Plant Physiology

Jacobsen, John V.; Scandalios, J. G.; Varner, J. E.

doi: 10.1104/pp.45.4.367pmid: 5427106

Abstract The addition of gibberellic acid to isolated aleurone layers of barley (Hordeum vulgare L.) causes the production and secretion of four α-amylases. Two of these are stable at pH 3.7 and are not inactivated by ethylenediaminetetraacetate. The other two represent the classical barley α-amylases; i.e., they are inactivated at pH 3.7 and by reagents which from complexes with divalent metal ions. All four forms are synthesized de novo in response to the addition of gibberellic acid. 1 This work was supported in part by the United States Atomic Energy Commission under Contract AT(11-1) 1338. 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)

Gamborg, Oluf L.

doi: 10.1104/pp.45.4.372pmid: 16657321

Abstract A suspension culture of soybean (Glycine max L.) was grown on a defined medium in which the nitrogen sources were nitrate (25 mM) and ammonium (2 mM). The cells did not grow on nitrate unless the medium was supplemented with ammonium or glutamine. The l- and d-isomers of 12 amino acids tested singly could not replace ammonium. Most amino acids (4 mM) inhibited growth when the cells were cultured on nitrate and ammonium. Cells from five other plants (Reseda luteoli L.; Triticum monococcum L.; flax, Linum usitatissimum L.; horseradish, Amoracia lapathifolia Gilib; Haplopappus gracilis L.) grew on the defined medium with nitrate (25 mM) as the sole nitrogen source. Higher cell yields were obtained when ammonium (2 mM) or glutamine also was present. Supplementing the defined medium with high concentrations of ammonium (20 mM) inhibited growth of soybean, Haplopappus, and wheat cells. Addition of citrate (5 mM) relieved the inhibitory effects of ammonium in soybean and wheat cells but not in the Haplopappus cells. 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, S. G.

doi: 10.1104/pp.45.4.376pmid: 16657322

Abstract The concentrations of adenosine triphosphate and phytic acid in testa, embryo plus scutellum, aleurone, and endosperm fractions from grain of Triticum vulgare cv. Insignia have been determined during development under both normal conditions and those of water stress. Phytic acid was not detected in the endosperm. In the embryo plus scutellum and aleurone fractions there was a rapid build-up of phytic acid, but the adenosine triphosphate level did not change markedly at this time. These results are not consistent with physiological roles previously suggested for phytic acid other than the role of phytin as a phosphorus and cation store for the germinating seed. 2 Present address: Wellcome Research Laboratories, Beckenham, England. 1 Financial assistance from the Australian Commonwealth Wheat Industry Research Council is gratefully acknowledged. 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)

Raison, John K.; Lyons, James M.

doi: 10.1104/pp.45.4.382pmid: 5427107

Abstract The respiration of mitochondria isolated from various plant tissues was studied over a range of mitochondrial concentrations and at various times after isolation. Respiration at 25 C expressed as nanomoles of O2 per minute per milligram of protein was constant for mitochondrial concentrations higher than some critical amount, usually 0.25 to 1.0 milligram of protein per reaction. Below this concentration the state 3 respiration rate declined and the mitochondria appeared to lose respiratory control. The respiration of isolated mitochondria stored in ice but measured at 25 C generally declined over long time periods although mitochondria from some tissues showed an initial increase. The results indicate that valid comparisons of the respiratory activity of mitochondria isolated from different tissues or from different parts of the same tissue cannot be made at least until the influence of the above factors has been evaluated. 1 This work was supported in part by a Commonwealth Scientific and Industrial Research Organization, Australia, study grant awarded to J. M. Lyons while on sabbatical leave from the Department of Vegetable Crops, University of California, Riverside, California 92502. 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)

Lyons, James M.; Raison, John K.

doi: 10.1104/pp.45.4.386pmid: 5427108

Abstract Arrhenius plots of the respiration rates of mitochondria isolated from chilling sensitive plant tissues (tomato and cucumber fruit, and sweet potato roots) showed a linear decrease from 25 C to about 9 to 12 C (with Q 10 values of 1.3 to 1.6), at which point there was a marked deviation with an increased slope as temperatures were reduced to 1.5 C (Q 10 of 2.2 to 6.3). The log of the respiration rate of mitochondria from chilling resistant tissues (cauliflower buds, potato tubers, and beet roots) showed a linear decrease over the entire temperature range from 25 to 1.5 C with Q 10 values of 1.7 to 1.8. Phosphorylative efficiency of mitochondria from all the tissues, as measured by ADP:O and respiratory control ratios, was not influenced by temperatures from 25 to 1.5 C. These results indicate that an immediate response of sensitive plant tissues to temperatures in the chilling range (0 to 10 C) is to depress mitochondrial respiration to an extent greater than that predicted from Q 10 values measured above 10 C. The results are also consistent with the hypothesis that a phase change occurs in the mitochondrial membrane as the result of a physical effect of temperature on some membrane component such as membrane lipids. 1 This work was supported in part by a Commonwealth Scientific and Industrial Research Organization, Australia, study grant awarded to J. M. Lyons while on sabbatical leave from the Department of Vegetable Crops, University of California, Riverside, California 92502. 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)

Howell, Gordon S.; Weiser, C. J.

doi: 10.1104/pp.45.4.390pmid: 16657323

Abstract The role of photoperiod and temperature in the cold acclimation of living Haralson apple (Pyrus malus L.) bark was studied in the autumn under field conditions in Minnesota. Whole trees, or different parts of the same tree, were exposed to either natural conditions, artifically lengthened days, or artificially warmed nights, or they were subjected to manual leaf removal. The results indicate that acclimation occurs in two stages which are induced by short days and frost (or low temperature), respectively. Leaves were stimulated by short days to produce translocatable substance(s) which promoted cold acclimation of the living bark. Leaves of plants grown under long days were the source of a translocatable substance(s) which inhibited acclimation. The second stage of hardiness, induced by frost (or low temperature), did not involve translocatable factors. Inductive short days could overcome the effect of high temperatures, and low temperatures could overcome the effect of noninductive long days in promoting the first stage of acclimation to −30 C. Frost was necessary for maximum hardiness to −55 C. Plants grown in a greenhouse, in the autumn, under long days and high temperatures acclimated slightly in spite of the noninductive conditions. Short days and frost (or low temperatures) appeared to regulate different and independent endogenous acclimation processes. 2 Present address: Department of Horticulture, Michigan State University, East Lansing, Michigan 48912. 1 Scientific Journal Series Paper 6937 of the Minnesota Agricultural Experiment Station. 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)

Abeles, F. B.; Forrence, L. E.

doi: 10.1104/pp.45.4.395pmid: 5427109

Abstract The endo-β-1, 3-glucanase (β-1, 3-glucan 3-glucanhydrolase, EC 3.2.1.6) extracted from Phaseolus vulgaris L. cv. Red Kidney had a pH optimum of 5 and a temperature optimum of 50 C. Excision of plant tissue resulted in an increase in β-1, 3-glucanase activity after a 6-hour lag period. The increase could be prevented by indole-3-acetic acid, gibberellic acid, and cytokinins. Ethylene (half-maximal concentration = 0.1 microliter/liter) promoted the synthesis of β-1, 3-glucanase, and 10% CO2 overcame some of the ethylene effect. Cycloheximide prevented the induction of β-1, 3-glucanase, but actinomycin D and chromomycin A3 had only a partial effect. The amount of callose in sieve tube cells correlated with levels of β-1, 3-glucanase, suggesting that this enzyme played a role in the degradation of β-1, 3-glucans. 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)

Ku, Lily Lim; Romani, Roger J.

doi: 10.1104/pp.45.4.401pmid: 5427110

Abstract Maceration at liquid nitrogen temperatures, use of poly-vinylpyrrolidone, and careful pH control are essential to the isolation of ribosomes and polysomes from deciduous fruit tissue. Characteristics of the ribosomes and constituent RNA are described. The distribution of ribosomes among monomer and polymer forms remains relatively constant until fruit reach the climacteric peak, after which there is a notable decline in the polymeric forms. In contrast to the relative stability in size distribution there is a marked change in ribosomal turnover during the climacteric rise. A transitory increase in rate of ribosomal synthesis is followed by a rapid decline coincident with the final portion of the climacteric rise. No incorporation of radioactive base into ribosomes could be detected once fruit had reached the climacteric peak. Coincidence of radioactivity with the ribosomal RNA on methylated albumin-Kieselguhr chromatograms and complete inhibition of ribosomal RNA synthesis by actinomycin D confirm that radioactive nucleotide was incorporated into newly synthesized ribosomes. Data are presented to distinguish between a cellular response to injury, as may result from the preparation of tissue slices, and the effects of physiological age. Superimposed intracellular radiation injury stimulates the synthesis of new ribosomes and underscores a major transition in the dynamics of the ribosomal system coincident with the climacteric rise. 1 This work was supported by the United States Atomic Energy Commission under Contract AT(11-1)-34, Project 112, Report UCD-34P112-36. 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)

Hiatt, A. J.

doi: 10.1104/pp.45.4.408pmid: 16657324

Abstract Excised barley roots accumulated 40 to 50% more K+ from 0.04 mm than from 0.06 mm KCl when incubated for 24 hours in KCl solutions containing 0.2 mm CaSO4. This phenomenon was not markedly influenced by the rate of absorption of the counteranion. The presence of Na+ in the treatment solutions decreased total K accumulation but did not alter the K+ concentration at which the accumulation peak occurred. Short interval studies indicated that this phenomenon is easily observable after 4 hours and begins to become apparent within 2 hours. In comparison with barley, accumulation of K+ by excised wheat roots decreased as KCl concentration was increased from 0.02 to 0.06 mm; but K+ accumulation curve for corn roots showed no peaks or depressions in the concentration range of 0.01 to 0.1 mm. A normal hyperbolic curve was noted for the accumulation of Na+ from 0.01 to 1 mm NaCl by barley roots. 1 Contribution (Article 69-3-92) of the Department of Agronomy, Kentucky Agricultural Experiment Station, Lexington, and published with approval of the Director. 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)

Hiatt, A. J.

doi: 10.1104/pp.45.4.411pmid: 16657325

Abstract When excised barley roots were incubated in 0.01 to 0.1 mm KCl solutions containing 0.2 mm CaSO4, there was a peak in the K+ accumulation against concentration curve at 0.02 to 0.04 mm KCl. The peak in the K+ accumulation curve was shifted to lower K+ concentrations when Ca2+ concentration was decreased and to higher K+ concentrations when Ca2+ concentration was increased. Increasing Ca2+ concentration in the treatment solution was observed to be stimulatory, inhibitory, or neutral depending on the K+ concentration. When 86Rb was used as an isotopic tracer for K+, accumulation of K+ was grossly overestimated, and the apparent K+ accumulation curve, as estimated with 86Rb-labeled K+, was hyperbolic over the concentration range of 0.01 to 0.1 mm. It was concluded that 86Rb is a poor tracer for K+ over the concentration range of 0.01 to 0.1 mm. Accumulation of Rb+ in the presence of K+ was accurately measured by 86Rb. 1 Contribution (Article 69-3-93) of the Department of Agronomy, Kentucky Agricultural Experiment Station, Lexington, and published with approval of the Director. 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)