Reflections on the phenomenon of rejuvenescence in nature, especially in the life and development of plants

Henfrey, Arthur; Braun, Alexander

doi:10.5962/bhl.title.55643

Cited by 6 publications

(3 citation statements)

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“…Development, senescence, and sex are all pleiotropic effects of intra‐generational unidirectional epigenetic changes. We are reviving the notion of sex causing rejuvenescence (Braun, 1853 [1851]; Maupas, 1886; Geddes & Thomson, 1889; Maupas, 1889; Maupas 1890; Bell, 1988). Epigenetic resetting must occur after a finite number of successive mitotic divisions, otherwise individuals run up against the Hayflick limit (Hayflick & Moorhead, 1961).…”

Section: Theorymentioning

confidence: 99%

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Origin and maintenance of sex: the evolutionary joys of self sex

Gorelick¹,

Carpinone²

2009

Biological Journal of the Linnean Society

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Sex is generally thought of as meiosis, conjugation, and syngamy, with the primary function of sex believed to be genetic mixing. However, conjugation does not occur with complete automixis, whereas syngamy does not occur with restitutional automixis. Self sex in the forms of automixis and autogamy does not include genetic mixing. Yet sex, including self sex, is necessary for most eukaryotic lineages. What is the purpose of sex without genetic mixing? Obligate self sex is not an evolutionary dead end, but holds the key to understanding the evolutionary origin, function, maintenance, and ubiquity of sex. We extend the rejuvenescence hypothesis that sex provides a necessary developmental reset for multicellular eukaryotes and even many unicellular eukaryotes. Sex reduces additive genetic variance of epigenetic signals, especially cytosine methylation, and of ploidy levels. Furthermore, we argue that syngamy is a modified form of meiosis that maintains ploidy and resets epigenetic signals. Epigenetic resetting is consistent with sex being induced by starvation or desiccation. Diminution of additive genetic variance is consistent with the origin and maintenance of an adaptive trait, sex, that has been present for approximately two billion years.

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Section: Theorymentioning

confidence: 99%

“…The notion that sex induces rejuvenescence dates back to Bütschli (1876), and Maupas (1886; 1889; 1890), and possibly back to Braun (1853 [1851]), but was largely and erroneously discredited by Weismann (1889–1891; Lustig, 2000). Margulis & Sagan (1986b, 1988) followed Maupas with regards to rejuvenescence.…”

Section: Historymentioning

confidence: 99%

Origin and maintenance of sex: the evolutionary joys of self sex

Gorelick¹,

Carpinone²

2009

Biological Journal of the Linnean Society

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“…The validity of the generalizations by Braun (1851) and by Hofmeister (1862) on the number of fronds produced per annum on the shoot of the mature plant, and the duration of the period from the first visible appearance of the frond to its emergence from the soil, have already been called in question (Watt, 1940). Further evidence on these matters and on departures from the 'normal' behaviour of bracken is provided by data from a plot on Lakenheath Warren, on a very acid podsolized sand (pH 3.6-4.0) (area E in Watt, 1940).…”

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confidence: 99%

THE DIFFERENTIATION AND FATE OF THE BRACKEN (PTERIDIUM AQUILINUM) FROND AND THEIR RELATION TO THE AGE‐STRUCTURE OF THE SHOOT AND FROND POPULATION

Watt

1967

New Phytologist

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On an acid, dry infertile soil in a frost pocket, there are more short shoots (potential fronds) in bracken than differentiated fronds, and more differentiated fronds than emerge from the soil, and more emergent fronds than live in August.Factors affecting the inception, differentiation and fate of fronds are examined. The inherent tendency of fronds from young shoots to develop and to emerge before those from old renders them more liable to lethal winter and spring frosts and to crippling spring frosts. Drought acts mainly on the late emerging fronds. The normal sequence of emergence may be upset.Through their destruction of reserves and their effect on the means of replenishing them, annually fluctuating frost and drought influence the number of shoots initiated yearly, and hence the age-structure of the shoot population. A senescent population of bracken is deflned as one in which the proportion of young to old shoots is lovi-, and fronds from young shoots to fronds from old is also low. Frost and drought are the causes (not necessarily exclusive) of senescence in this area.The validity of the generalizations by Braun (1851) and by Hofmeister (1862) on the number of fronds produced per annum on the shoot of the mature plant, and the duration of the period from the first visible appearance of the frond to its emergence from the soil, have already been called in question (Watt, 1940). Further evidence on these matters and on departures from the 'normal' behaviour of bracken is provided by data from a plot on Lakenheath Warren, on a very acid podsolized sand (pH 3.6-4.0) (area E in Watt, 1940). METHODIn a marked plot 2 x 2 ft (0.37 m^) the fronds, on emergence or at convenient times thereafter, were charted (Fig. i) and identified by numbered rings in three successive years, 1956, 1957 and 1958. The plot was then dug up on 7 August 1958 and the shoots and their number of nodes counted. In this technique, despite the care exercised, there is the possibility of mistakes in identification, where marked fronds, killed by frost whilst still young, then decayed and left the ring above the remains but separated from them. There is also the purely physical difficulty of disentangling from the grass-rootpermeated soil the ultimate shoots without detaching them from their parent short shoots. RESULTSThe data in Table i substantiate earlier findings (Watt, 1950): the small number of live fronds in August (16.7 per 10 ft^: 18.0 per m^-numbers which are close to the mean 75

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Cell wall permeability and its relationship to spore release in Achlya intricata

Money

Webster

1988

Experimental Mycology

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Reflections on the phenomenon of rejuvenescence in nature, especially in the life and development of plants

Cited by 6 publications

References 0 publications

Origin and maintenance of sex: the evolutionary joys of self sex

Origin and maintenance of sex: the evolutionary joys of self sex

THE DIFFERENTIATION AND FATE OF THE BRACKEN (PTERIDIUM AQUILINUM) FROND AND THEIR RELATION TO THE AGE‐STRUCTURE OF THE SHOOT AND FROND POPULATION

Cell wall permeability and its relationship to spore release in Achlya intricata

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