S. Wada, B.M. Reed
The genus Rubus exhibits morphological diversity and a wide range of reproductive systems and habitats. We examined seed coat ultrastructural morphology of seed accessions of 10 subgenera preserved at the US Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository (NCGR), Corvallis, Oregon, using scanning electron microscopy (SEM). SEM images were taken of 56 seed samples collected worldwide. Macromorphological characteristics differed among groups at the subgenus level. Chamaemorus, Cyclactis (except R. saxatilis L.), Idaeobatus, Lampobatus, Malachobatus, and Michranthobatus have similar exomorphic patterns. R. odoratus L. and R. parviflorus Nutt. (subg. Anoplobatus) had a unique hilar end hole. R. saxatilis had seed coat sculpturing inconsistent with its assigned subg. (Cyclactis) and appeared more in common with subg. Idaeobatus. The subg. Rubus and Idaeobatus showed conspicuous patterns of reticulate and rugose surface relief of the outer cell walls. Species belonging to the subg. Rubus had steeper-edged truncate or acute lateral ridges with a wide and protruded raphal region, while Idaeobatus had smoothly curved rounded ridges and raphal region. The two species in subg. Chamaemorus showed areticulate, finely textured surface with flat or no secondary cell wall protrusion and a ridged raphe. For R. arcticus L., subg. Cyclactis, accessions from three geographical regions had consistent microsculpture patterns. These morphological characteristics of Rubus seed revealed by SEM provide additional information to identify infrageneric levels.
Wada, S. and Reed, B.M. (2008). MORPHOLOGICAL ANALYSIS OF RUBUS SEED. Acta Hortic. 782, 67-74
DOI: 10.17660/ActaHortic.2008.782.5
blackberry, exomorphology, microsculpturing, raspberry, scanning electron microscopy, seed coat, subgenus, SEM, taxonomy, testa

Acta Horticulturae