A statistical approach to estimate the frequency of n, 2n and 4n pollen grains in diploid alfalfa

Tondini, F.; Tavoletti, Stefano; Mariani, A.; Veronesi, F.

doi:10.1007/bf00021733

Cited by 15 publications

(10 citation statements)

References 5 publications

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“…In our study, although the width (equatorial diameter) of the heat-treated pollen approximately followed a Gaussian frequency distribution, the pollen length (polar axis) conformed to a bimodal frequency distribution. This is consistent with the frequency distribution of the pollen diameter in unreduced pollen producers (TONDINI et al, 1993;WANG et al, 2010a), suggesting that the high-temperature treatment resulted in the divergence of pollen size and production of 2n pollen grains. In E. ulmoides, the length of pollen grains could be considered to be a criterion for distinguishing pollen with a high ploidy level, which is also possible in oat (KATSIOTIS and FORSBERG, 1995).…”

Section: Discussionsupporting

confidence: 88%

Morphological characterization and in vitro germination of heat-treated pollen in Eucommia ulmoides

Song

Tian

et al. 2015

Silvae Genetica

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Polyploid breeding has the potential to increase the economic secondary metabolites of Eucommia ulmoides. However, pollination with induced ploidy-mixed pollen has failed to produce polyploids (GAO, 2006). In this investigation, the morphological characterization and in vitro germination of heat-induced ploidy-mixed pollen of E. ulmoides were analysed to determine why there is no polyploid production. Heat-treated pollen grains were easily distinguished as large and small according to their length. The large pollen grains were significantly longer than both untreated and heat-treated small samples, suggesting that they were probably 2n pollen. Rather than the three germinal pores in small pollen, the large grains typically had four pores and, in some cases, shallow furrows, which might affect their germination. Although the maximal germination rates of the treated small and large pollen were not significantly different, the large pollen germinated tardily during the early stages of incubation. The small pollen maintained its growth during the incubation, but the tube growth of large pollen almost stopped after 24 h incubation. Both vegetative and generative nuclei in the large pollen moved into tubes later than in small pollen and the frequency of mitosis in generative nuclei of large pollen was low. Therefore, the tardy germination, poor tube growth, and weak activity of both vegetative and generative nuclei probably caused the poor competition of large pollen in certation. Finally, techniques to increase the competition of highploidy pollen and the prospect of 2n female gamete induction in the polyploid breeding program of E. ulmoides are discussed.

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Section: Discussionsupporting

confidence: 88%

Morphological characterization and in vitro germination of heat-treated pollen in Eucommia ulmoides

Song

Tian

et al. 2015

Silvae Genetica

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“…This is supported by the finding that when a plant produces mainly reduced pollen grains, the diameter distribution curve usually resembles a normal distribution (Tondini et al, 1993) unlike the curve obtained for M. ×giganteus. The stainability of pollen (despite their size) estimated by the acetocarmine test was moderate (54.9%) as compared with the pollen viability results for other allotriploids, ranging from 10% in Cucumis hytivus up to 90.3% in Populus tremula (Wang et el., 2010), and is in accord with results reported for M. ×giganteus by Adati (1958).…”

Section: Discussionmentioning

confidence: 64%

Sterility of Miscanthus × Giganteus Results from Hybrid Incompatibility

Słomka¹,

Kuta²,

Płażek³

et al. 2012

Acta Biologica Cracoviensia Series Botanica

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Miscanthus ×giganteus Greef et Deu. (Poaceae), a hybrid of Miscanthus sinensis and M. sacchariflorus native to Japan, is an ornamental and a highly lignocellulosic bioenergy crop, cultivated in the European Union as an alternative source of energy. This grass reproduces exclusively vegetatively, by rhizomes or via expensive in vitro micropropagation. The present study was aimed at finding the barriers that prevent sexual seed production, based on detailed embryological analyses of the whole generative cycle, including microsporogenesis, pollen viability, megasporogenesis, female gametophyte development, and embryo and endosperm formation. Sterility of M. ×giganteus results from abnormal development of both male and female gametophytes. Disturbed microsporogenesis (laggard chromosomes, univalents, micronuclei) was further highlighted by low pollen staining. The frequency of stainable pollen ranged from 13.9% to 55.3% depending on the pollen staining test, and no pollen germination was observed either in vitro or in planta. The wide range of pollen sizes (25.5-47.6 μm) clearly indicated unbalanced pollen grain cytology, which evidently affected pollen germination. Only 9.7% of the ovules developed normally. No zygotes nor embryos were found in any analyzed ovules. Sexual reproduction of M. ×giganteus is severely hampered by its allotriploid (2n=3x=57) nature. Hybrid sterility, a strong postzygotic barrier, prevents sexual reproduction and, therefore, seed formation in this taxon.K Ke ey y w wo or rd ds s: : Miscanthus ×giganteus, allotriploid, pollen viability, female gametophyte development, sterility.

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“…Therefore, the ploidy level of pollen can be distinguished by analyzing pollen grain diameter. In general, the frequency distribution of pollen grain diameter is unimodal in normal diploid plants and is bimodal in unreduced pollen producers (Tondini et al 1993). In this allotriploid poplar, the diameters of pollen grains followed a bimodal distribution, suggesting the production of unreduced pollen grains.…”

Section: Discussionmentioning

confidence: 79%

Variation in pollen formation and its cytological mechanism in an allotriploid white poplar

Wang

Kang

Zhu

2009

Tree Genetics & Genomes

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Variation in pollen formation and its cytological mechanism in an allotriploid white poplar were investigated by the squashed technique and indirect immunofluorescence. Besides 0.5% stuck pollen grains, this allotriploid produced regularly spherical pollen grains. It was estimated that 90.3% of pollen grains were viable. Diameters of the viable spherical pollen grains ranged from 23.2 to 72.9 μm, with a bimodal frequency distribution. Numerous meiotic abnormalities were found, including highly irregular chromosome pairing, lagging chromosomes and chromosome bridges, micronuclei, and multiple spindles, which indicate highly genetic imbalance of this allotriploid. Some micronuclei triggered minispindle formation in metaphase II and participated in cytokinesis to form microcytes in sporads. Abnormal orientation of metaphase II spindles contributed to production of dyads and triads, which produced unreduced microspores. However, parallel orientation of spindles was not necessary for dyad formation, because an organelle band positioned in the equatorial region prevented the spindles from coalescing. Some microsporocytes exhibited a complete or partial absence of cytokinesis, which resulted in the formation of monads and the increased frequency of dyads and triads. The perspective of this triploid in the polyploid breeding program of white poplar is discussed.

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A statistical approach to estimate the frequency of n, 2n and 4n pollen grains in diploid alfalfa

Cited by 15 publications

References 5 publications

Morphological characterization and in vitro germination of heat-treated pollen in Eucommia ulmoides

Morphological characterization and in vitro germination of heat-treated pollen in Eucommia ulmoides

Sterility of Miscanthus × Giganteus Results from Hybrid Incompatibility

Variation in pollen formation and its cytological mechanism in an allotriploid white poplar

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