Plant Physiology

Helgeson, John P.; Upper, C. D.

doi: 10.1104/pp.46.1.113pmid: 16657400

Abstract Logarithmic growth rates (either fresh or dry weight basis) of tobacco callus tissues grown on 10−4 to 10−1 μm cytokinin are increased if gibberellic acid (10−3-2 μm) is incorporated into the medium. At higher (1-10 μm) cytokinin concentrations gibberellic acid has little effect on growth rate but extends the duration of logarithmic growth. The gibberellic acid effect is noticeable only after one weight doubling, is dependent on concentration, and occurs when either glucose or sucrose is used as carbon source. The gibberellic acid response includes a decrease in percentage of dry weight relative to control tissues. The maximum dry weight yield, although achieved sooner than controls, does not differ appreciably from yields of tissue not treated with gibberellic acid. 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)

Upper, C. D.; Helgeson, John P.; Haberlach, G. T.

doi: 10.1104/pp.46.1.118pmid: 16657401

Abstract Growth rate, maximum dry weight yield, and carbohydrate utilization were measured with pith callus derived from Nicotiana tabacum L. var. Wisconsin No. 38. Maximum tissue dry weights increased as carbohydrate (either glucose or sucrose) in the medium was increased. The time at which maximum growth was obtained coincided with the time at which carbohydrate was exhausted from the medium. The addition of carbohydrate to the medium before the end of log phase growth supported that amount of additional growth which would have been obtained if all of the carbohydrate had been added to the medium prior to planting the tissue. Maximum obtainable dry weights at logarithmic growth rates greater than 0.16 doubling per day depended on the amount of carbohydrate in the medium and not on a particular hormonal regime. 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)

Williams, M. W.; Stahly, E. A.

doi: 10.1104/pp.46.1.123pmid: 16657402

Abstract Fruit from Red Delicious apple trees treated with the growth retardant succinic acid 2,2-dimethylhydrazide contained more N-malonyl-d-tryptophan than control fruit. When succinic acid 2,2-dimethylhydrazide and tryptophan were injected into immature fruits, more N-methyl-d-tryptophan was produced than when dl-tryptophan was injected alone. Our results suggest that succinic acid 2,2-dimethylhydrazide may control fruit and vegetative growth by interfering with auxin production. 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)

MacDonald, Paul W.; Strobel, Gary A.

doi: 10.1104/pp.46.1.126pmid: 16657403

Abstract The variation in starch content in healthy and Puccinia striiformsi-infected wheat leaves was measured from 5 to 15 days after inoculation. The starch content of diseased leaves relative to healthy leaves decreased from 5 to 9 days, increased from 9 to 12 days to twice that of healthy leaves, and decreased from 12 to 15 days after inoculation. Electron micrographs of plant tissues indicated that the starch accumulated in the chloroplasts of host cells adjacent to fungal hyphae. Variations in sugar phosphates, ATP, and inorganic phosphate were measured during the infection process. ADP-glucose pyrophosphorylase was extracted and partially purified from healthy and diseased leaves. When proportionate concentrations of sugar phosphates and inorganic phosphate found in healthy and diseased leaves during the infection process were placed in the assay mixture, ADP-glucose pyrophosphorylase activity was similar to the pattern of starch accumulation and was almost the inverse of the variation observed in inorganic phosphate in diseased leaves during the infection process. A mechanism to explain the accumulation of starch is presented and discussed. This mechanism is based on the regulation of ADP-glucose pyrophosphorylase by changes in effector molecule concentrations during the infection process. Reasons for these changes are presented. 2 Present address: Department of Plant Pathology, University of California, Riverside, California 92502. 3 United States Public Health Service Research Career Development Awardee 1-K4-GM-42, 475-01 from the National Institute of General Medical Sciences. 1 From a thesis presented by P. W. MacDonald in partial fulfillment of the requirements for the Ph.D. degree in Botany at Montana State University. Supported in part by National Science Foundation Grant GB-12956, and specific grant for research P.L. 85-943, Cooperative States Research Service, United States Department of Agriculture. Montana Agricultural Experiment Station Publication 147, Journal Series. 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)

Margulies, Maurice M.

doi: 10.1104/pp.46.1.136pmid: 16657405

Abstract A crude chloroplast preparation of primary leaves of Phaseolus vulgaris was allowed to incorporate 14C-leucine into protein. A chloroplast extract was prepared and purified for ribulose 1,5-diphosphate carboxylase by ammonium sulfate precipitation, chromatography on Sephadex G-200, and chromatography on Sepharose 4B. The distribution of radioactive protein and enzyme in fractions eluted from Sepharose 4B was nearly the same. The radioactivity in the product was in peptide linkage, since it was digested to a trichloroacetic acid-soluble product by Pronase. Whole cells in the plastid preparation were not involved in the incorporation of amino acid into the fraction containing ribulose 1,5-diphosphate carboxylase, since incorporation still occurred after removal of cells. The incorporation into the fraction containing ribulose 1,5-diphosphate carboxylase occurs on ribosomes of plastids, since this incorporation is inhibited by chloramphenicol. These plastid preparations may be incorporating amino acid into ribulose 1,5-diphosphate carboxylase, but the results are not conclusive on this point. 1 Published with the approval of the Secretary of the Smithsonian Institution. Research was supported in part by Smithsonian Research Foundation Grant Sg0400004/C1. 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)

Dalby, Arthur; Cagampang, Gloria B.

doi: 10.1104/pp.46.1.142pmid: 16657406

Abstract The elevated ribonuclease activity produced in the endosperm of a maize (Zea mays L.) inbred, W64A, by homozygous opaque-2, results from a more than doubled rate of ribonuclease accumulation occurring prior to 16 days post-pollination; after 16 days the rates in opaque-2 and normal are the same, suggesting that opaque-2 is no longer active. The pattern of ribonuclease increase in the opaque-2 dosage series indicates that opaque-2 is not fully recessive. Ribonuclease accumulation is not affected by floury-2 in a second inbred, B14. The results are discussed with reference to other proteins, notably zein, the net synthesis of which is affected by opaque-2. 2 IRRI Fellow. Present address: The International Rice Research Institute, Los Baños, Laguna, The Philippines. 1 Supported in part by National Science Foundation Grant GB 4511. This is Journal Paper 3970 of the Purdue University Agricultural Experiment Station, Lafayette, Indiana. 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)

Kaufmann, Merrill R.

doi: 10.1104/pp.46.1.145pmid: 16657407

Abstract Growing navel orange fruits (Citrus sinensis) 5.4 to 5.7 centimeters in diameter were used as a model system to determine the effects of transpiration and carbohydrate translocation on water and osmotic potentials in fruit tissues. Evidence supported the hypothesis that osmotic potential in the vesicles would be affected little by changes in transpiration or carbohydrate translocation because the vesicles are anatomically isolated from the transpiration stream and are at the end of the carbohydrate translocation pathway. In the mesocarp tissue, which contains a vascular network, osmotic potential decreased during the daytime when environmental conditions favored transpiration and increased at night. Exocarp water potential followed a similar pattern. Girdling of the stem above the fruits 5 days before sampling caused an increase of osmotic potential in the mesocarp but had no effect on exocarp water potential. Neither diurnal changes in transpiration nor girdling of the stem affected the osmotic potential of the vesicles. Osmotic potentials in all tissues of the fruit were in the range of −10 to −15 bars. Measurements of osmotic potential at 16 locations along a longitudinal plant through the fruit axis showed that osmotic potential increased from the stem to the stylar end, but it decreased from the pericarp tissues to the vesicles. As exocarp water potential decreased during a 20-day period after watering, osmotic potential decreased in the vesicles and exocarp. Turgor pressure, calculated as the difference between water and osmotic potentials, decreased with water potential in the vesicles but not in the exocarp. The lack of decrease of turgor pressure in the exocarp may result from a measurement error caused by pectins or from osmotic adjustment related to carbohydrate accumulation at low water potentials. 1 Work supported by National Science Foundation Grant No. GB-7621. 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)

Labarca, C.; Kroh, M.; Loewus, F.

doi: 10.1104/pp.46.1.150pmid: 16657408

Abstract Stigmatic exudate, a secretion product recovered from the upper surface of Lilium longiflorum pistils, has been examined. Over 99% of the exudate is accounted for as water, carbohydrate, and protein. Exclusive of water, 95% is a high molecular weight, protein-containing polysaccharide composed of galactose, arabinose, rhamnose, glucuronic acid, and galacturonic acid. Detached pistils supplied with myo-inositol-U-14C, myo-inositol-2-3H, d-glucose-1-14C, or l-proline-U-14C produce labeled stigmatic exudate. When myo-inositol is supplied, the exudate is rich in labeled arabinose and uronic acids, but some label also recycles through the hexose phosphate pool of secreting cells, causing label to appear in galactose and rhamnose residues. When glucose is provided, galactose is the major constituent labeled but all of the other carbohydrate constituents are also labeled. Proline produces a pattern very similar to that obtained with glucose. Stigmatic exudate also contains a small amount of low molecular weight carbohydrate. If myo-inositol is used to label exudate, free labeled myo-inositol cannot be detected in the low molecular weight fraction until it has been subjected to acid hydrolysis. Similarly, if d-glucose is the source of label, free labeled glucose is found in the low molecular weight fraction only after acid hydrolysis. 2 Present address: Department of Botany, University of Nijmegen, Nijmegen, The Netherlands. 1 This investigation was supported in part by a grant (GM-12422) from the National Institutes of Health, United States Public Health Service, and by postdoctoral support to C. L. from the Graduate School, State University of New York at Buffalo. 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)

Beyer, Elmo M.; Morgan, Page W.

doi: 10.1104/pp.46.1.157pmid: 16657409

Abstract The effect of ethylene on the uptake, distribution, and metabolism of indoleacetic acid (IAA)-1-14C, IAA-2-14C, and naphthaleneacetic acid (NAA)-1-14C in cotton stem sections (Gossypium hirsutum L., var. Stoneville 213) was studied. Stem sections excised from plants pretreated with ethylene for 15 hours transported significantly less 14C-IAA and 14C-NAA than control sections. Concomitant features of the reduction of 14C-IAA transport were an increase in decarboxylation and a trend toward a reduction in total uptake. With 14C-NAA, however, total uptake was significantly increased, and decarboxylation was unaffected. 14C-IAA was rapidly converted to indoleacetylaspartic acid and many other metabolites in both control and ethylene-pretreated stem sections. Following transport, similar amounts of 14C-IAA were recovered in the apical absorbing portion of the control and ethylene-pretreated sections. Significantly more 14C-IAA metabolites, however, were recovered in this region of the ethylene-pretreated sections. Conversely, 14C-NAA was metabolized more slowly than 14C-IAA under identical experimental conditions, with the only major metabolite being naphthaleneacetylaspartic acid. Following transport the apical absorbing portion of ethylene-pretreated stem sections contained significantly more 14C-NAA than the controls. These results suggested that the disruption of auxin transport by ethylene cannot be explained in terms of a more rapid metabolism of auxin in the treated sections. The increased 14C-IAA metabolites in the absorbing portion of ethylene-pretreated sections appear to be the result, rather than the cause, of the ethylene-mediated disruption of IAA transport. 2 Present address: Central Research Department, E. I. Du Pont de Nemours and Company, Wilmington, Del. 19898. 1 A contribution of the Texas Agricultural Experiment Station. Supported in part by Grant GB-5640 from the National Science Foundation and a grant from the Cotton Producers Institute and the National Cotton Council of America. 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)

Hiyama, Tetsuo; Nishimura, Mitsuo; Chance, Britton

doi: 10.1104/pp.46.1.163pmid: 16657410

Abstract Light- and oxygen-induced changes of cytochromes f, b 563, and b 559 and ferredoxin-flavoprotein were studied by a double beam spectrophotometer with combinations of inhibitors and lowered temperatures in the whole cells of the pale green mutant of Chlamydomonas reinhardi (ATCC 18302). At room temperature, the steady state changes of cytochrome f and ferredoxin-flavoprotein are small, but at low temperature slightly above 0 C, they are clearly defined. Phenylmercuric acetate inhibits photoreduction of ferredoxin-flavoprotein and cytochrome f simultaneously but not that of cytochrome b 563. 2-Heptyl-4-hydroxyquinoline-N-oxide shows a crossover point between cytochromes f and b 563 and partially inhibits photoreduction of cytochrome f. Two cyclic pathways operating in C. remhardi are postulated: (a) photosystem I → x → b 563 → f → photosystem I; and (b) photosystem I → x → ferredoxin-flavoprotein → f → photosystem I. 2 Present address: C. F. Kettering Research Laboratory, Yellow Springs, Ohio 45387. 3 Present address: Department of Biology, Kyushu University, Fukuoka, Japan. 1 Supported by Grants GM 12202 and GM 2G-277 from the National Institutes of Health. 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)