum. Material and Methods Plant material: the investigation is based herbarium specimens from GJO/GZU, which were collected from different parts of Austria. SEM of pollen, seeds and fruits: the samples were coated with Gold/Palladium layer with the thickness of 5-10 nm and examined with Zeiss Ultra 55 SE image using ETD (Everhart Thornly Detector) at 5.00 kV. Results: The trichome types on fruiting pedicels are various: capitate glands (short-stalked or with 2-celled stalk) or eglandular, which may be simple (short or long) or bifurcated (Y-type or with unequal arms). The siliquae are terete or ± flattened, glabrous and rarely with simple trichomes, straight or slightly curved, erect, or ascending to erect. The shapes of the seeds are very similar: elliptic to oblong, with a visible hilum and a more or less perceptible furrow, sometimes with apical wings. All investigated species present reticulate or ocellate-papillate seedcoat with epidermal cells showing tetra- to septagonal as well as ± isodiametric patterns that forms a network. The pollen is isopolar, inoperculate, prolatespheroid to subprolate, tricolpate, with a reticulate exina. b
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Pollen grains: a. H.m.ssp. matronalis, b. H.m.ssp. candida, c. H. sylvestris, d. H. tristis
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Seeds / fruits: a, A. H.m.ssp. matronalis, b, B. ssp. candida, c. H. sylvestris, d. H. tristis
Species
H. matronalis ssp. matronalis
H. matronalis ssp. candida
H. sylvestris
H. tristis
Pollen type [Fig. a-d] Size PxE (µm) Distal and proximal pole Polar view (P) Equatorial view (E) Exine type Lumen shape Seeds type [Fig. a-d] Shape of seed
tricolpate, isopolar 18,3-33,3 x 17,2-19,4 rounded to truncate circular prolate to subprolate, rare perprolate reticulate polyedrical 4-7 sided glabrous oblong to elliptic or elliptic-elongate, surface longitudinal pitted dark brown ± truncated, yellowish 2,2-2,8 x 0,9-1,1 smooth reticulate linear, terete or ± tortulose 40-100 x 1-1,9 max. 23 ± constricted btw. seeds, with conspicuous vein glabrous almost entire membranous ascending to erect, slender 2-9 x 0,6-1,8 absent glabrous // densely simple or bifurcated, short + long hairs
tricolpate, isopolar 17,2-31,9 x 15,2-17,3 rounded circular prolate to subprolate, rare spheroidal reticulate irregular-amorphous, sinuous muri glabrous oblong-elliptic to ovate-elongate, surface longitudinal pitted reddish-brown rounded, yellowish 2,9-3,3 x 1-1,2 sculptured ocelate-papillate in the middle of the lumen linear, terete 30-80 x 1-1,1 max. 26 constricted btw. seeds, with conspicuous vein simple or Y-like almost entire membranous ascending to erect, slender 2-8,5 x 0,6-1,7 absent glabrous // densely simple or bifurcated
tricolpate, isopolar 29,5-32,5 x 16,8-18,5 rounded circular prolate to subprolate reticulate polyedrical 3-6 sided glabrous ovate to prolong-elliptic, surface pitted in longitudinal rows cinnamon-brown ± rounded / absent 2,6-3 x 1-1,4 sculptured reticulate moderately curved, cylindrical 20-90 × 0,8-1,5 max. 17 ± constricted btw. seeds, inconspicuous vein glabrous almost entire membranous ascending to erect, ± thickened 2-9 x 0,5-1,9 present densely glandular (capitate) and simple or bifurcated
tricolpate, isopolar 34,9-35,7 x 20,9-22,1 rounded circular prolate to ± perprolate reticulate polyedrical 3-5 sided glabrous oblong to ovoid to ovate with a deep furrow on ventral side brown absent 1,8-2,3 x 1-1,2 sculptured ocelate-papillate in the middle of the lumen flattened-tetraquetrous 40-170 × 2,8-5,1 max. 16 straight, with a very thick median vein glabrous membranous to more than half thickened, ± divaricate 2-10 x 0,5-2,5 present densely glandular (capitate) and simple
Color Apical wings Size (mm) Seed coat Ornamentation Wart position Siliqua [Fig. A-B] Size L x W (mm) Number of seeds / fruit Valves Type of trichomes Septum Fruiting pedicel Size L x W (mm) Glandular trichomes Trichomes type and density