Carbon isotopic composition of Trichodesmium spp. colonies off Bermuda: effects of colony mass and season

Colonies of Trichodesmium spp. are conspicuous, macroscopiccomponents of the life in tropical and subtropical oceans. Thelarge size and the morphology of the colony raise questionsregarding the mechanism of carbon supply for photosynthesis.Constraints on these mechanisms may be indicated by the stablecarbon isotopic composition (¹³C) that reflects the balancebetween carbon supply and speciation, as well as the growthrate and colony size. The ¹³C of Trichodesmium off Bermuda measuredhere revealed a strong correlation between size of individualcolonies and season. The smallest colonies, 2–7 µgC colony^–1, showed the lightest ¹³C composition (–19),increasing to asymptotic values of –12 above 7 µgC colony^–1. The average ¹³C of the colonies was lightestimmediately after the onset of stratification in the SargassoSea, gradually increasing by 4 to heavier values during thesummer. We propose that the mass effect is due to increaseduse of HCO₃^– by the larger colonies, whereas the seasonalinfluence may be related to changes in irradiance and pCO₂ affectingthe internal carbon cycling.     

{delta}15N signatures of marine mesozooplankton and seston size fractions in Kiel Fjord, Baltic Sea

The ¹⁵N of marine mesozooplankton species was measured on fouroccasions. Significant differences were found between copepodsand meroplanktonic larvae, yet not between holoplanktonic species.On average, mesozooplankton was enriched by 3.4 ± 0.9relative to selected seston size fractions. Despite suggestingsmall differences (0.5 to 1) in the ¹⁵N of different phytoplanktontaxa on one occasion, the size fractionation procedure generallyproved inadequate in separating major taxonomic groups composingseston. This circumstance, and phase-shifts in the transmissionof rapid changes (>2) in seston ¹⁵N to mesozooplankton complicatethe calculation of mesozooplankton trophic levels.     

Temporal and spatial variations in phytoplankton carbon isotopes in a polymictic subtropical lake

Stable carbon isotopes (¹³C) were determined for phytoplanktonand dissolved inorganic carbon (DIC) from Lake Apopka, a shallow,polymictic and hypereutrophic lake in Florida, USA. Bulk planktondominated by pico- and nanqanobacteria were enriched in ¹³(–13.1± 1.1%) as a result of assimilation of extremely ¹³C-richDIC (¹³C = 9.6 ± 3.0%). Diatoms (Aulacoseira spp.) hada ¹³C of –14.3 ± 0.6% that was slightly more negativethan that of small cyanobacteria. Meroplanktonic diatoms hada ¹³C (–13.6 ± 1.8%), similar to their planktoniccounterparts. The ¹³C of a colonial cyanobacterium (Microcystisincerta) was exceptionally heavy (–3.0 ± 1.0%)and attributed to localized carbon limitation. Seasonal variationin ¹³C of bulk plankton was small (4%) relative to reports forother lacustrine systems No difference in the ¹³C of bulk planktonhorn surface water between stratified and non-stratified periodswas found. No measurable changes in ¹³C of bulk plankton wereindicated in light and dark incubation experiments Frequentwind mixing of the water column, high DIC concentration, andconsistently high lake productivity were used to explain thetemporal and spatial isotope consistency of phytoplankton inthis lake.     

Occurrence of mycosporine-like amino acids in the red-tide dinoflagellate Alexandrium excavatum: UV-photoprotective compounds?

Water extracts of the red-tide dinoflagellate Alexandrium excavatumgrown at ‘high’ light intensity (200 µE m^–2s^–1) show a broad absorbance maximum in the UV regionof the spectrum (310–360 nm). Using TLC and reverse-phaseHPLC a series of mycosporine-like amino acids have been characterized:mycosporine-glycine (_max = 310 nm), palythine (_max = 320 nm),asterina-330 (_max = 330 nm), shinorine (_max = 334 nm), porphyra-334(_max= 334 nm), palythenic acid (_max = 337 nm) and the isomericmixture of usujirene and palythene (_max = 359 nm). From theobserved spectral changes during transference from ‘low’(20 µE m^–2 s^–1) to ‘high’ (200µE m^–2 s^–1) light intensities and vice versa,the series of compounds are supposed to be biogenically relatedto one another. The presence of these compounds in A.excavatumis discussed in relation to their possible role in the photoprotectionto deleterious UV radiation.     

Interspecific variability and environmental influence on particulate organic carbon {delta}13C in cultured marine phytoplankton

The stable carbon isotope composition of particulate organicmatter expressed as ¹³C was measured in cultures of 13 speciesof marine microalgae in different phylogenetic groups. The effectsof salinity variations and changes in photoperiod were alsoassayed for three of them (i.e. Skeletonema costatum, Amphidiniumopercularum and Isochrysis galbana); the effect of nature ofnitrogen supply (nitrate. ammonium) was studied for one (S.costatum).These environmental parameters were chosen because of theirvariability in the ocean and their possible effects on ¹³C valuesof phytoplankton organic carbon. Batch culture conditions andsampling time after inoculum were strongly controlled in orderto provide cells in good physiological state which were comparablefrom one culture to the other. In the same way, sampling waslimited to the first 2 days of exponential growth, in orderto avoid a possible dissolved inorganic carbon (DIC) limitation.Carboxylase activities [of the enzyme ribulose 1,5-bisphosphatecarboxylase oxygenase (Rubisco), and the three ß carboxylases:phosphoenolpyruvate carboxylase (PEPC), phosphoenolpyruvatecarboxykinase (PEPCK) and pyruvate carboxylase (PC)] and totalchlorophyll a concentrations were assayed simultaneously. The¹³C values observed were between –30.2 and –12.7i.e. comparable to those observed in the world's oceans. Theisotopic composition of phytoplankton organic carbon was shownto be under the influence of the parameters tested but ¹³C variationsare specific to the species considered. The nature of ßcarboxylase found in each species, or systematic position, couldnot be linked to the isotopic composition of organic carbon.No linear or single correlation between ¹³C variations and environmentalmodifications were observed and there is no evidence for a simpleand universal relation between ¹³C of phytoplankters and theirenvironment. In monospecific cultures as in the field, ¹³C fractionationby Rubisco (and eventually by PEPCK) may be counterbalancedby other mechanisms.     

Isolation of Subunits of Coupling Factor 1 from Maize and Spinach Chloroplasts and Properties of Combinations of Subunits with ATPase Activity

Subunits (, ß, ) and mixtures of subunits ( ß, , ß , ß ) were isolated without denaturationfrom a chloroform extract of chloroplast coupling factor 1 (CF₁)from maize (Zea mays var. Ushiku 5-4) and from spinach by fastprotein liquid chromatography (FPLC), on an anion-exchange columnof Mono-Q in the presence of n-octylglucoside (OG) and on achromatofocusing column of Mono-P. The ß -subunitcomplex (CF¹ ß ) was the minimum unit required forATPase activity, as was confirmed by the reconstituted complexof ß and subunits. An subunit isolated from maizeinhibited the ATPase activity of CF₁ ß from bothmaize and spinach. CF₁ ß was found to contain anOG-dependent Mg²⁺-ATPase. The ATPase activity of CF₁ ß required divalent cations, such as Mg²⁺ or Mn²⁺, for its expressionin the presence of OG; its optimum pH was 8.0 and it was markedlyinhibited by NaN₃. The enzyme hydrolyzed ATP in prefernece toGTP but not CTP, UTP, ADP, AMP or pNPP. Lineweaver-Burk plotsof its activity were curvilinear in the range of 0.6–0.7mM ATP.Mg²⁺. ¹Present address: Department of Biology, School of Education,Waseda University, Shinjuku-ku, Tokyo, 160 Japan. (Received February 15, 1989; Accepted April 20, 1989)     

Pumpkin (Cucurbita sp.) seed globulin III. Comparison of subunit structures among seed globulins of various Cucurbita species and characterization of peptide components

Various Cucurbita seed globulins showed patterns similar toone another on SDS-gel electrophoresis, and ß bandsfor unreduced globulins and , ', and ' bands for reduced ones.On gel electrophoresis in 6 M urea, reduced globulin gave twoacidic and two basic bands. These corresponded to and ' chainsand ₁ and ₂ chains, respectively, identified by two-dimensionalurea-SDS gel electrophoresis. The compositions of the and ßsubunits were proposed. (Received September 8, 1977; )     

Variation in Natural Abundance of 15N among Plant Parts and in 15N/14N Fractionation during N2 Fixation in the Legume-Rhizobia Symbiotic System

Sixteen legumes were grown in N-free media so that N was suppliedentirely by symbiotic N₂ fixation. The plant tissues were analyzedfor natural ¹⁵N abundance (expressed as ¹⁵N per mil relativeto air N₂) with a ratio mass spectrometer. The nodules of desmodium,centro, siratro, soybean and winged bean showed high enrichmentin ¹⁵N (+9), while red clover showed slight enrichment (+2).The nodules of 9 other forage legumes (Townsville stylo, whiteclover, alsike clover, common vetch, Chinese milk vetch, senna,alfalfa, ladino clover, and hairy vetch) showed little enrichmentin ¹⁵N. In all the legumes investigated, particularly in the ureide-transportingplants such as desmodium, centro, siratro, soybean, winged beanand field bean, the ¹⁵N value of the shoots was negative (–3.2).The ¹⁵N value of the shoots in winged bean and field bean variedby about 1 depending on the Rhizobium strains used. The isotopicmass balance of 13 legumes indicated that isotopic fractionationoccurs during N₂ fixation by the legume-rhizobia symbiosis witha preference for ¹⁴N over ¹⁵N, resulting in a ¹⁵N value of –0.2to –2 in the whole plant. The results indicate that ¹⁵N/¹⁴N isotopic discrimination witha preference for the lighter atom may occur in both N₂ fixationand export of fixed N from nodules. ¹Present address: Department of Soils and Fertilizers, NationalAgriculture Research Center, Kannondai, Tsukuba, Ibaraki 305,Japan. (Received October 8, 1985; Accepted April 7, 1986)     

15N abundance in micronekton in Sagami Bay, Central Japan

The ¹⁵N values of micronekton collected from Sagami Bay rangedfrom 9.4 to 14.2%. The ¹⁵N values of the micronekton, Gonostomagracile, increased with growth (9.4 to 12.6%) and it seems thatmales, before sex reversal, and females consume different foodorganisms.     

'Nonparametric inference in multivariate mixtures' * Biometrika (2005), 92, pp. 667 678

The left-hand side of equation (2·8), on p. 671, shouldread {₁ (1 – ₁)}^–1/2 (2₁ – 1) rather than{(1 – ₁)/₁}^1/2 (2₁ – 1). Reflecting this change,the left-hand side of equation (3·1) on the same pageshould be altered to , and the formula at the foot of p. 677 should be modified to {₁ (1– ₁)}^–1/2 (2₁ – 1) + O_p(n^–1/2). No otherformula is affected, and the left-hand side of (2·8)is still increasing in ₁. The numerical results, discussed in4, are influenced in minor ways. In the simulation study, absolutebias is reduced, and variance is either slightly increased orslightly decreased. In the real-data example, using the nonparametricapproach to analysis, mean squared error is further reduced,from 0·0011 to 0·0004. We are grateful to HiroKasahara and Katsumi Shimotsu for pointing out the error.     

The Relationship Between Transpiration Rate, Water Potential, and Resistances to Water Movement in Sunflower (Helianthus annuus L.)

The effects of transpiration rate on the vertical gradientsof leaf and stem xylem water potential ( and ) were examinedusing hydroponic sunflower plants. Transpiration was variedby stepwise alterations of environmental conditions. The gradientsof and were relatively small (2.3 and 0.8 x 10⁵ Pa m^–1)when transpiration rates approached zero, but increased sharplyto 5.4 and 2.3 x 10⁵ Pa m^–1 as transpiration increased.However, the gradients were independent of transpiration ratesabove 0.4 g dm^–2 h^–1 owing to variability of theplant resistance. The gradients of _I were usually less thanhalf those of _I. ₁ in individual leaves remained constant over a wide range oftranspiration rates (0.4—2.4 g dm^–2 h^–1) andeach leaf possessed a characteristic plateau value related toits elevation. _I responded similarly but was approximately 2.0x 10⁵ Pa higher than _I at the same elevation. Identical resultswere obtained regardless of the procedure employed to vary transpiration. The drop in water potential between stem and leaf implies thatthe leaf resistance is appreciable. This was confirmed usingrapidly transpiring excised leaves freely supplied with water._I increased by 2.0–2.5 x 10⁵ Pa following removal of theroot resistance but remained 2 x 10⁵ Pa lower than similar excisedleaves in darkness. Furthermore, ^I in excised leaves remainedconstant over a wide range of transporting rates, demonstratingthat the leaf resistance is also variable. The results are discussed in relation to previous reports.     

An Assessment of Gibberellin Structure-activity Relationships

Information on the biological activities of gibberellins (GAs)in the barley aleurone, Tangin-bozu dwarf rice, dwarf pea, lettucehypocotyl and cucumber hypocotyl bioassays is reviewed and discussedin the context of GA structure-activity relationships. The barley aleurone bioassay exhibits a limited response toGAs and it is suggested that this may be because the aleuronecells are able to carry out few GA interconversions. Consequentlyactivity is determined by the degree of compatibility betweenthe GAs and a receptor site. In this assay high biological activityis associated with GAs having a 3ß-hydroxy--lactonestructure. This activity is substantially enhanced by the additionalpresence of a 13-hydroxyl group. The substitution of a -lactoneor a -lactol for a -lactone results in reduced activity while3ß,13-dihydroxy GAs with either 20-carboxyl or 20-methylfunctions are completely inactive. The Tanginbozu dwarf ricebioassay responds to many more GAs than the barley aleuronesystem possibly because the rice seedlings can carry out extensiveGA interconversions. Under these circumstances GAs that areinactive per se can be metabolically converted to active forms.There is no interaction between the 3ß- and 13-hydroxyfunctions of GA molecules in the rice assay. Activity appearsto be determined by the degree oxidation of the C-20 group.The order of activity is usually -lactone > -lactol >-lactone > methyl > carboxyl. It is suggested this mayindicate that in rice seedlings C₂₀-GAs are converted to C₁₉-GAsvia a Baeyer-Villiger type oxidation. Activity in the dwarfpea bioassay is dependent upon GAs possessing both 3ß-and 13-hydroxyl groups and is again related to the state ofoxidation at the C-20 locus. In the lettuce bioassay activityis restricted to GAs with a -lactone function. In some instancesa -lactone, but not a -lactol, can substitute effectively. Thismay imply that the applied C₂₀-GAs are not converted to C₁₉-GAsand that the response to the -lactone results from the six-memberedring mimicking the -lactone at the receptor site. Only GAs havinga 19,10 or a 19,20 lactonic bridge show substantial activityin the cucumber bioassay. The additional presence of eithera 12- or a 13-hydroxyl group severely reduces activity.     

Pumpkin (Cucurbita sp.) seed globulin V. Proteolytic activities involved in globulin degradation in ungerminated seeds

Two proteolytic activities I and II involved in the globulindegradation were detected in pumpkin seeds. Activity I, hydrolyzing and ß subunits of the globulin to form F_ß,was found in both dry seeds and cycloheximide-treated cotyledons,and decreased during germination. Activity II, hydrolyzing F_ßto produce small peptides and amino acids, was not observedin dry seeds but found in cycloheximide-treated cotyledons,increased up to 4 days, and gradually decreased during germination. Activity I gave limited hydrolytic products from the globulinand the chain, but not from F_ß, the chain and some animal proteins. It was inhibitedby EDTA. On the other hand, activity II hydrolyzed F_ßand the chain faster than the globulin, the chain and some animal proteins. It was inhibitedby EDTA and p-chloromer-curibenzoate, and activated by ß-mercaptoethanol,dithiothreitol and CoCl₂. Optimum pH's were at about 6.8 andat 6.0 to 6.8 for activities I and II, respectively. The degradation process of the globulin can be divided intotwo steps: the first step is the conversion of globulin to F_ßand the second step, F_ß to small peptides and aminoacids. (Received November 9, 1979; )     

Water-Relations Parameters of the Phloem. Determinations of Volumetric Elastic Modulus and Membrane Conductivity using an Applied Force Method and Shrinkage and Swelling of Tissues in Solutions at Differing Osmotic Pressure

Water-relations parameters were measured on sections of secondaryphloem from red oak (Quercus borealis michx. f.) and white ash(Fraxinus americana var. biltmoreana [Beadle] J. Wright) usinga linear displacement transducer. Changes in tissue thicknessin response to changes in the osmotic pressure of the bathingsolution were used to calculate the volumetric elastic modulusplus osmotic pressure (_v + ) of the tissue, and an applied forcemethod was used to estimate the time constant for water equilibration(T). The hydraulic conductivity of the cell membranes (L_p) wascalculated utilizing _v + and r values. The time-dependent behaviour of the tissue was much more complexthan originally expected. A correction for a time-dependentprocess that we call ‘drift’ was required to obtainnumbers for _v + . Furthermore, _v + was calculated on two assumptionsin order to relate changes in tissue dimensions to sieve elementparameters. In the first case, a lower limit for _v + of thesieve elements was determined by attributing all changes intissue dimensions to these cells. For red oak the average _v+ on this assumption is 72 bars. Assuming that all cell typeswere equally responsible for the changes in tissue dimensionsresulted in an _v + value of 192 bars for oak. If _v + and rare the same for all cells in the tissue, L_p for the sieve elementsof oak is 9.6 x 10^–8 cm s^–1 bar^–1. Exudationfrom the sieve elements of white ash during excision of thephloem led to artificially high values of _v + for that species. Quercus borealis michx. f., Fraxinus americana var, biltmoreana (Beadle) J. Wright, red oak, white ash, water relations, phloem, volumetric elastic modulus, membrane hydraulic conductivity     

{delta}15N and {delta}13C Measurements of Antarctic Peninsula Fauna: Trophic Relationships and Assimilation of Benthic Seaweeds

Measurements of ¹³C, ¹⁵N, and C/N for a variety of Antarcticpeninsula fauna and flora were used to quantify the importanceof benthic brown algae to resident organisms and determine foodweb relationships among this diverse littoral fauna. ¹³C valuesranged from–16.8 for benthic algal herbivores (limpets)to –29.8 for the krill, Euphausia superba; the averagepooled value for brown macroalgae, including their attachedfilamentous diatoms, was–20.6. There was no correlationbetween biomass ¹³C or ¹⁵N with C/N content, and consequentlyboth ¹³C and ¹⁵N values were useful in evaluating trophic relationships.¹⁵N values of the fauna ranged from 3.1 to 12.5, with lowestvalues recorded in suspension feeders (e.g., bryozoans) andhighest values in Adelie penguins (12.5) collected in 1989.The comparatively lower ¹⁵N value for a Chinstrap penguin (6.9)collected in 1997 is attributed to the different dietary foodsources consumed by these species as reflected in their respective¹³C values. Significant amounts of benthic macroalgal carbonis incorporated into the tissues of invertebrates and fishesthat occupy up to four trophic levels. For many benthic andepibenthic species, including various crustaceans and molluscs,assimilation of benthic algal carbon through detrital pathwaysranges from 30 to 100%. Consequently, the trophic importanceof benthic brown algae may well extend to many pelagic organismsthat are key prey species for birds, fishes, and marine mammals.These data support the hypothesis that benthic seaweeeds, togetherwith their associated epiphytic diatoms, provide an importantcarbon source that is readily incorporated into Antarctic peninsulafood webs.     

Abscisic Acid Accumulation and Water Relations of Four Cultivars of Phaseolus vulgaris L. under Drought

Larqué-Saavedra, A., Rodriguez, M. T., Trejo, C. andNava, T. 1985. Abscisic acid accumulation and water relationsof four cultivars of Phaseolus vulgaris L. under drought.—J.exp. Bot 36: 1787–1792. Plants of four cultivars of Phaseolus vulgaris L. differingin drought resistance were grown in pots under greenhouse conditionsand prior to flowering water was withheld from the pots untilthe mid-day transpiration rate reached values below 1.0 µgH₂O cm^–2 s^–1 (designated the ‘drought’stage). At this point leaves were harvested on 3 or 4 occasionsover 24 h to determine the abscisic acid (ABA) concentration,total water potential (), solute potential (₁) and turgor potential(_p). Results showed that values of , ₁, and _p differed between cultivarswhen they reached the ‘drought’ stage. The stomatalsensitivity to changes in and _p, was as follows: Michoacán12A3 > Negro 150 Cacahuate 72 > Flor de Mayo. These datacorrelated well with the pattern of drought resistance reportedfor the cultivars. ABA accumulation at the ‘drought’ stage differedbetween cultivars at each sampling time, but overall differencesin ABA level between cultivars were not significant. ABA levelsdid not, therefore, correlate with the drought resistance propertiesreported for the cultivars. Results are discussed in relationto and hour of the day when bean samples were taken for ABAanalysis. Key words: Phaseolus vulgaris L., drought resistance, abscisic acid     

A Transient Stimulation of Net Photosynthesis of Rye Leaves by {alpha}-Hydroxy-2-pyridinemethanesulphonic Acid ({alpha}-HPMS) due to Inhibition of Photorespiratory CO2 Release

The effects of -hydroxy-2-pyridinemethanesulphonic acid (-HPMS)upon net photosynthesis (P_n, the CO₂ compensation point (),post-lower illumination burst of CO₂ (PLIB) and post-lower temperatureburst of CO₂ (PLTB) in detached rye (Secale cereale L.) leaveswere investigated. At low concentrations ( 0.5 mol m^–3),-HPMS initially stimulated P_n and decreased the magnitude ofboth PLIB and PLTB. The decreased at all concentrations of-HPMS (0.05–5.0 mol m^–3. The effects of -HPMS onP_n and were time-dependent and, after a few minutes, the P_nwas inhibited while values increased considerably. At a higherconcentration (5.0 mol m ^–3), the transient effects of-HPMS were shorter () or not observed at all (P_n. Both PLIBand PLTB, when expressed in relation to P_n, increased at higherlevels of this compound. Similar data with respect to the effectsof -HPMS on PLIB and PLTB were found for leaves of dandelion(Taraxacum officinale L.). The results suggest that -HPMS may stimulate P_n by inhibitingphotorespiration, as originally suggested by Zelitch (1966),but only at low concentrations and over a short time span. Thedecrease of PLIB and PLTB values at low -HPMS levels is consistentwith these processes being a residual activity of the glycolatepathway. Key words: CO₂ compensation point, -hydroxy-2-pyridinemethanesulphonic acid, photorespiration, photosynthesis     

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; )     

Alterations in the Components of Peanut Leaf Water Potential during Desiccation

Changes in components of leaf water potential during soil waterdeficits influence many physiological processes. Research resultsfocusing on these changes during desiccation of peanut (Arachishypogeae L.) leaves are apparently not available. The presentstudy was conducted to examine the relationships of leaf water_l, solute _s and turgor _p potentials, and percent relative watercontent (RWC) of peanut leaves during desiccation of detachedleaves and also during naturally occurring soil moisture deficitsin the field. The relationship of _p to _l and RWC was evaluated by calculating_p from differences in _l and _s determined by thermocouple psychrometryand by constructing pressure-volume (P-V) curves from the _land RWC measurements. Turgor potentials of ‘Early Bunch’and ‘Florunner’ leaves decreased to zero at _l of–1.2 to –1.3 MPa and RWC of 87%. There were no cultivardifferences in the _l at which _p became zero. P-V curves indicatedthat the error of measuring _s after freezing due to dilutionof the cellular constituents was small but resulted in artefactualnegative _p values. Random measurements on two dates of _l, _s, and calculation of_p from well-watered and water-stressed field plots consistingof several genotypes indicated that zero _p occurred at _l of–1.6 MPa. It was concluded that the relationships of _p,_l, _s, and RWC of peanut leaves were similar to leaves of othercrops and that these relationships conferred no unique droughtresistance mechanism to peanut.     

On filament width in oceanic plankton distributions

A plankton patch deformed by diffusion, straining flow and biologicalgrowth is demonstrated to have a minimum width, /, which ispurely a function of the effective diffusivity, , and the strainrate, .