Plant Physiology

Filner, Barbara; Klein, Attila O.

doi: 10.1104/pp.43.10.1587pmid: 16656942

Abstract The phytochrome controlled increase in total protein in the primary leaf pair of etiolated bean (Phaseolus vulgaris var. Black Valentine) seedlings, which occurs during growth in the dark subsequent to a brief illumination, was investigated. Enzymes from the chloroplasts, the mitochondria, and the soluble cytoplasm all increase in total activity after the illumination. The total protein and the ribulose carboxylase increases are not inhibited by FUdR, an inhibitor of DNA synthesis. Cycloheximide, an inhibitor of protein synthesis, applied at a time when the ribulose carboxylase activity increase has already commenced, blocks further increase. It was concluded that the total protein and the enzyme increases in the leaf are the result of increases in the per cell levels. The initial brief illumination is saturating, but 40 minutes later the seedlings have acquired the ability to respond to a second brief illumination. The rate of increase in ribulose carboxylase activity in seedlings that have been illuminated twice is greater than the rate in seedlings that have been illuminated only once. Far-red light prevents further increase in enzyme activity 48 hours after the initial illumination. There is a lag period interposed between the time of illumination with far-red light and the time at which the seedlings show the greatest effect of far-red light. It was concluded that the phytochrome influence on protein synthesis is not at the terminal steps. 3 Present address: AEC Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48823. 1 Investigation supported in part by Grant GB3415 from the National Science Foundation, and in part by Developmental Biology Training Grant T1-HD-22 of the Public Health Service. 2 This work represents part of a thesis presented by B. Filner to the faculty of the Graduate School of Brandeis University 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)

Robinson, J. Michael; Stocking, C. R.

doi: 10.1104/pp.43.10.1597pmid: 16656943

Abstract A rapid oxygraph method of studying the permeability of the envelope of isolated chloroplasts was used. The outer envelope of aqueously isolated whole spinach (Spinacia oleracea L.) chloroplasts in buffer is readily permeable to 3-phosphoglyceric acid, which induces an immediate light dependent oxygen evolution. This light dependent oxygen evolution was completely eliminated by swelling these plastids in an osmotically dilute solution. Exogenous adenosine diphosphate, but not inorganic phosphate, strongly stimulated this oxygen evolution. This indicated that the chloroplast envelope is relatively permeable to adenosine diphosphate. Oxygen evolution and swelling studies indicated that the chloroplast envelope is relatively impermeable to NADP and to ferredoxin. A method is described whereby the percent of whole chloroplasts present in a chloroplast preparation may be rapidly estimated. 1 This research was supported in part by a National Science Foundation grant GS-5342X. 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)

Shiroya, Michi

doi: 10.1104/pp.43.10.1605pmid: 16656944

Abstract When single leaves attached at a given node were allowed to carry on photosynthesis in 14CO2 for 30 min, younger plants showed a higher proportion of upward translocation than did older plants. Downward translocation of 14C-photosynthate was stimulated by ATP pre-treatment of the translocating leaf, while upward translocation was not affected by ATP. A similar phenomenon was observed in the translocation of 14C-sucrose infiltrated into a leaf with or without ATP. Downward translocation of photosynthate was inhibited by DNP pre-treatment of a fed leaf. Upward translocation, however, was not affected by DNP. Thirty min after infiltration of 14C-glucose into a leaf, almost all the 14C translocated upwards was found to be in the form of glucose, while a great part of the 14C translocated downwards was in the form of sucrose. In the case of translocation of infiltrated 14C-sucrose, 14C found both above and below the fed leaf was mainly in the form of sucrose. 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)

Benedict, C. R.; Kohel, R. J.

doi: 10.1104/pp.43.10.1611pmid: 16656945

Abstract The virescent cotton (Gossypium hirsutum) mutant described here differs from normal cultivated cotton by a single mutation in the nucleus. The mutant exhibits nuclear control of chlorophyll and carotenoid development. Young leaves are distinctly yellow and become green with age. There is no unusual photometabolism of 14CO2 or 14C-acetate in this mutant. It is probable that the nuclear virescent mutation is in a locus concerned with making structural units. The yellow leaves do show a high photosynthetic capacity on a chlorophyll basis. At saturating light intensity the rate of CO2 fixation is 8 fold higher than the green control leaves. Thus, impaired pigment synthesis which could be lethal is offset by a high photosynthetic capacity in the virescent leaves. 1 This work was supported in part by the Cotton Producers Institute and the Cotton Genetics Regional Project S-1. 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)

Gordon, John C.; Larson, Philip R.

doi: 10.1104/pp.43.10.1617pmid: 16656946

Abstract Rates of net photosynthesis and dark respiration, and distribution of 14C were determined for new (current season's) and old (previous season's) needles at 10 times during the seasonal development of young Pinus resinosa Ait. trees. The seasonal changes in these factors associated with the development of the new shoot were related to known seasonal patterns of wood formation. Net photosynthesis per gram of needle dry weight (photosynthetic efficiency) was maximum in the old needles at the time of first new needle elongation; at the same time translocation of 14C from old to new needles was greatest. Photosynthetic efficiency of new needles was maximum at the end of the period of rapid new needle elongation, when the new needles also began exporting much greater quantities of 14C to other plant parts. In particular, the amount translocated from the new needles to the stem was greatly increased. At this time thick-walled xylem cells were first observed in the stem. These results, together with those of previous studies, indicate that the production of thick-walled xylem tracheids normally associated with latewood is physiologically correlated with maturation of the current season's needles. Because there is a lesser demand for photosynthate in the new shoot and a high rate of photosynthesis in the whole plant at the time of new needle maturity, a sharply increased amount of photosynthate becomes available for wall synthesis by cambial derivatives. 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)

Cleland, Robert

doi: 10.1104/pp.43.10.1625pmid: 16656947

Abstract A study has been made of the effects on hydroxyproline formation of 4 factors that influence the rate of cell elongation in the Avena coleoptile; auxin, sugars, an external osmoticum, and actinomycin D. Hydroxyproline formation is increased by a combination of auxin and sucrose, but is affected to a much lesser extent by either factor alone. Its formation is inhibited by an external osmoticum but is scarcely affected by actinomycin D. The lack of correlation between the amount of hydroxyproline synthesis and the growth rate suggests that hydroxyproline formation is not involved in the actual process of wall loosening. It is suggested, instead, that if the wall is to retain its capacity for rapid extension, those hemicelluloses which are incorporated into it by intussusception rather than by apposition must be attached to a hydroxyproline-protein. 1 Supported by Grant GB-5385 from the National Science Foundation 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)

Hendrix, John E.

doi: 10.1104/pp.43.10.1631pmid: 16656948

Abstract One mature blade of each squash plant was continuously labeled with 14CO2 for 15, 30, or 70 minutes in light. The ethanol soluble materials from serial sections of petioles were extracted and separated by paper chromatography. The ratios of label in the various components of this fraction were determined. Stachyose, which contained the major portion of the label of this fraction, was hydrolyzed and the resultant hydrolysate was separated by paper chromatography. Specific activities of the hexoses derived from stachyose were determined. It was found that the glucose and fructose moieties of stachyose became labeled at the same rates; however, the galactose moiety became labeled more rapidly. 2 Present address: Department of Botany and Plant Pathology, Colorado State University, Fort Collins, Colorado 80521. 1 This investigation was supported in part by a National Science Foundation grant to Dr. C. A. Swanson (G-24040). These data are from a thesis presented to the Graduate School of The Ohio State University in partial fulfillment of the requirements for the doctorate degree. Publication No. 748 of the Graduate Faculty of Botany, The Ohio State University. 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)

Macey, Michael J. K.; Stumpf, P. K.

doi: 10.1104/pp.43.10.1637pmid: 16656949

Abstract A low lipid, high starch containing tissue, namely cotyledons of germinating pea seedlings was examined for its capacity to synthesize fatty acid. Intact tissue slices readily incorporate acetate-14C into fatty acids from C16 to C24. Although crude homogenates synthesize primarily 16:0 and 18:0 from malonyl CoA, subsequent fractionation into a 10,000g pellet, a 105g pellet and supernatant (soluble synthetase) revealed that the 105g pellet readily synthesizes C16 to C28 fatty acids whereas the 10,000g and the supernatant synthesize primarily C16 and C18. All systems require acyl carrier protein (ACP), TPNH, DPNH if malonyl CoA is the substrate and ACP, Mg2+, CO2, ATP, TPNH, and DPNH if acetyl CoA is the substrate. The cotyledons of germinating pea seedlings appear to have a soluble synthetase and 10,000g particles for the synthesis of C16 and C18 fatty acid, and 105g particles which specifically synthesize the very long chain fatty acid from malonyl CoA, presumably via malonyl ACP. 2 Present address: Department of Botany, University of New South Wales, Kensington, N.S.W. 2033, Australia. 1 This investigation was supported by the United States Department of Agriculture through Agricultural Research Service, Western Utilization Research and Development Division, Albany, California, under Grant No. 7990-74 and National Science Foundation GB 5879X. 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)

Worley, J. F.

doi: 10.1104/pp.43.10.1648pmid: 16656950

Abstract All visible protoplasmic streaming in sections of various plant stems was reversibly stopped by 2,4-dinitrophenol (DNP). Sections contained epidermal, cortical, and fiber cell types. Cells treated with DNP retained their semipermeability as evidenced by their plasmolysis in sucrose solutions. Washing out the DNP resulted in the rapid resumption of protoplasmic streaming in all 3 cell types. Both the rate of movement of sodium fluorescein and the shape of the advancing dye front were greatly altered by DNP treatment. Dye transport was decreased in the fibers and little affected in cortical cells. The results suggest that rotational streaming accelerates the translocation of soluble substances in fiber cells. 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)

Zimmerman, Don C.

doi: 10.1104/pp.43.10.1656pmid: 16656951

Abstract The delay in, or loss of, flaxseed lipoxidase activity in N-tris (hydroxymethyl) methylglycine and N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid buffers with linolenic acid as a substrate appears due to an alteration of the lipid micelle. Flaxseed lipoxidase activity is dependent on the ionic strength of the assay solution. These effects are not observed with linoleic acid as substrate. The influence of these 2 buffers on linolenic acid micelles may have a direct bearing on recent reports of chloroplast structure and activity in these buffers. 1 Research Chemist, Crops Research Division, Agricultural Research Service, United States Department of Agriculture, in cooperation with the North Dakota Agricultural Experiment Station. Published with the approval of the Director, North Dakota Agricultural Experiment Station as Journal article No. 159. 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)