Plant Physiology

Wong, Peter P.; Zucker, Milton; Creasy, Leroy L.

doi: 10.1104/pp.54.5.659pmid: 16658948

Abstract The increase in phenylalanine ammonia-lyase (PAL) activity in strawberry (Fragaria vesca var. WSU-1232) leaf disks required wounding, sucrose, and light and was cycloheximide-sensitive. In injured leaves and in leaf disks, the highest PAL activity was detected nearest the wounded tissues. Without wounding, no increase in activity was observed when leaves were cultured in sucrose and light. The optimal concentration of sucrose for enzyme activity increase ranged from 0.15 m to 0.4 m. At the suboptimal sucrose concentration, the level of PAL activity was dependent upon the concentration of sucrose. A low but constant level of activity was detected in leaf disks maintained in 0.15 m sucrose and in darkness. Light accelerated the rate of PAL increase but did not change the total level of enzyme activity which was determined by the sucrose concentration. Enzyme activity disappeared rapidly when leaf disks cultured in sucrose and light were transferred to darkness or to water in light. Unlike in Xanthium leaf disks, cycloheximide could not completely inhibit the decay of enzyme activity, suggesting that an inactivating system was synthesized during the induction period, and the activity of the inactivating system increased as the induction period lengthened. The effect of light on accumulation of PAL activity appeared to be linked to photosynthesis. In the presence of 25 μm 3-(3,4-dichlorophenyl)-1,1-dimethylurea, the effect of light on enzyme increase was completely nullified. Addition of 25 μm 3-(3,4-dichlorophenyl)-1,1-dimethylurea to culture medium caused rapid decay of PAL activity from leaf disks which had been previously cultured in sucrose and light. The relation between effect of light and photosynthesis was further demonstrated by the action spectrum. Leaf disks incubated in sucrose and light of different wavelengths exhibited maximum accumulation of PAL activity at two wavelengths (475 nm and 625 nm). Action spectrum for protection against PAL decay exhibited a plateau at 475 to 525 nm and a peak at 625 nm. Action spectra for accumulation and protection against inactivation of PAL activity, therefore, appeared to be very similar to the action spectrum of photosynthesis. 2 Milton Zucker died in July, 1973. This paper is his final contribution to science. Dr. Zucker was a good and dedicated scientist. His friendship and his guidance will be long cherished. 1 Scientific paper No. 4238, Project 0125 from the Agricultural Research Center, College of Agriculture, Washington State University, Pullman, Wash. This content is only available as a PDF. © 1974 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)

Sands, David C.; Lukens, Raymond J.

doi: 10.1104/pp.54.5.666pmid: 16658949

Abstract Production of carbohydrases by Alternaria solani is inhibited by glucose under low growth conditions. In an enriched medium, glucose has little effect on the production of polygalacturonase and cellulase while it still suppresses production of β-glucosidase. Low levels of all three enzymes were produced in the absence of their respective substrates. Such regulation has been found with many organisms. However, far greater production of these carbohydrases occurred with additions of adenosine phosphates to the growth media. Highest stimulation of enzyme production was by adenosine 5′-phosphate. Adenosine 5′-triphosphate and cyclic 3′, 5′-adenosine monophosphate gave lesser amounts. Starvation appears to induce production of extracellular carbohydrases and adenosine 5′-phosphate may have a role in the starvation process. 1 We dedicate this paper in memory of Milton Zucker, our friend and former colleague. Milton often stressed the dual importance of understanding one's field of study and having competence to study. His success as an outstanding investigator is based in part on his thorough grasp of physiology and his high degree of competence to study biochemistry. This content is only available as a PDF. © 1974 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)

Kolattukudy, P. E.; Croteau, Rodney; Brown, Linda

doi: 10.1104/pp.54.5.670pmid: 16658950

Abstract The structure and composition of the cutin monomers from the flower petals of Vicia faba were determined by hydrogenolysis (LiAlH4) or deuterolysis (LiAlD4) followed by thin layer chromatography and combined gas-liquid chromatography and mass spectrometry. The major components were 10, 16-dihydroxyhexadecanoic acid (79.8%), 9, 16-dihydroxyhexadecanoic acid (4.2%), 16-hydroxyhexadecanoic acid (4.2%), 18-hydroxyoctadecanoic acid (1.6%), and hexadecanoic acid (2.4%). These results show that flower petal cutin is very similar to leaf cutin of V. faba. Developing petals readily incorporated exogenous [1-14C]palmitic acid into cutin. Direct conversion of the exogeneous acid into 16-hydroxyhexadecanoic acid, 10, 16-dihydroxy-, and 9, 16-dihydroxyhexadecanoic acid was demonstrated by radio gas-liquid chromatography of their chemical degradation products. About 1% of the exogenous [1-14C]palmitic acid was incorporated into C27, C29, and C31 n-alkanes, which were identified by combined gas-liquid chromatography and mass spectrometry as the major components of the hydrocarbons of V. faba flowers. The radioactivity distribution among these three alkanes (C27, 15%; C29, 48%; C31, 38%) was similar to the per cent composition of the alkanes (C27, 12%; C29, 43%; C31, 44%). [1-14C]Stearic acid was also incorporated into C27, C29, and C31 n-alkanes in good yield (3%). Trichloroacetate, which has been postulated to be an inhibitor of fatty acid elongation, inhibited the conversion of [1-14C]stearic acid to alkanes, and the inhibition was greatest for the longer alkanes. Developing flower petals also incorporated exogenous C28, C30, and C32 acids into alkanes in 0.5% to 5% yields. [G-3H]n-octacosanoic acid (C28) was incorporated into C27, C29, and C31 n-alkanes. [G-3H]n-triacontanoic acid (C30) was incorporated mainly into C29 and C31 alkanes, whereas [9, 10, 11-3H]n-dotriacontanoic acid (C32) was converted mainly to C31 alkane. Trichloroacetate inhibited the conversion of the exogenous acids into alkanes with carbon chains longer than the exogenous acid, and at the same time increased the amount of the direct decarboxylation product formed. These results clearly demonstrate direct decarboxylation as well as elongation and decarboxylation of exogenous fatty acids, and thus constitute the most direct evidence thus far obtained for an elongation-decarboxylation mechanism for the biosynthesis of alkanes. 3 Author to whom inquiries should be made. 1 This work was supported in part by National Science Foundation Grant GB-23081 and United States Public Health Service Grant GM-18278. Scientific paper No. 4250, Project 2001, Agricultural Research Center, College of Agriculture, Washington State University, Pullman, Washington 99163. 2 Dedicated to the memory of our friend Milton Zucker. This content is only available as a PDF. © 1974 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)

Laing, William A.; Ogren, William L.; Hageman, Richard H.

doi: 10.1104/pp.54.5.678pmid: 16658951

Abstract Kinetic properties of soybean net photosynthetic CO2 fixation and of the carboxylase and oxygenase activities of purified soybean (Glycine max [L.] Merr.) ribulose 1, 5-diphosphate carboxylase (EC 4.1.1.39) were examined as functions of temperature, CO2 concentration, and O2 concentration. With leaves, O2 inhibition of net photosynthetic CO2 fixation increased when the ambient leaf temperature was increased. The increased inhibition of CO2 fixation at higher temperatures was caused by a reduced affinity of the leaf for CO2 and an increased affinity of the leaf for O2. With purified ribulose 1,5-diphosphate carboxylase, O2 inhibition of CO2 incorporation and the ratio of oxygenase activity to carboxylase activity increased with increased temperature. The increased O2 sensitivity of the enzyme at higher temperature was caused by a reduced affinity of the enzyme for CO2 and a slightly increased affinity of the enzyme for O2. The similarity of the effect of temperature on the affinity of intact leaves and of ribulose 1,5-diphosphate carboxylase for CO2 and O2 provides further evidence that the carboxylase regulates the O2 response of photosynthetic CO2 fixation in soybean leaves. Based on results reported here and in the literature, a scheme outlining the stoichiometry between CO2 and O2 fixation in vivo is proposed. Oxygen competitively inhibited carboxylase activity with respect to CO2, and CO2 competitively inhibited oxygenase activity with respect to O2. Within the limits of experimental error, the Michaelis constant (CO2) in the carboxylase reaction was identical with the inhibition constant (CO2) in the oxygenase reaction, and the Michaelis constant (O2) in the oxygenase reaction was identical with the inhibition constant (O2) in the carboxylase reaction. The Michaelis constant, (ribulose 1,5-diphosphate) was the same in both the carboxylase and oxygenase reactions. This equality of kinetic constants is consistent with the notion that the same enzyme catalyzes both reactions. 3 Present address: Plant Physiology Division, Department of Scientific and Industrial Research, Palmerston North, New Zealand. 1 This investigation was supported in part by Agricultural Research Service, United States Department of Agriculture Cooperative Agreements 016-15-18 and 716-15-10. and by the Department of Scientific and Industrial Research, New Zealand. 2 Dedicated to the memory of Milton Zucker. This content is only available as a PDF. © 1974 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)

Stafford, Helen A.

doi: 10.1104/pp.54.5.686pmid: 16658952

Abstract Three types of activation of 4-hydroxycinnamate hydroxylase have been observed in extracts of Sorghum bicolor. One involves the elimination of a lag period either by increasing the enzyme concentration or by the addition of a catalytic amount of caffeic acid. Two involve increases after freezing of incubation mixtures containing both hydroxycinnamate and ascorbate, one being a rapid but short-lived increase that may be limited to the freeze-thaw period, the other a slower and more sustained effect on the maximum linear rate obtained during the incubation period after thawing. 1 This work was supported by National Science Foundation Grant GB 28597X. 2 Dedicated to the memory of Milton Zucker, a pioneer in the study of the metabolism of esters of caffeic acid. This content is only available as a PDF. © 1974 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)

Teasdale, John; Daniels, Donna; Davis, William C.; Eddy, Robert; Hadwiger, Lee A.

doi: 10.1104/pp.54.5.690pmid: 16658953

Abstract Excised pea pods responded similarly to both the invasion of plant pathogenic fungi and the presence of bean tissue, bean pollen, and mouse tumor cells by synthesizing pisatin and by developing a characteristic yellow-green fluorescence. Both responses were dependent on RNA and protein synthesis. Conversely, the foreign pollen and incompatible fungi were sensitive to the pea pod tissue and were subject to abnormal development. The induction of pisatin and the yellow-green fluorescence development were mediated by multiple compounds of varying sizes released by fungi or mouse tumor cells. The incompatibility between a bean pathogen, Fusarium solani f. sp. phaseoli, and pea pod tissue was hypothesized to occur as a result of the cross contamination of such inducing compounds. 1 Scientific paper No. 4248, College of Agriculture Research Center, Washington State University, Project 1844. Supported in part by United States Public Health Service Grant GM 18483. 2 A portion of this work was inspired by Milton Zucker, who reported that the disease resistance responses of potatoes inoculated with fluorescent Pseudomonas sp. are dependent on a continuing synthesis of protein (15). I (L.A.H.) also had the good fortune to be a friend and colleague of Dr. Zucker. This content is only available as a PDF. © 1974 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)

Taylor, Anthony O.; Slack, C. Roger; McPherson, Hugh G.

doi: 10.1104/pp.54.5.696pmid: 16658954

Abstract The activity of several photosynthetic enzymes was unaltered by exposure of sorghum or maize to low temperatures (10 C) and light (170 w m−2). Two light-activated C4-pathway enzymes, NADP-malate dehydrogenase and pyruvate Pi dikinase, were reduced in activity, and this was largely attributable to a loss of enzyme rather than to incomplete enzyme activation. Loss of NADP-malate dehydrogenase was more marked in sorghum than in maize, and in both species no loss occurred at 10 C when light levels were reduced from 170 to 50 w m−2. A light-dependent, low temperature-induced loss of catalase activity was also observed in maize leaves. The rate of in vivo activation of pyruvate Pi dikinase following illumination was reduced at 10 C compared with that at 25 C, but no immediate effect of low temperature on the in vivo activation of NADP-malate dehydrogenease could be measured. A similar differential effect of temperature on the rates of activation of these two enzymes was found in vitro. Arrhenius type plots of pyruvate Pi dikinase from sorghum and maize demonstrated a further sensitivity to low temperature. A sharp increase in the activation energy of this enzyme was observed below 12 C, both in the presence and absence of Triton X-100. No change in the activation energy of maize leaf malic enzyme, NADP-malate dehydrogenase, fructose-1, 6-diphosphate aldolase, or NADP-glyceraldehyde 3-P dehydrogenase occurred over a temperature range of 6 to 30 C. The postillumination time course of pyruvate Pi dikinase activation, net photosynthesis and stomatal opening was followed. Reduction in the rate of response that occurred with decreasing temperature was similar in all cases, and at any one temperature, pyruvate Pi dikinase activation slightly preceded increasing photosynthesis rates. Causal relationships could not, however, be proved. 1 This paper is dedicated to the memory of Milton Zucker, an understanding friend and fine scientist. This content is only available as a PDF. © 1974 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)

Engelsma, Gerrit

doi: 10.1104/pp.54.5.702pmid: 16658955

Abstract Irradiation with ultraviolet light causes in the hypocotyl of dark-grown gherkin seedlings the partial conversion of trans-hydroxycinnamic acids to the cis-isomers. The trans-hydroxycinnamic acids inhibit the development of phenylalanine ammonia-lyase activity, and the transformation of these compounds to the much less inhibitory cis-isomers forms a ready explanation for the increase in phenylalanine ammonia-lyase activity in the hypocotyl of gherkin seedlings irradiated with ultraviolet light. Arguments are advanced that the increase in phenylalanine ammonia-lyase activity caused by irradiation with blue light is also (at least in part) initiated by trans-cis isomerisation of the hydroxycinnamic acids. 1 Dedicated to the memory of Milton Zucker who in 1965 was the first to report the photoinduction of phenylalanine ammonia-lyase. The present author was privileged to have many discussions with him in the years thereafter about the regulatory mechanisms concerning this enzyme. This content is only available as a PDF. © 1974 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)

McFarland, Douglas; Ryan, Clarence A.

doi: 10.1104/pp.54.5.706pmid: 16658956

Abstract Thirty-nine plant species representing 20 families from the four major divisions of plants were surveyed for the presence of proteinase inhibitor-inducing factor activity in leaves or other tissues. Tissue juices were assayed for their capacity to induce accumulation of proteinase inhibitor I in excised tomato (Lycopersico esculentum) leaves. In tissues of only 2 of the 39 species was proteinase inhibitor-inducing factor-like activity not found. The activity was absent in cabbage leaves and celery stalks. Fruiting bodies from one of three fungi genera assayed contained exceptionally large quantities of proteinase inhibitor-inducing factor-like activity. Extracts from Agraricus campestris fruiting bodies contained over 20 times more activity than tomato leaf juice. The survey confirms that substances with proteinase inhibitor-inducing factor-like activity are widespread in the plant kingdom. 3 Career Development Awardee of the United States Public Health Service. 1 This work was supported in part by United States Public Health Service Grant 2-K3-GM 17059, the United States Department of Agriculture Cooperative States Research Service Grant 316-15-60, and National Science Foundation Grant GB 37972. College of Agriculture Research Center, Scientific Paper No. 4242, Project 1791. 2 Dedicated to the memory of Milton Zucker, a scientist, a colleague, and a friend. This content is only available as a PDF. © 1974 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, George J.

doi: 10.1104/pp.54.5.709pmid: 16658957

Abstract Increasing pretreatment day temperatures of 20, 30, and 40 C resulted in decreased net photosynthesis in Agropyron smithii (C3) while in Bouteloua gracilis (C4) net photosynthesis was increased. The effect on photosynthesis of increasing analysis temperatures was the same as observed by increasing pretreatment temperatures. Resistance of the stomata and boundary layer were less affected by pretreatment temperatures than were the remaining resistances of a physical and chemical nature. Resistances for A. smithii were increased and those for B. gracilis were decreased by increasing pretreatment temperatures. Phenology of the species in the shortgrass prairie is such that A. smithii has its greatest growth activity during the cool portion of the growth season, whereas B. gracilis is most active in the warm portion. Thus, photosynthetic adaptation to temperature is strongly suggested as a strategy for ecosystem utilization by reduction of interspecific competition. 1 This research was supported by National Science Foundation Grants GB-31862X and GB-41233X to the Grassland Biome, United States International Biological Program for Analysis of Structure, Function, and Utilization of Grassland Ecosystems. 2 This paper is dedicated to the memory of Milton Zucker, a colleague and a most respected plant scientist. This content is only available as a PDF. © 1974 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)