Ultrastructural investigations on Lycopersicum peruvianum pollen activation and pollen tube organization after self-and cross-pollination

Sheepgrass (Leymus chinensis (Trin.) Tzvel.) is an economically and ecologically important forage in the grass family. Self-incompatibility (SI) limits its seed production due to the low seed-setting rate after self-pollination. However, investigations into the molecular mechanisms of sheepgrass SI are lacking. Therefore, microscopic observation of pollen germination and pollen tube growth, as well as transcriptomic analyses of pistils after self- and cross-pollination, were performed. The results indicated that pollen tube growth was rapidly inhibited from 10 to 30 min after self-pollination and subsequently stopped but preceded normally after cross-pollination. Time course comparative transcriptomics revealed different transcriptome dynamics between self- and cross-pollination. A pool of SI-related signaling genes and pathways was generated, including genes related to calcium (Ca2+) signaling, protein phosphorylation, plant hormone, reactive oxygen species (ROS), nitric oxide (NO), cytoskeleton, and programmed cell death (PCD). A putative SI response molecular model in sheepgrass was presented. The model shows that SI may trigger a comprehensive calcium- and phytohormone-dominated signaling cascade and activate PCD, which may explain the rapid inhibition of self-pollen tube growth as observed by cytological analyses. These results provided new insight into the molecular mechanisms of sheepgrass (grass family) SI.

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Evaluation of morphological traits of flowers and crossing possibility of haskap (Lonicera L) cultivars depending on their origin

Journal of Berry Research ◽

10.3233/jbr-211507 ◽

2021 ◽

pp. 1-15

Author(s):

Monika Bieniasz ◽

Ewa Dziedzic ◽

Tadeusz Kusibab

Keyword(s):

Pollen Tube ◽

Morphological Traits ◽

Temperate Region ◽

Open Flower ◽

Cross Pollination ◽

Flower Stage ◽

New Perspective ◽

Pollination Mode ◽

Pollination Methods

BACKGROUND: Haskap (Lonicera L.) is as a new perspective berry species for growing in temperate region climate. According to nowadays knowledge haskap is absolutely self-sterile species hence the studies on pollination mode are required. OBJECTIVE: The aim was to evaluate new haskap cultivars of Canadian and Russian origin in terms of their matching for cross-pollination. METHODS: The overlapping of flowering time of cultivars for mutual cross pollination was selected. The effectiveness of pollination was assessed: in terms of pollen tube overgrowth through the pistil tissue and the quality of set fruit. RESULTS: The Russian cultivars bloomed much earlier than the Canadian cultivars. The stigma is most receptive in the freshly open flower stage and directly after the anther burst. The minimum qualitatively acceptable weight of a berry is 1 g, which corresponds to the formation of about 6 seeds in the fruit. The most compatible pairs of cultivars were: ‘Aurora’×‘Jugana’, ‘Aurora’×‘Sinij Utes’ and ‘Aurora’×‘Vostorg’. CONCLUSION: The Russian cultivars bloomed much earlier than the Canadian cultivars, the stigma is most receptive in the freshly open flower, minimum qualitatively acceptable weight of berry is 1 g (what represents 6 seeds in fruit), best mutual pollinating cultivars are the cultivars within the same breeding group (Russian x Russian and Canadian x Canadian)

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Causes of infertility in the endangered Australian endemic plant Borya mirabilis (Boryaceae)

Australian Journal of Botany ◽

10.1071/bt14229 ◽

2015 ◽

Vol 63 (7) ◽

pp. 554 ◽

Cited By ~ 1

Author(s):

Noushka H. Reiter ◽

Neville G. Walsh ◽

Ann C. Lawrie

Keyword(s):

Genetic Diversity ◽

Pollen Tube ◽

National Park ◽

Diploid Number ◽

Tube Formation ◽

Ex Situ ◽

Endangered Plants ◽

Endemic Plant ◽

Cross Pollination ◽

Herbaceous Perennial

Borya mirabilis Churchill (Boryaceae, Asparagales) is a herbaceous perennial and one of Australia’s most endangered plants. Only one population of four colonies remains, on a rock ledge in the Grampians (Gariwerd) National Park in Victoria, Australia. The reasons why B. mirabilis flowers freely but does not set seed were investigated. Borya mirabilis had a greater proportion of floral abnormalities than other, fertile Borya species. The pollen was often mis-shapen, with ≤ 1% pollen tube formation, but the ovules showed no structural dissimilarity from other, fertile Borya species. The flowers offered a nectar reward and many insects visited the pollen-bearing flowers in the field. Artificial cross-pollination resulted in the first recorded seed for this species. Borya mirabilis has ~66 chromosomes, relative to the diploid number of ~26 in Borya constricta Churchill, strongly suggesting that B. mirabilis is polyploid. Only 4–7% genetic diversity was found within the remaining B. mirabilis field population using 25/60 RAPD primers that showed heterogeneity. An ex-situ nursery collection was found not to contain all genotypes. Recommendations for the conservation of B. mirabilis include capturing all the known genetic diversity in cloned plants in preference over further attempts to produce seed.

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Pollen Tube Growth and Early Seed Development in Eucalyptus regnans F. Muell. (Myrtaceae) in Relation to Ovule Structure and Preferential Outcrossing

Australian Journal of Botany ◽

10.1071/bt9890397 ◽

1989 ◽

Vol 37 (5) ◽

pp. 397 ◽

Cited By ~ 16

Author(s):

M Sedgley ◽

FC Hand ◽

RM Smith ◽

AR Griffin

Keyword(s):

Pollen Tube ◽

Phase Contrast ◽

Pollen Tubes ◽

Central Canal ◽

Transmitting Tissue ◽

Bright Field ◽

Eucalyptus Regnans ◽

Cross Pollination ◽

Early Seed Development ◽

Scanning Electron

Pistils of Eucalyptus regnans were observed by bright field, fluorescence, phase contrast, Nomarski, and scanning electron microscopy from 4 weeks prior to anthesis to 16 weeks after self- and cross- pollination. The transmitting tissue of the style had a central canal which extended for half its length. The unfertilised ovary contained a mean of 30.5 ovular structures with 16.5 normal ovules, 2.5 abnor- mal ovules, and 11.5 sterile ovulodes. The ovules were arranged in two rows in three (occasionally four) locules. The ovulodes always occupied positions at the stylar end of the ovary, but with this exception there was no pattern to the occurrence of the abnormal ovules. Pollen tubes grew between the cells'of the transmitting tissue, and not in the stylar canal. Penetration of the ovules had commenced by 5 days after both self- and cross-pollination. The early fertilised ovule contained a zygote and free-nuclear endosperm, and embryos with between 1 and 16 cells were present at 16 weeks after pollination. Not all normal ovules were fertilised, despite adequate numbers of pollen tubes. Ovulodes were never observed to be penetrated by a pollen tube, but with this exception there was no relationship between position on the placenta and either the penetration of ovules by a pollen tube or the occurrence of fertilised ovules. There was no difference between self- and cross-pollination in either the number of ovules penetrated by a pollen tube, or the number of fertilised ovules up to 16 weeks following pollination.

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Reciprocal intercompatibility between Byrsonima Rich. exKunth species (Malpighiaceae), in an urban ecotonal fragment of Semi-Deciduous Seasonal Forest and Cerrado

Anales de Biología ◽

10.6018/analesbio.43.20 ◽

2021 ◽

pp. 211-221

Author(s):

Frederic Mendes Hughes

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Tube Growth ◽

Self Incompatibility ◽

Prezygotic Isolation ◽

Stigmatic Surface ◽

Cross Pollination ◽

Self Pollination ◽

Isolation Mechanisms ◽

Hypothesis Evaluation

Byrsonima species present floral monomorphism and sharing visitor/pollinator guild. These traits suggest the hypothesis evaluation of reciprocal inter-incompatibility between two syntopic Byrsonima species: B. pachyphylla and B. crassifolia. Pollen tube growth with similar behavior was observed in the stigmatic surface, pistil canal, ovary and micropylar channel to both species. In addition, partial self-incompatibility in self-pollination with greater fruiting in autogamy was observed. Cross-pollination and self-pollination coexist, and reciprocal intercompatibility occurs. Prezygotic isolation mechanisms are unlikely by the absence of abnormal pollen tubes, higher fruiting production and absence of hybrids in the study site. Las especies de Byrsonima presentan monomorfismo floral y comparten gremio de visitantes/polinizadores. Estos rasgos sugieren la evaluación de hipótesis de interincompatibilidad recíproca entre dos especies sintópicas de Byrsonima: B. pachyphylla y B. crassifolia. Se observó el crecimiento del tubo polínico con comportamiento similar en la superficie estigmática, canal del pistilo, ovario y canal micropilar de ambas especies. Además, se describió la autoincompatibilidad parcial en la autopolinización con mayor fructificación en la autogamia. La polinización cruzada y la autopolinización coexisten y se produce una intercompatibilidad recíproca. Los mecanismos de aislamiento precigóticos son improbables por la ausencia de tubos polínicos anormales, producción de frutos y ausencia de híbridos en la área de estudio.

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Comparison of Self- and Cross-pollination on Pollen Tube Growth, Seed Development, and Germination in Crapemyrtle

HortScience ◽

10.21273/hortsci.41.3.575 ◽

2006 ◽

Vol 41 (3) ◽

pp. 575-578 ◽

Cited By ~ 3

Author(s):

Cecil Pounders ◽

Sandra Reed ◽

Margaret Pooler

Keyword(s):

Seed Germination ◽

Pollen Tube ◽

Seed Production ◽

Pollen Tube Growth ◽

Tube Growth ◽

Cross Pollination ◽

Landscape Plants ◽

Incompatibility System ◽

Self Fertilization ◽

Self Compatibility

Crapemyrtle (L. indica and L. indica × L. fauriei hybrids) is one of the most popular flowering landscape plants in the U.S. Although many cultivars have been developed through breeding efforts, little has been published on the reproductive biology of the genus. The objective of this study was to evaluate barriers to successful self-seed production in crapemyrtle. Self-compatibility was assessed by comparing pollen tube growth, fruit and seed production, and seed germination following controlled self- and cross-pollinations. Observations of pollen tube growth at intervals up to 24 hours after self- and cross-pollination indicated no barriers to self-fertilization acting at the stigmatic or stylar level in L. indica, L. fauriei or cultivars derived from inter-specific hybrids of these two species. Self-pollinations of `Catawba', `Whit IV', `Tonto' and `Tuscarora' had lower percent seed pod set and seed germination than did cross-pollinations of these cultivars. The number of seeds per pod was lower when `Catawba', `Whit IV' and `Tuscarora' were self-rather than cross-pollinated, but no difference between `Tonto' self- and cross-pollinations was observed. When decreased pod set is combined with much lower seed germination for self-pollinations, selfing of crapemyrtle is extremely unproductive when compared to cross-pollination. A late-acting self-incompatibility system or inbreeding depression is indicated for L. indica and inter-specific crosses with L. fauriei.

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