Pollination, Mating, and Reproduction in Plants

2011 ◽  
Author(s):  
Pat Willmer
Keyword(s):  
Life Cycle ◽  
Sexual Reproduction ◽  
Male Gamete ◽  
Plant Reproduction ◽  
Pollen Grain ◽  
Evolutionary Change ◽  
Self Fertilization ◽  
Plant Mating Systems ◽  
Cross Fertilization ◽  
Plant Sex

This chapter examines pollination, mating, and reproduction in plants. Plant reproduction can be either sexual or asexual, but the generation of new variants (which is the underlying necessity for adaptation to new or changing conditions and for evolutionary change) requires that at some point in the life cycle sexual reproduction occurs. In the case of angiosperms, the pollen grain is the male gamete, the equivalent of a spore in simpler plants. The ovule (egg) contains the female gamete. The chapter first provides an overview of plant fertilization before discussing plant sex and plant mating systems. It then considers the benefits of cross-fertilization and self-fertilization in plants, along with methods for avoiding selfing within a flower. It also describes methods for avoiding selfing between flowers within a plant and concludes with an analysis of methods for ensuring selfing.

Cross-fertilization as a reproductive strategy in a tissue flukesDidymosulcus katsuwonicola(Platyhelmintes: Didymozoidae) inferred by genetic analysis

Parasitology ◽  
2015 ◽  
Vol 142 (11) ◽  
pp. 1422-1429
Author(s):  
IVONA MLADINEO ◽  
MARINA TOMAŠ ◽  
RINO STANIĆ
Keyword(s):  
Life Cycle ◽  
Haplotype Diversity ◽  
Common Mechanism ◽  
High Haplotype Diversity ◽  
Atlantic Bluefin Tuna ◽  
Food Borne ◽  
Self Fertilization ◽  
Successful Fulfillment ◽  
Cross Fertilization ◽  
Host Tissues

SUMMARYMitochondrial DNA locus cytochrome oxidase I was used to asses intraspecific genetic diversity of a didymozoid speciesDidymosulcus katsuwonicola.Adult forms of this species live encapsulated in pairs in the gills of the reared Atlantic bluefin tuna (Thunnus thynnus). The life cycle of this food-borne parasites and its migration in the host tissues after releasing from the digestive tract to the definitive site in the gills are unknown. Our goal was to assess whether two encysted didymozoids share the same haplotype, indicative of a common maternal origin, as well as the extent of cross- in respect to self-fertilization strategy. Intraspecific comparison showed high haplotype diversity, while the presence of two matching haplotypes within a single cyst encompassed only 17% of sampled individuals. This infers that cross-fertilization between paired individuals within the cyst is more common mechanism than self-fertilization. Such hermaphroditic parasite's trait suggests the existence of intricate infection and reproduction mechanisms, presumably as an adaptation for successful fulfillment of their indirect life cycle through dissemination of genetically more diverse and consequently more fit offspring.

scholarly journals Serological estimation of the level of cross-fertilization in the monoecious liverwort Pellia epiphylla n = 9

2014 ◽  
Vol 56 (3) ◽  
pp. 391-398
Author(s):  
Wiesław Prus-Głowacki ◽  
Roman Zieliński
Keyword(s):  
Life Cycle ◽  
Genetic Variability ◽  
Shikimic Acid ◽  
Self Incompatibility ◽  
Protein Antigens ◽  
Acid Dehydrogenase ◽  
Self Fertilization ◽  
Cross Fertilization

Using protein antigens as markers, antigenic differentiation of progenies obtained from individual sporangia was examined. The experiments were expected to permit estimation of cross-fertilization frequency in the monoecious liverwort species, <em>Pellia epiphylla</em>, n = 9. The results obtained indicated segregation into two serological types, i.e. pointed to cross-fertilization, in approximately, 80% progenies. In correlation with electrophoretic studies, employing two peroxidase alleles and two shikimic acid dehydrogenase alleles as markers, the result made possible the establishment of cross-fertilization frequency at approximately 93% The data may indicate an absence of self-fertilization in this liverwort species and, thus, self-incompatibility. This may be included among the facors responsible for maintenance of genetic variability in populations of this species, in which haplophase is the prevalent phase of its life-cycle.

scholarly journals Unholy marriages and eternal triangles: how competition in the mushroom life cycle can lead to genomic conflict

2016 ◽  
Vol 371 (1706) ◽  
pp. 20150533 ◽  
Author(s):  
Sabine Vreeburg ◽  
Kristiina Nygren ◽  
Duur K. Aanen
Keyword(s):  
Life Cycle ◽  
Sexual Reproduction ◽  
Male Gamete ◽  
Life Cycles ◽  
Spore Formation ◽  
Sexual Life ◽  
Gamete Fusion ◽  
Extramarital Affairs ◽  
Living Apart Together ◽  
Genomic Conflict

In the vast majority of sexual life cycles, fusion between single-celled gametes is directly followed by nuclear fusion, leading to a diploid zygote and a lifelong commitment between two haploid genomes. Mushroom-forming basidiomycetes differ in two key respects. First, the multicellular haploid mating partners are fertilized in their entirety, each cell being a gamete that simultaneously can behave as a female, i.e. contributing the cytoplasm to a zygote by accepting nuclei, and a male gamete, i.e. only donating nuclei to the zygote. Second, after gamete union, the two haploid genomes remain separate so that the main vegetative stage, the dikaryon, has two haploid nuclei per cell. Only when the dikaryon produces mushrooms, do the nuclei fuse to enter a short diploid stage, immediately followed by meiosis and haploid spore formation. So in basidiomycetes, gamete fusion and genome mixing (sex) are separated in time. The ‘living apart together’ of nuclei in the dikaryon maintains some autonomy for nuclei to engage in a relationship with a different nucleus. We show that competition among the two nuclei of the dikaryon for such ‘extramarital affairs’ may lead to genomic conflict by favouring genes beneficial at the level of the nucleus, but deleterious at that of the dikaryon. This article is part of the themed issue ‘Weird sex: the underappreciated diversity of sexual reproduction’.

Life cycle of Spirogyra decimina var. juergensii (Kütz.) O.V. Petlovany from Lake Baikal

2018 ◽  
pp. 1-7
Author(s):  
Ekaterina A. Volkova
Keyword(s):  
Life Cycle ◽  
Sexual Reproduction ◽  
Lake Baikal

Identification of Spirogyra species is based on the morphology of the fertile specimens. This work provides characteristics of growth and the time of reproduction of Spirogyra decimina var. juergensii in Lake Baikal and describes sexual reproduction and conditions for germination of new filaments of this species isolated from the lake.

Heterozygote advantage and the evolution of a dominant diploid phase.

Genetics ◽  
1992 ◽  
Vol 132 (4) ◽  
pp. 1195-1198 ◽  
Author(s):  
D B Goldstein
Keyword(s):  
Life Cycle ◽  
Sexual Reproduction ◽  
Genetic Factor ◽  
Higher Plants ◽  
Heterozygote Advantage ◽  
Seed Plants ◽  
Sexual Species ◽  
Evolutionary Forces ◽  
Eukaryotic Species ◽  
Selection For

Abstract The life cycle of eukaryotic, sexual species is divided into haploid and diploid phases. In multicellular animals and seed plants, the diploid phase is dominant, and the haploid phase is reduced to one, or a very few cells, which are dependent on the diploid form. In other eukaryotic species, however, the haploid phase may dominate or the phases may be equally developed. Even though an alternation between haploid and diploid forms is fundamental to sexual reproduction in eukaryotes, relatively little is known about the evolutionary forces that influence the dominance of haploidy or diploidy. An obvious genetic factor that might result in selection for a dominant diploid phase is heterozygote advantage, since only the diploid phase can be heterozygous. In this paper, I analyze a model designed to determine whether heterozygote advantage could lead to the evolution of a dominant diploid phase. The main result is that heterozygote advantage can lead to an increase in the dominance of the diploid phase, but only if the diploid phase is already sufficiently dominant. Because the diploid phase is unlikely to be increased in organisms that are primarily haploid, I conclude that heterozygote advantage is not a sufficient explanation of the dominance of the diploid phase in higher plants and animals.

scholarly journals Observation of asexual reproduction with symbiont transmission in planktonic foraminifera

2020 ◽  
Vol 42 (4) ◽  
pp. 403-410 ◽  
Author(s):  
Haruka Takagi ◽  
Atsushi Kurasawa ◽  
Katsunori Kimoto
Keyword(s):  
Life Cycle ◽  
Sexual Reproduction ◽  
Vertical Transmission ◽  
Asexual Reproduction ◽  
Planktonic Foraminifera ◽  
Gamete Release ◽  
Symbiotic Algae ◽  
Laboratory Cultures ◽  
Symbiont Transmission

Abstract Gamete release has been frequently observed in laboratory cultures of various species of planktonic foraminifera. Those observations have been taken as evidence that these organisms produce new generations exclusively by sexual reproduction. We report here the first observation of asexual reproduction in Globigerinita uvula, a small, microperforate foraminifera. The asexual phase was associated with the release of ca. 110 offspring, all of which hosted symbiotic algae that must have been passed on directly from the parent. This event was also the first observation of vertical transmission of symbionts in planktonic foraminifera. Although the trigger of the observed asexual reproduction and its frequency in nature remain unknown, our observation indicates that among the planktonic foraminifera, at least G. uvula has not abandoned the asexual phase of its life cycle.

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