Plant Physiology

Miller, Raymond J.; Dumford, S. W.; Koeppe, D. E.; Hanson, J. B.

doi: 10.1104/pp.45.6.649pmid: 16657366

Abstract The oxidation of reduced nicotinamide adenine dinucleotide, malate-pyruvate, and succinate by corn mitochondria in buffered 0.2 m KCl was determined as a function of divalent cations. Ni2+, Mg2+, Co2+, Ca2+, Mn2+, Sr2+, and Ba2+ stimulated reduced nicotinamide adenine dinucleotide oxidation in the absence of inorganic phosphate, with Ca2+ and Sr2+ having the greatest effect. Malate-pyruvate and succinate oxidation was stimulated by Ca2+, Ba2+, and Sr2+, but only in the presence of inorganic phosphate. Ca2+, Sr2+, and Ba2+ produced a simulated state 4 to state 3 transition with all three substrates, but only with malate-pyruvate and succinate was there a return to state 4. The order of divalent cation effectiveness suggests that the rate of water substitution from the cation inner coordination hydration sphere may be a rate-limiting step in certain mitochondrial reactions involving electron transport and phosphorylation. 2 Present Address: Geigy Chemical Corporation, Ardsley, New York 10502. 1 Supported in part by Grant 14-01-0001-1088 from the Office of Saline Water, Department of Interior. This content is only available as a PDF. © 1970 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)

Louie, D. S.; Addicott, F. T.

doi: 10.1104/pp.45.6.654pmid: 16657367

Abstract The influence of applied auxin on abscission in explants (excised cotyledonary nodes) of cotton was investigated. Proximal applications to the stem stump accelerated abscission with all concentrations applied. Distal applications to the petiole stumps retarded abscission with all concentrations applied. Simultaneous applications to petiole and stem stumps accelerated, retarded, or were without effect on abscission depending on the relative amounts applied. Relatively high concentrations proximal on stem stumps accelerated abscission whereas relatively high concentrations distal on petiole stumps retarded abscission. The abscission rates from various combinations resulted in a multiphasic abscission response curve as the amounts applied were increased. Consideration of these and related data in the literature indicates that many factors can have profound effects on the nature of abscission responses to auxin. 2 Present address: 14008 Davanna Terrace, Sherman Oaks, California 91403. 3 Present address: Department of Agronomy and Range Science, University of California, Davis, California 95616. 1 This investigation was supported in part by a donation from the California Planting Cotton Seed Distributors. This content is only available as a PDF. © 1970 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)

Sondheimer, E.; Blank, G. E.; Galson, Eva C.; Sheets, F. M.

doi: 10.1104/pp.45.6.658pmid: 16657368

Abstract The seeds of six woody species of Oleaceae representing three genera, contain high concentrations of water-soluble glucosides, with major absorption maxima below 240 nanometers. In Fraxinus americana seeds three of these compounds, designated GL-3, GL-5, and GL-6, account for almost 10% of the dry weight. They are found in the endosperm and embryo but not in the pericarp. While the level of GL-5 is not particularly influenced by the physiological state of the embryo, that of GL-3 and GL-6 decreases as a result of germination and growth during a 10-day period. As the concentrations of GL-3 and GL-6 decrease, new ultraviolet-absorbing compounds are formed. The changes in the concentration of the ultraviolet-absorbing glucosides during cold temperature after-ripening, prior to germination, are small. When germination of dormant embryos is induced with gibberellic acid, the concentrations of GL-3 and GL-6 decrease in a manner similar to that observed with nondormant embryos. In the presence of abscisic acid no losses of GL-3 and GL-6 were observed. It is suggested that GL-3 and GL-6 fulfill some definite functions in the germination and growth of F. americana embryos, and that gibberellic acid and abscisic acid can exert a regulatory effect on the metabolism of these glucosides. This content is only available as a PDF. © 1970 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)

Grunwald, C.

doi: 10.1104/pp.45.6.663pmid: 16657369

Abstract All membrane-containing fractions isolated from tobacco leaves contained free sterols, sterol glycosides, and sterol esters. The three sterol forms increased, on a dry weight basis, with a decrease in particle size. The supernatant fraction contained only trace amounts of sterol. The major sterols in all cellular fractions, in the order of decreasing amounts, were: stigmasterol, β-sitosterol, campesterol, and cholesterol. The 500g pellet contained the largest percentage of free sterol, while the 46,000g pellet contained the largest percentage of esterified sterol. The individual sterol composition of the free sterol and sterol glycoside fraction was very similar; however, the composition of the sterol ester fraction varied widely among intracellular fraction. The intracellular distribution pattern of cholesterol-14C added to the isolation medium provided evidence that the intracellular sterol distribution pattern is not an artifact. These results support the suggestion that sterols in plant cells may have a physiological function associated with membranes. 1 This paper (No. 68-3-105) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with approval of the Director. The work was supported by Crops Research Division, Agricultural Research Service, United States Department of Agriculture Contracts 12-14-100-8945(34) and 12-14-100-9559(34). This content is only available as a PDF. © 1970 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)

Fiscus, Edwin L.; Kramer, Paul J.

doi: 10.1104/pp.45.6.667pmid: 16657370

Abstract The radial movement of oxygen in excised corn and jack bean roots was measured with a platinum wire electrode embedded in the root tissue. Measurements were made with the roots exposed to air and with the roots immersed in nutrient solution in the presence and absence of millimolar sodium azide. Effective rates of oxygen diffusion in the root tissue were also measured from 5 to 30 C and compared to the respiration rates of similar root segments over the same temperature range. Under conditions which allow the roots to exude freely, the interior of the root operates under an oxygen deficit. Inhibition of respiratory oxygen uptake by low temperature or azide treatment increased the flux of oxygen to the root interior. 2 Present address: Department of Agronomy and Soils, Auburn University, Auburn, Alabama 36830. 1 This research was supported by Atomic Energy Commission Contract AT (40-1)-1827. This content is only available as a PDF. © 1970 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)

Shear, C. B.; Faust, Miklos

doi: 10.1104/pp.45.6.670pmid: 16657371

Abstract 45Ca, applied to roots of apple seedlings, moved readily to the developing leaves. Kinetin, benzyladenine, and B sprays increased movement. NO3− as the source of N increased movement and accumulation of Ca into mature leaves; NH4+ increased movement into new leaves. Translocation in the stem is effected by a nonspecific ion exchange. Any divalent cation can free Ca for ascent. The exchange may be a property of lignin. Genetic differences in the uptake and translocation of Ca exist among apple seedlings. Those which show juvenile leaf characteristics translocate Ca into mature leaves more readily. Translocation of Ca in woody species appears to be similar to that reported for herbaceous plants. This content is only available as a PDF. © 1970 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)

Keegstra, Kenneth; Albersheim, Peter

doi: 10.1104/pp.45.6.675pmid: 16657372

Abstract Several glycosidases have been isolated from suspensioncultured sycamore (Acer pseudoplatanus) cells. These include an α-galactosidase, an α-mannosidase, a β-N-acetyl-glucosaminidase, a β-glucosidase, and two β-galactosidases. The pH optimum of each of these enzymes was determined. The pH optima, together with inhibition studies, suggest that each observed glycosidase activity represents a separate enzyme. Three of these enzymes, β-glucosidase, α-galactosidase, and one of the β-galactosidases, have been shown to be associated with the cell surface. The enzyme activities associated with the cell surface were shown to possess the ability to degrade to a limited extent isolated sycamore cell walls. It was found that the activities of β-glucosidase and of one of the β-galactosidases increase as the cells go through a period of growth and decrease as cell growth ceases. 2 Predoctoral Fellow of the United States Department of Health, Education and Welfare under Title IV of the National Defense Education Act. 1 Research was supported in part by Grant AT(11-1)-1426 from the United States Atomic Energy Commission. This content is only available as a PDF. © 1970 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)

Everett, Marylee S.; Briggs, Winslow R.

doi: 10.1104/pp.45.6.679pmid: 16657373

Abstract The transformation difference spectrum for phytochrome (Pr spectrum minus Pfr spectrum) in pea tissue is determined below 560 nanometers and compared with similar data on phytochrome in vitro The difference spectrum in vivo between phytochrome intermediates and Pfr is also shown for comparison with the data on phytochrome solutions. These comparisons show that the peaks in the spectra occurring in the blue wave lengths are shifted to shorter wave lengths and are much enhanced when phytochrome is extracted from the cell and placed in solution. The results indicate that the physicochemical state of phytochrome in the cell may be different from that of the extracted pigment. 1 Supported by a National Institutes of Health postdoctoral fellowship. 2 Supported by National Science Foundation Grants GB-2846 and GB-6683 and a grant from the Research Corporation. This content is only available as a PDF. © 1970 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)

Kuiper, P. J. C.

doi: 10.1104/pp.45.6.684pmid: 16657374

Abstract The lipid composition of the leaves of hardy Vernal and cold-sensitive Caliverde alfalfa plants, grown at different temperatures, was determined. Phosphatidyl glycerol, phosphatidyl inositol, and the sulfolipid content were directly related to growth temperature. Mono- and digalactose diglyceride and phosphatidyl choline and ethanolamine were inversely related to temperature. At corresponding growth temperatures Vernal plants showed higher percentages of mono- and digalactose diglyceride and phosphatidyl choline and ethanolamine than Caliverde plants, while the opposite was true for phosphatidyl glycerol and inositol and sulfolipid. Differences in fatty acid composition of corresponding leaf lipid fractions of plants grown at different temperatures or differences in fatty acid composition between lipid fractions of plants of different varieties in general were negligible. 1 Communication 286 of the Laboratory of Plant Physiological Research, Agricultural University, Wageningen, The Netherlands. This content is only available as a PDF. © 1970 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)

Posner, Herbert B.

doi: 10.1104/pp.45.6.687pmid: 16657375

Abstract Flowering of Lemna perpusilla strain 6746 grown on 0.1 strength Hutner's medium in short days was inhibited by sucrose, glucose, fructose, and mannose, but not by various other sugars or metabolic intermediates. Only those sugars that inhibited flowering supported heterotrophic growth. Experiments with a single inductive long night indicated that an early stage in flowering was the sugar-sensitive process. Inhibition of flowering by carbohydrates was accompanied by reduced levels of chlorophyll and β-carotene. The inhibitory effects of carbohydrates on flowering were partially reversed by iminodiacetate, glycine, and l-aspartate but not by d-aspartate, ethylenediaminetetraacetate, acetate, δ-aminolevulinic acid, or mevalonic acid. The possibility is discussed that carbohydrate repression of flowering and of chloroplast pigments resulted from inadequate levels of amino acids. 1 This work was supported by National Science Foundation Grants GB-6559 and GB-12955. This content is only available as a PDF. © 1970 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)