scholarly journals Correlated Changes in the Activity, Amount of Protein, and Abundance of Transcript of NADPH:Protochlorophyllide Oxidoreductase and Chlorophyll Accumulation during Greening of Cucumber Cotyledons

1995 ◽  
Vol 109 (1) ◽  
pp. 231-238 ◽  
Author(s):  
K. Yoshida ◽  
R. M. Chen ◽  
A. Tanaka ◽  
H. Teramoto ◽  
R. Tanaka ◽  
...  
Keyword(s):  
Nadph:Protochlorophyllide Oxidoreductase ◽  
Chlorophyll Accumulation ◽  
Cucumber Cotyledons

scholarly journals No effect of plant growth retarding compounds and growth stimulators on indolo-3-acetic acid oxidase activity in greening cucumber cotyledons

2015 ◽  
Vol 42 (3) ◽  
pp. 441-452 ◽  
Author(s):  
J. S. Knypl
Keyword(s):  
Oxidase Activity ◽  
Chlorophyll Synthesis ◽  
Lag Phase ◽  
Acid Oxidase ◽  
Iaa Oxidase ◽  
Crude Enzyme Extract ◽  
Chlorophyll Accumulation ◽  
Cucumber Cotyledons ◽  
Amo 1618 ◽  
Molecular Sieving

Cotyledons dissected from 5-day-old etiolated cucumber seedlings were incubated in solutions on AMO-1618, B-Nine, CCC and Phosfon D for 48 h in light. In some tests the retardants were applied in mixed solutions with GA<sub>3</sub> or BAP. IAA oxidase was extracted and purified by means of molecular sieving through a bed of Sephadex G-25. The retardants inhibited chlorophyll synthesis by 50 % or more, and had essentially no effect on IAA oxidase activity per cotyledon basis. GA<sub>3</sub> and BAP also had no effect on enzyme activity in spite of a fact that the compounds stimulated growth of the cotyledons. The crude enzyme extract from B-Nine treated cotyledons showed lower IAA oxidase activity in comparison with the water treated control, the effect being due to a longer lag-phase preceding the initiation of IAA oxidation. KNO<sub>3</sub> strikingly stimulated expansional growth of the cotyledons, the effect being correlated with the accelerated chlorophyll accumulation. KNO<sub>3</sub> had no effect on IAA oxidase activity per cotyledon and decreased it per gram fr wt. It is concluded that [1] the growth rate of cucumber cotyledons is not correlated with IAA oxidase activity, and ;[2] the growth retarding compounds do not affect IAA oxidase system is this tissue.

scholarly journals Calcium Variously Mediates the Effect of Cytokinin on Chlorophyll and LHCPII Accumulation During Greening in Barley Leaves and Cucumber Cotyledons

2015 ◽  
Vol 56 (2) ◽  
pp. 27-34 ◽  
Author(s):  
Jolanta Legocka ◽  
Ewa Sobieszczuk-Nowicka
Keyword(s):  
Photosystem Ii ◽  
Channel Blocker ◽  
Indirect Evidence ◽  
Chelating Agent ◽  
Tetraacetic Acid ◽  
Plant Materials ◽  
Hormonal Effect ◽  
Chlorophyll Accumulation ◽  
Barley Leaves ◽  
Cucumber Cotyledons

Abstract During greening, excised etiolated barley leaves and cucumber cotyledons that were depleted of exogenous Ca2+ by a chelating agent (ethylene glycol-bis (beta aminoethyl ether)-N,N,N`N`-tetraacetic acid, EGTA) showed ∼50% reduced chlorophyll (Chl) accumulation and ∼30% accumulation of apoprotein of the light-harvesting chlorophyll a/b-binding protein complex of photosystem II (LHCPII). The Ca2+ channel blocker lanthanum chloride (LaCl3) applied to cucumber cotyledons reduced LHCPII accumulation more than EGTA did. In both plant mate-rials, cytokinins enhanced chlorophyll accumulation by 50-60% and this effect was completely canceled by EGTA application. Hormones significantly increased LHCPII accumulation but EGTA application reduced that effect in barley leaves by ∼30% and in cucumber cotyledons by ∼80%. A similar effect was observed in LaCl3-treated cotyledons. CaCl2 application boosted chlorophyll accumulation in both plant materials. CaCl2 applied together with cytokinin reduced the hormonal effect on chlorophyll accumulation by ∼38% in barley leaves and 23% in cucumber cotyledons, but almost totally inhibited cytokinin-stimulated LHCPII accumulation. Our results indicate that calcium variously mediates the effect of cytokinin on chlorophyll and LHCPII accumulation. Cytokinin-induced enhancement of chlorophyll accumulation seems totally dependent on the exogenous pool of Ca2+, while Ca2+-dependent and Ca2+-independent pathways are involved in the hormonal effect on LHCPII accumulation. The effect of cytokinin on the increase of light-induced LHCPII accumulation appears to be sensitive to exogenously applied Ca2+, which almost totally blocked the hormonal effect. Our results give indirect evidence that the responses to cytokinin and light act on different events leading to Chl and LHCPII accumulation.

Effect of EPTC on Plastid Membrane Constituents in Germinating Cucumber Cotyledons

Weed Science ◽  
1975 ◽  
Vol 23 (3) ◽  
pp. 185-187 ◽  
Author(s):  
Mitchell B. Weinberg ◽  
Paul A. Castelfranco
Keyword(s):  
Cucumis Sativus ◽  
Chlorophyll Accumulation ◽  
Cucumber Cotyledons

Cotyledons of 6-day old etiolated cucumber (Cucumis sativus L. ‘Alpha Green’) seedlings treated on the second day with EPTC (S-ethyl dipropylthiocarbamate) accumulated 35 to 45% more protochlorophyll and 30 to 40% more glycolipids than the controls. on illumination the treated cotyledons accumulated chlorophyll faster than the controls. Exposure of cucumber cotyledons to a variety of amide, carbamate, and other thiocarbamate herbicides did not produce a similar effect. EPTC, was found to cause an increase in chlorophyll accumulation.

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