PubMed · 13629102
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1959-03-14. OCCUPATIONAL groups.. https://pubmed.ncbi.nlm.nih.gov/13629102/
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Megagametogenesis of soybean, Glycine max (L.) Merr., cultivars Clark and Clark k2, and F1 hybrid of Clark (female parent) crossed with Clark k2 (male parent) were studied using stereo light microscopy and confocal scanning laser microscopy. Reproductive development in Clark and Clark k2 plants was compared to F1 hybrid plants. In mature pods, 6.4% of the ovules of Clark, 8.1% of the ovules of Clark k2, and 41.4% of the ovules of F1 hybrid plants were aborted. This female partial sterility was due to incomplete megagametophyte development: undeveloped polar nuclei-or developed but not in a position for fertilization; increased megagametophyte wall thickness; abnormal shape and/or premature degeneration of synergids and intact synergids throughout the life of the ovule; egg cell not well-developed or absent; and megagametophyte remaining uninucleate. Each of these abnormalities contributed to either lack of double fertilization or early megagametophyte abortion.
Semen analysis is a basic step in the investigation of several disturbances affecting the male genital tract. Analysis of seminal parameters provides important clinical information on the spermatogenesis and functional competence of spermatozoa, as well as on the secretory pattern of the accessory genital glands. Semen analysis is particularly useful in the evaluation of couples requiring fertility investigation (to detect genital infections and pathologies) and in verifying the influence of environmental factors, drugs, lifestyle, chemical products, and professional activities on several diseases affecting male reproductive health. Measure of semen quality is of substantial interest for diagnoses in clinical urology, andrology, and gynecology. Currently, basic requirements for semen analysis are standardized by World Health Organization (WHO) guidelines that describe several procedures for an objective evaluation of the semen quality with diagnostic purposes. These guidelines include: parameters for the physical and biochemical evaluation of semen; parameters for the analysis of sperm characteristics; and other seminal parameters that can be easily adopted in any laboratory. This report summarizes current concepts on semen analysis and the significance of the seminal parameters for reaching a diagnosis based on the procedures recommended by WHO guidelines.
Recent discoveries show that LAT52 and LePRK2, two pollen-specific proteins, interact in what might be an autocrine signaling system. This exciting finding indicates that successful fertilization requires ligand-receptor kinase signals that regulate pollen-tube growth. The stage is now set to identify other components of this pathway and to explore their connections with the many signals exchanged between pollen and pistil.