#fertilization

• Acrogamy — A physiological and structural fertilization process in seed plants characterized by the pollen tube entering the ovule exclusively through the micropyle (the apical opening); porogamy.
• Acrosome — A vesicular cellular formation, resembling a specialized lysosome, located as a cap or protective envelope on the anterior portion of the spermatozoon head nucleus. This structural organelle, derived from the Golgi apparatus during spermiogenesis, contains a large amount of potent hydrolytic enzymes (such as hyaluronidase and acrosin) destined to dissolve the outer protective zones of the ovum (zona pellucida) to allow penetration and biological fertilization.
• Adelphogamic — A term describing an organism, plant, or biological structure that reproduces through fertilization between closely related individuals or through the fusion of sexual cells originating from the same strain or sister strains. As a noun, it represents any plant specimen that exhibits this particular type of reproductive isolation and restricted genetic compatibility.
• Adelphogamy — A form of reproduction or fertilization method found in some plants, fungi, and lower organisms, consisting of the fusion of two gametes or two sexual cells originating from sibling individuals, directly related strains, or the same parent organism. This type of extreme biological inbreeding tends to fix existing genetic traits, limiting diversity and variability within the population.
• Allogamous — A term describing a plant organism or a species that reproduces exclusively or predominantly through cross-fertilization (allogamy), meaning the union of gametes originating from different individuals. In a structural sense, allogamous plants have developed complex adaptive morphological and physiological mechanisms (such as self-incompatibility, dioecy, or protandry) to prevent self-pollination and ensure high genetic variability.
• Allogamy — A biological phenomenon and mode of plant reproduction characterized by cross-pollination; the process whereby the ovules of a flower are fertilized by pollen originating from another flower of the same specimen or from a different individual of the same species. Allogamy represents the primary evolutionary engine in the plant kingdom, ensuring a constant flow of new genes and heightened disease resistance.
• Androplasm — A specific cytoplasmic component or male germ plasm contained within male gametes (spermatozoa or sperm cells), which plays an essential structural role during the fertilization process, interacting with the gynoplasm (female cytoplasm) to ensure the early metabolic activation of the fertilized egg.
• Apogamous — Developing through apogamy, pertaining to the formation of a sporophyte directly from a vegetative cell of the gametophyte, without the occurrence of fertilization or gametic fusion; characterized by independent asexual reproduction. This biological phenomenon is frequently found in certain species of pteridophytes (ferns) and angiosperms, ensuring species perpetuation under ecological isolation.
• Apogamy — A biological phenomenon and type of asexual reproduction in plants (a form of apomixis) consisting of the development of a sporophyte directly from the vegetative cells of the gametophyte (such as synergids or antipodals), without gametic participation and without fertilization occurring. It represents a crucial anatomical mutation studied in angiosperm and pteridophyte evolution, allowing multiplication without genetic recombination.
• Apomixis — A biological phenomenon and mode of asexual reproduction in higher plants (angiosperms and pteridophytes) consisting of embryo formation and viable seed production directly from the ovule's maternal tissues, without gametic fusion and without fertilization occurring; natural seed cloning. It represents a major evolutionary strategy studied in phytogenetics for the integral preservation of the maternal genotype.
• Autocarp — A structural fruit resulting exclusively from the process of self-fertilization (autogamy) without any intervention of pollen from another flower or surrounding plant. As an adjective, it describes a plant structure capable of self-fruiting.
• Self-fertilization — The act of self-fertilizing and its result; the biological process of fusing male and female sexual elements produced by the same individual organism. In botany, this phenomenon is also known as autogamy and is considered an efficient reproductive strategy in unstable environments, though it reduces the genetic variability of offspring.
• Self-fertilization — A less frequent morphological variant of the term 'autofecundare'; the biological phenomenon through which male and female gametes produced by the same individual fuse to form a zygote. It is sometimes used in older scientific literature or plant physiology treatises to emphasize the biochemical act of self-fertilization, being synonymous with autogamy.
• Autogamous — The feminine form of the adjective autogamous; it characterizes a plant species, a flower, or a biological population within which reproduction occurs exclusively or predominantly through self-fertilization. In plant genetics, an autogamous line is utilized to obtain genetically pure organisms, eliminating the risks of unpredictable variations brought by foreign pollen.
• Autogamy — A mode of reproduction characteristic of certain plants and lower organisms, consisting of self-fertilization or self-pollination, a process whereby the fusion of gametes originates from the same individual. This evolutionary biological mechanism guarantees the genetic stability of the species and its perpetuation in isolated or harsh habitats, eliminating structural reliance on external factors such as pollinating insects, wind, or water, although it limits long-term genetic diversity and recombination.
• Autohomogamy — A biological phenomenon and reproductive mechanism found in certain plant species or lower organisms, characterized by the simultaneous maturation of male and female sexual organs (androecium and gynoecium) within the same flower or individual, directly facilitating mandatory self-fertilization. This strict temporal correlation guarantees reproductive success in isolated environments but severely limits the genetic diversity of the offspring.
• Automixis — A modified form of sexual reproduction or self-fertilization characterized by the fusion of two haploid nuclei originating from the same mother cell or the same individual, without the intervention of any external gamete. In genetics and mycology, this biological process ensures the perpetuation of the species under extreme ecological isolation, allowing the restoration of the zygote's diploid state from a single lineage, though it reduces the genetic variability of offspring.
• Self-pollination — A biological reproductive process in spermatophyte plants, characterized by the transfer of pollen grains from the anthers to the stigma of the same flower (autogamy) or of another flower belonging to the same individual (geitonogamy). This endogenous structural mechanism ensures fertilization in the absence of external pollination vectors, but limits the genetic variability of the offspring by increasing homozygosity.