ERRATUM

Equation (2) should read: Equation (5) should read:      

ERRATUM

Equation (2) should read: Equation (5) should read:      

Parameters of photosynthesis: definitions, theory and interpretation of results

Regrettably, parentheses are missing in Equation 16 on p. 1649.Equation 16 should read:      

Sensitivity analysis of a mathematical model of phytoplankton growth and nutrient distribution in the Pacific Ocean off the northwestern U.S. coast

Equations (1), (2), and (3) on page 269 of the above paper shouldread:      

Diel variations in inorganic carbon and nitrogen uptake by phytoplankton in an arctic lake

Time—depth variations in inorganic carbon and nitrogenuptake by phytoplankton in Toolik Lake were examined over 36h using isotope tracer techniques. Rates of dissolved inorganiccarbon (DIC = CO₂ + + ) and maximum uptake were phased with the did high light/low light regime characteristic of the briefarctic summer with the amplitude of oscillation greater forDIC than for . Ammonium uptake was continuous at uptake-saturating concentrations. No conclusive evidencewas found for a diel periodicity in nitrogenous nutrient levelsor uptake of and ambient concentrations. A pronounced light—temperature effecton dissolved inorganic nitrogen (DIN = + ) uptake was evident at depth when rates of uptake were maximum. Depth-integrated daily C/N uptake ratios(mol) estimated as the mean of four consecutive 6 h incubationsranged from 1.8–6.4 under conditions of substrate saturationand from 6.0–16.1 at ambient levels of DIN. The efficacyof 24 h incubations to estimate accurately day-rates of DICand substrate-saturated DIN uptake was assessed by comparingestimates obtained from 24 h exposures to those approximatedby summing results from serial short-term incubations. Experimentsof 24 h duration accurately predicted day-rates of maximum uptake but underestimated daily DIC uptake by 13 7% ( SD). Day-length incubations introduced serious errors in the estimation of day-rates of maximum uptake, effecting an underestimation of 29 5%( SD). ¹Institute of Marine Science Contribution No. 538.     

A constant flow rate olfactometer with seven calibrated concentrations

Page 4, equation (1) should read Page 5, equation (2) should read      

A comparison of nitrogen and carbon metabolism in the shallow and deep-water phytoplankton populations of a subalpine lake: response to photosynthetic photon flux density

Rates of , and CO₂ assimilationby the organisms in the shallow and deepchlorophyll layers ofCastle Lake were measured over a gradient of photosyntheticphoton flux densities (PPFD) during the 1979–1980 ice-freeseasons. The results of these experiments could be fitted witha hyperbolic function in the manner of the Michaelis-Mentenequation (excluding rates of dark assimilation) up to –40%of the surface PPFD after which photon inhibition occurred.The half saturation constants relative to incidence PPFD (K_LT)for assimilation ( = 1.1 E m^–2d^–2) were about twice those for ( = 0.5 E m^–2d^–1).All of the K_LT values correspond to depths in thelakerangingfrom 17–29 m(–1% of surface PPFD). Dark assimilationof both and was –50% of the assimilation at saturating PPFD implying that part ofthe immediate energy required for inorganic nitrogen assimilationmay come from intermediary metabolism. This contention was supportedfor assimilation by the results of experiments performed with specific inhibitors of non-cyclic photophosphorylationand oxidative phosphorylation. The K_LT values for the assimilationof CO₂ were from 2–10 times higher than those for inorganicnitrogen. These values for CO₂ assimilation were not significantlyaltered by the addition of either or during 12 h incubations.     

Nitrate Uptake and Assimilation following Nitrate Deprivation

Upon first exposure to , the uptake and reduction capacities of dark-grown corn (Zea maysL.) roots are initially low, but increase markedly within 6h. The development of the accelerated uptake rate appears to be substrate ‘induced’ as is reductase (NR), the first enzyme in the assimilatory pathway. However, the ‘induction’of uptake is independent of NR induction. The effect of deprivation was studied to determine the role of endogenous on subsequent uptake and reduction. Corn roots were ‘induced’ for 24 h in 0–5 mol m^–3 nutrient solution and then exposed for 0 to 32 h to -free nutrient solution. Uptake and reduction of were determined periodically by exposing sets of roots to a1 h pulse of 0.5 mol m^–3 . Neither uptake (4.57 µmol root^–1 h^–1)nor the percentage of absorbed reduced (27%) was changed significantly (P 0.05) by exogenous deprivation. However, the estimated ‘induced’ componentof uptake decreased significantly (50% after 32 h). Concurrently, the ‘non-induced’ basal componentof uptake increased. Previously accumulated decreased from 23 to 4.5 µmol root^–1 after 32 h of exogenous deprivation. Nearly equivalent quantities of endogenous were used for translocation and reduction during deprivation. During each 1 h pulse, the amounts of translocation and net efflux of to the uptake solution were similar. Net efflux of was strongly correlated (r = 0.991) to the amount of endogenous . The remaining endogenous and its rate of utilization were apparently sufficient to minimize a rapid declineor complete loss in both the ‘induced’ uptake state and the rate of in vivo assimilation. Key words: reduction, translocation, efflux, root, Zea mays L     

Effect of Nitrogen Form and Counterion on Establishment of the Rhizobium trifolii-Trifolium repens Symbiosis

The effect of level of different counterion forms of or or both, on establishment of the Rhizobium trifolii-Trifolium repens symbiosis was evaluatedin plants cultured under bacteriologically controlled conditions. Ammonium had little effect on nodule formation, and even after exhaustion there was little compensatory nodule formation. Plant growth, nodule mass and acetylene reductionactivity all declined with increasing levels of . Except for , different counterion forms had little effect on plant growth, nodule numberand mass, and acetylene reduction activity. Ammonium markedlydecreased pH, the extent being dependent upon level and counterion present. Nitrate inhibited nodulation while levels remained in excessof plant uptake. Compensatory nodulation followed exhaustionof or at lower or levels. Nodule mass and acetylene reduction activity decreased, but plant growth increased withincreasing or levels. Nitrate raised the pH of the nutrient solution by one unit orless. Different or counterion forms had little effect on the symbiosis or plant growth. Ammonium nitrate severely inhibited nodulation but on exhaustionmarked compensatory nodulation occurred. The patterns of nodulemass, acetylene reduction activity and plant growth with increasingNH₄NO₃ levels were similar to or alone. Plants provided with NH₄NO₃ or no nitrogenwere similar in only slightly decreasing pH. Key words: Ammonium, Nitrate, Ammonium nitrate, Nitrogen fixation, Rhizobium trifolii, Trifolium repens, Symbiosis establishment, Nodulation     

ERRATA

Page 806, Preparation of Mitochondrial Fraction, line 4: The following should be inserted between ‘centrifugedat’ and ‘20 000 g for’: 3000 for 10 mm. Thesupernatant was centrifuged at The following corrections are required: Page 104, line 20: ‘2-hydroxylation’ should read ‘2-ß3-hydroxylation’ Page 106, line 11: ‘of Ga₈’ should read ‘to GA₈’ Page 113, last line:‘length 50 µm’ shouldread ‘length 150 µm’ Formula 15 should read: Formula 17 should read: y(0)– y^* = ß₁V₁+ß₂V₂ page 118: Formula 18 should read: Formula 23 should read: Formula 24 should read:      

Expression of Characteristics of Ammonium Nutrition as Affected by pH of the Root Medium

To study the effect of root-zone pH on characteristic responsesof -fed plants, soybeans (Glycine max {L.}Merr. cv. Ransom) were grown in flowing solution culture for21 d on four sources of N (1.0 mol m^–3 , 0.67 mol m^–3 plus 0.33 mol m^–3, 0.33 mol m^–3 plus 0.67 mol m^–3 , and 1.0 mol m^–3) with nutrient solutions maintained at pH 6.0, 5.5, 5.0, and 4.5. Amino acid concentration increased inplants grown with as the sole source of N at all pH levels. Total amino acid concentration in the rootsof -fed plants was 8 to 10 times higher than in -fed plants, with asparagine accounting for more than 70% of the total in the roots of these plants.The concentration of soluble carbohydrates in the leaves of-fed plants was greater than that of -fed plants, but was lower in roots of -fed plants, regardless of pH. Starch concentration was only slightlyaffected by N source or root-zone pH. At all levels of pH tested,organic acid concentration in leaves was much lower when was the sole N source than when all or part of theN was supplied as . Plants grown with mixed plus N sources were generally intermediate between - and -fed plants. Thus, changes in tissue compositioncharacteristic of nutrition when root-zone pH was maintained at 4.5 and growth was reduced, still occurredwhen pH was maintained at 5.0 or above, where growth was notaffected. The changes were slightly greater at pH 4.5 than athigher pH levels. Key words: Ammonium, nitrogen nutrition, root-zone pH, soybean, tissue composition     

Estimation of restriction maps with known site order using a generalized linear model

The publishers wish to apologise for typesetting errors thatappeared in two equations, on pages 541 and 547, of the abovepaper. The correct versions are presented below.      

Interactions Between the Uptake and Assimilation of Inorganic Nitrogen and Carbon in Amphidinium spp. (Dinophyceae)

The rate of exponential growth of Amphidinium carterae Hulburtwas the same (0.025 h^–1) with either or as sole N-source. Nevertheless, in short-term experiments, cells growing exponentially with as N-source took up added 5–6 times faster than . accumulated in the cells. Addition of inhibited, reversibly, disappearance of from the medium; prior N-deprivation of the cells did not affect this inhibition. N-repIetecells, grown with as N-source, took up for several hours both in light and darkness, butthe uptake by such cells soon ceased in darkness although it continued in light. When uptake ceased, the cells could still take up rapidly in darkness. Ammonium taken up was assimilated rapidly into organic-N includingglutamine, other amino acids and protein. Ammonium uptake in darkness was accompanied by the utilizationof cellular polysaccharide, mainly glucose polysaccharide. Mostof this carbon was unavailable for the dark assimilation of. Addition of the analogue, methylammonium, did not initiate polysacchande catabolism. Itis suggested that a control mechanism is in operation, througha product of assimilation, which operates on one or more of the enzymes concerned with polysaccharidebreakdown, for example, -amylase or phosphorylase. Uptake of was accompanied by a high rate of dark ¹⁴CO₂ fixation and with both Amphidintum klebsii Kof.et Swezy and A. carterae N-deprivation led to a marked increasein this rate following addition of ; addition of had much less effect. The possible implications of these findings for the eco-physiology of marine dinoflagellatesare discussed. Key words: Ammonium, nitrate, CO₂ fixation     

Cyclic Variations in Nitrogen Uptake Rate of Soybean Plants: Effects of External Nitrate Concentration

Net uptake of by non-nodulated soybean plants [Glycine max (L.) Merr.cv. Ransom] growing in flowing hydroponiccultures containing 0–5, 1.0 and 10-0 mol m^–3 was measured daily during a 24-d period of vegetativedevelopment to determine if amplitude of maximum and minimumrates of net uptake are responsive to external concentrations of . Removal of from the replenished solutions during each 24-h period was determinedby ion chromatography. Neither dry matter accumulation nor theperiodicity of oscillations in net uptakerate was altered bythe external concentrations. The maxima of the oscillations in net uptake rate, however, increased nearly3-fold in response to external concentrations. The maxima and minima, respectively, changed from 4.0 and 0–6mmol per gram root dry weight per day at an external solution level of 05 mol m^–3 to 15–2and -2–7 mmol per gram root dry weight per day at an external solution level of 10–0mol m^–3 . The negative values for minimum net uptake rate from10–0 mol m^–3 solutions show that net efflux was occurring andindicate thatthe magnitude of the efflux component of net uptake was responsiveto external concentration of . Key words: Nitrate uptake rate, carbon-nitrogen partitioning, flowing solution culture     

The maximum quantum yield of phylopiankton photosynthesis in situ

Light-limited photosynthetic carbon incorportion is expectedto be directly proportional to the scalar quantum irradiance.The proportionality constant is , where _mis the maximum quantum yield (mol C Einstein^–1 absorbed)and $$\stackrel{\¯}{{\hbox{ k }}_{\hbox{ c }}}$$ isthe mean spectral absorption coefficient (m² mg^–1 chla). Recent efforts to evaluate of in situphytoplankton photosynthesis are variously flawed. Lack of evidenceof proportionality and lack of correction of cosine to scalarirradiance are common deficiencies. Most data, as we interpretthem, indicate values in the range 0.0003 – 0.0006 mol C m² Einstein1 abs mg1 chl a. New determinationsin lrondequoit Bay, New York, lie in this range. Most estimatesof at depth have been about 0.010 m² mg^–1chl a. Similar values are being obtained for total particulatesfrom lrondequoit Bay; whether detritus contributes significantlyis not yet known. Published data, in our view, all point tovalues of m in situ in the range 0.03–0.07 mol C Einstein^–1abs. Published values >0.10 are almost certainly due to imprecisionor systematic error. ^*This paper is the result of a study made at the Group for AquaticPrimary Productivity (GAP) First International Workshop heldat the Limnological Institute, University of Konstanz, in April1982.     

ATP Synthesis Coupled to Nitrate Photoreduction in the Alga Hydrodictyon africanum

The presence of exogenous stimulates O₂evolution in illuminated H. africanum cells at the CO₂ compensationpoint, and it is likely that reduction in the light uses reductant produced in non-cyclic electron flow.When sources of ATP other than fermentation are absent, thepresence of , light, and a functional non-cyclic electron transport pathway stimulates active, ATP-dependentH₂ influx. This is consistent with non-cyclic electron flow associated with reduction being coupled to ATP synthesis. This -dependent ATP synthesis may be quantitatively important as a source ofATP during photolithotrophic growth with as N source in H. africanum and other algal unicells.     

Comparison of the Effects of Root Temperature on Nitrate and Ammonium Nutrition of Oilseed Rape (Brassica napus L.) in Flowing Solution Culture: I. GROWTH UPTAKE OF NITROGEN

Oilseed rape plants (Brassica napus L. cv. Bien venu) were grownin flowing nutrient solution and acclimatized over 49 d to lowroot temperature (5 ?C) prior to treatment at root temperaturesof 3, 7, 11 or 17?C for 14 d, with common air temperature of20/15?C day/night and solution pH 6.0. The effects of root temperatureon growth, uptake and assimilation of N were compared with Nsupplied either as or at 10 mmol m^–3. Plant fresh weight, dry weight and leafarea increased with root temperature. Q₁₀ values for specificgrowth rates between 7?C and 17?C were 1.10 and 1.33, respectively,under and nutrition. Fresh weight and leaf area were favoured by nutrition, particularly at 11 ?C and 17 ?C. At each temperaturethe net uptake of over 14 d was similar to that of , increasing 4-fold between 3?C and 17 ?C. Unit absorption rates of increased over the first 3 or 4 d, to an extent that increased with roottemperature. Thereafter, near constant values were maintainedat 3, 7 and 11 ?C. Unit absorption rates of at 3 ?C and 7 ?C did not increase over the first 3 or 4 d. Plantsat 17?C responded differently from those at other temperatures,with steep increases in unit absorption rates of and after day 8. The tendency for plants to adjust unit absorption rates of N over 14 d to become independentof root temperature was limited to the range 7–11 ?C.Q¹⁰ values between 7 ?C and 17 ?C for unit absorption rateswere 1.7—1.8 and 1.4—1.5, respectively, for and . Plants at 7, 11 and 17?C absorbed more than was subsequently assimilated, but at 3 ?C the absorption of was insufficient to meet the assimilatory demand. The results are discussed comparativelyfor and and in terms of the factors that determine unit absorption rates of N inresponse to a change in root temperature. Key words: Brassica napus, oilseed rape, root temperature, nitrate, ammonium, ion uptake rate     

Translocation of Some Anions, Cations, and Acids in Turnip (Brassica napus L.) Mitochondria

The translocation of various anions, cations, and acids acrossthe membrane system of turnip mitchondria has been investigatedby light scattering techniques. The results imply that the membranesof turnip mitochondria are not permeable to choline, K⁺, Na⁺,, , , and . It has been established that Cl^–,, and SCN– passively permeate the mitochondrial membrane. It is probable that permeates as NH₃ and that and cross the membrane either as the corresponding acid or on ananion/ hydroxide antiporter. The alkali metals Na⁺ and K⁺ equilibrateacross the membrane via specific H⁺/Na⁺ and H⁺/K⁺ antiporters,having similar activity at neutral pH.     

Pumpkin (Cucurbita sp.) seed globulin IV. Terminal sequences of the acidic and basic peptide chains and identification of a pyroglutamyl peptide chain

Pumpkin seed globulin is composed of heterogeneous polypeptidechains, acidic and chains and basic ₁ and ₂ chains (12). This study showed that the basicchains had similar N-terminal sequences, Gly-Leu-Asp-Glu-Thr-Ile-for the ₁ chain and Gly-Leu-Glu-Glu-Thr-Ile- for ₂. On the contrary,the N-terminal sequences of the acidic and chains were dissimilar, Ile-Gln-Gly-Tyr- for the chain and no N-terminal residue for the chain, according to routine terminal analysis. Pyrrolidonylpeptidase digestion of the chain and its thermolysin digestion followed by Edman degradationsrevealed that the N-terminal sequence of the chain was < Glu-Ile-Glu-Gln-Gln-Glu-Pro(Trp,Ser)-. The N-terminal sequences and the C-terminal residuesindicated that the acidic and chains were more heterogeneous than the basic ₁ and ₂ chains.A preliminary study on the degradation of storage globulin isalso presented. (Received November 9, 1979; )     

A survey of the statistical power of research in behavioral ecology and animal behavior

We estimated the statistical power of the first and last statisticaltest presented in 697 papers from 10 behavioral journals. Firsttests had significantly greater statistical power and reportedmore significant results (smaller p values) than did last tests.This trend was consistent across journals, taxa, and the typeof statistical test used. On average, statistical power was13–16% to detect a small effect and 40–47% to detecta medium effect. This is far lower than the general recommendationof a power of 80%. By this criterion, only 2–3%, 13–21%,and 37–50% of the tests examined had the requisite powerto detect a small, medium, or large effect, respectively. Neitherp values nor statistical power varied significantly across the10 journals or 11 taxa. However, mean p values of first andlast tests were significantly correlated across journals ( ), with a similar trend for mean power ( ). There is therefore some evidence that power and p values are repeatable among journals. Mean p valuesor power of first and last tests were, however, uncorrelatedacross taxa. Finally, there was a significant correlation betweenpower and reported p value for both first ( ) and last tests ( ). If true effect sizes are unrelated to study sample sizes, the averagetrue effect size must be nonzero for this pattern to emerge.This suggests that failure to observe significant relationshipsis partly owing to small sample sizes, as power increases withsample size.