Relationship between a mineral deficiency and metabolic processes : The effect of N-, P- and K-deficiencies on RNA metabolism in TN-1 rice

The effects of a deficiency of N, P or K on DNA and RNA synthesisas evidenced by ³²P incorporation in TN-1 rice plants were studied.Deficiency effects were more marked in shoot and root tissuesat the l/9th level of the element than at the l/3rd level withrespect to both the content and incorporation of ³²P in nucleicacids. The effects were marked on the 43rd day; the plants hadrecovered considerably by the 68th day, but a marked declinewas observed again on the 97th day at the time of flowering.The decrease in ³²P incorporation was evident both on a perplant and a per unit weight basis, but it was more prominentin the former. Although ³²P uptake was reduced, this reductionwas less than that of ³²P incorporation in the nucleic acids.Separation of the RNA fractions revealed that all the fractionswere affected. Deficiency effects also enhanced DNase activity,particularly when there was a K deficiency, but RNase activitywas little affected. ¹This work was supported by a grant from the Department of AtomicEnergy, Government of India. ²Central Sericulture Research Institute Berhampore, West Bengal,India. (Received May 27, 1980; )     

Germination of Phaseolus vulgaris III. The role of nucleic acid and protein synthesis in the initiation of axis elongation

Excised embryonic axes of Phaseolus vulgaris L. (var. WhiteMarrowfat) begin cell elongation after approximately 4 hr ofincubation at 26°C. The incorporation of ³²P into nucleicacids and phenylalanine-l-¹⁴C into protein markedly increasesduring the 4th hr of incubation, prior to initiation of cellelongation. CH, which inhibits incorporation of phenylalanine-l-¹⁴C intoprotein by 93% during the 2nd hr after its addition, completelyprevents the initiation of axis elongation if added up to 2hr after the beginning of imbibition. Actinomycin D reducesthe fresh weight increase of the axes, and inhibits both ³²Pincorporation into nucleic acids and phenylalanine-l-¹⁴C incorporationinto protein. 5-FU inhibits ³²P incorporation into nucleic acidsbut not phenylalanine-l-¹⁴C incorporation into protein or thefresh weight increase of the axes. MAK column chromatography indicates that actinomycin D inhibitsthe synthesis of all types of nucleic acids to about the sameextent, while 5-FU almost completely inhibits the accumulationof ³²P in ribosomal RNA with lesser but significant inhibitoryeffects on accumulation of ³²P in tRNA. The results suggest an absolute requirement for protein synthesisprior to initiation of cell elongation and at least a partialrequirement for synthesis of nucleic acid species other thanribosomal RNA, tRNA and DNA. The kinetic data suggest that theaxes develop a greatly increased capacity for nucleic acid andprotein synthesis prior to initiation of axis elongation. ¹This research was supported by NSF grant GB 4145 and a grantfrom the U. S. Forest Service. (Received December 16, 1968; )     

Cell elongation in the soybean root: The influence of inhibitors of RNA and protein biosynthesis

A possible requirement for RNA and protein synthesis duringcell elongation of intact seedling tissue was studied usingthe soybean seedling foot with the elongating zone being delineatedby India ink marks at 2 and 7 mm back of the root tip. In contrastto most excised plant tissues, there was marked net synthesisof RNA and protein during cell elongation of the intact root.AD and CH were potent inhibitors of cell elongation in the soybeanroot. CH essentially eliminated protein synthesis, whether measuredby net accumulation of protein or by ¹⁴C-leiicine incorporation,while completely inhibiting cell elongation after a short lag.AD, on the other hand, only partially inhibited protein synthesiswhile causing almost total inhibition of cell elongation aftera lag. The capacity of the tissue to synthesize protein in thepresence of AD was correlated with the maintenance of functionalpolyribosomes, thus suggestive that m-RNA associated with theregulation of cell elongation is more unstable (i.e., a shortermean life) than total root m-RNA. FU did not inhibit cell elongation,protein synthesis or the level of functional polyribosomes.The requirement for RNA synthesis during cell elongation ofthe seedling root, as in excised plant tissues, appears to berestricted to the AMPrich species of RNA presumed to be m-RNA. ¹This research was supported by NIH grant GM 10157. ²Purdue University AES paper No. 3359. ³Present address: Dept. of Botany, National Taiwan University,Taipei, Taiwan.     

Phytochrome regulation of peroxidase activity in maize V. Role of RNA and protein synthesis

The phytochrome mediated enhancement of peroxidase activityin maize leaves was repressed by inhibitors of cytoplasmic proteinsynthesis, whereas inhibitors of RNA and organelle protein synthesiswere ineffective. Continuous far-red light had no effect onthe DNA level in the leaves, but it increased the RNA levelafter a lag of 2 hr. Under continuous far-red light the totalcontent of polyribosomes also increased after a lag of 2 hr.Isolated polyribosomes from far-red grown plants showed an enhancedrate of the in vitro incorporation of amino acids into proteinsas compared to dark grown plants. These results indicate thatthe phytochrome regulation of peroxidase activity occurs atthe translational level. ¹Present address: School of Life Sciences, University of Hyderabad,Hyderabad-500001, India (Received July 25, 1979; )     

THE INCORPORATION OF 32P ORTHOPHOSPHATE INTO THE PHOSPHOLIPIDS OF ELONGATING AVENA COLEOPTILES

Four phospholipids of Avena coleoptile tissue were identifiedas phosphatidyl inositol, phosphatidyl glycerol, phosphatidylethanolamine and phosphatidyl choline. IAA caused an increase in total uptake of ³²P and incorporationof ³²P in phospholipids. IAA also caused a shift in the proportionsof identified ³²P phospholipids. Incorporation of ³²P into phosphatidylcholine was greater while incorporation into phosphatidyl glyceroland phosphatidyl ethanolamine was less in IAA-treated tissuecompared with untreated control tissue. ¹Contribution No. 338 from the Department of Botany, PennsylvaniaState University and 3001 from the Pennsylvania AgriculturalExperiment Station. ²Present address: Juniata College, Huntingdon, Pennsylvania,U.S.A.     

The nature of N-, P- and K-deficiency effects in rice

Effects of N-, P- and K-deficiencies on RNA synthesis in TN-1rice, Sonalika wheat and B-75 gram was examined at the molecularlevel. The melting temperatures of the chromatin of TN-1 rice,Sonalika wheat and B-75 gram was increased by deficiency conditions.In TN-1 rice the template activity of chromatin was reducedconsiderably, most remarkably in the case of the N-deficiency.The base composition of the newly synthesized RNA of the deficientroots also was altered. These changes were accompanied by anincrease in the histone-DNA ratio. There was, however, no qualitativechange in the histone patterns. The chromatin of deficient tissuesbound less actinomycin D than did that of the control, and thebinding of labelled cations and anions also decreased. In deficientplants endo- and exo-nuclease activities were enhanced, accompaniedby decreases in the intrinsic viscosity, sedimentation co-efficientand chain lengths of DNA. ¹This work was supported by a grant from the Department of AtmicEnergy, Government of India. ²Central Sericulture Research Institute, Berhampore, West Bengal,India. (Received May 27, 1980; )     

The nature of N-, P- and K-deficiency effects in rice

Effects of N-, P- and K-deficiencies on RNA synthesis in TN-1rice, Sonalika wheat and B-75 gram was examined at the molecularlevel. The melting temperatures of the chromatin of TN-1 rice,Sonalika wheat and B-75 gram was increased by deficiency conditions.In TN-1 rice the template activity of chromatin was reducedconsiderably, most remarkably in the case of the N-deficiency.The base composition of the newly synthesized RNA of the deficientroots also was altered. These changes were accompanied by anincrease in the histone-DNA ratio. There was, however, no qualitativechange in the histone patterns. The chromatin of deficient tissuesbound less actinomycin D than did that of the control, and thebinding of labelled cations and anions also decreased. In deficientplants endo- and exo-nuclease activities were enhanced, accompaniedby decreases in the intrinsic viscosity, sedimentation co-efficientand chain lengths of DNA. ¹This work was supported by a grant from the Department of AtmicEnergy, Government of India. ²Central Sericulture Research Institute, Berhampore, West Bengal,India. (Received May 27, 1980; )     

Nucleotide ratios and quantitative RNA changes in potato plants elicited by photoperiod and temperature

The nucleotide composition of potato plants, Solanum tuberosumL., grown under four environmental regimes was studied. Althoughthere were marked quantitative differences in RNA followingthe temperature and photoperiod treatments as previously observed,nucleotide composition of all types of RNA did not change appreciably. ¹ Scientific Journal Series Article Number 7642 of the MinnesotaAgricultural Experiment Station. (Received August 23, 1971; )     

RNA synthesis in germinating red bean seeds

Nucleic acids from ³²P-labelled germinating red bean seeds wereinvestigated by means of MAK column chromatography. 1) In cotyledons,synthesis of D-RNA occurred in the early stages of germination,3 to 24 hr after the onset of imbibition. ³²P was also incorporatedinto rRNA continuously at rather a moderate rate. DNA-RNA hybridizationexperiments revealed that the proportion of heterogeneous RNA(D-RNA) to rRNA decreased gradually. Nucleotide analysis suggestedthat tRNA was synthesized de novo, and that its CCA-end exchangewas remarkable at early stages of germination. 2) In embryos,however, the incorporation of ³²P into rRNA was very much greaterthan into D-RNA, and the exchange reaction at CCA-end of tRNAwas not detected. The role of D-RNA, found in cotyledons inthe initial stages of germination, was discussed. ¹Present address: Research Institute for Biochemical Regulation,Faculty of Agriculture, Nagoya University, Chikusa-ku, Nagoya,Japan. (Received May 10, 1972; )     

AUXIN-INDUCED GROWTH OP TUBER TISSUE OP JERUSALEM ARTICHOKE: III. EFFECT OF ACTINOMYCIN D ON AUXIN-INDUCED EXPANSION GROWTH AND RNA SYNTHESIS

1. The following results were obtained using tissue slices excisedfrom cold-stored Jerusalem artichoke tubers.
2. Actinomycin Dat the concentration of 20 µg/ml given duringthe agingperiod did not affect the subsequent expansion growthcausedby auxin or auxin plus kinetin.
3. Actinomycin D given in thegrowth period, on the other hand,strongly inhibited the expansiongrowth of tissue slices agedin the absence of the antibiotic.
4. In the growth period, auxin or auxin plus kinetin promotedtheincorporation of uracil-2-¹⁴C into RNA fraction.
5. ActinomycinD inhibited the incorporation of ³²P orthophosphateinto ribosomalRNA during the aging period.
6. In the growth period, the incorporationof ³²P into RNA wasenhanced by auxin and was inhibited by actinomycinD, more remarkablyin ribosomal RNA than in lighter RNA.

¹A part of this paper was presented at the Conference on PlantGrowth Regulators held by the New York Academy of Sciences onMay 16, 1966.     

Effect of temperature on the ethylene-synthesizing systems in apple, tomato and Penicillium digitatum

Arrhenius plots of ethylene-synthesizing systems of apple andtomato showed discontinuities while the plot for Penicilliumdigitatum was linear. Triton X-100 markedly lowered the activationenergies of the apple and tomato systems without altering thatof the fungal system. The data presented suggest that the lipidmicro-environment of the ethylene-synthesizing enzyme systemsin higher plants and P. digitatum are different, and that cellmembrane-cell wall complex may be the site of ethylene-synthesizingenzymic systems in higher plants. ¹ On leave from the M. S. University of Baroda, India. ² On leave from the Agricultural Research Organization, TheVolcani Center, Israel. (Received February 7, 1977; )     

The effect of low temperature upon the polyribosome, nucleic acid and protein content of potato leaves

Short periods of low temperature exposure, or longer periodsof cool temperature growth did not cause a decline or "run-off"of potato leaf polyribosomes. In fact, polyribosome levels werehigher in the leaves of plants grown in the cool temperatureregime. The ribosomal RNA levels were higher in cool grown leavesafter day 12 of treatment, while the protein and amino acidlevels did not exhibit a dramatic change. The results are discussedin respect to efficient plant protein synthesis in cooler climates. ¹This research was supported in part by a grant from the RockefellerFoundation. ²Scientific Journal Series Article 8745 of the Minnesota AgriculturalExperiment Station. (Received June 20, 1974; )     

DISTRIBUTION AND TURNOVER OF PHOSPHATE COMPOUNDS IN GROWING CHLORELLA CELLS

1. Using the Chlorella cells which had been uniformly labeled with³²P, the distribution of phosphorus in various fractions ofcell material was investigated. Uniformly ³²P-labeled Chlorellawas further grown in a P-free medium or in a standard "cold"medium, and the change of distribution of ³²P (as well as theuptake of exogenous P) in various cell fractions was followed.
2. Analysis of the ³²P-labeled algal cells showed that the highestin P-content was the fraction of RNA followed by those of polyphosphates,lipid, nucleotidic labile phosphate compounds, DNA and protein(in decreasing order). ATP and ADP were found to be only minorfractions of the total labile phosphates.
3. On incubating the³P-labeled alga in a P-free medium, the P.contentsin the fractionsof DNA, protein, lipid and ATP increased, thosein polyphosphatesand ADP decreased, and that in RNA remainedalmost unchanged.When the ³²P-labeled alga was further grownin the normal "cold"medium, DNA and protein increased withthe expenditure of endogenous³²P, but with practically no incorporationof external P. Inthe meantime the P in polyphosphates decreasedconsiderably,and the RNA fraction incorporated a large amountof externalP but only a little of endogenous³²P.
4. It was inferred that,under the experimental conditions of thepresent study, thephosphorus used in the syntheses of DNA andprotein was primarilytaken from polyphosphates, while thatused in the synthesesof RNA, phospholipid and polyphosphateswas, for the most part,taken from the extracellular P-source.

¹A part of this paper was read at the Vth International Congressof Biochemistry, Moscow, August 10–16, 1961. (Received June 4, 1961; )     

Responses of normal and dwarf Pharbitis nil to an extended dark period and gibberellic acid

The effects of a 24 hr short day, a 24 hr long day, and a 48hr short day were analyzed with regard to flowering and stemgrowth of normal and dwarf Pharbitis nil, and were comparedto effects of these photoperiodic treatments plus applied GA₃.Both short day treatments produced the same number of flowersper plant after seven cycles. The applied GA₃ was effectivein overcoming the growth deficiency of the dwarf; however, theextended dark period of the 48 hr short day and applied GA₃were both required to enhance a flowering response in the dwarfequal to that of the normal. These results indicate that somefactor is present during the extended dark period which enhancesflowering. ¹ This work was supported by NSF Grant GB-7510 and State supportedresearch TTU-191-4771 to M. W. C. ² Present address: Department of Biology, Union University,Jackson, TN 38301, U.S.A. (Received September 4, 1979; )     

CO2 Assimilation and Partitioning of Carbon in Maize Plants Deprived of Orthophosphate

In order to study the effects of inorganic phosphate (P1) starvationon C₄plants, 3-week-old maize plants (Zea maysL cv. Brulouis)were grown in a growth chamber on a nutrient solution withoutP1 over 22 d During the first 2 weeks, Pi-starved plants grewas well as control plants The Pi concentration in the planttissue decreased rapidly with time, which suggests that normalbiomass production can be maintained at the expense of internalP1 In addition, photosynthetic CO2 assimilation measured 4-6h after dawn was not affected, but the concentration of glucose,sucrose, and starch in leaves was much higher than in the controls¹⁴CO₂ pulse-chase experiments earned out on the ninth day oftreatment showed that ¹⁴CO₂ assimilation was perturbed duringthis initial period, resulting in a larger flow of carbon toboth starch and sucrose At the beginning of the third week ofP1 starvation (15 d after treatment) ¹⁴C incorporation intosucrose stayed high relative to controls but this was not thecase for starch At the end of the third week of P1-deficiency,shoot growth was considerably reduced and fresh weight was onlyone-third of that of the control plants. The P1 concentrationof both the leaf and root tissues was less than 1.0 µmolg^–1 FW compared to 20-25µmol g¹ FW in the controls.Photosynthetic CO₂ assimilation was reduced and the leaf concentrationof sucrose and starch, which had begun to decrease after theend of the second week of P1 limitation, became lower than inthe controls. These results obtained on maize plants show thatphotosynthesis and carbon partitioning between sucrose and starchwere strongly affected by P1 deficiency, similar to C₃ species. Key words: CO₂ assimilation, corn, orthophosphate deficiency, starch, sucrose     

Effect of Phosphorus Deficiency on Source-Sink Interactions Between the Flag Leaf and Developing Grain in Barley

Chapin, F. S. Ill and Wardlaw, I. F. 1988. Effect of phosphorusdeficiency on source-sink interactions between the flag leafand developing grain in barley.—J. exp. Bot. 39: 165-177. Photosynthetic rate and stomatal conductance of P-deficientbarley plants were increased by manipulations that increasedplant demand for carbohydrates (shading of the ear or removalof other leaves). This was associated with retarded senescenceof the flag leaf. Similarly, small flag leaves (i.e. those havinglarge sinks relative to their own size) had high rates of photosynthesis.These relationships were most pronounced under conditions ofP deficiency. Distribution of ³²P and ¹⁴C from the flag leafwas determined by the carbohydrate demand of a plant part andwas unaffected by altering the sink strength for P. Thus, earshading increased accumulation by developing grains of ³²P and¹⁴C applied to the flag leaf, grain removal reduced accumulationby grain of both radioisotopes, and removal of lower leavesincreased movement of both radioisotopes to vegetative plantparts; in contrast, P addition to the ear had no effect upon³²P or ¹⁴C distribution. P deficiency reduced the amount oftillering and, therefore, the movement of ³²P and ¹⁴C to developingtillers and increased retention of ¹⁴C and ³²P in the sheathof the flag leaf but otherwise had no major effect on patternsof carbon and phosphorus distribution. We conclude that themajor effects of P deficiency upon source-sink interactionsare (1) to reduce the number or activity of sinks in the shoot(grains and daughter tillers) and (2) to increase the sensitivitywith which photosynthesis responds to demand for carbohydrate.The strengthened source-sink interaction under conditions ofP deficiency provides a regulatory mechanism for reducing carbohydrateaccumulation under conditions where carbohydrates do not stronglylimit growth. Key words: Source-sink, phosphorus, photosynthesis     

Studies on ribonucleic acids from Chlorella protothecoides with special reference to the degradation of chloroplast RNA during the process of "glucose-bleaching"

By growing Chlorella protothecoides under certain nutritionaland light conditions the following three different types ofalgal cells were obtained: (i) normal "green" cells grown ina medium rich in a nitrogen source (urea) and poor in glucoseunder illumination, (ii) "etiolated" cells cultivated in thesame medium in darkness, and (iii) "glucose-bleached" cellsgrown, in the light or in darkness, in a medium rich in glucoseand poor in the nitrogen source. The "glucose-bleached" cellscontain profoundly degenerated plastids, and the "etiolated"cells have only partially organized plastids. From these algalcells RNA was extracted by the cold phenol method, and fractionatedby MAK column chromatography and sucrose density gradient centrifugation,making use of ³²P-labelled E. coli RNA as the internal marker.It was found that in comparison with the green cells that arerich in chloroplast ribosomal RNA as well as in nonchloroplastic("cytoplasmic") ribosomal RNA, the etiolated cells possess acomparable amount of "cytoplasmic" rRNA but a significantlylesser amount of chloroplast rRNA. Both types of rRNA existat extremely low levels in the glucose-bleached cells. During the process of bleaching (chloroplast degeneration) ofthe green cells induced by the addition of a high concentrationof glucose, marked changes were observed in the patterns offractionation of RNA as followed by the above procedures. Itwas disclosed that the chloroplast rRNA is rapidly degradedduring an early phase of the bleaching process, while the quantityof "cytoplasmic" rRNA remained almost unaltered. ¹Part of this work was reported at the Symposium on Cell Differentiationsponsored by the Institute of Applied Microbiology, Universityof Tokyo, in November 1965, and at the Symposium on Biogenesisof Subcellular Particles, the 7th Internatl. Congress of Biochemistry,Tokyo, 1967. ²Present address: Faculty of Pharmaceutical Sciences, Universityof Hokkaido, Sapporo.     

Metabolic responses to lycorine in plants

Lycorine, an alkaloid found in Amarillidaceae, inhibits growthin higher plants and in yeasts. Lycorine-treated pea internodes,Avena coleoptiles and yeasts revealed a decrease in the amountof both ¹⁴C-leucine incorporated into protein and ³H-uridineincorporated into RNA. The time course of these incorporations,however, shows that the drop in ¹⁴C-leudne incorporated intoprotein appears prior to any inhibitory effect of ³H-uridineincorporation into RNA. Moreover, in lycorine-treated plants,the ascorbic acid/dehydroascorbic acid ratio is lowered. Nevertheless,our data seem to indicate that this latter effect becomes evidentlater than the inhibition of ¹⁴C-leucine incorporation intoprotein. In vitro experiments with a cell-free system showedno inhibitory effect by lycorine on elongation of the polypeptidechain when yeast ribosomes were used. At this point in our experimentalwork, we would venture to suggest that lycorine might affectplant growth by inhibiting protein synthesis at some step whichis not, however, the elongation of the polypeptide chain. ¹This research was supported by contract between the NationalResearch Council of Italy and the University of Bari, Instituteof Botany. (Received November 27, 1972; )     

Inhibition by kinetin of cell elongation and RNA synthesis in excised soybean hypocotyl M 2

The effects of kinetin on growth and RNA metabolism in excisedsoybean hypocotyl were investigated, and compared to the effectsof 5-fluorouracil. Kinetin inhibits auxin-induced growth, butnot control growth. RNA synthesis is also inhibited by kinetin,but in a differential fashion. Ribosomal RNA synthesis is almostcompletely inhibited, while TB-RNA synthesis is partially inhibited.D-RNA synthesis is apparently not affected. Base compositionanalysis of these fractions of RNA was carried out. The implicationsfor RNA-mediated auxin-induced growth are discussed. ¹The research was supported by NIH grant GM-10157 from the U.S. Public Health Service. ²Purdue University AES Paper No. 3334