The Role of Abscisic Acid in Senescence of Detached Tobacco Leaves

Even‐Chen, Zeev; Itai, Chanan

doi:10.1111/j.1399-3054.1975.tb03799.x

Cited by 37 publications

(23 citation statements)

References 23 publications

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“…In addition to allowing ABA accumulation in wilted leaves, BA did not change the ABA levels in ABA-treated leaves. This result can be taken as an indication that BA does not cause ABA to be converted to a bound form in barley leaves, unlike tobacco leaves maintained over a period of days (6).…”

Section: Resultsmentioning

confidence: 89%

The Effects of Benzyladenine, Cycloheximide, and Cordycepin on Wilting-Induced Abscisic Acid and Proline Accumulations and Abscisic Acid- and Salt-Induced Proline Accumulation in Barley Leaves

Stewart¹,

Voetberg²,

Rayapati³

1986

Plant Physiol.

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Benzyladenine inhibits proline accumulation in wilted, abscisic acid (ABA)-treated, and salt-shocked barley leaves. It does not affect ABA accumulation or disappearance in wilted leaves. Inhibition of proline accumulation in salt-shocked leaves was observed both when benzyladenine was added at the beginning ofor after salt treatment. Cycloheximide (CHX) and cordycepin inhibited both ABA and proline accumulations in wilted barley leaves and proline accumulation in ABA-treated leaves. In salt-shocked leaves, cordycepin inhibited proline accumulation when added after salt treatment but before proline began to accumulate but not when added after the onset of proline accumulation. CHX delayed the accumulation of proline in salt-shocked leaves but, after a period of time, proline accumulated in the CHX-treated leaves at rates comparable to the salt-treated control. This delay and subsequent accumulation was observed when CHX was added before, during, and after salt treatment. However, the earlier in the salt treatment period that CHX was given, the longer was the observed delay. These results are interpreted to indicate that gene activation is involved in proline accumulation in response to wilting, to ABA, and to salt in barley leaves. This gene activation is in addition to the gene activation that is required for ABA accumulation in wilted leaves. If ABA accumulation is required for proline accumulation in wilted barley leaves, then two sets of gene activation are involved in wilting-induced proline accumulation. All of our results are consistent with this possibility but do not prove it. The inhibition of proline accumulation by benzyladenine is probably neither due to an effect on gene activation nor to an effect on the ABA level.

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Section: Resultsmentioning

confidence: 89%

The Effects of Benzyladenine, Cycloheximide, and Cordycepin on Wilting-Induced Abscisic Acid and Proline Accumulations and Abscisic Acid- and Salt-Induced Proline Accumulation in Barley Leaves

Stewart¹,

Voetberg²,

Rayapati³

1986

Plant Physiol.

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“…However, in a long-term experiment invoh'ing the daily spraying of 0-1 mM (26 mg 1"^) ABA onto wheat plants for 84 d, it has been noted that ABA does not promote leaf senescence under these conditions, and actually increases leaf longevity (Hall & McWha, 1981). The endogenous level of ABA increases in the early stages of senescence of detached tobacco leaves and declines rapidly later in the process (Even-Chen & Itai, 1975). The le\-el of ABA also increases under conditions of stress such as drought, low temperature and high salt (Zeevaart & Creelman, 1988), which predispose a plant to senesce.…”

Section: Plant Grozcth Regulators (A) Cytokininsmentioning

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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“…Auxin-like activity increased and then decreased in senescing tobacco leaves (27) as did ABA content in senescing bean leaves (10). The considerable rise in leaf ABA was associated with the phase of rapid Chl breakdown (3).…”

Section: Rates Of Ethylene Production and Respiration By Leaves Duringmentioning

confidence: 99%

Patterns of Ehtylene Production in Senescing Leaves

1979

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Changes in the patterns of ethylene production, chlorophyll content, and respiration were studied in relation to the senescence of intact leaves and leaf discs. The primary leaves of pinto bean, which abscise readily during natural senescence, and tobacco and sugar beet leaves, which do not abscise, were used. A decrease in the rate of ethylene production and respiration, during the slow phase of chlorophyl degradation, was observed in leaf-blade discs cut from mature leaves and aged in the dark. During rapid chlorophyl loss both ethylene production and respiration increased and then decreased. These climacteric-like patterns were shown by leaf discs of all three species. Discs taken from leaves that had been senescing on the plant also showed a climacteric-like rise in ethylene production but not in respiration, which decreased continuously with leaf age. Climactericlike patterns in the rise of ethylene and respiration for leaf discs were also shown by the petioles of both bean and tobacco leaves. This indicates that the rise of ethylene and respiration is characteristic of the general process of senescence in leaves and is not restricted to the abscission process. In contrast to the ethylene-forming systems in climacteric fruits and many flowers, the one in leaves declines sharply in the early stages of senescence. The subsequent rise of ethylene production appears to be associated with the rapid phase of chlorophyl breakdown, and may indicate the final stage of the senescence process during which ethylene could be actively involved in inducing leaf abscission.Ethylene is known to be involved with both Chl degradation in leaf blades and with the abscission process (9,24, 25). Beyer (6) demonstrated that the leaf blade is the primary receptor site for exogenous ethylene in leaf abscission. Aharoni (1) found that the principal site of ethylene production in response to a short period of water stress was also the blades rather than the petioles of leaves. McAfee and Morgan (21) found that ethylene levels in cotton leaf petioles were two to six times as high as those in leaf blades. Less attention was paid to the changing pattern of ethylene production by leaf blades during their senescence. Some studies in which ethylene production by the whole leaf was measured revealed a decrease in ethylene production with leaf age (12,13,20,23) climacteric in fruits. This study did not distinguish between the contribution of the tomato petiole and leaf blade to the ethylene production pattern observed. Since abscission is directly concerned with the petiole it seemed important to determine patterns of ethylene production in leaf blades and petioles in abscising and nonabscising leaves during senescence. In this study we examined patterns of ethylene production by senescing leaf blades and by leaf petioles with and without abscission zones. The capacity of leaves at various ages to produce ethylene in response to IAA and kinetin was also studied. MATERIALS AND METHODSTobacco (Nicotiana tabacum L. cv. Xanthi), pinto be...

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The Role of Abscisic Acid in Senescence of Detached Tobacco Leaves

Cited by 37 publications

References 23 publications

The Effects of Benzyladenine, Cycloheximide, and Cordycepin on Wilting-Induced Abscisic Acid and Proline Accumulations and Abscisic Acid- and Salt-Induced Proline Accumulation in Barley Leaves

The Effects of Benzyladenine, Cycloheximide, and Cordycepin on Wilting-Induced Abscisic Acid and Proline Accumulations and Abscisic Acid- and Salt-Induced Proline Accumulation in Barley Leaves

Gene expression during leaf senescence

Patterns of Ehtylene Production in Senescing Leaves

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