Plant Physiology

Halaban, Ruth; Hillman, William S.

doi: 10.1104/pp.46.5.641pmid: 16657522

Abstract The flowering of Lemma perpusilla grown on half-strength Hutner's medium with sucrose under inductive photo-periods is inhibited in a periodic manner by daily transfers to water for short periods of time. The phase of maximal inhibition of flowering caused by water treatment is about 1 to 2 hours after the time of maximal sensitivity to light pulses. The rhythm of sensitivity to water treatments does not persist under continuous blue light. Supplementing the water with either Ca(NO3)2 or K2HPO4 partially reverses the inhibition of flowering, with the first salt being more effective. Supplementation with NH4NO3 or MgSO4 increases the inhibition. The water effect on flowering is not observed in plants grown on half-strength Hutner's medium without sucrose. The water treatments may act by removing or destroying a crucial precursor for photoperiodic induction, with the other conditions modifying permeability. The system provides a new technique for investigating the mechanism of photoperiodic induction. 1 Research carried out at Brookhaven National Laboratory under the auspices of 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)

El-Sheikh, Adel M.; Ulrich, Albert

doi: 10.1104/pp.46.5.645pmid: 16657523

Abstract The effect of Rb on the growth and the development of sugar beet plants (Beta vulgaris, var. MS NB1 × NB4) depends on the Rb concentration, the K supply, and the relative abundance of Na. Rubidium added either to a low or high K solution with or without added Na increased leaf blade size greatly, possibly through an effect on phytohormones or through a “partitioning effect” on the distribution of carbohydrates, with top growth favored over storage roots. Sodium increased the growth of sugar beet plants when they were either K-deficient or adequately supplied with K. Sodium or Rb added to a high K solution increased the sucrose percentage and total sucrose of the storage roots significantly. Sodium and Rb supplied simultaneously to the nutrient solution resulted in synergetic effects only at low K supply. Potassium was translocated in mature leaves from the petiole to the blade when Na was added to a low K solution, or when Rb was added either to a low or a high K solution. Rb + K had little to no effect on Na redistribution. 1 Present address: Ministry of Agriculture, Plant Analysis Section, Division of Plant Nutrition, Orman, Giza, Cairo, Egypt, United Arab Republic. 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)

Tanaka, Yoshimasa; Ito, Tomoko; Akazawa, Takashi

doi: 10.1104/pp.46.5.650pmid: 16657524

Abstract The formation of amylase isozymes in germinating rice (Oryza sativa) seeds was studied by isoelectric focusing on polyacrylamide gel disc electrophoresis. Time sequence comparisons of the amylase zymogram were made between extracts from gibberellic acid-treated embryoless and embryo-attached half-endosperm of rice seeds. In both cases, 4 major and 9 to 10 minor isozyme bands were detectable at the maximal stage of the enzyme induction. However, in the embryo-attached half-seeds, bands started to diminish after the 5th day of incubation, in agreement with the results of time sequence analyses of enzyme activities. Nearly identical patterns of amylase isozyme bands on a polyacrylamide gel disc electrophoresis in combination with isoelectric focusing indicate the intrinsic role of gibberellic acid in the starch breakdown in germinating rice seeds. We tentatively assign the newly synthesized enzymes to be α-amylases based on experimental results concerning the lability of the preparation on a prolonged treatment at pH 3.3 and the stability on heat treatment for 15 minutes at 70 C. 1 This investigation was supported in part by the United States Department of Agriculture under the PL 480 Program (FG-JA-126). 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)

Morgan, P. W.; Baur, J. R.

doi: 10.1104/pp.46.5.655pmid: 16657525

Abstract The relationship of root-applied 4-amino-3,5,6-trichloropicolinic acid (picloram) to ethylene production and the leaf movement response in honey mesquite (Prosopis juliflora [Swartz] DC. var. glandulosa [Torr.] Cockerell) and huisache (Acacia farnesiana [L.] Willd.) was studied in detail. The threshold and saturation levels of exogenous ethylene and root-applied picloram necessary to inhibit leaf movement were determined. Internal levels of ethylene in excess of those necessary to saturate the leaf movement inhibition response occurred in tops of treated plants before and after symptom expression. These internal levels of ethylene, while averages for the entire plant tops, probably occur at the specific site of action and thus account for the action of picloram in inhibition of leaf movement and related responses. Quantitative differences in the leaf movement response of both species to picloram and ethylene were observed. In huisache alone, a very small change in ethylene levels was necessary to produce a major blockage of the leaf movement response, suggesting that the gas may have a natural function in that species. 1 Cooperative investigations of the Texas Agricultural Experiment Station, Texas A&M University, and Crops Research Division, Agricultural Research Service, United States Department of Agriculture. Supported in part by Grant GB-5640 from the National Science Foundation. Preliminary reports of this study appear in Abstracts of the 1970 Meeting of the Weed Science Society of America and ASB Bulletin, 1970 (Southern Section ASPP). 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)

Okoloko, George E.; Lewis, Lowell N.; Reid, Brian R.

doi: 10.1104/pp.46.5.660pmid: 16657526

Abstract Red light, which produces the physiologically active form of phytochrome (Pfr), inhibited epicotyl elongation in intact dark-grown Alaska pea seedlings. This red light response was detectable 3 hours after the light treatment and became pronounced after 5 hours. The growth inhibition was completely reversed by far red light applied immediately after the red or by pretreatment of the seedlings with the plant hormone gibberellin A3. Comparison of the total 32P-labeled nucleic acids from control and red light-treated Alaska pea epicotyls on methylated albumin-kieselguhr columns revealed a marked alteration of the pattern of nucleic acid synthesis in this plant material with little or no effect on total isotope incorporation into nucleic acids. A single 5-minute red light perturbation caused a 2-fold stimulation of 32P incorporation into the tRNA fraction while, simultaneously, 32P incorporation into tenaciously bound RNA was reduced to 50% of control levels. Red light treatment had no effect on 32P incorporation into the DNA-RNA, rRNA, or mRNA fractions. Far red light reversed the effect of red light on tRNA synthesis but did not restore tenaciously bound RNA levels to the control value. Gibberellin A3 treatment did not cause reversal of any of the red light effects on RNA synthesis. These light-induced changes in nucleic acids were measurable before any changes in the physiological response (epicotyl elongation) could be detected. These results are consistent with a phytochrome-mediated differential gene activation mechanism in the Alaska pea epicotyl elongation system. 1 Present address: Cocoa Research Institute of Nigeria, Ibadan, Nigeria. 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)

Pierce, Wayne S.; Higinbotham, N.

doi: 10.1104/pp.46.5.666pmid: 16657527

Abstract By the compartmental analysis method of MacRobbie and Dainty, and Pitman, estimates of K+, Na+, and Cl− concentrations and fluxes were obtained for the cytoplasm and vacuole of coleoptile cells of oat, Avena sativa L. cv. Victory. Double labeling was used in experiments with 42K plus 22Na and with 42K plus 36Cl in a complete nutrient solution. At the plasmalemma, according to the Ussing-Teorell flux ratio equation, Na+ is pumped out and Cl− is actively transported inward. The results with K+ are less conclusive, but it is probably pumped in. At the tonoplast there is an active inward transport of Na+ and probably of K+, but the status of Cl− is uncertain, depending upon whether there is an electrical potential difference between the cytoplasm and vacuole. The results suggest that ion selectivity resides mostly in the plasmalemma. Possible errors in the estimates and interpretations are discussed. 1 This research was supported by the National Science Foundation under Grant GB 5117X. 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)

Badr, Sayed A.; Hartmann, Hudson T.; Martin, George C.

doi: 10.1104/pp.46.5.674pmid: 16657528

Abstract Comparative analyses of reproductive and vegetative tissues of the olive (Olea europaea L. cv. Manzanillo) for endogenous hormones, particularly inhibitors and gibberellin like substances, were made to study the relation between such hormones and thermoinduction of flowering. Qualitative and quantitative changes in gibberellin-like subtance(s) were observed in lateral buds (potential flower buds) but not in leaves or terminal buds (potential vegetative buds) sampled from orchard trees at intervals during the winter and spring. At least two types of gibberellin-like substances were found in extracts of lateral buds; their levels increased progressively during the low temperature induction period, reaching a maximum shortly before floral initiation. Two types of inhibitors were extracted from buds and leaves. A nonacidic type did not change during the induction stage but decreased considerably during the initiation period. An acidic inhibitor, which was identified as an abscisic acid-like substance, was present at a relatively lower level in lateral (flower) buds than in terminal (vegetative) buds during the induction period. It was concluded that winter chilling induces flowering in the olive possibly by altering a balance between endogenous gibberellins and inhibitors, including abscisic acid. Inflorescence development following the winter chilling period was associated with an increase in the level of endogenous inhibitors and gibberellins. Shoot growth, however, was correlated with a decrease in the inhibitor(s) level. A rise in gibberellin-like activity is believed to be a result, not a cause, of shoot growth. 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)

Scott, Peter C.; Morris, Roy O.

doi: 10.1104/pp.46.5.680pmid: 16657529

Abstract The internal concentrations of four auxin herbicides— 2,4-dichlorophenoxyacetic acid, dicamba, picloram, and naphthaleneacetic acid—were measured in the roots of treated pea seedlings. Intact seedlings were immersed in solutions of labeled herbicides at concentrations sufficient to produce toxic symptoms (inhibition of elongation, radial enlargement, and lateral root proliferation). Measurements of volume and herbicide content of segments taken sequentially along the root showed that an acropetal concentration gradient of each herbicide was established within the root immediately following treatment. Although there was a net loss of herbicide in the following 24 hours, the gradient was maintained. Initially, the concentration of herbicide in the root tips exceeded that in the external medium. In support of the contention that toxic symptoms due to herbicide treatment are caused by the presence of unmetabolized chemical at the site of action, it was found that metabolism was negligible for all herbicides except naphthaleneacetic acid. 1 This work was supported in part by a grant from the Herman Frasch Foundation and constitutes Technical Paper 2841 from the Oregon State University 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)

Dolphin, Warren D.

doi: 10.1104/pp.46.5.685pmid: 16657530

Abstract Light induces β-carotene synthesis in streptomycin-bleached Euglena gracilis Z. Light-adapted, chemostat-grown cells have up to 10-fold as much β-carotene and 25% more protein than similarly grown, dark-adapted cells. Carotenogenesis does not occur under anaerobic conditions or in the presence of diphenylamine, cyanide, or cycloheximide. The blue portion of the spectrum (360-560 nm) is most active in initiating carotenogenesis. The level of cellular carotenoids is influenced by the type of carbon source and to some degree by pH. Phytofluence and ζ-carotene are present in dark-grown cells but not in cells grown aerobically in white light (360-1120 nm). These pigments, however, were present in cells grown in yellow or green light (above 486 nm) or in cells exposed to white light anaerobically. The carotenoids are localized in two types of structures at the light microscope level. A protoporphyrin was isolated from Euglena, and its role as a possible photoreceptor during carotenogenesis is suggested. 2 Present address: Department of Zoology and Entomology, Iowa State University, Ames, Iowa 50010. 1 This work was supported by United States Public Health Service Grant GM-12179 to J. R. Cook and United States Public Health Service Postdoctoral Fellowship GM-35,542 to W. D. Dolphin. 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)

Keck, Robert W.; Dilley, Richard A.; Allen, C. Freeman; Biggs, Susanne

doi: 10.1104/pp.46.5.692pmid: 16657531

Abstract A nuclear mutation of Glycine max (soybean) segregates 1:2:1 in regard to chlorophyll content. The heterozygous (LG) leaf blade contains about one-half the pigment content of the wild type (DG) per gram fresh weight. A lethal yellow (LY) type contains about 1 to 2% of the DG leaf pigment values. The chlorophyll a/b ratio in the LG is about 5 compared to about 2 in the DG. Protein/leaf values are lower in the LG and LY types when compared to DG. The LG plastid lamellae contain more protein/chlorophyll, cytochromes/chlorophyll, and quinones/chlorophyll than the DG. P700/chlorophyll values are similar in the DG and LG types. The chlorophyll-depleted LG and LY types had less total acyl lipids per leaf weight when compared to the DG type. Similar amounts of sulfolipid and phosphatidyl glycerol per protein residue weight were found in the LG and DG plastids; however, the monogalactosyl and digalactosyl diglycerides were reduced in the LG paralleling the chlorophyll depletion. Thin sections of leaf tissue show similar-sized LG and DG plastids but reduced grana formation in the LG. The LY has very few grana and very small grana compared to either DG or LG. The two characteristic particles revealed in higher plant chloroplasts by freeze-etching are about 15% smaller in the LG compared to the DG plants. 2 Supported by Grant A1-04788 of the National Institutes of Health, United States Public Health Service. 1 Contribution 399 from the Charles F. Kettering Research Laboratory, Yellow Spr ngs, Ohio 45387. Supported by National Institutes of Health Postdoctoral Fellowship FO2-GM-40707 to R. W. K. and in part by National Science Foundation Grant GB-8462 to R. A. D. 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)