Pollen germination, pollen tube growth and fertilization following self and interspecific pollination of Paspalum species

Burson, Byron L.

doi:10.1007/bf00041514

Cited by 18 publications

(11 citation statements)

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“…Pollen tube growth through the pistil under self‐pollinated conditions appeared to be slower in buffelgrass than other warm‐season grasses. In dallisgrass, Paspalum dilatatum Poir., and P. juergensii Hackel, the tubes grew to the micropyle within 45 min after pollination (Burson, 1987) The same was true for kleingrass, Panicum coloratum L.; however, in P. deustum Thunb. and P. antidotale Retz., from 1.75 to 2 h were required for the tubes to reach the micropyle (Burson and Young, 1983) An important finding from this study is that the pollen tubes were observed at the micropyle, whether pollination occurred 3, 2, 1, or 0 d prior to anthesis.…”

Section: Resultsmentioning

confidence: 63%

Stigma Receptivity and Seed Set in Protogynous Buffelgrass

2000

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parent, new genotypes are produced when the reduced egg cells in meiotically derived embryo sacs are fertil-Buffelgrass, Pennisetum ciliare (L.) Link syn ϭ Cenchrus ciliaris ized. Another fertilization event in apomict plants oc-L., is an important warm-season perennial forage grass that is widely grown throughout the arid tropics. It has perfect florets, and emascula-curs when the unreduced egg in an apomictic sac is tion is thought to be required to produce controlled hybrids. This is fertilized by a reduced sperm nucleus. This phenomenon a tedious, difficult undertaking because of the small floret size. The is known as the fertilization of an unreduced egg (2n ϩ flowering behavior of buffelgrass is such that the stigmas are exserted n) or B III hybridization (Bashaw and Hignight, 1990). from the floret prior to anthesis, which is referred to here as the Fertilization of an unreduced egg provides a means for protogynous interval. This investigation was conducted to determine producing new genotypes by the incorporation of whole the duration of the protogynous interval in 447 buffelgrass accessions alien genomes while retaining the entire somatic chroand to ascertain stigma receptivity during the protogynous intervals. mosome complement of the apomictic female parent. Protogynous intervals in a field nursery near College Station, TX, for Bashaw and Hignight (1990) demonstrated that 2n ϩ n all accessions ranged from 1 to 4 d. Six accessions with protogynous intervals ranging from 1 to 3 d were used to investigate stigma receptiv-fertilization can be used to develop unique apomictic ity under both self-and cross-pollinated conditions in a greenhouse.buffelgrass germplasm. Pollen germination and tube growth were observed with fluorescentA range of chromosome numbers has been reported microscopy at different time increments following pollination. Across for buffelgrass with the most common number being all accessions, pollen germinated within 15 min of contacting the 2n ϭ 4x ϭ 36 (Fisher et al., 1954). The species apparently stigma, and pollen tubes grew to the micropyle within 2 to 6 h, deis a segmental allotetraploid because its chromosomes pending on the accession and pollen source. Mean seed set ranged typically pair as one or two quadrivalents and 16 or 14 from 11 to 76% and from 22 to 80% among accessions following selfbivalents during diakinesis of meiosis I. However, it is and cross-pollination, respectively. This investigation revealed that not uncommon to find plants with 2n ϭ 5x ϭ 45 and variation exists for protogynous interval within buffelgrass, and the stigmas are receptive when exserted from the floret and remain re-6x ϭ 54 chromsomes as well as aneuploids of these three ceptive throughout duration of the protogynous interval regardless ploidy levels (Fisher et al., 1954; Bashaw and Higof whether it occurs 3, 2, or 1 d prior to anthesis. These findings night, 1990). demonstrate that protogyny can be used to produced controlled hy-Like most warm-season perennial grasses, buffelgrass brids in sexual b...

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Section: Resultsmentioning

confidence: 63%

Stigma Receptivity and Seed Set in Protogynous Buffelgrass

2000

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“…Two techniques, percent seed set and pollen tube growth, were used to determine fertility under self and open-pollinated conditions. Pollen tube growth was observed after dusting the stigmas with pollen from either the same plant or a different plant using fluorescent microscopy (Burson, 1987).…”

Section: Methodsmentioning

confidence: 99%

Cytology of Sexual and Apomictic Paspalum Species.

Quarín

Burson

1991

CYTOLOGIA

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“…W e report here our efforts to obtain intraspecific 3x hybrids between 2x and 4x cytotypes of five Paspalum species. Because of the low crossability reported for crosses in other species of the genus (Bennett et al 1969;Quarin et al 1984;Burson 1987), we included in vitro ovary culture after crossing. The nature of barriers was explored through controlled crosses and surveys of post-pollination events.…”

Section: Introductionmentioning

confidence: 99%

Post-Zygotic Seed Abortion in Sexual Diploid × Apomictic Tetraploid Intraspecific Paspalum Crosses

Norrmann¹,

Bovo²,

Quarín³

1994

Aust. J. Bot.

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In many species of Paspalum, diploid (2x) cytotypes are usually outbreeders due to a self incompatibility system, while tetraploid (4x) conspecific counterparts are pseudogamous self-fertile apomicts. Intraspecific crossability between 2x female and 4x male cytotypes was investigated using classical methods of crossing in P. almum, P. brunneum, P. rufum, P. intermedium and P. quadrifarium. Expected triploid B,, hybrids were obtained in P. intermedium (crossability: 0.004%) and in P. brunneum (crossability: 0.015%). In P. rufum, only tetraploid B, , hybrids were achieved with a crossability of 0.025%. Looking for a better performance, in vitro ovary rescue was attempted 5 days after pollination in intraspecific 2x x 4x crosses of P. almum, P. quadrifarium, P. intermedium and P. rufum. The method was useful to recover some triploid B,, hybrids in P. almum (success rate: 0.49%) and in P. rufum (0.59%), but failed in P. intermedium and P. quadrifarium. Pollen tube growth was usually inhibited at the stigma or style levels after self-pollination in 2x plants, confirming that diploids are self-incompatible. Pollen of 4x cytotypes germinated and penetrated the pistils of diploid conspecific cytotypes. This indicated that no incompatibility system exists in these species to keep the 2x cytotypes from hybridising with 4x conspecific cytotypes as pollen donors. However, after pollination of 2x cytotypes with pollen of 4x counterparts, most ovules showed embryo and endosperm development, but a few days later, endosperms collapsed and embryos stopped their development. As a result of these processes, sexual self-incompatible 2x cytotypes of Paspalum species produced very few triploid hybrids when pollinated with pollen of their apomictic 4x counterparts. Thus, the low diploidtetraploid crossability was due to the existence of a post-zygotic abortive system and not caused by prefertilisation barriers.

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Pollen germination, pollen tube growth and fertilization following self and interspecific pollination of Paspalum species

Cited by 18 publications

References 13 publications

Stigma Receptivity and Seed Set in Protogynous Buffelgrass

Stigma Receptivity and Seed Set in Protogynous Buffelgrass

Cytology of Sexual and Apomictic Paspalum Species.

Post-Zygotic Seed Abortion in Sexual Diploid × Apomictic Tetraploid Intraspecific Paspalum Crosses

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