Patterns of Stem Cell Divisions Contribute to Plant Longevity

The lifespan of plants ranges from a few weeks in annuals to thousands of years in trees. It is hard to explain such extreme longevity considering that DNA replication errors inevitably cause mutations. Without purging through meiotic recombination, the accumulation of somatic mutations will eventually result in mutational meltdown, a phenomenon known as Muller’s ratchet. Nevertheless, the lifespan of trees is limited more often by incidental disease or structural damage than by genetic aging. The key determinants of tree architecture are the axillary meristems, which form in the axils of leaves and grow out to form branches. The number of branches is low in annual plants, but in perennial plants iterative branching can result in thousands of terminal branches. Here, we use stem cell ablation and quantitative cell-lineage analysis to show that axillary meristems are set aside early, analogous to the metazoan germline. While neighboring cells divide vigorously, axillary meristem precursors maintain a quiescent state, with only 7–9 cell divisions occurring between the apical and axillary meristem. During iterative branching, the number of branches increases exponentially, while the number of cell divisions increases linearly. Moreover, computational modeling shows that stem cell arrangement and positioning of axillary meristems distribute somatic mutations around the main shoot, preventing their fixation and maximizing genetic heterogeneity. These features slow down Muller’s ratchet and thereby extend lifespan.

Soybeans for health, longevity, and economy,

Edition for 1973 published under title: Soybeans for health and a longer life.

Local records; or, Historical register of remarkable events which have occurred in Northumberland and Durham, Newcastle-upon-Tyne, and Berwick-upon-Tweed, with biographical notices of deceased persons of talent, eccentricity, and longevity;

A compilation of similar character, bearing a title almost identical, was made by J. Latimer, covering the period from Oct. 8, 1832, to Aug. 10, 1857.

Modern Methuselahs; or, Short biographical sketches of a few advanced nonagenarians or actual centenarians who were distinguished in art, science, literature, or philanthropy. Also, brief notices of some individuals remarkable chiefly for their longevity.

Introduction.--"Long-lasting."--St. Anthony the Great.-- Joannes Cantacuzenus, emperor of the East.--George Gemisthus Pletho.--Luigi Cornaro.--Titian.--Fontenelle.--Thomas Amory.--A group of far-advanced nonagenarians.--Eva Maria Garrick.--Caroline Lucretia Herschel.--Mary Somerville.--Sir Moses Montefiore.--Martin Joseph Routh.--Mr. Thoms' investigated case of centenarianism.--A group of unquestionable centenarians.--A few recent and probable cases of centenarianism.--Conclusion.

Health and longevity through rational diet; practical hints in regard to food and the usefulness or harmful effects of the various articles of diet.

Includes tables.

On regimen and longevity: comprising materia alimentaria, national dietetic usages, and the influence of civilization on health and the duration of life.

Mode of access: Internet.

The duration of life and conditions associated with longevity. A study of the Hyde genealogy,

Mode of access: Internet.

Laboratory studies on the development, longevity, and fecundity of six Lepidopterous pests of cotton in Arizona /

Bibliography: p. 72-73.

Local records; or, Historical register of remarkable events, which have occurred in Northumberland and Durham, Newcastle upon Tyne, and Berwick upon Tweed, from the earliest period of authentic record, to the present time; with biographical notices of deceased persons of talent, eccentricity, and longevity.

For continuation to 1857 see Latimer, John, Local records.

The effects of arts, trades, and professions : and of civic states and habits of living, on health and longevity: with suggestions for the removal of many of the agents which produce disease, and shorten and duration of life /

Advertisements: 16 p. of first group and 2 p. at end.

Rising longevity, education, savings, and growth

This paper examines the impact of declines in adult mortality on growth in an overlapping generations model. With public education and imperfect annuity markets, a decline in mortality affects growth through three channels. First, it raises the saving rate and thereby increases the rate of physical capital accumulation. Second, it reduces accidental bequests, lowers investment, and thereby lowers the rate of physical capital accumulation. Third, it may lead the median voter to increase the tax rate for public education initially but lower the tax rate in a later stage. Starting from a high mortality rate as found in many Third World populations, the net effect of a decline in mortality is to raise the growth rate. However, starting from a low mortality rate such as is found in most industrial populations, the net effect of a further decline in mortality is to reduce the growth rate. The findings appear consistent with recent empirical evidence. (C) 2002 Elsevier Science B.V All rights reserved.

Effects of 6-benzylaminopurine treatments on the longevity of harvested Grevillea 'Sylvia' inflorescences

Exogenous treatments with cytokinins, such as 6-benzylaminopurine (BA), can delay senescence of some plant tissues. Grevillea 'Sylvia' inflorescences have a short vase life. BA supplied in vase solutions at up to 0.1 mM did not delay senescence of G. 'Sylvia' in florescences. However, BA applied by dipping at concentrations up to 10 mM extended their vase life (longevity). Senescence parameters of relative fresh weight, flower abscission, flower opening, flower discolouration and flower wilting were all suppressed by BA dips. Dip treatment with BA (1 mM) was effective on G. 'Sylvia' in florescences at three different maturity stages.

Effects of vase solution pH and abscisic acid on the longevity of cut 'Baccara' roses

Abscisic acid (ABA) supplied in the vase solution can induce stomatal closure in the leaves of cut flowers, including roses (Rosa hybrida L.). This effect may be beneficial in reducing water deficit stress. Extracellular pH can affect active ABA concentrations in the apoplast of guard cells, with sap alkalisation enhancing the physiological activity of ABA. Accordingly, it was hypothesized that vase solution pH may affect ABA-mediated stomatal closure of cut roses. Two experiments were conducted to study the interaction of vase solution pH and ABA. In the first, cut 'Baccara' roses were held in vase solutions with +/- 10(-5) M ABA at pH 6, pH 7 and pH 8. In the second experiment, roses were held with +/- 10(-5) M ABA at pH 6 and pH 8 in the presence and absence of 1 mg l(-1) AgNO3 as a bactericide. Supply of ABA increased vase life and reduced vase solution usage of flowers held in low pH 6 solutions, indicating induction of stomatal closure. Conversely, ABA supplied at pH 8 was associated with reduced vase life. This negative result was associated with enhanced development of vase solution microbes at high pH, which overrode any potential pH-mediated ABA efficacy effects.