Results 171 to 180 of about 1,802 (206)
Some of the next articles are maybe not open access.
COMPARATIVE POLLEN MORPHOLOGY AND TAXONOMIC AFFINITIES IN CYCADALES
American Journal of Botany, 1988Scanning and transmission electron microscopy of pollen grains of 29 species, representing the ten extant genera of Cycadales, has provided valuable insight into their relationships. Pollen grains of these taxa are boat‐shaped, monosulcate, and bilaterally symmetrical.
Bijan Dehgan, Nancy B. Dehgan
exaly +4 more sources
Karyotype evolution by centromeric fission inZamia (Cycadales)
Plant Systematics and Evolution, 1984The chromosome numbers of several species ofZamia from Mexico are reported.Z. paucijuga, distributed from central Oaxaca to Nayarit, has been found to have 2n = 23, 25, 26, 27 and 28. 2n = 28 is the highest chromosome number yet found in the cycads. Karyotypes of this species differ principally in the number of telocentric and metacentric chromosomes ...
MORETTI, ALDO, SABATO S.
openaire +2 more sources
Somatic Embryogenesis in the Cycadales
1995The cycads (Fig. 1) constitute remnant species of an ancient class of gymnosperms, the cycadophytes, that evolved from the free-sporing progymnosperms, which also gave rise to the coniferophytes. According to Gifford & Foster (1989), the cycadophytes have included 3 orders of plants, the extinct Cycadeoidales and Pteridospermales (seed ferns), that are
Richard E. Litz +2 more
openaire +1 more source
General Traits of the Cycadales
1990Vegetative Morphology and Anatomy. Notable contributions to the study of cycad morphology were made by Chamberlain (1919, 1935 and numerous other publications) and his students. The bibliography in Read and Solt (1986) provides entry into the literature.
L. A. S. Johnson, K. L. Wilson
openaire +1 more source
Genome sizes for all genera of Cycadales
Plant Biology, 2011AbstractNuclear DNA content (2C) is reported for all genera of the Cycadales, using flow cytometry with propidium iodide. Nuclear DNA content ranges from 24 to 64 pg in cycads. This implies that the largest genome contains roughly 40 × 109 more base pairs than the smallest genome. The narrow range in nuclear DNA content within a genus is remarkable for
openaire +2 more sources
Maternal inheritance of plastids in Encephalartos Lehm. (Zamiaceae, Cycadales)
Genome, 2001The mode of inheritance of chloroplast DNA has been determined in Encephalartos by employing a restriction fragment length polymorphism analysis of chloroplast DNA. Artificial F1 hybrids were produced between a female specimen of E. natalensis and a male specimen of E. woodii.
CAFASSO D. +3 more
openaire +6 more sources
WHAT IS ZAMIA PRASINA (ZAMIACEAE: CYCADALES)?
2009(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.
Calonje, Michael, Meerman, Jan
openaire +1 more source
Biflavonoids from the seed testa of cycadales
Phytochemistry, 1982Abstract Biflavonoid patterns from ethanolic extracts of the brightly coloured testa of eight species of Cycadales have been determined. Species from the genus Macrozamia are characterized by the occurrence of cupressuflavone- and amentoflavone-based patterns, while the Cycas species contain only amentoflavone-based patterns.
exaly +2 more sources
Possible Early Pennsylvanian Ancestor of the Cycadales
Science, 1990A specimen of Lesleya , previously known only as isolated sterile foliage, has been found with two rows of ovule-bearing receptacles on opposite sides of the petiole. This specimen is from the Lower Pennsylvanian (Namurian B or C) of western Illinois.
openaire +2 more sources
Seed Coat Anatomy of Ceratozamia mexicana (Cycadales)
The Botanical Review, 2004I. Abstract The seed coat furnishes protection with a thick cuticle, tannin cells, mucilage, and a hard sclerotesta. The external layer of the seed coat is a sarcotesta; a thick cuticle covers the external walls of its epidermal cells. This epidermis bears stomates and, in the early stages, trichomes. The subepidermal cells have druses.
María Ydelia Sánchez–Tinoco +1 more
openaire +1 more source