The control of whole plant senescence

Kelly, Maureen O.; Davies, Peter J.; Woolhouse, H. W.

doi:10.1080/07352688809382262

Cited by 49 publications

(30 citation statements)

References 175 publications

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“…Cytokinins can only delay senescence if they are supplied before the start of the third phase, suggesting that protein disassembly is not activated as long as the rate of protein synthesis remains abo've some undefined threshold. Molisch (1938) and, more recently, Kelly & Davies (1988) have propounded that a shift in nutrient allocation from the vegetative to the reproductive tissue is the primary cause of senescence. They put forward the theory that this occurs early in reproductive development and may be mediated by plant growth regulators.…”

Section: What Is the Threshold?mentioning

confidence: 99%

Gene expression during leaf senescence

1994

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SUMMARY Leaf senescence is a hiphly‐controlled sequence of events comprising the final stage of development. Cells remain viable during the process and new gene expression is required. There is some similarity between senescence in plants and programmed cell death in animals. In this review, different classes of senescence‐related genes are defined and progress towards isolating such genes is reported. A range of internal and external factors which appear to cause leaf senescence is considered and various models for the mechanism of senescence‐ initiation are described. The current understanding of senescence at the wrganelle and molecular levels is presented. Finally, same ideas are mooted as to why senescence occurs and why it should be studied further.

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Section: What Is the Threshold?mentioning

confidence: 99%

Gene expression during leaf senescence

1994

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“…They concluded that the relative strength of the young reproductive and vegetative sinks is mediated by photoperiod and genotype in peas. Relative sink strength, via control of assimilate allocation, regulates the rate of reproductive development relative to vegetative growth and senescence (Gifford and Evans, 1981;Kelly and Davies, 198813;Sklensky and Davies, 1993).…”

Section: The Relationship Among Hormonal Levels Nutrient Partitioninmentioning

confidence: 99%

The Control of Apical Bud Growth and Senescence by Auxin and Gibberellin in Genetic Lines of Peas

Zhu

Davies

1997

Plant Physiology

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Pea (Pisum safivum L.) lines G2 (dwarf) and NCBl769 (tall) (Sn Hr) produce flowers and fruit under long (LD) or short (SD) days, but senesce only under LD. Endogenous gibberellin (CA) levels were inversely correlated with photoperiod (over 9-1 8 h) and senescence: CA,, was 3-fold and CA, was 10-to 11-fold higher in flowering SD C2 shoots, and the vegetative tissues within the SD apical bud contained 4-fold higher levels of CA,,, as compared with the LD tissues. Prefloral C2 plants under both photoperiods had CA, and CA,, levels similar to the flowering plants under LD. Levels of indole-3-acetic acid (IAA) were similar in C2 shoots in LD or SD; SD apical bud vegetative tissues had a slightly higher IAA content. Young floral buds from LD plants had twice as much IAA as under SD. In NCB1769 shoots CA, decreased after flower initiation only under LD, which correlated with the decreased growth potential. We suggest that the higher CA, content of G2 and NCB1769 plants under SD Under LD conditions fruit development in G2 pea plants results in apical senescence, but under SD conditions apical growth continues, despite the presence of a large number of fruit. This is dependent on the presence of dominant alleles at the Sn and Hr genetic loci. The photoperiodic response of G2 plants is nonphotosynthetic and quantitative, such that a brief exposure of light during the night does not reverse its SD growth habit (Proebsting et al., 1976). The growth rate of developing seeds on G2 plants is more rapid under LD than under SD conditions, which is indicative of a greater nutrient drain exerted on LD plants

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“…These interactions between vegetative and reproductive structures are generally referred to as correlative controls. A number of hypotheses concerning the nature of these correlative control signals have been presented (reviewed in Woolhouse, 1983;Kelly and Davies, 1988;Noodén, 1988b), but the biochemical nature of the signaling mechanisms has not been unequivocally established for any higher plant.…”

Section: Introductionmentioning

confidence: 99%

Developmental and age-related processes that influence the longevity and senescence of photosynthetic tissues in arabidopsis.

et al. 1993

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Factors that influence the longevity and senescence of photosynthetic tissues of Arabidopsis were investigated. To determine the influence of reproductive development on the timing of somatic tissue senescence, the longevity of rosette leaves of the Landsberg efecta strain and of isogenic mutant lines in which flowering is delayed (co-2) or sterile flowers are produced (ms7-7) were compared. No difference in the timing of senescence of individual leaves was observed between these lines, indicating that somatic tissue longevity is not governed by reproductive development in this species. To examine the role of differential gene expression in the process of leaf senescence, cDNA clones representing genes that are differentially expressed in senescing tissues were ísolated. Sequence analysis of one such clone indicated homology to previously cloned cysteine proteinases, which is consistent with a role for the product of this gene in nitrogen salvage. RNA gel blot analysis revealed that increased expression of senescence-associated genes is preceded by declines in photosynthesis and in the expression of photosynthesis-associated genes. A model is presented in which it is postulated that leaf senescence is triggered by age-related declines in photosynthetic processes.

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The control of whole plant senescence

Cited by 49 publications

References 175 publications

Gene expression during leaf senescence

Gene expression during leaf senescence

The Control of Apical Bud Growth and Senescence by Auxin and Gibberellin in Genetic Lines of Peas

Developmental and age-related processes that influence the longevity and senescence of photosynthetic tissues in arabidopsis.

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