BACKGROUND AND AIMS In temperate woody perennials, flower bud development is halted during the winter, when the buds enter dormancy. This dormant period is a prerequisite for adequate flowering, is genetically regulated, and plays a clear role in possibly adapting species and cultivars to climatic areas. However, information on the biological events underpinning dormancy is lacking. Stamen deve...

In the course of a study of pollen wall development in the Gramineae two interesting relationships were noted: the locule wall and tapetal cells were bordered by spheroids which were similar chemically (resistant to acetolysis) and morphologically to the pollen exine. The pollen exine as well as the wall of the spheroids was perforated by submicroscopic channels. In the mature anther the sphero...

in this research, the isolated microspore culture system in 15 rose cultivars was tested. in the first experiment, the effect of rose cultivars on microspore viability and multicellular formation was examined. results showed that the most multicellular structures obtained in ‘apollo’, ‘amarosa’, ‘majic’, ‘candy’, ‘exotic’ and ‘velvet’ varieties. in the second experiment, the effect of various i...

The change in developmental fate of microspores reprogrammed toward embryogenesis is a complex but fascinating experimental system where microspores undergo dramatic changes derived from the developmental switch. After 40 years of study of the ultrastructural changes undergone by the induced microspores, many questions are still open. In this work, we analyzed the architecture of DNA-containing...

radiographic evaluation of the third molar tooth to determine its position and degree of development is an important part in diagnosis and treatment planning, as well as in forensic dentistry procedures. the objective was to investigate the developmental stages of third molars in relation to chronologic age, gender and location (maxillary/mandibular) in an iranian population.the data were colle...

*Address correspondence to: María del Carmen Risueño. Plant Development and Nuclear Organization, Centro de Investigaciones Biológicas, CSIC, Velázquez 144, 28006 Madrid, Spain. e-mail: [email protected] ABSTRACT The use of dihaploid plants for obtaining new varieties has been widely reported in different plant species. The regeneration of these plants is carried out by in vitro induction of ...

Carbohydrate starvation is an efficient stress treatment for induction of microspore embryogenesis. Transcriptome analysis of anthers response to mannitol treatment using the 22k Barley1 GeneChip revealed large changes in gene expression. Statistical analysis and filtering for 4-fold or greater changes resulted in 2,673 genes, of which 887 were up-regulated and 1,786 down-regulated. Great diffe...

The maize (Zea mays) spikelet consists of two florets, each of which contains three developmentally synchronized anthers. Morphologically, the anthers in the upper and lower florets proceed through apparently similar developmental programs. To test for global differences in gene expression and to identify genes that are coordinately regulated during maize anther development, RNA samples isolate...

Callose plays an important role in pollen development in flowering plants. In rice, 10 genes encoding putative callose synthases have been identified; however, none of them has been functionally characterized. In this study, a rice Glucan Synthase-Like 5 (GSL5) knock-out mutant was isolated that exhibited a severe reduction in fertility. Pollen viability tests indicated that the pollen of the m...

Grain sorghum (Sorghum bicolor) crop yield is significantly compromised by high temperature stress-induced male sterility, and is attributed to reduced cell wall invertase (CWI)-mediated sucrose hydrolysis in microspores and anthers leading to altered carbohydrate metabolism and starch deficiency in pollen (Jain et al., 2007). Sorghum plants were grown under season-long ambient (30/20 degrees C...