Plant Physiology

Cleland, Robert

doi: 10.1104/pp.42.9.1165pmid: 16656634

Abstract Free hydroxyproline inhibits the formation of protein-bound hydroxyproline from proline to a considerably greater extent than it does the incorporation of proline into protein of auxin-treated Avena coleoptiles. This inhibition is greater in the wall than in the cytoplasmic fraction. In the absence of auxin, free hydroxyproline exerts little or no inhibition of hydroxyproline formation. Furthermore free hydroxyproline has no effect on respiration, RNA synthesis or the incorporation of leucine into protein. Hydroxyproline is not a general inhibitor of metabolism or protein synthesis in Avena coleoptiles. These results suggest that free hydroxyproline may inhibit auxin-induced cell elongation by blocking the formation or utilization of a particular hydroxyproline-rich protein which must be incorporated into the cell wall during auxin-induced wall extension. 1 Supported by Grant GM-12881 from the United States Public Health Service and Grant GB-5385X from the National Science Foundation. 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)

Pearson, George A.

doi: 10.1104/pp.42.9.1171pmid: 16656635

Abstract At the end of a 4 hour absorption period approximately 95% of the sodium absorbed by bean plants was retained in the secondary roots. The sodium translocated to the shoot was retained in the stem. 2,4-Dinitrophenol decreased the amount retained in the secondary roots of bean plants and increased the amount translocated to the shoot. The stem retained most of the translocated sodium. Bean plants without roots absorbed considerably more sodium than plants with roots and translocated a greater proportion of the sodium to the petioles and blades. 2,4-Dinitrophenol reduced the amount of sodium in the stem and petioles and increased the amount in the blades. 2,4-Dinitrophenol reduced the amount of sodium retained by the secondary roots of cotton plants but did not appreciably affect the amounts translocated to the shoot. 2 Present address: Soil and Water Conservation Research Division, ARS, USDA, Norfolk, Virginia 23501. 1 Contribution from the United States Salinity Laboratory, Soil and Water Conservation Research Division, ARS, USDA, Riverside, California, in cooperation with the 17 Western States and Hawaii. Funds for the study were provided by 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)

Dove, Lewis D.

doi: 10.1104/pp.42.9.1176pmid: 16656636

Abstract Homogenates of leaflets of desiccated tomato plants show increased ribonuclease activity compared to homogenates of turgid controls. Much of this increase is independent of changes in translocation to and from the leaflet. Interruption of translocation through living cells by detachment of leaflets or steam damage to the petiolules produces increased ribonuclease activity, but this activity is increased further when excised leaflets are allowed to wilt. Increases in ribonuclease often parallel or precede increases in the soluble nitrogen content. Further increases in activity occur when excised leaves become yellow. Exposure of leaflets to CO2-free air has little effect on activity at low-light intensity (120 ft-c). These results suggest that water stress directly affected ribonuclease activity at the cellular level. 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)

Parenti, Francesco; Margulies, Maurice M.

doi: 10.1104/pp.42.9.1179pmid: 16656637

Abstract The incorporation of uniformly labeled leucine-14C into protein by a chloroplast containing fraction from developing primary leaves of bean is reported. Chloroplasts, obtained from week old plants grown in darkness, and then illuminated with white light for 12 hours, were shown to be the principal sites of incorporating activity. Incorporation may continue for 2 hours. Rates of up to 50 μμmole leucine incorporated per mg protein per hour are observed when a 1 hour assay period is used. Incorporation is only partially sensitive to ribonuclease. 3 The work reported was carried out while Dr. Parenti was holder of a National Research Council Visiting Research Associateship at the Smithsonian Institution. 1 Research was supported in part by funds provided by the United States Atomic Energy Commission Contract No. AT (30-1) 2372. 2 Published with the approval of the Secretary of the Smithsonian Institution. 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)

Poskuta, G.; Nelson, C. D.; Krotkov, G.

doi: 10.1104/pp.42.9.1187pmid: 16656638

Abstract Detached spruce twigs, wheat and soybean leaves were infiltrated with various metabolic inhibitors, placed in a closed system in CO2-free air and the amounts of CO2 evolved in either light or darkness were determined with an infra-red CO2 analyzer. In light, metabolic inhibitors always greatly suppressed evolution of CO2, the magnitude of suppression varying between 50 to 80% of that without an inhibitor. This depressing effect became less pronounced with increasing oxygen. In darkness, metabolic inhibitors sometimes suppressed and sometimes stimulated CO2 evolution. These observations have been taken as further support for a conclusion made earlier, that evolution of CO2 in light and darkness is not the same process. 2 Present address: Department of Plant Physiology, University of Warsaw, Warsaw, Poland. 3 Present address: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia. 1 The financial support for this work came from the Committee on Extra-Mural Research Projects, Department of Forestry, Ottawa, Ontario. 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)

Irving, R. M.; Lanphear, F. O.

doi: 10.1104/pp.42.9.1191pmid: 16656639

Abstract The development of cold hardiness in 2 woody plant species (Acer negundo and Viburnum plicatum tomentosum) was shown to be independent of the induction of bud dormancy. Substantial hardiness levels were obtained under controlled conditions with long days and certain low temperatures—without dormancy development as a prerequisite. Low temperatures given during the dark period with long days induced hardiness to a level not significantly different from that of short days. Giving plants continuous 10° temperatures under long days forced plants to harden as if they were under short days, even though they were not dormant. Development of hardiness was shown to be a photoperiodic response. Increasing weeks of short days, followed by a low temperature hardening period in darkness, brought about a progressive increase in hardiness. The short day stimulus could be reversed by long days. Following 6 weeks of short days, the rate of hardening in darkness at 5° was over twice that of plants previously exposed to long days. 2 Present address: Department of Horticulture, Oklahoma State University, Stillwater, Oklahoma. 1 Journal Paper 3055, Agricultural Experiment Station, Purdue University, Lafayette, Indiana. Part of a Ph.D. Thesis, submitted by R. M. Irving. 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)

Steer, B. T.; Beevers, Harry

doi: 10.1104/pp.42.9.1197pmid: 16656640

Abstract The rates of utilization of exogenously supplied 14C labeled acids by corn roots was compared to the utilization of these acids generated endogenously in the mitochondria from acetate-3H. 14C-labeled citrate, pyruvate, succinate, glutamate or aspartate were supplied with acetate-3H in a 15 minute pulse and the 14C and 3H contents of extracted acids were measured over a 4 hour period. It was found, in contrast to previous experiments with malate, that these exogenously added acids were used as rapidly as the endogenous forms. Apparently, therefore, these acids penetrate readily into the mitochondria and do not enter cytoplasmic pools which are not in ready equilibrium with those in the mitochondria. Small amounts of labeled glutamate were produced from succinate-2,3-3H by corn root tissue. Since glutamate would not be expected to be labeled by reactions of the tricarboxylic acid cycle it was concluded that it was produced rather directly from succinate. The minor pool of glutamate generated in this way retained its radioactivity while that generated in the cycle was rapidly lost. An extra-mitochondrial location of this pool of glutamate is therefore suggested. 2 Present address: Department of Biology, Brandeis University, Waltham, Massachusetts. 1 Supported by National Science Foundation Grant GB 2599. 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)

El-Sheikh, A. M.; Ulrich, A.; Broyer, T. C.

doi: 10.1104/pp.42.9.1202pmid: 16656641

Abstract This study concerned the degree to which Na or Rb could substitute for K in the growth of sugar beet plants when K in the culture solution was low (1 meq/liter) or high (12 meq/liter). Sodium at high concentrations increased the growth of plants in a basal nutrient medium when either deficient in K or when adequately supplied with K alone. Redistribution of K from petioles to blades could not fully explain these results. Therefore, the essentiality of Na per se for growth of sugar beet plants may be inferred. Rubidium increased the growth of plants significantly when supplied in small doses to a nutrient medium deficient or adequately supplied with K. The amount of K added and the mode of Rb addition to solution cultures should be carefully considered when studying the effect of Rb on growth. High Rb concentrations were toxic, especially to the growth of fibrous roots. Sodium or Rb have been shown to enhance the growth of sugar beet plants under either low or high K conditions. Essentiality of either Na and/or Rb per se for growth of sugar beets may be inferred, but other criteria should be fulfilled also for conclusive proof. 1 Present address: Ministry of Agriculture, Giza, Cairo, U.A.R. 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)

Brian, R. C.

doi: 10.1104/pp.42.9.1209pmid: 16656642

Abstract The adsorption of chloro-aromatic acids to monomolecular layers of oat squashes is reported in earlier papers but it was not possible by the technique used, to measure unambiguously the adsorption of unsubstituted and 2,6-dichloro-aromatic acids. This has now been achieved by a modification of the earlier method and involves assessments of competitive adsorption between the unknown acid and a standard acid, using measurements of surface potential. Benzoic and phenoxyacetic acids were not adsorbed but phenylacetic acid was weakly adsorbed. The second ring in naphthalene and naphthoxyacetic acids greatly increased adsorption. Substitution of the 2 and 6 positions in the phenyl and phenoxyacetic acids resulted in low adsorption but 2,6-disubstituted phenoxybutyric and benzoic acids were more highly adsorbed. The adsorption values from earlier work are combined and discussed in relation to the growth-regulating activity of the acids. It is conciuded that there is no direct relation embracing all acids between adsorption and activity, notable exceptions being those substituted by chlorine in the 3-position of the aromatic ring. However, for a number of acids it is suggested that activity is limited not only by their ability to interact at enzyme sites but also by the amount of acid immobilised by adsorption when moving to these sites. It is also concluded that the hydrophilic/lipophilic balance of a growth regulator sometimes used as a guide to its activity, is an unreliable indication of interfacial behaviour. 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)

Roberts, Karen; Siegel, S. M.

doi: 10.1104/pp.42.9.1215pmid: 6076112

Abstract A stress-tolerant strain of Penicillium notatum, isolated by passage through a nutrient solution saturated with calcium acetate, was found to have a tolerance to boron in several states of oxidation. Growth in the presence of elementary boron, saturating amounts of boric acid, and with various concentrations of sodium borohydride was observed and mycelial mats were spectrographically analyzed for boron accumulation. 1 Research carried out under contract NAS2-767, 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)