Deficient Photosystem II in Agranal Bundle Sheath Chloroplasts of C
            <sub>4</sub>
            Plants

Woo, K. C.; Anderson, Jan M.; Boardman, N.K.; Downton, W. J. S.; Osmond, C. B.; Thorne, S.W.

doi:10.1073/pnas.67.1.18

Cited by 170 publications

(114 citation statements)

References 6 publications

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“…Such correlations suggest that the leaves greened in far red light or chloroplast fragments from such leaves should be examined for relative photosystem 1 and photosystem 2 activities. Although we would not be surprised to find a relative enrichment of the photosystem 1 activity in such chloroplasts, our results do not support the contention of Woo et al (27) that grana are required for photosystem 2 activity.…”

Section: Discussioncontrasting

confidence: 55%

Greening of Etiolated Bean Leaves in Far Red Light

1971

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Eight-day-old dark-grown bean leaves were greened by prolonged irradiation with far red light. Growth, chlorophyll content, oxygen-evolving capacity, photophosphorylation capacity, chloroplast structure (by electron microscopy), and in vivo forms of chlorophyll (by low temperature absorption and derivative spectroscopy on intact leaves) were followed during the greening process. Chlorophyll a accumulated slowly but continuously during the 7 days of the experiment (each day consisted of 12 hours of far red light and 12 hours of darkness). Chlorophyll b was not detected until the 5th day. The capacity for oxygen evolution and photophosphorylation began at about the 2nd day. Electron microscopy showed little formation of grana during the 7 days but rather unfused stacks of primary thylakoids. The thylakoids would fuse to give grana if the leaves were placed subsequently in white light.The low temperature spectroscopy of intact leaves showed that the chlorophyll a was differentiated into three forms with absorption maxima near 670, 677, and 683 nanometers at -196 C during the first few hours and that these forms accumulated throughout the greening process. Small amounts of two longer wavelength forms with maxima near 690 and 698 nanometers appeared at about the same time as photosynthetic activity.The development of etiolated tissue of higher plants in the light involves phototransformations of both phytochrome and protochlorophyll. Phytochrome controls a number of developmental processes from the synthesis of specific proteins (14) to the gross morphological characteristics such as leaf expansion (15). The development of photosynthetically active plastids, however, requires the phototransformation of protochlorophyll and the accumulation of chlorophyll. Even though both pigment systems play decisive roles in directing the development of the plant, there appears to be little interaction between the two systems with the exception that the rate of protochlorophyll synthesis after the initial transformation is influenced by phytochrome (16). Long before the discovery of phytochrome as the photomorphogenic pigment (5) of California, San Diego, La Jolla, California 92037 sources of different spectral quality and red and blue sources of low intensity, that protochlorophyll and chlorophyll did not participate in the photomorphogenic growth responses.Phytochrome in dark-grown seedlings is entirely in the Pr' form (3). It was shown, however, that a low level of Pfr is established as a photostationary state by far red light (because of the long wavelength absorption tail of Pr), and it was suggested that the photomorphogenic responses obtained with prolonged far red irradiation were due to the maintenance of the low level of Pfr over a long period of time (in darkness Pfr reverts to Pr) (3). Mohr and his co-workers (13) have shown in a number of cases that prolonged irradiation with far red light activates the phytochrome system. Hicker (9) illuminated etiolated mustard seedlings with continuous far red light (740 nm ...

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Section: Discussioncontrasting

confidence: 55%

Greening of Etiolated Bean Leaves in Far Red Light

1971

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“…Since there has been a report that photosystem II activity in the corn plant may be correlated with grana formation (26), the rates of 02 evolution by fragmented chloroplasts of the 4-day and 12-day plants fortified with spinach ferredoxin and TPN were compared and found to be roughly comparable (J. M. Robinson, unpublished data). Rates of 02 evolution in the order of 40 ,moles/ mg chl -hr were observed (see also ref.…”

Section: Resultsmentioning

confidence: 99%

Photosynthetic Carbon Metabolism of Isolated Corn Chloroplasts

O'Neal¹,

Hew²,

Latzko³

et al. 1972

Plant Physiol.

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MATERIALS AND METHODSChloroplasts have been isolated from 4-to 6-day-old corn (Zea ,nays) The data supporting the existence of this pathway (often referred to as the "C-4 pathway" or the "C-4 dicarboxylic acid cycle" and the plants as "C-4 plants") have been the subject of a recent review (12).The studies leading to the postulation of the C-4 pathway included in vivo pulse label experiments and enzymic studies with chloroplasts isolated in nonaqueous media. Another approach to the study of photosynthetic CO2 fixation is the study of the kinetics of "4CO2 fixation and product determination using chloroplasts isolated in aqueous media, as has been done successfully with spinach and pea chloroplasts (9, 24). Until recently it has not been possible to obtain chloroplasts from a C-4 plant (such as corn or sugarcane) which were capable of assimilating CO2 at reasonable rates. Some degree of success was recently achieved by isolating chloroplasts from young corn seedlings, and the results were described in a short communication (10). A more complete description of the carbon metabolism of these chloroplasts is the subject of this report. Zea mays seeds were obtained from Agway, Inc., Waltham, Massachusetts. They were germinated in vermiculite and grown at a light intensity of approximately 2000 ft-c in a controlled environment. The day temperature was 25 C, the night temperature was 20 C, and the photoperiod was 12 hr. Plants were generally harvested 2 to 5 hr after the lights came on and were used immediately to prepare chloroplasts. For most of the studies var. Early Fortune was used, although var. Golden Beauty was employed in a few studies with similar results.The seedlings used for chloroplast isolation were generally 4 to 6 days old. Ten to 25 g (fresh weight) of seedlings were ground in a stainless steel Waring microblender with 2 to 5 volumes of solution I containing 0.35 M sorbitol, 40 mM MES buffer, 5 mM MgCl2, 0.3 mM MnCl2, 0.25 mM KH2PO,, 3.0 mM Na2 EDTA, 40 mm sodium ascorbate, and 5% (w/v) polyvinylpyrrolidone 40, pharmaceutical grade (Sigma Chemical Co.). The pH was adjusted to 6.8 with NaOH.The seedlings were blended in ice-cold solution I twice or three times at the highest speed, each burst lasting about 3 sec. The mixture was filtered through Miracloth (Calbiochem) and centrifuged at 1250g for 2 min. The pellet was resuspended in approximately 5 ml of solution II containing 0.35 M sorbitol, 40 mM HEPES, 0.4 mM MgCl2, 0.2 mM KH,PO4, 1 mM Na2 EDTA, and 5 to 6 mm DTT.V The pH was adjusted to 7.8 with NaOH. It was found subsequently that the optimal molarity of sorbitol or mannitol in solution II (assay medium) was roughly 0.12 to 0.14 M and not 0.35 M. Therefore, some studies were performed using 0.14 M mannitol.The suspended chloroplasts were centrifuged for 2 min at 755g, and the pellet was suspended in 1 to 3 ml of solution II by means of the tip of a stirring rod covered with 4 layers of cheesecloth. Aliquots of these chloroplasts were added to tubes containing solution II plus 4 to 6 mm ...

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“…Chloroplasts from bundle sheath and mesophyll cells of C4 plants have been used to demonstrate a correlation between grana and PS2 activity (5,19). Later PS2 activity was found in the agranal bundle sheath chloroplasts, but these chloroplasts appeared to lack a component needed to connect electron transport between PS2 and PS1 (2).…”

Section: Discussionmentioning

confidence: 99%

The Development of Photophosphorylation and Photosynthesis in Greening Bean Leaves

Oelze‐Karow

Butler

1971

Plant Physiol.

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Photophosphorylation and oxygen evolution were measured in 8-day-old dark-grown bean leaves (Phaseolus vulgaris) after various times of greening in far red light and in white light. The sequence of development was the same for both greening regimes, but the processes were much more rapid in white light. The capacity for photophosphorylation, as assayed by the firefly luciferase assay, appeared after 12 hours in far red light. At this stage and for times up to 24 hours, photophosphorylation was not inhibited by 10-M 3-(3,4-dichlorophenyl)-1,1-dimethylurea. At 24 hours, the capacity for oxygen evolution appeared and photophosphorylation became partially inhibited by 3-(3,4-dichlorophenyl)-l,l.dimethylurea at concentrations which inhibited oxygen evolution. In white light photophosphorylation appeared after 15 minutes, and oxygen evolution at one hour. Photophosphorylation became partially sensitive to 3-(3,4-dichlorophenyl)-1 , 1-dimethylurea when oxygen evolution appeared. Carbonylcyanide m-chlorophenylhydrazone inhibited photophosphorylation and photosynthesis at low concentrations, 10' M, with immature leaves, but the leaves developed resistance to carbonylcyanide m-chlorophenyl. hydrazone as they greened.A previous study (4) capacity for oxygen evolution indicated that a high degree of synchrony was maintained in the developing plastids even though the development time was prolonged.In the previous paper (4) no attempt was made to distinguish between the onset of oxygen evolution and photophosphorylation or to differentiate between cyclic and noncyclic photophosphorylation. In the present paper we show that cyclic and noncyclic photophosphorylation can be distinguished in the intact leaves during development and that cyclic photophosphorylation appears well before noncyclic photophosphorylation. The onset of noncyclic photophosphorylation is coincident with the onset of oxygen evolution. This sequence of appearance occurs with leaves greened in white light as well but over much shorter periods of time. MATERIALS AND METHODS Primary leaves of Phaseolus vulgaris cultivar Topcrop (W.Atlee Burpee Co., Riverside, Calif.) were used for all experiments. The conditions of growth and far red light source were the same as described previously (4). The temperature in darkness was 20 C; in light, 25 C. Greening experiments were made with far red light with 12-hr light, 12-hr dark irradiation cycles (4); with continuous far red illumination; and with continuous white light. The source of white light for greening consisted of 4 cool-white lamps (General Electric F40CW) giving 4 X 10' ergs cm' sec1 at the plants.The chlorophyll a and b contents of the leaves were determined spectrophotometrically according to the method of Ogawa and Shibata (15). Extractions were carried out under green light.The phosphorylation capacity of the leaves was determined by the firefly luciferase assay (9, 16). At selected stages of greening, primary leaves were taken and cut into 10 segments (4 to 9 mm') under green safelight. Five of t...

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Deficient Photosystem II in Agranal Bundle Sheath Chloroplasts of C ₄ Plants

Cited by 170 publications

References 6 publications

Greening of Etiolated Bean Leaves in Far Red Light

Greening of Etiolated Bean Leaves in Far Red Light

Photosynthetic Carbon Metabolism of Isolated Corn Chloroplasts

The Development of Photophosphorylation and Photosynthesis in Greening Bean Leaves

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Deficient Photosystem II in Agranal Bundle Sheath Chloroplasts of C 4 Plants

Cited by 170 publications

References 6 publications

Greening of Etiolated Bean Leaves in Far Red Light

Greening of Etiolated Bean Leaves in Far Red Light

Photosynthetic Carbon Metabolism of Isolated Corn Chloroplasts

The Development of Photophosphorylation and Photosynthesis in Greening Bean Leaves

Contact Info

Product

Resources

About

Deficient Photosystem II in Agranal Bundle Sheath Chloroplasts of C ₄ Plants