On the role of ß-carotene in the reaction center chlorophyll a antennae of photosystem I

Absorption and low temperature fluorescence emission spectra were measured on chloroplast thylakoids and on purified reaction center chlorophyll a-protein complexes of photosystem I, CP-a₁. A clear association between the presence of ß-carotene and the occurrence of far red absorbing and emitting chlorophyll a components of the reaction center antennae of photosystem I was demonstrated. For this study chloroplasts and CP-a₁ were obtained from normal and carotenoid deficient plant material of various sources. The experimental material included 1) lyophilized pea chloroplasts extracted with petroleum ether, 2) the carotenoid deficient mutant C-6E of Scenedesmus obliquus and 3) wheat chloroplasts derived from normal and SAN-9789 treated plants. Removal of carotenoids, most likely principally ß-carotene, caused a loss of long wavelength absorbing chlorophylls in chloroplasts and purified CP-a₁, and the loss or diminution of the long wavelength peak seen in the low temperature fluorescence emission spectrum. This association between ß-carotene and special chlorophyll a forms may explain both the photoprotective and antenna functions ascribed to ß-carotene. In the absence of carotenoids in wheat and in the Scenedesmus mutant, the chlorophyll a antenna of photosystem I was extremely photosensitive. A triplet-triplet resonance energy transfer from chlorophyll a to ß-carotene and a singlet-singlet energy transfer from excited ß-carotene to chlorophyll would explain the photoprotective and antenna functions, respectively. The role of this association in determining some of the fluorescence properties of photosystem I is also discussed.     

The effects of photooxidative stress on photosystem I measured in vivo in Chlamydomonas

The effects of different photooxidative stresses on the function of photosystem I were measured in vivo in Chlamydomonas reinhardtii. Pholooxidative stresses included strong light, light combined with chilling to 0 °C, and light combined with several concentrations of methyl viologen. Photosystem I function was measured in vivo using the absorbance change at 820 nm associated with P₇₀₀ oxidation. Photosystem II function was measured in vivo using chlorophyll fluorescence. Strong light or light combined with chilling caused inhibition of photosystem II function earlier than inhibition of photosystem I function. When photosystem I was inhibited, however, it did not recover. Light combined with 5 mmol m^?3 methyl viologen caused inhibition of photosystem I function earlier than inhibition of photosystem II. If the methyl viologen concentration was reduced to 1 mmol m^?3, the damage to PSI was accelerated by addition of 90 mmol m^?3 chloramphenicol. This effect of chloroamphenicol suggests a role for chloroplast-encoded proteins in protecting photosystem I against photooxidative damage caused by methyl viologen.     

Effect of Iron Deficiency Induced Changes on Photosynthetic Pigments,Ribulose-1,5-Bisphosphate Carboxylase,and Photosystem Activities in Field Grown Grapevine (Vitis Vinifera L. cv. Pinot Noir) Leaves

The effect of iron deficiency on photosynthetic pigments, ribulose-1,5-bisphosphate carboxylase (RuBPC), and photosystem activities were investigated in field grown grapevine (Vitis vinifera L. cv. Pinot noir) leaves. The contents of chlorophyll (Chl) (a+b) and carotenoids per unit fresh mass showed a progressive decrease upon increase in iron deficiency. Similar results were also observed in content of total soluble proteins and RuBPC activity. The marked loss of large (55 kDa) and small (15 kDa) subunits of RuBPC was also observed in severely chlorotic leaves. However, when various photosynthetic electron transport activities were analysed in isolated thylakoids, a major decrease in the rate of whole chain (H₂O methyl viologen) electron transport was observed in iron deficient leaves. Such reduction was mainly due to the loss of photosystem 2 (PS2) activity. The same results were obtained when F_v/F_m was evaluated by Chl fluorescence measurements in leaves. Smaller inhibition of photosystem 1 (PS1) activity was also observed in both mild and severely chlorotic leaves. The artificial electron donors, diphenyl carbazide and NH₂OH, markedly restored the loss of PS2 activity in severely chlorotic leaves. The marked loss of PS2 activity was evidently due to the loss of 33, 23, 28-25, and 17 kDa polypeptides in iron deficient leaves.     

A single step separation of PS 1, PS 2 and chlorophyll-antenna particles from spinach chloroplasts

After solubilization of photosynthetic membranes by digitonin, three main protein pigment complexes were isolated by electrophoresis with deoxycholate as detergent.The band with the slowest mobility, fraction 1, had PS 1 activity and was devoid of PS 2 activity. This fraction was four times enriched in P700 when compared with chloroplasts. Fraction 1 had little chl b, a long wavelength absorption maximum in the red, a maximum of low temperature emission fluorescence at 730nm, and a circular dichroism spectrum characteristic of PS 1 enriched fraction.Fraction 2 exhibited a PS 2 activity and no PS 1 activity. It was enriched five times in PS 2 reaction centre and had little chl b and carotenoids. The absorption maximum was at 674 nm and the low temperature fluorescence emission maximum was at 700 nm. Fraction 2 might be useful PS 2 enriched particle because of the great stability of this fraction with regard to photochemical activity and also rapidity and simplicity of its preparation.Fraction 3, which had the fastest migration, was devoid of photochemical activities; It was rich in chl b and had the fluorescence and the circular dichroism spectrum characteristic of an antenna complex.Abbreviations PS 1 (2) photosystem 1 (2) - chl chlorophyll - car carotenoid - Q primary plastoquinone electron acceptor - P700 primary electron donor of PS 1 - P680 primary electron donor of PS 2 - K₃Fe(CN)₆ potassium ferricyanide - DCMU dichlorophenyldimethylurea - DCPIP dichlorophenolindophenol - DPC diphenyl-carbazide     

Photochemical Apparatus Organization in the Chloroplasts of Two Beta vulgaris Genotypes

The composition and structural organization of thylakoid membranes of a low chlorophyll mutant of Beta vulgaris was investigated using spectroscopic, kinetic and electrophoretic techniques. The data obtained were compared with those of a standard F1 hybrid of the same species. The mutant was depleted in chlorophyll b relative to the hybrid and it had a higher photosystem II/photosystem I reaction center (Q/P₇₀₀) ratio and a smaller functional chlorophyll antenna size. Analysis of thylakoid membranes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the mutant lacked a portion of the chlorophyll a/b light-harvesting complex but was enriched in the photosystem II reaction center chlorophyll protein complex. Comparison of functional antenna sizes and of photosystem stoichiometries determined electrophoretically were in good agreement with those determined spectroscopically. Both approaches indicated that about 30% of the total chlorophyll was associated with photosystem I and about 70% with photosystem II. A greater proportion of photosystem II_β was detected in the mutant. The results suggest that a higher photosystem II to photosystem I ratio in the sugar beet mutant has apparently compensated for the smaller photosystem II chlorophyll light-harvesting antenna in its chloroplasts. Moreover, a lack of chlorophyll a/b light-harvesting complex correlates with the abundance of photosystem II_β. It is proposed that a developmental relationship exists between the two types of photosystem II where photosystem II_β is a precursor form of photosystem II_α occurring prior to the addition of the chlorophyll a/b light-harvesting complex and grana formation.     

High photosynthetic efficiency of a rice (Oryza sativa L.) xantha mutant

Comparative analysis revealed that a xantha rice mutant (cv. Huangyu B) had higher ratios of chlorophyll (Chl) a/b and carotenoids/Chl, and higher photosynthetic efficiency than its wild type parent (cv. II32 B). Unexpectedly, the mutant had higher net photosynthetic rate (P _N) than II32 B. This might have resulted from its lower non-photochemical quenching (q_N) but higher maximal photochemical efficiency (F_V/F_M), higher excitation energy capture efficiency of photosystem 2 (PS2) reaction centres (F_V′/F_M′), higher photochemical quenching (q_P), higher effective PS2 quantum yield (Φ_PS2), and higher non-cyclic electron transport rate (ETR). This is the first report of a chlorophyll mutant that has higher photosynthetic efficiency and main Chl fluorescence parameters than its wild type. This mutant could become a unique material both for the basic research on photosynthesis and for the development of high yielding rice cultivars.     

Temperature dependent reduction of protochlorophyllide in darkness followed by the assembly of active photosystems in pigment mutant C-2A' of Scenedesmus obliquus

In the wild type of Scenedesmus obliquus strain D3 grown heterotrophically, the chlorophyll biosynthesis and thus the reduction of protochlorophyllide to chlorophyllide takes place in darkness. However, in pigment mutant C-2A' of Scenedesmus obliquus only traces of protochlorophyllide are reduced under optimal growth conditions in darkness. By lowering the growth temperature from 33° to 15–25°C, protochlorophyllide can be reduced in darkness. At 20°C this process is about 10 times more active than at 33°C, but reaches only about 13% of the light-dependent chlorophyll biosynthesis. The chlorophylls synthesized at the lower temperatures are inserted into the pigment-protein complexes and photosystem I as well as photosys-tem II capacities are developed. The rate of light-independent protochlorophyllide reduction at lower temperatures is not limited by the enzyme PChlide-oxidoreductase itself, but rather by its substrate, being in turn limited by the amount of 5-amino levulinic acid (ALA) available.     

Analysis of Rice Mutants by Low Temperature-Derivative Spectrophotometry in Relation to Pigment Compositions and Photochemical Activities

The chloroplasts of five rice (Oryza sativa) mutants examined in the present study possessed the following pigment and activity characteristics as compared with those of normal strain (Nohrin No. 8); a) less chlorophylls (especially, chlorophyll b, the molar ratio of a to b= 6 ～ 41) and less carotenoids but higher ratios of β-carotene to chlorophylls; b) only photosystem 1 particles were obtained by density gradient centrifugation of digitonin-treated mutant chloroplasts while both photosystem 1 and 2 particles were obtained from normal strain chloroplasts; c) the photosystem 2 activities of mutant chloroplasts were lower (48 ～ 81 %) than that of normal chloroplasts while their photosystem 1 activities were 1.9 ～ 2.4 times higher. The derivative absorption spectrum of the normal chloroplasts (a/b= 4) measured at liquid nitrogen temperature showed many small but distinct maxima and minima in the red region in addition to those observable for chlorophylls in solution. These band structures including the French inflection were lost partially in the derivative spectra of three mutants with a/b= 6, 8 and 11 and almost completely in those of the remaining two mutants with a/b= 18 and 41. The lack of such band structures reflecting specific states of chlorophylls in vivo was attributed to the absence of some conformational structures such as those expected in photosystem-2 particles, which are formed by the presence of chlorophyll b and are resistant to the digitonin treatment. Chlorophylls in specific states in such structures were thought to exhibit a higher photosystem 2 activity.     

Selective photobleaching of PSI-related chlorophylls in heat-stressed pea chloroplasts

Measurements of electron transport activity point to the occurrence of major changes in the organisation of the photosynthetic apparatus of heat-stressed chloroplasts. One of the consequences of these changes is shown to be a greatly increased susceptibility of chlorophyll to photobleaching. Despite the fact that the threshold temperature for this photobleaching coincides closely with that for the inhibition of PSII activity, the bleached components were found to be specifically associated with PSI. This increased susceptibility of PSI pigments to photobleaching is shown to be a direct consequence of an interruption of the flow of reductants from PSII to PSI that would normally protect PSI from photooxidation.Abbreviations PSI photosystem I - PSII photosystem II - chl a chlorophyll a - chl b chlorophyll b - LHCP chlorophyll a/b light-harvesting protein - CP₁ P700-chlorophyll a protein - DCMU 3-(34 dichlorophenyl)-11-dimethylurea - DCPIP dichlorophenolindophenol - Fecy potassium ferricyanide - MV methyl viologen Biochemistry Department, King's College (KQC), University of London     

Stoichiometric determination of pheophytin in photosystem II of oxygenic photosynthesis

Pheophytin and chlorophyll extracted from oxygen-evolving photosystem II particles, chloroplast thylakoids and cyanobacterial cells were separated by column chromatography with DEAE-Toyopearl, and quantitatively determined by spectrophotometry. The molecular ratio of chlorophyll a+b to pheophytin a was about 100 in spinach photosystem II particles and about 140 in spinach thylakoids. Using flash spectrophotometry of P680 and measurement of flash-induced oxygen yield, the molecular ratio of the chlorophyll to the photochemical reaction center II was determined to be about 200 in the photosystem II particles. These findings suggest that the stoichiometry in photosystem II particles is one reaction center II and two pheophytin a molecules per about 200 chlorophyll molecules. The same stoichiometry for pheophytin to the reaction center II was obtained in the cyanobacteria, Anacystis nidulans and Synechocystis PCC 6714. A quantitative determination of pheophytin a and the electron donor P700 in stroma thylakoids from pokeweed suggests that photosystem I does not contain pheophytin.Dedicated to Prof. L.N.M. Duysens on the occasion of his retirement.     

Photoinhibition of Photosystem I electron transfer activity in isolated Photosystem I preparations with different chlorophyll contents

Photoinhibition of the light-induced Photosystem I (PS I) electron transfer activity from the reduced dichlorophenol indophenol to methyl viologen was studied. PS I preparations with Chl/P700 ratios of about 180 (PS I-180), 100 (PS I-100) and 40 (PS I(HA)-40) were isolated from spinach thylakoid membranes by the treatments with Triton X-100, followed by sucrose density gradient centrifugation and hydroxylapatite column chromatography. White light irradiation (1.1 × 10⁴E m^–2 s^–1) of PS I-180 for 2 hours bleached 50% of the chlorophyll and caused a 58% decrease in the electron transfer activity with virtually no loss of the primary donor, P700. The flash-induced absorbance change showed the decay phase with a half time of about 10 s that was attributed to the P700 triplet, suggesting that the photoinhibitory light treatment caused the destruction of the PS I acceptor(s), F_x and possibly A₁. PS I-100 was similarly photobleached by the irradiation and the electron transfer activity decreased. There was, however, no apparent photoinhibition of the electron transport activity in PS I(HA)-40. Photoinhibition similar to that seen in PS I-180 also occurred in membrane fragments that were isolated without any detergent from a PS II-deficient mutant strain of the cyanobacterium Synechocystis sp. PCC 6803. PS I-180 was not photoinhibited under anaerobic conditions. The production of superoxide and fatty acid hydroperoxide during white light irradiation was significantly greater in PS I-180 than in PS I(HA)-40. The mechanism of photoinhibition in PS I preparations is discussed in relation to the formation of toxic oxygen molecules.Abbreviations A₀,A₁ primary and secondary electron acceptors of PS I - CD circular dichroism - DCPIP 2,6-dichlorophenol indophenol - F_A, F_B, F_X iron-sulfur centers A, B, X - HA hydroxylapatite - LHCI lightharvesting complex of PS I - MDA malondialdehyde - MV methyl viologen - Na-Asc sodium L-ascorbate - P700 primary electron donor of PS I - PFD photon flux density - PS I-A and PS I-B psaA and psaB gene products - TBA thiobarbituric acid     

Pigments and Gas Exchange Characteristics in Leaves of Chlorophyll Mutants of Pisum sativum

Quantitative and qualitative characteristics of pigment composition and gas exchange were studied in chlorophyll mutants of pea, Pisum sativum L.: chlorotica 2004 and 2014. The mutant 2004 had light-green color, whereas the mutant 2014 has yellow-green leaves and stems; they contained about 80 and 50% of chlorophyll, respectively, compared to the initial line. cv. Torsdag. Leaves of the mutant 2004 had significantly lower carotene content and accumulated more lutein and violaxanthin. In the mutant 2014, the contents of chlorophyll and all carotenoids were reduced almost proportionally. The quantum efficiency of photosynthesis was by 29–30% lower in the mutants, and it was 1.5–2 times higher in F₁ hybrids, as compared to control plants. Our data allow us to conclude that the impairment of photosynthesis in the mutant 2014 is caused by the changed mesostructure of leaves, whereas in the mutant 2004, it may be caused by an impairment of photosystem reaction centers.     

Euploidy in Ricinus: EUPLOIDY EFFECTS ON PHOTOSYNTHETIC ACTIVITY AND CONTENT OF CHLOROPHYLL-PROTEINS

The effects of nuclear genome duplication on the chlorophyll-protein content and photochemical activity of chloroplasts, and photosynthetic rates in leaf tissue, have been evaluated in haploid, diploid, and tetraploid individuals of the castor bean, Ricinus communis L. Analysis of this euploid series revealed that both photosystem II (2,6-dichlorophenolindophenol reduction) and photosystem I oxygen uptake (N,N,N′,N′-tetramethyl-p-phenylenediamine to methyl viologen) decrease in plastids isolated from cells with increasingly larger nuclear complement sizes. Photosynthetic O₂-evolution and ¹⁴CO₂-fixation rates in leaf tissue from haploid, diploid, and tetraploid individuals were also found to decrease with the increase in size of the nuclear genome. Six chlorophyll-protein complexes, in addition to a zone of detergent complexed free pigment, were resolved from sodium dodecyl sulfate-solubilized thylakoid membranes from cells of all three ploidy levels. In addition to the P700-chlorophyll a-protein complex and the light-harvesting chlorophyll a/b-protein complex, four minor complexes were revealed, two containing only chlorophyll a and two containing both chlorophyll a and b. The relative distribution of chlorophyll among the resolved chlorophyll-protein complexes and free pigment was found to be similar for all three ploidy levels.     

Changes in Carotenoid Composition and Function of the Photosynthetic Apparatus during Light-dependent Chloroplast Differentiation in Mutant C-6D of Scenedesmus obliquus*

Changes in pigment composition during light-dependent chloroplast differentiation in mutant C-6D of Scenedesmus obliquus were followed by HPLC. The system used enables the separation and quantitative determination of five xanthophylls (neoxanthin, violaxanthin, antheraxanthin, lutein and zeaxanthin), α- and β-carotene and chlorophyll a and b (and their epimeric forms). Dark-grown cells of the mutant contain only chlorophyll a, traces of chlorophyll b and acyclic precursors of carotenoids. During subsequent illumination, precursors decrease and high amounts of xanthophylls, carotenes and chlorophyll a and b are formed. Dark-grown cultures of mutant C-6D show high photosystem I-activity and contain the photosystem I-complex CP I, but lack photosystem II-activity, the photosystem II-complex CPa and the LHCP. Immediately after transfer to light, photosystem II-activity increases rapidly, as also do the amounts of CPa and lutein. Under anaerobiosis no lutein and PS II-activity can be detected. This indicates a role of lutein in the assembly of an active photosystem II-complex. All other xanthophylls and the LHCP exhibit high rates of synthesis only after a delay of about 1 hour. Thus, our results reveal an asynchronous fashion of formation of CPa and LHCP.     

Changes in ultrastructure and photosynthetic capacity withinScenedesmus obliquus mutants C-2 A′, C-6 D,and C-6 E on transfer from dark grown to illuminated conditions

Summary The ultrastructure, pigments and photosynthetic capacities of 3 X-ray induced mutants (C-2 A, C-6 D, and C-6 E) ofScenedesmus obliquus were studied whilst growing heterotrophically in the dark and upon transfer into the light (10,000 lux).Dark grown C-2 A, having no photosynthetic capacity and sparse amounts of chlorophylls a and b, greened at a faster rate than mutant C-6 D which already had photosystem I activity and chlorophyll a in the dark. Ultrastructural development to the wild-type situation was similar in both, but again much faster in C-2 A (24 hours) than in C-6 D (48 hours). In the dark grown C-2 A mutant the single lamellae differed from C-6 D in that they were already perforated. In the light, membrane overlapping took place in both to form first double, and later triple, thylakoid bands. A distinct phase of association of plastid ribosomes in a whorl-like arrangement with the developing thylakoids was shown by both only during the greening process. Over a similar period, mitochondrial appressions to these plastids were observed.In the dark, mutant C-6 E resembled dark grown C-6 D and possessed considerable photosystem I activity but no carotenoids. In the light it did not green, no ultrastructural changes were apparent and the unprotected chlorophyll a was photo-oxidized.All mutants in the dark showed tubular connections, resembling but not identical with the prolamellar bodies of higher plant etioplasts. Occasionally tubular connections similar to those in the dark-grown mutants were also found in the light.     

Acclimation of the Photosynthetic Apparatus to Growth Irradiance in a Mutant Strain of Synechococcus Lacking Iron Superoxide Dismutase

The acclimation of the photosynthetic apparatus to growth irradiance in a mutant strain of Synechococcus sp. PCC 7942 lacking detectable iron superoxide dismutase activity was studied. The growth of the mutant was inhibited at concentrations of methyl viologen 4 orders of magnitude smaller than those required to inhibit the growth of the wild-type strain. An increased sensitivity of photosynthetic electron transport near photosystem I (PSI) toward photooxidative stress was also observed in the mutant strain. In the absence of methyl viologen, the mutant exhibited similar growth rates compared with those of the wild type, even at high growth irradiance (350 [mu]E m-2 s-1) where chronic inhibition of photosystem II (PSII) was observed in both strains. Under high growth irradiance, the ratios of PSII to PSI and of [alpha]-phycocyanin to chlorophyll a were less than one-third of the values for the wild type. In both strains, cellular contents of chlorophyll a, [alpha]-phycocyanin, and [beta]-carotene, as well as the length of the phycobilisome rods, declined with increasing growth irradiance. Only the cellular content of the carotenoid zeaxanthin seemed to be independent of growth irradiance. These results suggest an altered acclimation to growth irradiance in the sodB mutant in which the stoichiometry between PSI and PSII is adjusted to compensate for the loss of PSI efficiency occurring under high growth irradiance. Similar shortening of the phycobilisome rods in the sodB mutant and wild-type strain suggest that phycobilisome rod length is regulated independently of photosystem stoichiometry.     

A Spectroscopic Analysis of a High Fluorescent Mutant of Chlamydomonas Reinhardi

Chloroplast fragments of a high fluorescent mutant of Chlamydomonas reinhardi, hfd 91, were compared against those of Acl⁺, a low chlorophyll variant of the wild type. The chloroplast fragments of the mutant which have a high invariant fluorescence yield lacked photochemical activities associated with photosystem II (PSII) but retained normal photosystem I (PSI) activities. The mutant fragments also lacked the low temperature (-196°C) light-induced absorbance changes due to the photoreduction of C-550 and the photooxidation of cytochrome (cyt) b-559 which are PSII-mediated reactions. A fourth-derivative analysis of the absolute spectra of the chloroplast fragments at different stages of reduction (obtained with ferricyanide, ascorbate, and dithionite) showed both the oxidized and reduced forms of C-550 and the reduced forms of cyt c-553, b-559, and b-564 in wild-type fragments. The mutant fragments lacked C-550 and an ascorbate-reducible cyt b-559 but contained cyt c-553, a dithionite-reducible cyt b-559, and cyt b-564.     

Reduction of the primary donor P700 of photosystem I during steady-state photosynthesis under low light in <Emphasis Type="Italic">Arabidopsis</Emphasis>

During steady-state photosynthesis in low-light, 830-nm absorption (A₈₃₀) by leaves was close to that in darkness in Arabidopsis, indicating that the primary donor P700 in the reaction center of photosystem I (PSI) was in reduced form. However, P700 was not fully oxidized by a saturating light pulse, suggesting the presence of a population of PSI centers with reduced P700 that remains thermodynamically stable during the application of the saturating light pulse (i.e., reduced-inactive P700). To substantiate this, the effects of methyl viologen (MV) and far-red light on P700 oxidation by the saturating light pulse were analyzed, and the cumulative effects of repetitive application of the saturating light pulse on photosynthesis were analyzed using a mutant crr2-2 with impaired PSI cyclic electron flow. We concluded that the reduced-inactive P700 in low-light as revealed by saturating light pulse indicates limitations of electron flow at the PSI acceptor side.     

Response of photosynthesis and chlorophyll fluorescence quenching to leaf dichotocarpism in Ligustrum vicaryi, an ornamental herb

Net photosynthetic rate of yellow upper leaves (UL) of Ligustrum vicaryi was slightly, but not significantly higher than that of green lower leaves (LL). Diurnally, maximum photochemical efficiency of photosystem 2, PS2 (F_v/F_m) of LL did not significantly decline but the UL showed fairly great daily variations. Yield of PS2 of UL showed an enantiomorphous variation to the photosynthetically active radiation and was significantly lower than in the LL. Unlike F_v/F_m, the efficiency of energy conversion in PS2 and both non-photosynthetic and photosynthetic quenching did not differ in UL and LL. Significant differences between UL and LL were found in contents of chlorophyll (Chl) a, b, and carotenoids (Car) and ratios of Chl a/b, Chl b/Chl (a+b), and Car/Chl (a+b). Leaf colour dichotocarpism in L. vicaryi was mainly caused by different photon utilization; sunflecks affected the LL.     

Reduction of the chloroplast membrane system caused by disorders in early stages of chlorophyll biosynthesis

A chlorophyll-deficient xantha mutant of cotton (Gossypium hirsutum L.) was examined with respect to development and structural organization of the chloroplast membrane system as affected by disruption of early stages of chlorophyll biosynthesis in the light. The analysis of early chlorophyll precursors showed that the mutant is unable to synthesize 5-aminolevulinic acid (5-ALA) in the light. The disorders in early stages of chlorophyll biosynthesis arrested the development of chloroplast membrane system at the stage of vesicles and single thylakoids. The accumulation of 2–5% chlorophyll in the mutant was related to the formation of light-harvesting chlorophyll-a/b-protein complexes I and II, whereas pigment-protein complexes composing reaction centers of photosystem I and photosystem II were lacking. It is concluded that the chloroplast membrane system in the mutant with impaired 5-ALA synthesis is incapable of development and is even reduced upon long-term growing under light.