Meiosis and Pollen Formation in Larix

Ekberg, Inger; Eriksson, Gunilla; Šulíková, Zusana

doi:10.1111/j.1601-5223.1968.tb02187.x

Cited by 20 publications

(7 citation statements)

References 9 publications

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“…Although meiosis in L. leptolepis persists through the cold winter at the diffuse diplotene stage, this stage cannot be regarded as a resting stage as previously described in some literature (Ekberg and Eriksson 1967;Ekberg et al 1968;Owens and Molder 1979). Our results clearly showed that during this stage the chromosomes undergo very profound changes in their organization.…”

Section: Discussionsupporting

confidence: 67%

“…Female meiosis, which is started and completed during spring, is delayed relative to male meiosis for about half a year. Therefore, the significance of the diffuse diplotene stage in L. leptolepis may be not only an adaptation to meiotic overwintering (Ekberg et al 1968) under natural selection, but a regulation of synchrony among male and female gametes.…”

Section: Discussionmentioning

confidence: 99%

“…However, microsporogenesis and microgametogenesis differ between them, especially in conifers (Andersson et al 1969). First, there are the long duration of meiosis and the diffuse appearance of diplotene within most gymnosperm species as in conifers, which is typical for pollen mother cells (PMC) of Larix (Ekberg et al 1968). Second, the male gametophyte of different gymnosperm species consists of a cell (the microspore) or a number of cells up to several score at dispersal (Singh 1978;Pacini et al 1999), rather than bicellular or tricellular pollen.…”

Section: Introductionmentioning

confidence: 99%

“…During autumn, male meiosis proceeds to the diplotene stage, and then has a resting stage after pachytene or early diplotene. During this stage, known as the diffuse stage, the cells undergoing meiosis remain in that phase for several months (Ekberg et al 1968;Klášterská 1977). Although the significance of the diffuse stage has not yet been completely established, it is a striking step in meiotic prophase.…”

Section: Introductionmentioning

confidence: 99%

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Development of male gametophyte of Larix leptolepis Gord. with emphasis on diffuse stage of meiosis

Zhang

Yang

et al. 2008

Plant Cell Rep

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A basic developmental framework of the Larix leptolepis Gord male gametophyte is presented in detail by squashing technique. The duration of the meiosis stage was more than 6 months, and included a long diffuse stage during winter. This long duration of the diffuse appearance of the diplotene stage makes L. leptolepis a unique suitable experimental material for studying the structure and function of the diffuse stage of meiosis. In particular, the processes of desynapsing and unpairing, which so far have received little attention, can be examined in detail. In L. leptolepis, the chromosomes undergo a dramatic structural reorganization during the diffuse diplotene stage. Based on the clearly visible differences in chromosome morphology, the diffuse diplotene stage was divided into four periods with suggested nomenclature as follows: schizonema, pre-diffuse diplotene, diffuse diplotene and post-diffuse diplotene. Both simultaneous and successive microsporogenesis were observed within L. leptolepis, and there was no strict relationship between the microsporogenesis types and the tetrad configurations, which are strongly influenced by spindle orientation, especially during meiosis II. The mature pollen grain at pollination consists of five cells aligned in an axial row. The prothallial cells cannot be regarded as senescent cells because they remain capable of division.

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Section: Discussionsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Development of male gametophyte of Larix leptolepis Gord. with emphasis on diffuse stage of meiosis

Zhang

Yang

et al. 2008

Plant Cell Rep

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“…The earlier stages occur in the preceding fall, and the divisions go to completion in the following spring. However, in some locales in Sweden, poor seed set occurs (Ekberg, et 1968),…”

Section: Piplotenementioning

confidence: 99%

The ultrastructure of meiotic chromosomes of Lilium longiflorum

Braselton

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Ultrastructure and Development of the Microsporangium of Pseudotsuga Menziesii (Mirb.) Franco. I. Dormant Stages

Singh

Owens

Dietrich

1983

American J of Botany

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The dormant (mid‐November to mid‐February) microsporangia of Pseudotsuga menziesii (Douglas‐fir) contain pollen mother cells (PMC's) in diffuse diplotene, surrounded by 1–2 layers of tapetal cells and 3–4 layers of microsporangial wall cells. At the beginning of dormancy, PMC's are large and their walls are lysed. The cell walls contain a thick layer of loosely‐arranged fibrils which are produced in large vesicles in the PMC cytoplasm and are secreted across the plasma membrane. PMC's contain several layers of rough ER. The inner tangential and the radial walls of the tapetal cells are lysed. During dormancy the PMC's form many new autophagic vacuoles, the chromatin consists of a network of fine threads comprised of medium‐sized granules of uniform size and the nucleoli split. The outer tapetal wall is thick and becomes encrusted by an irregular lipid layer. The tapetal cytoplasm is similar to the PMC cytoplasm but is devoid of amyloplasts. The tapetal cytoplasm shows secretory activity at the beginning of dormancy and again near the end of dormancy. The later secretory activity results in the deposition of a spongy material, especially along the radial and inner walls of the tapetal cells. Tapetal cells contain 1–2 large nuclei which show prominent and irregular clumps of chromatin. Subcellular developmental changes occur in the dormant microsporangia of Pseudotsuga in much the same manner as has been reported for Pinus.

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Meiosis and Pollen Formation in Larix

Cited by 20 publications

References 9 publications

Development of male gametophyte of Larix leptolepis Gord. with emphasis on diffuse stage of meiosis

Development of male gametophyte of Larix leptolepis Gord. with emphasis on diffuse stage of meiosis

The ultrastructure of meiotic chromosomes of Lilium longiflorum

Ultrastructure and Development of the Microsporangium of Pseudotsuga Menziesii (Mirb.) Franco. I. Dormant Stages

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