Cytokinin interaction with free radical metabolism and senescence: Effects on endogenous lipoxygenase and purine oxidation

Leshem, Y.; Wurzburger, Judith; Grossman, Shlomo; Frimer, Aryeh A.

doi:10.1111/j.1399-3054.1981.tb05037.x

Cited by 65 publications

(26 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Linoleic acid is a constituent of plant membranes, and the association of ethylene production with membranes was noted above. Leshem has shown that the activity of lipoxygenase in pea leaves increases greatly during senescence and that cytokinins decrease its level in leaves (19,20); these findings give support to the idea of a parallel betweel senescence and the lipoxygenase system. The presence of lipoxygenase in the etiolated pea shoots is proven by the great decrease in the liberation of ethylene by the extract when linoleate is omitted (Table 4).…”

Section: Discussionmentioning

confidence: 66%

“…Unless otherwise stated, the reaction mixture contained 1 mM ACC, 1 mM linoleic acid, 0.1 mM MnCl2, 0.1 mM pyridoxal phosphate (pyridoxal-P), and 10 mM sodium [4-(2-hydroxyethyl)-1-piperazinepropanesulfonate (NaEPPS) buffer (pH 8.0). To this, 20 10,000 x g for 20 min. The supernatant was then centrifuged at 100,000 x g for 1 hr.…”

Section: Methodsmentioning

confidence: 99%

“…The requirement for oxygen (and not mere proton transfer) in the conversion of ACC to ethylene indicates the participation of an oxidase or free radicals, or both. Among the enzymatic changes in leaf senescence, for instance, is a marked increase in lipoxygenase (linoleate:oxygen oxidoreductase, EC 1.13.11.12) (19,20). Another lead was given by our own preliminary experiments in which peroxidase plus H202 yielded some ethylene; however, not only has peroxidase been shown to be inactive (21,22), but also in our experiments the boiled enzyme was equally effective, which indicates that probably a metallic impurity was acting as a catalyst.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Lipid peroxidation forms ethylene from 1-aminocyclopropane-1-carboxylic acid and may operate in leaf senescence

Bousquet

Thimann

1984

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

An enzyme system is described which oxidizes 1-aminocyclopropane-l-carboxylic acid (ACC) to ethylene under physiological conditions. It comprises linoleic acid, pyridoxal phosphate, manganese, and lipoxygenase (linoleate:oxygen oxidoreductase, EC 1.13.11.12). It requires oxygen and is specific for manganese; it can operate but only with greatly reduced yield in the absence of pyridoxal phosphate.An enzyme with the same properties was prepared from microsomal membranes of the seedling shoots of peas. Both have similar reactions to a variety of inhibitors and other reagents. The properties also resemble those of at least two of the in vivo systems recorded ih the literature. Intact green oat leaves also contain a similar system. Because there is a growing body of evidence that ethylene formation is associated with cell membranes and because the yields of ethylene from the complete system are much higher than those recorded for' other enzymes, it may be identical with the in vivo system acting in senescent leaves.

show abstract

Section: Discussionmentioning

confidence: 66%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Lipid peroxidation forms ethylene from 1-aminocyclopropane-1-carboxylic acid and may operate in leaf senescence

Bousquet

Thimann

1984

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…134 It has been shown that cytokinins inhibits the activity of xanthine oxidase, one of the cellular free radical sources, and also act as a direct free radical scavenger. 135 Gidrol et al…”

Section: Staxen and Bornmanmentioning

confidence: 99%

Interaction of cytokinins with UV-B (280 -315nm) on the expansion growth of cucumber cotyledons

Kataria¹,

Kn²

2018

HIJ

View full text Add to dashboard Cite

The negative effect on plant responses are expected due to increased amounts of ultraviolet-B (UV-B) radiation reaching on the Earth's surface by stratospheric ozone depletion. Cytokinins (CKs) are essential phytohormones in plant growth and development. Perusal of relevant literature reveals that CKs mitigate the oxidative damage caused by abiotic stresses like salt, drought, high temperature and heavy metal due to their antioxidant effects. However, very few reports are available on the interaction of CKs with UV-B stress on the expansion growth of the cucumber cotyledons. CKs induced the expansion growth of the excised cucumber cotyledons in the darkness. CKs induced expansion growth of cucumber cotyledons in darkness was inhibited by supplemental UV-B. UV-B radiation enhanced the level of oxyradicals like superoxide and hydroxide radicals in the excised cucumber cotyledons, which was evident by EPR spectroscopy. CKs like Zeatin, TDZ, BAP and FAP reduced the level of oxyradicals produced in the dark grown cucumber cotyledons, while promoting the expansion growth of the cotyledons. Production of oxyradical in UV-B exposed cotyledons showed that these oxyradicals might partially account for inhibition of expansion growth. Since considerable amount of oxyradicals were quenched by CKs at higher concentrations (10 and 20 µg/ml) it partially restores the inhibition of expansion growth caused by UV-B stress. It indicates that overproduction of oxyradicals by UV-B could not be entirely responsible for the inhibition of CKs induced expansion growth of cotyledons; which might be caused by some other physiological changes caused by UV-B irradiation in addition to the production of oxyradicals. UV-B is also known to inactivate protein inhibitor of peroxidase in cucumber cotyledons. This may reduce the antioxidants defence and enhance the damaging effects of oxyradicals for the growth of cotyledons.

show abstract

“…Cytokinins also take part in the regulation of plant response to stress (Georgiev et al 1992, which may be the result of their possible function as antioxidants (Leshem et al 1981). Georgiev et al (1992) reported a strong protective effect of phenylurea cytokinin 4-PU-30 on marrow (Cucurbita pepo var.…”

mentioning

confidence: 99%

Effect of Putrescine, 4-PU-30, and Abscisic Acid on Maize Plants Grown under Normal, Drought, and Rewatering Conditions

Todorov

Alexieva

Karanov

1998

J Plant Growth Regul

View full text Add to dashboard Cite

The experiments were carried out with maize (Zea mays L.) seedlings, hybrid Kneja 530, grown hydroponically in a growth chamber. Twelve-day-old plants were foliar treated with putrescine, N1-(2-chloro-4-pyridyl)-N2-phenylurea (4-PU-30), and abscisic acid (ABA) at concentrations of 10(-5) m. Twenty-four hours later the plants were subjected to a water deficit program, induced by 15% polyethylene glycol (PEG; molecular weight, 6,000). Three days after drought stress half of the plants were transferred to nutrient solution for the next 3 days. The effects of the water shortage, rewatering, and plant growth regulator (PGR) treatment on the fresh and dry weights, leaf pigment content, proline level, relative water content (RWC), transpiration rate, activities of catalase and guaiacol peroxidase, hydrogen peroxide content, and level of the products of lipid peroxidation were studied. It was established that the application of PGRs alleviated to some extent the plant damage provoked by PEG stress. At the end of the water shortage program the plants treated with these PGRs possessed higher fresh weight than drought-subjected control seedlings. It was found also that putrescine increased the dry weight of plants. Under drought, the RWC and transpiration rate of seedlings declined, but PGR treatment reduced these effects. The accumulation of free proline, malondialdehyde, and hydrogen peroxide was prevented in PGR-treated plants compared with the water stress control. The results provided further information about the influence of putrescine, 4-PU-30, and ABA on maize plants grown under normal, drought, and rewatering conditions. Key Words. Maize-Putrescine-4-PU-30-ABA-Drought

show abstract

Cytokinin interaction with free radical metabolism and senescence: Effects on endogenous lipoxygenase and purine oxidation

Cited by 65 publications

References 14 publications

Lipid peroxidation forms ethylene from 1-aminocyclopropane-1-carboxylic acid and may operate in leaf senescence

Lipid peroxidation forms ethylene from 1-aminocyclopropane-1-carboxylic acid and may operate in leaf senescence

Interaction of cytokinins with UV-B (280 -315nm) on the expansion growth of cucumber cotyledons

Effect of Putrescine, 4-PU-30, and Abscisic Acid on Maize Plants Grown under Normal, Drought, and Rewatering Conditions

Contact Info

Product

Resources

About