Plant Physiology

Chang, Chong W.

doi: 10.1104/pp.43.5.669pmid: 16656825

Abstract Investigation was made for the effect of fluoride on plant growth, acid soluble nucleotides, and RNA in germinating corn seedling roots. Fluoride suppresses root growth as measured by changes in fresh weight. Column chromatographic analyses demonstrated that fluoride modifies ratios of acid soluble nucleotide species. The relative amount of nucleotides is altered mainly due to triphosphate nucleotides of which ATP is most accumulated. Paper chromatographic analyses showed that fluoride induces changes of RNA structure. The RNA is characterized by lowered relative content of cytosine and by increased ratio of cytosine to guanine. Adenine is depressed significantly only in the root tissue treated by the highest fluoride concentration. 2 Present address: Plant Air Pollution Laboratory, Plant Industry Station, USDA, Beltsville, Maryland 20705. 1 This investigation was supported in part by the Statewide Air Pollution Research Center, University of California, Riverside, California and in part by the Agricultural Research Service, USDA. This content is only available as a PDF. © 1968 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)

Kirk, Susan C.; Jacobs, William P.

doi: 10.1104/pp.43.5.675pmid: 16656826

Abstract A critical review of the few papers on IAA-14C movement in roots revealed apparent contradictions, as well as flaws in experimental design that would be apt to cause artifacts. The movement of 14C from IAA-14C was studied in sections of Lens and Phaseolus roots, using a system 20 or more times as sensitive as any previously used. To make sure that our results with roots could be compared validly with published work on petioles and stems, we used the same techniques as we had earlier used for shoot structures. The results with Lens were similar in many ways to those for shoots: net movement into receiver blocks was very strongly polar, followed a linear course for several hours, and showed a velocity of the same order of magnitude as in shoots (and, in fact, very close in absolute value to that found in Coleus stem cylinders). Also, as with shoots, all the radioactivity in receiver blocks ran to the RF of IAA. The time-course of loss of counts from donor blocks was similar to that found in shoots. The 2 most striking differences from shoots were 1) the very low percentage of added 14C that was moved into the receivers (about one-tenth of the values for bean petioles), and 2) the fact that the polar movement was acropetal in roots, rather than basipetal as in shoots. Results with Phaseolus roots were similar to those for Lens, although an additional complication with Phaseolus roots was the indication of a transitory stage of weak basipetal polarity in the first few hours after excising the section. This stage was followed in a few hours by a stronger acropetal polarity. 2 Guggenheim Fellow, 1967. 1 Research supported in part by an NSF grant to W. P. Jacobs. 3 Permanent Address: Biology Department, Princeton University, Princeton, New Jersey 08540. 4 This paper is dedicated to Prof. Dr. H. Söding on his seventieth birthday. This content is only available as a PDF. © 1968 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)

Arneson, P. A.; Durbin, R. D.

doi: 10.1104/pp.43.5.683pmid: 5661492

Abstract Removal of 1 or more sugar residues from the α-tomatine molecule markedly decreased its fungitoxicity. While partial hydrolysis of α-tomatine did not greatly affect its surfactant properties, it did destroy the ability of this alkaloid to form a complex with cholesterol. Only unprotonated α-tomatine was capable of binding cholesterol; the protonated form did not. Since α-tomatine was far more toxic at a high pH than at a low pH, this suggests that the unprotonated alkaloid is the active form and that it acts by complexing with fungal sterols. 2 Present address: Division of Tropical Research, Tela Railroad Company, La Lima, Honduras. 1 Work supported by National Science Foundation Grant No. IN-35F. This content is only available as a PDF. © 1968 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)

Ryrie, I. J.; Scott, K. J.

doi: 10.1104/pp.43.5.687pmid: 16656827

Abstract Nicotinamide nucleotide coenzymes were estimated spectrophotometrically in noninfected barley leaves and leaves infected with Erysiphe graminis var hordei (powdery mildew). Amounts of NADH, NADP+ and NADPH were not altered by infection. In contrast, the NAD+ content rose sharply and at 144 hours was 100% greater than in noninfected leaves. The respiratory rate was increased in infected leaves and the pattern of this increase was similar to that of NAD+. The effect of infection on the intracellular distribution of NADP+ was examined by fractionating lyophilized leaves in a nonaqueous medium. In noninfected leaves almost all of the NADP+ was localized in the chloroplasts. In infected leaves where some chloroplast breakdown occurs, about 60% of the NADP+ was detected in the nonchloroplast part of the cell. This intracellular redistribution of NADP+ is discussed in relation to the increased pentose-P pathway activity occuring after infection. 1 This work was supported by a grant from the Rural Credit Development Fund of Australia. This content is only available as a PDF. © 1968 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)

Sander, Carol; Laber, L. J.; Bell, W. D.; Hamilton, R. H.

doi: 10.1104/pp.43.5.693pmid: 16656828

Abstract Dark grown albescent corn seedlings are deficient in colored carotenoids but accumulate phytoene, phytofluene and an unidentified substance in the carotenol fraction. They bleach upon exposure to bright light and appear albino. Seedlings grown under low level incandescent light are normal in appearance and contain almost as much colored carotenoid as control seedlings. The existing leaf tissue of seedlings grown under low level light does not bleach upon exposure to bright light. The enhanced carotenoid synthesis and stabilization of plastids is not affected by brief illumination with red light but requires several hours of low level incandescent light. 2 Present Address: W. D. Bell, Department of Genetics, University of Minnesota, St. Paul, Minnesota 55101. L. J. Laber, Department of Biochemistry, University of Georgia, Athens, Georgia 30601. 1 Contribution No. 4 from Department of Biology The Pennsylvania State University and 3323 from the Pennsylvania Agricultural Experiment Station. A portion of this work was presented by Carol Sander as a B.S. Honors Thesis in Botany. This content is only available as a PDF. © 1968 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)

Koukkari, Willard L.; Hillman, William S.

doi: 10.1104/pp.43.5.698pmid: 16656829

Abstract The fact that far-red pretreatment slows the closing response of Albizzia julibrissin pinnules to darkness was used to locate the photoreceptor region for the role of phytochrome in nyctinasty, and to determine whether the effect is localized or translocated. Illumination of pinnule tissue alone induced no response, while illumination of an area as narrow as 1 mm, including only the tertiary pulvini and adjacent portions of rachilla and pinnules, was sufficient for a full response. This suggests that the pulvini themselves, the sites of the response, act as photoreceptors. In experiments with various shielding devices, pinnules on the same rachilla responded independently to local illumination, suggesting the absence of any translocatable effects. 2 Present address: Department of Botany, University of Minnesota, Minneapolis, Minnesota 55455. 1 Research carried out at Brookhaven National Laboratory under the auspices of the United States Atomic Energy Commission. This content is only available as a PDF. © 1968 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)

Breidenbach, R. W.; Kahn, Albert; Beevers, Harry

doi: 10.1104/pp.43.5.705pmid: 16656830

Abstract Electron micrographs are presented which establish the identity of the components of the 3 major bands observed after sucrose density centrifugation of the crude particulate fraction from the endosperm of germinating castor bean seedlings. These are: mitochondria (density 1.19 g/cc), proplastids (density 1.23 g/cc) and glyoxysomes (density 1.25 g/cc). Further evidence is provided on the enzymatic composition of the glyoxysomes. Essentially all of the particulate malate synthetase, isocitrate lyase, catalase, and glycolic oxidase is present in these organelles. The distribution of glyoxysomal enzymes on sucrose density gradients is contrasted with that of the strictly mitochondrial enzymes fumarase, NADH oxidase, and succinoxidase. Malate dehydrogenase and citrate synthetase are present in both organelles. The functional role of glyoxysomes and their relationship to cytosomes from other tissues is discussed. 2 USPHS Postdoctoral Fellow (1-F2-GM-23, 105-01). 3 Present address: Department of Agronomy, University of California, Davis, California 95616. 1 Research supported in part by NSF Grants GB 2599 and GB 2897 and AEC Contract 11-1-330. This content is only available as a PDF. © 1968 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)

Miller, David H.; Machlis, Leonard

doi: 10.1104/pp.43.5.714pmid: 16656831

Abstract Fragments of thalli of the liverwort, Sphaerocarpos donnellii Aust., inoculated into liquid medium containing sucrose and mineral salts, attain a much greater dry weight after 9 days growth in continuous white light than in darkness. Light causes this difference by increasing the rate of growth of the plants. This growth response is mediated by the pigment systems of photosynthesis and phytochrome. An inhibitor of photosynthesis, DCMU, at concentrations which inhibit light-mediated CO2 fixation, decreases the growth rate of light-grown but not dark-grown plants. Light still slightly increases the growth rate of plants in the presence of DCMU. This latter response is mediated by phytochrome, since it can be effected by a 2 minute exposure to low intensity red light every 12 hours, and far-red light reverses the effect of red. The increased growth rate effected by red light is related to a change in the morphology of the plants. Dark-grown plants form compact balls of tissue consisting of lobes. These lobes are rounded and thick and exhibit an abnormal callus-type growth, with few well-defined meristematic regions. Plants grown in red light form fluffy balls of tissue. The lobes of these plants have a morphology more typical of Sphaerocarpos in nature. They are 2 cell layers thick, flattened, and have numerous well-defined meristematic areas. The greater number of meristems allows for the increased growth rate of the plants grown in red light. 2 Present address: MSU/AEC Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48823. 1 This work was supported in part by National Science Foundation and National Aeronautic and Space Administration fellowships to D. H. Miller and National Science Foundation grant GB 1107 to L. Machlis. The material is a portion of a thesis submitted by D. H. Miller to the Graduate Division of the University of California, Berkeley in partial fulfillment of the requirements for the Ph. D. degree. This content is only available as a PDF. © 1968 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)

Miller, David H.; Machlis, Leonard

doi: 10.1104/pp.43.5.723pmid: 16656832

Abstract Dark-grown plants of Sphaerocarpos, incubated in a liquid medium containing sucrose and mineral salts, have a much lower chlorophyll and nitrogen content than do light-grown plants. Two minutes of red light per 12 hours is about two-thirds as effective in increasing chlorophyll and nitrogen content as is continuous white light. These red light-induced increases are mediated by phytochrome, as they are reversible by alternating exposures to red and far-red light. They appear to be related to differences in the ultrastructure of the chloroplasts. Plastids from dark-grown plants are full of starch and develop few lamellae, while light-grown plastids contain little starch and have many lamellae. The ultrastructural studies are supported by starch determinations which revealed a phytochrome-mediated decrease in starch content. The effect of white light in increasing the chlorophyll and nitrogen content above the level attained in red light-treated plants is not mediated by photosynthetic activity. These results are related to similar responses in other archegoniates and angiosperm seedlings. 2 Present address: MSU/AEC Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48823. 1 This work was supported in part by National Science Foundation and National Aeronautic and Space Administration fellowships to D. H. Miller and National Science Foundation grant GB 1107 to L. Machlis. The material is a portion of a thesis submitted by D. H. Miller to the Graduate Division of the University of California, Berkeley in partial fulfillment of the requirements for the Ph.D. degree. This content is only available as a PDF. © 1968 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)

Sugiyama, Tatsuo; Goto, Yoshiaki; Akazawa, Takashi

doi: 10.1104/pp.43.5.730pmid: 16656833

Abstract The activity of pyruvate kinase was determined in the first leaves of wheat plants grown under K+-deficient conditions. An enhancement of the enzyme activity compared with the normal plants was found to start from eighth day of growth, and about 4-fold increase in the enzyme activity was observed in 14-day wheat leaves. The addition of K2SO4 to the nutrient solution given to the K+-deficient plants at tenth day resulted in the restoration of the enzyme activity to the normal level after 3 days. The levels of K+ as well as carbohydrates and chlorophyll were found to return normal over the same period. These findings are discussed in relation to the metabolic pattern of plants at the early stages of K+-deficiency. 1 Supported in part by a research grant of USPHS No. AM 10792-01. This content is only available as a PDF. © 1968 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)