scholarly journals The Effect of Nutrient Deficiencies on the Hill Reaction of Isolated Chloroplasts From Tomato

1960 ◽  
Vol 13 (4) ◽  
pp. 441 ◽  
Author(s):  
D Spencer ◽  
JV Possingham

Tomato plants were grown deficient in each known essential macro- and micronutrient (except chlorine) and the effect of each deficiency on the Hill reaction activity of chloroplasts isolated from these plants was studied.

1969 ◽  
Vol 24 (6) ◽  
pp. 764-769 ◽  
Author(s):  
Hartmut K. Lichtenthaler ◽  
Manfred Tevini

The changes in quinone and pigment composition of isolated spinach chloroplasts were investigated after treatment with UV-light of 254 mμ, which is known to decrease the Hill- reaction activity. The plastidquinones are more UV-sensitive than carotenoids (except neoxanthin) and chlorophylls. Neoxanthin, reduced plastoquinone 45 and α-tocopherol function consecutively as lipid antioxidants and are first destroyed. The latter are oxidized to the corresponding quinones plastoquinone 45 and α-tocoquinone, which thus seem to be less UV-sensitive. The decrease of the Hillreaction activity runs parallel with the decomposition of plastoquinol (= Plastohydrochinon) and not with that of plastoquinone as has been assumed so far. This indicates that plastoquinol is needed for performance of the Hill - reaction.The naphthoquinone vitamin K1, bound to the pigment system I of photosynthesis, is less UV-sensitive than the plastidquinones of the benzoquinone type which are associated mainly with the pigment system II. The possible function of vitamin K1 as one natural cofactor of cyclic photophosphorylation is discussed.


1965 ◽  
Vol 43 (1) ◽  
pp. 119-127 ◽  
Author(s):  
Norman E. Good

Heretofore Warburg's one-quantum theory of photosynthesis has seemed inconsistent with the existence of the Hill reaction. The one-quantum theory states that massive oxygen uptake and CO2 release are preconditions of photosynthetic oxygen production, yet isolated chloroplasts produce oxygen at high rates apparently without consuming any oxygen or producing any CO2. Warburg has attempted to resolve the dilemma by pointing out a CO2 dependence of the Hill reaction. On the basis of this observation he proposed a reinterpretation of the Hill reaction which is consistent with the one-quantum theory. The effect of CO2 on isolated chloroplasts has been confirmed and some of the conditions which are necessary for the demonstration of the effect have been defined. It is not clear if CO2 is actually metabolized as Warburg claims. Contrary to Warburg's model, its participation seems to be at a site remote from the photochemical act. A number of other reasons for doubting the reality of the one-quantum mechanism are presented.


Weeds ◽  
1962 ◽  
Vol 10 (3) ◽  
pp. 229 ◽  
Author(s):  
D. E. Moreland ◽  
K. L. Hill

1973 ◽  
Vol 12 (2) ◽  
pp. 391-401
Author(s):  
R. MACHE ◽  
S. LOISEAUX

The growth rate of the shade plant Marchantia was at its maximum for a low illumination, 2-3 x 103 lx, and was inhibited by an excess of light. Photosynthesis by intact thalli and by isolated chloroplasts of Marchantia was saturated by a light intensity of 2-3 x 103 lx. These isolated chloroplasts were able to carry on satisfactory rates of photosynthesis, up to 35 µM CO2/h/mg chlorophyll. The Hill reaction and photosystem II were also saturated by the same light intensities, demonstrating that the factor limiting the light saturation of photosynthesis is located in the chloroplast. The structure of chloroplasts was strongly modified by an excess of light, small grana and fret membranes being replaced by continuous grana.


1970 ◽  
Vol 25 (10) ◽  
pp. 1157-1159 ◽  
Author(s):  
A. Trebst ◽  
E. Harth ◽  
W. Draber

A halogenated benzoquinone has been found to inhibit the photosynthetic electron transport system in isolated chloroplasts. 2·10-6ᴍ of dibromo-thymoquinone inhibit the Hill- reaction with NADP, methylviologen or anthraquinone to 100%, but do not effect the photoreduction of NADP at the expense of an artificial electron donor. The Hill - reaction with ferricyanide is inhibited even at the high concentration of 2·10-5ᴍ of dibromo-thymoquinone to only 60%. The remaining reduction in the presence of the inhibitor reflects the rate of ferricyanide reduction by photosystem II. It is concluded that the inhibition of electron transport by the quinone occurs between photosystem I and II and close to or at the functional site of plastoquinone.


1981 ◽  
Vol 61 (3) ◽  
pp. 723-726 ◽  
Author(s):  
J. WEISS ◽  
W. D. BEVERSDORF

Effects of atrazine concentrations (10−7 to 10−4 M) on the Hill reaction were evaluated using isolated chloroplasts from parentals, F1 and BC3 of triazine-resistant biotype of bird’s-rape (Brassica campestris) × B. napus ’Tower’ and bird’s-rape × B. campestris ’Torch’. Atrazine did not affect the Hill reaction of bird’s-rape, hybrids or BC3 with cytoplasm from the triazine-resistant bird’s-rape, but interfered with the Hill reaction in triazine-susceptible Tower and Torch.


1984 ◽  
Vol 64 (3) ◽  
pp. 707-713 ◽  
Author(s):  
A. ALI ◽  
V. SOUZA MACHADO

Leaf chlorophyll fluorescence in susceptible B. campestris L. plants was greatly enhanced and the Hill reaction activity of isolated chloroplasts was inhibited by 10−4 M atrazine. The herbicide did not produce similar responses in resistant plants. 14C-atrazine was used to determine if, in addition, there were differences in uptake, translocation, and metabolism of the herbicide by the susceptible and resistant biotypes. The 14C-atrazine in nutrient solution was readily taken up by the roots of both biotypes and was rapidly translocated to the shoot. The 14C-atrazine was quickly metabolized and after a 24-h period 56 and 63% of the extractable radioactivity in susceptible and resistant plants, respectively, was present as metabolites, the major one being 2-hydroxyatrazine. Following a foliar application, less than 1% of the applied radioactivity moved into other parts of the plant. These results clearly show that triazine resistance in wild turnip rape is based in the chloroplast and that uptake, translocation, and metabolism of the herbicide play no decisive role in selectivity between the susceptible and resistant biotypes.Key words: Atrazine selectivity, Brassica campestris, chlorophyll fluorescence, Hill reaction, atrazine metabolism.


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