scholarly journals Comparative reproduction mechanisms of three species of Ocimum L. (Lamiaceae)

2016 ◽  
Vol 69 (1) ◽  
Author(s):  
Matthew Oziegbe ◽  
Temitope Olatayo Kehinde ◽  
Joshua Olumide Matthew

<em>Ocimum</em> species have a combination of reproductive system which varies with the locality and cultivar. We have studied here the reproductive mechanisms of five variants of three <em>Ocimum</em> species in Nigeria, namely: <em>Ocimum canum</em> Sims., <em>O. basilicum</em> L., and <em>O. americanum</em> L. Flowers from each variant were subjected to open and bagged pollination treatments of hand self-pollination, spontaneous self-pollination and emasculation. All open treatments of the five <em>Ocimum</em> variants produced more fruit and seed than the corresponding bagged treatments. The two <em>O. canum</em> variants and <em>O. basilicum</em> ‘b<span><sub>1</sub></span>’ produced high fruit and seed set in the open and bagged treatments of spontaneous self-pollination. <em>Ocimum basilicum</em> ‘b<span><sub>2</sub></span>’ and <em>O. americanum</em> produced higher fruit and seed set in the self-pollination open treatment but significantly lower fruit and seed set in the bagged treatment. Fewer fruit and seeds were produced in the emasculated open treatments but none in the emasculated bagged treatments of the five <em>Ocimum</em> variants. The floral foragers comprising of bees, wasps and butterflies visited the <em>Ocimum</em> species to collect pollen or nectar in the open treatments. The two <em>O. canum</em> variants and <em>O. basilicum</em> ‘b<span><sub>1</sub></span>’ variant reproduced mainly through autogamy but <em>O. basilicum</em> ‘b<span><sub>2</sub></span>’ and <em>O. americanum</em> showed mixed reproduction of autogamy and outcrosssing. Insect visitation to the flowers enhanced pollination resulting in higher fruit and seed set in all the <em>Ocimum</em> species studied.

1996 ◽  
Vol 74 (9) ◽  
pp. 1363-1368 ◽  
Author(s):  
Heléne Fröborg

Using experimental manipulations, I examined if pollen quality affected fruit and seed production in five ericaceous understory shrubs in a coniferous forest in central Sweden. Flowers of Vaccinium myrtillus L., Vaccinium uliginosum L., Vaccinium vitis-idaea L., Vaccinium oxycoccos Gil., and Andromeda polifolia L. were (treatment 1) open-pollinated, (treatment 2) bagged without further treatment, (treatment 3) bagged and self-pollinated, (treatment 4) cross-pollinated with pollen from neighbouring plants, or (treatment 5) supplied with pollen from distant plants. Finally, flowers were (treatment 6) open-pollinated with a supply of extra pollen of distant origin. To investigate pollen or resource limitations to fruit and seed production, V. vitis-idaea was subjected to partial flower removal followed by open- and hand-pollination. Fruit and seed set were estimated for each treatment. The main conclusion is that natural levels of outcrossing are sufficiently high for full seed production and that the availability of pollen is not limiting in natural habitats. There were significant reductions in fruit and seed set after self-pollination in V. myrtillus. Fruit set was reduced in V. vitis-idaea, and V. uliginosum failed to set fruit after self-pollination. Self-pollination caused a decreased seed set in A. polifolia. There was no significant variation across treatments in V. oxycoccos. Since fruits tend to develop regardless of seed number, resources are likely to limit seed production in species with costly fruits. Keywords: self-fertility, pollination, Vaccinium, fruit set, seed set.


1994 ◽  
Vol 119 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Richard E. Harrison ◽  
James J. Luby ◽  
Peter D. Ascher

Pollination of the half-high blueberry (Vaccinium corymbosum L./V. anugustifolium Ait.) cultivars St. Cloud, Northsky, Northcountry, and Northblue with self, outcross, and outcross/self pollen mixtures suggests that outcross fertilization maximizes percent fruit set, berry weight, seeds per berry, and seeds per pollination while minimizing days to harvest. Based on these results, mixed plantings of at least two blueberry cultivars are recommended for these cultivars. Fruit and seed set were negatively associated with increased percentages of self pollen in outcross/self pollen mixtures. These responses were linear for `Northblue' due to a tendency to parthenocarpy, and nonlinear for `St. Cloud', `Northsky', and `Northcountry', due to low fruit set following self-pollination. These data indicate that post-fertilization abortion affected seed formation, which was, in turn, correlated positively with fruit set.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 815
Author(s):  
Sandra V. Rojas-Nossa ◽  
José María Sánchez ◽  
Luis Navarro

Floral development depends on multifactor processes related to genetic, physiological, and ecological pathways. Plants respond to herbivores by activating mechanisms aimed at tolerating, compensating, or avoiding loss of biomass and nutrients, and thereby survive in a complex landscape of interactions. Thus, plants need to overcome trade-offs between development, growth, and reproduction vs. the initiation of anti-herbivore defences. This study aims to assess the frequency of phloem-feeding herbivores in wild populations of the Etruscan honeysuckle (Lonicera etrusca Santi) and study their effects on floral development and reproduction. The incidence of herbivory by the honeysuckle aphid (Hyadaphis passerinii del Guercio) was assessed in three wild populations of the Iberian Peninsula. The effect of herbivory on floral morphology, micromorphology of stigmas and pollen, floral rewards, pollination, and fruit and seed set were studied. The herbivory by aphids reduces the size of flowers and pollen. Additionally, it stops nectar synthesis and causes malformation in pollen and microstructures of stigmas, affecting pollination. As a consequence, fruit set and seed weight are reduced. This work provides evidence of the changes induced by phloem-feeding herbivores in floral development and functioning that affect the ecological processes necessary to maintain the reproductive success of plants.


Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 432
Author(s):  
Yaling Chen ◽  
Benchang Hu ◽  
Fantao Zhang ◽  
Xiangdong Luo ◽  
Jiankun Xie

Dendrobium officinale is a rare and traditional medicinal plant with high pharmacological and nutritional value. The self-incompatibility mechanism of D. officinale reproductive isolation was formed in the long-term evolution process, but intraspecific hybridization of different germplasm resources leads to a large gap in the yield, quality, and medicinal value of D. officinale. To investigate the biological mechanism of self-incompatibility in D. officinale, cytological observation and the transcriptome analysis was carried out on the samples of self-pollination and cross-pollination in D. officinale. Results for self-pollination showed that the pollen tubes could grow in the style at 2 h, but most of pollen tubes stopped growing at 4 h, while a large number of cross-pollinated pollen tubes grew along the placental space to the base of ovary, indicating that the self-incompatibility of D. officinale may be gametophyte self-incompatibility. A total of 63.41 G basesum of D. officinale style samples from non-pollinated, self-pollination, and cross-pollination by RNA-seq were obtained, and a total of 1944, 1758, and 475 differentially expressed genes (DEGs) in the comparison of CK (non-pollinated) vs. HF (cross-pollination sample), CK vs. SF (self-pollination sample) and SF vs. HF were identified, respectively. Forty-one candidate genes related to self-incompatibility were found by function annotation of DEGs, including 6 Ca2+ signal genes, 4 armed repeat containing (ARC) related genes, 11 S-locus receptor kinase (SRK) related genes, 2 Exo70 family genes, 9 ubiquitin related genes, 1 fatty acid related gene, 6 amino acid-related genes, 1 pollen-specific leucine-rich repeat extensin-like protein (LRX) related gene and 1 lectin receptor-like kinases (RLKs) related gene, showed that self-incompatibility mechanism of D. officinale involves the interaction of multiple genes and pathways. The results can provide a basis for the study of the self-incompatibility mechanism of D. officinale, and provide ideas for the preservation and utilization of high-quality resources of D. officinale.


1970 ◽  
Vol 12 (4) ◽  
pp. 905-913 ◽  
Author(s):  
T. Swamy Rao

The correlated response with changes in self-compatibility in three varieties of brown sarson subjected to gamma irradiation was examined. Selection for improved seed set in the irradiated populations showed that substantial correlated response can result for a constellation of other characters in which the self-compatible and self-incompatible forms differ. The correlated response was in a direction opposite to that of the previous history of selection.


2021 ◽  
Vol 25 (03) ◽  
pp. 710-721
Author(s):  
Écio Souza Diniz ◽  
◽  
Rodolfo Oliveira Costa ◽  
Larissa Areal Carvalho Müller ◽  
Jan Thiele ◽  
...  

Chrestas capigera (Less.) Gardner is an important medicinal herb which, however, has been poorly studied for its biology and ecology. This study aimed to investigate its phenology, floral biology, reproductive biology (self-pollination tests), spatial distribution and correlations between phenophases and climatic data in two sites (Cerrado stricto sensu and Campo rupestre) in southern Minas Gerais, Brazil. From August of 2012 to August of 2013, we monitored phenophase occurrence for 70 individuals: emission of new leaves, flowering, production of immature fruits, and mature fruits. Floral anthesis occurred during daytime and remained all day until fruit formation. Peak leaf emergence was observed in April, correlating with minimum monthly temperature and mean monthly precipitation. Flowering and green fruit peaked in May and June, respectively, and correlated negatively with all climatic variables. Mature fruits peaked in June, but did not correlate significantly with any of the climatic variables. However, no difference was found between the two sites regarding the timing of phenophases. The spatial distribution pattern of individuals within sites was random. The self-pollination tests showed that the individuals pollinated and fertilized themselves. Our findings allow us to conclude that the phenology of C. scapigera has pronounced phenological seasonality with reproductive peak activities in the drier and colder season, which is congruent with the self-pollination and anemochoric dispersion strategy.


Botany ◽  
2010 ◽  
Vol 88 (3) ◽  
pp. 241-249 ◽  
Author(s):  
Diana Bizecki Robson

Flower-visiting insect activity to the rare Symphyotrichum sericeum (Vent.) G.L. Nesom and the common Solidago nemoralis Ait. var. longipetiolata (Mack. & Bush) Pal. & Steyerm. was examined to detect compositional and temporal similarities. A hand pollination experiment was conducted to determine whether pollen was limiting seed set. Of the 31 insect taxa that visited these plants, Bombus bifarius Cresson was the most common visitor to both species. More insect visitors of the Halictidae and Bombyliidae were received by S. sericeum than S. nemoralis, which received more visitors of the Syrphidae and Tachinidae. The insect visitation rate was not significantly different between the two plant species. Solidago nemoralis was visited by fewer insect taxa per day than S. sericeum, but the constancy of its visitors was higher. The insect visitor composition changed over time, with B. bifarius ignoring S. sericeum plants initially, then visiting them more frequently as the number of receptive S. nemoralis capitula declined. Hand pollination increased seed set in the earliest flowering capitula of S. sericeum, but not for those flowering during the peak. This research shows that the quantity of insect visits to the rare plant is comparable with that of the common plant but that pollination quality may be lower, particularly for early blooming capitula.


1980 ◽  
Vol 58 (6) ◽  
pp. 712-716 ◽  
Author(s):  
Shirley Dobrofsky ◽  
W. F. Grant

Self-incompatibility, a prefertilization event, and self-sterility, a postfertilization event, have both been suggested as causes for differences in seed set between cross- and self-pollinated florets in Lotus corniculatus L. Ovary protein subunits of selfed, crossed, and unpollinated florets of L. corniculatus cv. Mirabel were studied using polyacrylamide gel electrophoresis. Banding patterns differed for all three conditions. Ovary protein differences were found prior to the time fertilization is known to occur, thereby providing evidence that self-incompatibility is at least partially responsible for the reduced seed set after self-pollination.


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