Plant Physiology

Geisler, G.

doi: 10.1104/pp.42.3.305pmid: 16656508

Abstract Barley and pea plants were grown under several regimens of different compositions of soil atmosphere, the O2 concentration varying from 0 to 21% and the CO2 concentration from 0 to 8%. In absence of CO2, the effect of O2 on root length in barley was characterized by equal root lengths within the range of 21 to 7% O2 and a steep decline between 7 and 0%. In peas, while showing the same general response, the decline occurred between 14 and 7% O2. Root numbers of the seminal roots of barley decreased already with reduction in O2 concentration from 21 to 14%. Dry matter production was affected somewhat differently by O2 and CO2 concentration. Dry matter production in barley was reduced at 14% O2 while root length decreased between 7 and 0%. In peas, dry matter production was favored by low CO2 concentrations except where there was no oxygen. At 21% O2, increasing CO2 concentrations did not seem to affect root length up to concentrations of 2% CO2. At 8% CO2, root length was decreased. The inter-active effects of CO2 and O2 are characterized by a reduced susceptibility to CO2 at O2 values below 7%, and a very deleterious effect of 8% CO2 at 7% O2. This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Katayama, Masayuki; Benson, A. A.

doi: 10.1104/pp.42.3.308pmid: 6045293

Abstract Green cells of Chlorella protothecoides grown in nitrogen-rich low glucose media may be reversibly transformed to entirely chlorophyll-less cells in low nitrogen high glucose media. Photosynthetic rates and fatty ester compositions were determined during light and dark bleaching and during greening. Linolenic acid content remained unchanged during greening or bleaching. During light greening chlorophyll content and photosynthetic activity increased while oleic acid content decreased dramatically. As a result, the percent composition of linolenate appeared to parallel photosynthetic capability. Implication of α-linolenate in oxygen production, therefore, can not be based upon fatty acid percentage composition data alone. 2 Present address: Laboratory of Biological Chemistry, Department of Agricultural Chemistry, University of Tokyo, Bunkyo-Ku, Tokyo. 1 Research was supported by United States Public Health Service Grant 1 RO1 GM 12310 and National Science Foundation Grant GB 590. This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Rains, D. W.; Epstein, Emanuel

doi: 10.1104/pp.42.3.314pmid: 16656509

Abstract Radioactively labeled Na+ absorbed by barley roots was sequestered in an intracellular compartment or compartments (“inner” spaces) in which it was only very slowly exchangeable with exogenous Na+. Absorption of this fraction proceeded at a constant rate for at least 1 hour. When the rate of Na+ absorption was examined over the range of concentrations, 0.005 to 50 mm, the isotherm depicting the relation showed dual kinetics as follows. Over the range, 0.005 to 0.2 mm, a single Michaelis-Menten term describes the relation between the concentration of Na+ and the rate of its absorption. The mechanism of Na+ absorption operating over this range of concentrations, mechanism 1 of alkali cation transport, is severely inhibited in the presence of Ca2+ and virtually rendered inoperative for Na+ transport by the combined presence of Ca2+ and K+. The mechanism is equally effective in Na+ transport whether Cl− or F− is the anion, but is somewhat inhibited when the anion is SO42−. Over the high range of concentrations, 0.5 to 50 mm Na+, a second, low-affinity mechanism of Na+ absorption comes into play. In the presence of Ca2+ and K+, this mechanism 2 is the only one to transport Na+ effectively, since Na+ absorption via mechanism 1 is virtually abolished under these conditions. Anaerobic conditions, low temperature, and the uncoupler, 2,4-dinitrophenol, inhibit Na+ absorption both at low and high Na+ concentrations. 2 Present address: Kearney Foundation of Soil Science, University of California, Davis, California 95616. 1 Supported by grants from the National Science Foundation and the Office of Saline Water, United States Department of the Interior. This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Rains, D. W.; Epstein, Emanuel

doi: 10.1104/pp.42.3.319pmid: 16656510

Abstract When barley roots absorb Na+ at concentrations ranging from 1 to 50 mm, in the presence of low concentrations of Ca2+ and K+, absorption of Na+ is mediated by carrier mechanism 2 of alkali cation transport, mechanism 1 being unavailable for Na+ transport under these conditions. The absorption isotherm depicting the rate of Na+ absorption as a function of the external Na+ concentration, over the 1 to 50 mm range of concentrations, shows several inflections. This stepwise response occurs whether Cl− or SO42− is the counterion, but actual rates of Na+ absorption are lower in the latter case. When the concentration of Na+ is 50 mm, and the concentration of either K+ or Ca2+ is increased from nil to 50 mm, the rate of absorption of Na+ is diminished not as a smooth function of increasing concentrations of the interfering ions but stepwise. Similarly, when the concentration of K+ is 50 mm, and the concentration of either Na+ or Ca2+ is increased from nil to 50 mm, the rate of absorption of K+ is diminished not as a smooth function of increasing concentrations of the interfering ions but stepwise. Together, this evidence supports the previous conclusion to the effect that mechanism 2 of alkali cation transport possesses a spectrum of carrier sites with different ionic affinities. When both K+ and Na+ are presented at equivalent concentrations over the 1 to 50 mm range, mechanism 2 transports Na+ almost exclusively, and mechanism 1 K+ almost exclusively. These findings support previous conclusions to the effect that the active sites of mechanism 2 have higher affinity for Na+ than for K+, whereas the reverse is true for mechanism 1. 2 Present address: Kearney Foundation of Soil Science, University of California, Davis, California 95616. 1 Supported by grants from the National Science Foundation and the Office of Saline Water, United States Department of the Interior. This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Mayer, A M

doi: 10.1104/pp.42.3.324pmid: 6045294

Article PDF first page preview Close This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Nomura, T.; Nakayama, N.; Murata, T.; Akazawa, T.

doi: 10.1104/pp.42.3.327pmid: 4292567

Abstract The enzymic synthesis of ADP-glucose and UDP-glucose by chloroplastic pyrophosphorylase of bean and rice leaves has been demonstrated by paper chromatographic techniques. In both tissues, the activity of UDP-glucose-pyrophosphorylase was much higher than ADP-glucose-pyrophosphorylase. Glycerate-3-phosphate, phosphoenolpyruvate and fructose-1,6-diphosphate did not stimulate ADP-glucose formation by a pyrophosphorylation reaction. The major metabolic pathway for UDP-glucose utilization appears to be the synthesis of either sucrose or sucrose-P. On the other hand, a specific precursor role of ADP-glucose for synthesizing chloroplast starch by the ADP-glucose-starch transglucosylase reaction is supported by the coupled enzyme system of ADP-glucose-pyrophosphorylase and transglucosylase, isolated from chloroplasts. None of the glycolytic intermediates stimulated the glucose transfer in the enzyme sequence of reaction system employed. 2 Present address: Tohoku National Agricultural Experiment Station, Morioka, Japan. 1 Supported in part by a Research Grant of United States Public Health Service No. AM 10792-1. This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Mancinelli, Alberto L.; Yaniv, Zohara; Smith, Phyllis

doi: 10.1104/pp.42.3.333pmid: 16656511

Abstract Germination of the dark-germinating seeds of 3 varieties of tomato is controlled by the phytochrome system. Germination is inhibited by far red radiation and repromoted by red applied after far red. At low temperatures, 17 to 20°, a single, low energy far red irradiation is sufficient to inhibit germination in all 3 varieties. At higher temperatures far red is less effective in the inhibition of the germination of the tomato seeds. The phytochrome fraction present as PFR in the dark-germinating seeds of the Ace variety is about 40% of the total phytochrome present. This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Hartt, Constance E.

doi: 10.1104/pp.42.3.338pmid: 16656512

Abstract Low moisture supply, controlled by 3 methods (adding NaCl to a complete nutrient solution, allowing a cut stalk to wilt, or withholding irrigation in the field), decreased the velocity and percentage rate of translocation of 14C-photosynthate. The surplus sucrose not used in growth moved more slowly in the phloem and was stored in the stalk. Low moisture supply depressed translocation of 14C-photosynthate more severely than it curtailed formation of 14C-photosynthate in the same leaf: therefore, the effect of moisture supply upon translocation was primary. Low moisture supply retarded profile development in the stem, and a loss in moisture gradient was associated with a steepened slope of the profile. These results indicate a flow mechanism of translocation rather than diffusion. Results reported now and previously point to the operation of a slow pressure-flow mechanism particularly during the night but also during the day; superimposed upon this general mass transport is the more rapid process of phototranslocation which is independent of sugar gradients and which can cause the accumulation of sucrose at the storage-sink. During ripening, storage of sucrose in the stalk may be increased by withholding water because less sucrose is hydrolyzed in transit, less is used in growth, and the slowly moving sucrose has more time for transfer from the phloem to the storage parenchyma. 1 Published with the approval of the Director as Paper No. 185 of the Journal Series of the Experiment Station, Hawaiian Sugar Planters' Association. This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Prakash, Surya; Krishnam, P. S.; Tewari, K. K.

doi: 10.1104/pp.42.3.347pmid: 16656513

Abstract The leaves of Dendrophthoe falcata growing on different trees had differing dry solid content. With 1 exception, the parasite leaf contained less dry solid than host leaf. A characteristic feature of the loranthus parasite was the accumulation of phosphate in excess of that present in host leaves. Expressed as percent of the total phosphorus, the parasite tissue contained significantly less acid-insoluble phosphate than the host leaves. When the acid-insoluble material was fractionated into phospholipid, RNA, DNA and phosphoprotein, every component was found to be present in a smaller amount in parasite than in host leaf, expressed as percent of total phosphate in leaves. A comparative study of the phosphate fractions in the infected and uninfected branch of infected host tree revealed that, without exception, there was a demonstrable increase in the DNA content of the infected branch. 2 Present address: Department of Botany and Plant Biochemistry, University of California, Los Angeles. 1 This investigation was supported by grants from the United States Department of Agriculture under a P.L. 480 programme. This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Shen-Miller, J.; Gordon, S. A.

doi: 10.1104/pp.42.3.352pmid: 16656514

Abstract Avena seedlings were germinated and grown while continuously rotated on the horizontal axis of a clinostat. The coleoptiles of these gravity-compensated plants were phototropically more responsive than those of plants rotated on a vertical axis. When the plants were compensated after unilateral irradiation, phototropic curvature of the shoot progressed for the next 6 hours, with the rate of curving decreasing about 3 hours after irradiation. The decrease in rate was less in the plants gravity-compensated before irradiation than in those vertically rotated. In the period 70 to 76 hours after planting, the growth rate of the compensated coleoptiles was significantly less than that of the vertically rotated seedlings. The greater phototropic curvature, the decreased growth rate, and the slower rate of straightening of the curved, compensated shoot can be correlated with several consequences of compensation: an increase in sensitivity to auxin, a lowering of auxin content in the coleoptile tip, and possibly, from an interaction between compensation and phototropic stimulation, an enhanced difference in auxin transport between the illuminated and shaded halves of the unilaterally irradiated shoot. The phototropic response of the vertically rotated seedling was significantly different from that of the vertical stationary, indicating the importance of vertically rotated controls in clinostat experiments. 1 Work performed under the auspices of the United States Atomic Energy Commission and the National Aeronautics and Space Administration. This content is only available as a PDF. © 1967 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)