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Seed development in Astragalus cemerinus and A. ruscifolius [Fabaceae], and its systematic implications

100%

Riahi M., Zarre S.

Acta Biologica Cracoviensia. Series Botanica

2009

tom 51

nr 1

111-117

This study focuses on seed development in Astragalus cemerinus and A. ruscifolius, two endemic species of Astragalus in Iran. In both species the ovules are campylotropous, bitegmic and crassinucellate. Two polar nuclei fuse before fertilization, forming the diploid secondary nucleus. Division of the primary endosperm nucleus gives rise to coenocytic endosperm; however, part of it becomes cellular at the late globular stage. The first division of the zygote is transverse and the embryo proper forms after several divisions of the terminal cell. The mature suspensor consists of a mass of cells equal in size to the globular embryo proper, with several inflated cells towards its base. This massive suspensor seems to be plesiomorphic, as compared with the biseriate suspensor known only in section Incani. Abnormalities in the embryo proper as well as in the suspensor are observed at the globular stage. In both A. cemerinus and A. ruscifolius, fusion of the polar nuclei occurs in the median regions of the central cell and before fertilization occurs, as is the rule in most of the Papilionoideae, but in species of section Incani as in a few other species of the family, the polar nuclei approach the egg apparatus before fertilization and do not fuse until fertilization. The embryological characters of A. cemerinus and A. ruscifolius are compared with those of other species of Astragalus, and the taxonomic application of these characters as well as their phylogenetic significance are discussed.

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Flower initiation and development in endemic Iranian lily (Lilium ledebourii Boiss.)

71%

Salehi M., Hatamzadeh A., Jafarian V., Zarre S., Cuevas J.

Acta Scientiarum Polonorum. Hortorum Cultus

2018

tom 17

nr 6

This study was performed to depict the anatomical changes in apical meristems in order to determine the flower initiation and development of Iranian lily (Lilium ledebourii). Observations carried out by scanning electron microscope (SEM) on groups of bulbs with different age and size showed that only large (≥55 g and ≥6 cm in diameter) 9-year-old and older bulbs expressed flowering transition, abandoning the juvenile condition. The switch from vegetative to reproductive in the apical meristem was characterized by flattening its dome. Flower initiation started between 10 and 20 days after planting, once the bulbs have passed a period of vernalization of two months at 3°C. The first hint of floral organ definition was noted 30 to 50 days after planting when the outer perianths started to grow followed by inner perianths in a pattern of 3−3. After complementation of flower formation by stamen and pistil appearance and development, flower abortion occurred in some bulbs 30 days after flower initiation. Flower bud abortion could not be linked to the bulb size. Identification of the exact time of flower initiation will be useful to provide proper management of Iranian lily in the process of domestication of this endemic endangered lily.

Ograniczanie wyników

1 Acta Biologica Cracoviensia. Series Botanica

1 Acta Scientiarum Polonorum. Hortorum Cultus

2 Zarre S.

1 Cuevas J.

1 Hatamzadeh A.

1 Jafarian V.

1 Riahi M.

1 Salehi M.

1 2018

1 2009

Wyniki wyszukiwania

Seed development in Astragalus cemerinus and A. ruscifolius [Fabaceae], and its systematic implications

Flower initiation and development in endemic Iranian lily (Lilium ledebourii Boiss.)