Biochemical Changes in Seed of Pinus radiata D. Don during Stratification

Stratification at 0 °C accelerates subsequent germinationof seed of Pinus radiata D. Don when transferred to 25 °C;the effect of low temperature is on the megagametophyte, notthe embryo. Organic acids, sucrose, and organic phosphates accumulatein the seed during stratification but lipase and invertase havelow activities which do not increase during treatment at 0 °C.We conclude that this accumulation of metabolites underliesthe increase in rate of germination of stratified seed. Treatingseeds at 0 °C rather than 5 °C separates effects dueto stratification and growth.     

Growth Characteristics and Substrate Specificity of Aerobic Photosynthetic Bacterium, Erythrobacter Sp. (OCh 114)

Optimal growth conditions and substrate specificity of the aerobicphotosynthetic bacterium, Erythrobacter sp. (OCh 114), wereinvestigated. Erythrobacter utilized 19 out of 26 substratestested, including several sugars and amino acids. Glycerol andlactate were the most effective as electron donors or carbonsources. Maximum growth was obtained at a salinity of about25, pH 8–9 and temperature 28°C in a glycerol-enrichedmedium. A suitable growth medium for Erythrobacter sp. (OCh114) is proposed. (Received October 18, 1985; Accepted January 10, 1986)     

Influence of temperature on growth, reproduction and longevity of Moina salina Daday, 1888 (Cladocera, Moinidae)

This paper presents the results of a study of the effects oftemperature on the growth, reproduction and longevity of thecladoceran Moina salina, a species of potential use as livefood in marine aquaculture. The growth rate of M.salina increasedwith increasing temperature. Some parameters of development,such as length at death and the number of adult instars, werealso positively related to temperature. Other parameters (durationof juvenile and adult instars) decreased with increasing temperature,while the number of juvenile instars was unaffected. An increasein temperature resulted in a reduction in age at maturity anda decrease in the number of days between broods. The numberof young per female, the number of broods per female, the numberof youngper day of reproductive life, and the number of youngper brood, increased up to a temperature of 25°C. At 15and 20°C. substantial degeneration of eggs and/or embryosoccurred. Likewise, temperature affected the type of reproductioncarried out by sexual females. Temperature and longevity wereinversely correlated. It was concluded that temperature actsas a very important factor regulating the life cycle of M.salina.Temperature >30°C may correspond to sublethal levels,while a temperature of 15°C is considered to impose stress.The range 20–25°C is optimal for the development andreproduction of this species.     

The relative importance of food and temperature to copepod egg production and somatic growth in the southern Benguela upwelling system

The fecundity and somatic growth rates of Calanus agulhensisand Calanoides carinatus, the dominant large calanoid copepodsin the southern Benguela upwelling system, as well as the fecundityof several other common copepods, were measured between Septemberand March of 1993/94 and 1994/95. Mean egg production of mostcopepods was low at >30 eggs female^-1 day^-1 {Calanoides carinatus23.7, Calanus agulhensis 19.0, Neocalanus tonsus 16.1 and Rhincalanusnasutus 26.1), whereas the mean fecundity of Centropages brachiatuswas significantly greater (83.6 eggs female^–1 day^-1).This study also presents the first comprehensive field estimatesof the fecundity of Nanno-calanus minor (mean: 26.1 eggs female^–1day^–1, range: 0.0–96.2 eggs female^–1 day^–1)and of somatic growth of N6 and all copepodite stages of Calanoidescarinatus (decreasing from 0.58 day^–1 for N6 to 0.04 day^–1for C5). Somatic growth rates of Calanus agulhensis also declinedwith age: from 0.57 day1 for N6 to 0.09 day1 for C5. Data ongrowth rates were used to assess the relative importance offood [as measured by total chlorophyll (Chi) a concentration],phytoplankton cell size (proportion of cells >10 µm)and temperature to the growth of copepods. Multiple regressionresults suggested that fecundity and somatic growth rates werepositively related to both Chi a concentration and phytoplanktoncell size, but not to temperature. Although it was not possibleto separate the effects of Chi a concentration and phytoplanktoncell size, data from previous laboratory experiments suggestthat copepod growth is not limited by small cells per se, butby the low Chi a concentrations that are associated with theseparticles in the field. Despite growth not being directly relatedto temperature, a dome-shaped relationship was evident in somespecies, with slower growth rates at cool (<13°C) andwarm (>18°C) temperatures. The shape of this relationshipmirrors that of Chi a versus temperature, where poor Chi a concentrationsare associated with cool and warm temperatures. It is concludedthat the effect of food limitation on growth of copepods outweighsthat of temperature in the southern Benguela region. Sourcesof variability in relationships between growth and Chi a concentrationare discussed.     

Growth, metabolism and growth efficiency of a euphausiid crustacean Euphausia pacifica in the southern Japan Sea, as influenced by temperature

Growth (assessed from intermolt period and molt increment) andmetabolism (oxygen consumption) of the post-larva of Euphausiapacifica from the southern Japan Sea were determined at sevengraded temperatures ranging from 1 to 25°C. The intermoltperiod shortened progressively as temperature increased from1 to 20°C, but an effect of temperature on molt-to-moltgrowth increment was not seen. Oxygen consumption rates wereaccelerated by the increase in temperature up to 20°C. Beyond20°C, E.pacifica exhibited reduced oxygen consumption anddied within 1 day without molting. After removing the effectof body size, the relationships between growth rate and temperature,and between oxygen consumption rate and temperature, were established.The carbon budget was calculated as a function of temperature.Because of differential effects of temperature on growth andmetabolism, the net growth efficiency [K₂ growthx100/(growth+metabolism)]changed with temperature. The optimum temperature at which E.pacificaattained the maximum K₂ was 11.4°C, which was derived fromcalculation of cumulative carbon invested in growth and metabolismin this animal. In an alternative method, the optimum temperaturewas obtained mathematically by solving a set of differentialequations. The biological and ecological significance of theoptimum temperature which leads to the maximum K₂ is discussed.     

Some Growth Regulators of Tobacco in Relation to the Symptoms of the Physiological Disease 'Frenching'

Extracrts of the shoot tips of normal and ‘frenched’tobacco plants were chemically separated into acidic, neutral,and basic ether–soluble fractions. On chromatograms ofthese, some plant growth regulators were assayed using the Avenacoleoptile section extension test. The acidic auxins and an acids and a neutral growth inhibitorwere found. One auxin, with the samew R_F value as indole-3-aceticacid, was four times more concentrated on normal as in ‘frenched’plants. No differences could be established between the twotypes of plants in regard to other growth regulators detected. It is argued that the symptoms of the physiological disease‘frenching’ could be explained in terms of a auxindeficiency.     

Apple Fruit Bud Development and Growth; Analysis and an Empirical Model

Analysis of the information available on apple bud developmentand growth after dormancy leads to an empirical model of growthto full bloom. The analysis and model are set in the frameworkof the physiological mechanisms considered to be responsiblefor dormancy and subsequent bud growth. It is necessary to introducean arbitrary ‘growth unit’ scale to describe theseprocesses quantitatively, which is done by the equation G = A/(I+be^–k(I).P) where G and A are in growth units, the value of k is controlledby a dormancy index I and P is a temperature summation. Themodel fulfils the main requirements laid down for it and thevalues of P at full bloom, derived from controlled environmentwork and field observations, are very similar.     

Growth and production of heterotrophic nanoflagellates in a meso-eutrophic lake

The growth of heterotrophic nanoflagellates (HNF) in mesotrophicLake Constance was measured in situ during a 13 month period.Experiments were conducted with 10 µm pre-filtered lakewater incubated in diffusion chambers at 3 m water depth atthe sampling location for 24 h. Growth rates were calculatedfrom changes in cell numbers occurring during the period ofincubation. Growth rates of all dominant taxa showed pronouncedseasonal variation (–0.13 to 1.76 day^–1 and weregenerally highest in summer at high water temperatures. In situgrowth rates were well below maximum growth rates known forthe respective and similar species from laboratory experiments.While water temperature was a key parameter positively relatedto the growth of all HNF species, the effect of various potentialfood items was taxon specific and less clear. Bacterial abundancewas equally important as temperature for growth in the smallbactenvorous Spumella sp., but was insignificant for growthrates of the larger omnivorous Kathablepharis sp. In Spuniellasp., 84% of the observed seasonal variation of its growth ratecould be explained by temperature and bacterial food supply.Based on these results, a multiple linear regression equationwith temperature and bacterial concentration as dependent variableswas calculated for the growth rate of Spumella. Taxon-specificproduction rates were derived from growth rates and averagebiomass of these two species, and compared to total HNF productionestimated from previously measured community growth rates andbiomass in Lake Constance. Production peaks of Spumella sp.and Kathablepharis sp. alternated seasonally. Total HINF productionranged from –0.01 to 10 mg C m^–3 day^–1. Theaverage seasonal production varied between 1.4 and 33 mg C m^–3day^–1 over 6 consecutive years. These small protozoa thuscontribute a substantial amount to total zooplankton productionin Lake Constance.     

Effects of temperature and salinity on the growth of the red tide flagellates Heterocapsa circularisquama (Dinophyceae) and Chattonella verruculosa (Raphidophyceae)

Growth responses of the red tide flagellates, Heterocapsa circularisquama(Dinophyceae) and Chattonella verruculosa (Raphidophyceae),were examined with 36 different combinations of temperature(5–30°C) and salinity (10–35 PSU). Heterocapsacircularisquama did not grow at or below a temperature of 10°C.The maximum growth rate of H.circularisquama (1.3 divisionsday^–1) was obtained with a combination of 30°C and30 PSU. In contrast, C. verruculosa did not grow at 10 PSU andat temperatures of 25°C or more. The maximum growth rateof C. verruculosa (1.74 divisions day^–1) was obtainedwith a combination of 15°C and 25 PSU. A significant temperature-salinityinteraction on growth was found by factorial analysis. Basedon the physiological characteristics obtained in the presentstudy, these novel flagellates have a potential for future outbreaksof red tides in pre viously unaffected waters.     

The effect of temperature on the post-embryonic growth of Neomysis intermedia Czernlawsky (Crustacea, Mysidacea) under laboratory conditions

The effect of temperature on post-embryonic growth of Neomysisintermedia was investigated under unlimited food conditionsin the laboratory. The effect of temperature on the size ofnewly released animals was negligibly small, but body size wasinversely related to temperature in adults. This was mainlycaused by the difference in the number of molts before maturation.The specific growth rate of N. intermedia increased exponentiallywith a temperature coefficient, Q₁₀ of 4.6 from 0.018 d^–13C to 0.21 d^–1 at 20C in juveniles, and with a temperaturecoefficient of 2.7 from 0.006 d^–1 at 3C to 0.05 d^–1at 25C in adults. The rate in juveniles levelled off above20C, and dropped at 29C. Brood size and brood interval decreasedwith temperature increase, while the daily specific reproductionrate increased. The specific growth rate of gravid females,including production of egg matter, increased exponentiallywith a temperature coefficient of 3.3 from 0.015 d^–1 at10C to 0.093 d^–1 at 25C. The present laboratory experiments confirmed the temperaturecontrol on the growth of N. intermedia suggested in a hyper-eutrophiclake.     

Effects of temperature on metabolism, growth and growth efficiency of Thysanoessa longipes (Crustacea: Euphausiacea) in the Japan Sea

Growth (assessed from intermolt period and molt increment) andmetabolism (oxygen consumption) of juvenile and adult Thysanoessalongipes from central Japan Sea were determined at eight differenttemperatures ranging from 0 to 14°C. The intermolt periodshortened progressively as temperature increased from 0 to 14°C.The molt increment was not assessed satisfactorily in the rearingexperiments, and therefore this was estimated from the naturalgrowth curve and habitat temperature, combined with laboratory-obtainedintermolt data. Oxygen consumption rates increased exponentiallyfrom 0 to 8°C and then leveled off. From these results,the growth was expressed as a function of temperature and bodysize and metabolism as a function of temperature. Because ofthe differential effects of temperature on growth and metabolism,the net growth efficiency [NGE: 100 x growth/(growth + metabolism)]changed with temperature. The temperature at which T. longipesattained maximum NGE varied from 0 to 8°C, depending onthe body length of specimens of 5, 10, 15 and 20 mm. The presentresults are compared with our previous data on Euphausia pacificain relation to the body composition and habitat usage of thesetwo trophically important species in the food web of the JapanSea.     

Physiological evaluation of temperature effect on the growth processes of the mysid, Neomysis intermedia Czerniawsky

Ingestion, respiration, and molting loss rates were measuredover the 3 – 29°C range in Neomysis intermedia. Weightspecific rates of these physiological processes ranged from2 to 140% body C day^–1 for ingestion, from 2 to 15% bodyC day^–1 for respiration, and from 0.1 to 5% body C day^–1for molting loss. All weight-specific rates showed a logarithmicdecrease with a logarithmic increase in body weight, and a logarithmicincrease with a linear increase in temperature below 20 or 25°C.The effect of temperature, however, was different between thephysiological rates, with a large temperature dependency foringestion (Q₁₀ = 2.6 –3.9) and molting loss (Q¹⁰ = 2.9– 3.6) and a moderate temperature dependency for respiration(Q₁₀ = 1.9 – 2.1). Calculated assimilation efficiencychanged with body size, but was constant over the temperaturerange examined. Allocation of assimilated materials varied witha change in temperature, reflecting the different temperaturedependence between physiological processes. It was deduced thatthe strong temperature dependency of the growth rate in N. intermediaobserved in the previous studies resulted from the large temperatureeffect on ingestion and assimilation rates, superimposed bythe different allocation of assimilated materials. ¹Present address: Department of Botany, University of Tokyo,Hongo, Tokyo 113, Japan     

On the causes of interspecific differences in the growth-irradiance relationship for phytoplankton. II. A general review

The causes of interspecific differences in the µ-l relationshipare examined in the context of a mechanistic model which relatesµ to irradiance in terms of six factors:, k_c photosyntheticquotient (PQ), Chl a:C, respiration and excretion. The effectof cell size on the light saturated growth rate is also considered.It is shown that photosynthetic efficiency and PQ exhibit remarkablylittle interspecific variability, and average 0.024 ±0.005 µg C(µg Chl a)^–1 h^–1 (µEm^–2 s^–1)^–1 and 1.5 ± 0.2 mol 02 molC^–1 (when NO₃^– is the nitrogen source) respectively.Two useful relationships were derived: (i) between growth efficiency,_g and Chl a:C at µ. = 0; (ii) between the compensationintensity, I_c and the Chl a-specific maintenance respirationrate. Both relationships were independent of temperature anddaylength. Species best adapted to growth at low light werefound to exhibit high Chl a:C ratios and low maintenance respirationrates. As a group, diatoms were consistently the best adaptedfor growth at low irradiance. Chiorophytes, haptophytes, chrysophytesand cryptophytes were intermediate in their performance at lowirradiance. Dinoflagellates exhibited extreme diversity, withspecies spanning the spectrum from very good performance atlow irradiance to very poor. A new µ_max-cell carbon relationshipis given based on growth rates normalized to 15°C. Evidenceis presented to show that noise in this relationship can besignificantly reduced by using only carbon-specific growth ratesand using only data for species grown at the same daylength.     

Development, growth and egg production of Centropages abdominalis in the eastern subarctic Pacific

Centropages abdominalis is a neritic, omnivorous, temporallyabundant copepod present throughout the subarctic Pacific andits marginal seas. The two main objectives of this study wereto determine how temperature influences the development of C.abdominalis and whether growth rates of in situ populationsmay be limited by available food. At 6.9°C, median developmenttime from eggs laid to 50% adults was 42 days and the averageweight-specific somatic growth rate was 0.17 day^–1. At4.6°C, median development time to adult was 59 days (projected)and growth rate averaged 0.08 day^–1, suggesting that 4.6°Cmay be approaching the lower temperature for development andgrowth in this species. The functional relationship betweendevelopment time and temperature was established over the temperaturerange in which this species occurs. The in situ adult growthrates between 10 and 13°C averaged 0.14 day^–1 andwere generally lower than the laboratory-reared juvenile growthrates, which may indicate that adult C. abdominalis are foodlimited in the field during summer and autumn.     

Effects of Nutrient Supply on Seed Growth of Field Bean (Vicia faba L.). 1. Effects of Different Sulphur and Methionine Regimes on Cotyledon Growth, Protein and Uncombined Amino Acids In vivo

The effects of exogenous methionine on growth of developingVicia faba seeds in vivo was studied. Methionine (51 or 102µmol in total) injected into the base of the pod overa period of 15 d (26–40 d after pollination) decreasedgrowth and protein accumulation in proximal seeds but increasedin distal seeds. Distal seeds of methionine injected pods accumulatedmore d. wt and protein than distal seeds of water-injected pods.However, on a pod basis methionine reduced overall seed growthand protein accumulation. Exogenous methionine caused a relative increase in legumin buta decrease in vicilin. Injected methionine also affected thecomposition of uncombined amino acids, especially those derivedfrom aspartic acid. In contrast, the amino acid compositionof the protein fraction did not change appreciably. The data suggest that seed growth is not limited by methioninebiosynthesis but seed protein composition is regulated by methionine. Vicia faba L., field bean, cotyledon, growth, in vitro culture, uncombined amino acids, protein composition, legumin, vicilin, methionine, sulphur     

In Vitro Propagation of Potato (Solanum tuberosum L.)

Potato shoots were propagated in vitro by placing nodes fromsprouted tubers on Murashige and Skoog type medium without hormones.The vigour of growth and the rate of node production increasedwith both day-length and temperature over the ranges 8–24h and 15–25 °C respectively. Propagation rates ofup to x 10 per month were obtained. In vitro plantlets spontaneouslyformed roots either in agar or liquid cultures. Plantlets leftin the culture jars for 3–4 months eventually senescedand formed small tubers in 16 and 24 h day-lengths. In a day-lengthof 8 h vegetative growth continued by branching and no tuberswere formed. Solanum tuberosum L., potato, tissue culture, propagation, temperature, day-length     

Analysis of Low-temperature Tolerance of a Tomato (Lycopersicon esculentum) Cybrid with Chloroplasts from a more Chilling-tolerant L. hirsutum Accession

Growth and photosynthesis of an alloplasmic tomato (cybrid),i.e. line AH47, containing the nuclear genome of the chilling-sensitivecytoplasmic albino mutant of L. esculentum Mill. ‘LargeRed Cherry’ (LRC) and the plastome of a more chilling-toleranthigh-altitude accession of the related wild species L. hirsutumHumb. & Bonpl. LA 1777, were investigated at an optimal(25/20°C) and suboptimal (16/14°C) day/night temperatureregime and their performance compared with that of both euplasmicparents. The cybrid shoot had a similar biomass and developmentrate to the nuclear tomato (L. esculentum) parent at both temperatureregimes. Compared with the biomass production of shoots grownat optimal temperature, the reduction in shoot biomass at suboptimaltemperature was smaller for L. hirsutum than for L. esculentumand the cybrid. This difference was related to a stronger inhibitionof leaf area expansion in L. esculentum and the cybrid in thesuboptimal temperature regime than in L. hirsutum. Irrespectiveof the temperature regime under which the plants were grown,photosynthetic performance and leaf pigment, carbohydrate andsoluble-protein contents of the cybrid resembled those of thenuclear parent. No advantages of the alien L. hirsutum chloroplastwith respect to growth and photosynthesis-related characteristicswere observed in the cybrid in the suboptimal temperature regime,indicating that the temperature sensitivity of the photosyntheticapparatus is regulated by nuclear genes. An adverse consequenceof interspecific chloroplast transfer was the increased susceptibilityto chill-induced photoinhibition of the cybrid. It is concludedthat cybridization is not a useful tool for improving low-temperaturetolerance of tomato. Copyright 2000 Annals of Botany Company Alloplasmic tomato, chloroplast, cybrid(ization), growth, low-temperature tolerance, Lycopersicon esculentum, L. hirsutum, photosynthesis, plastome, tomato     

Control of heat-shock response of young gametophytes of the sensitive fern is at the translational level

Young gametophytes of the sensitive fern, Onoclea sensibilis,respond to heat-shock by synthesizing in excess certain proteinsthat are made at normal growth temperature. Enhanced proteinsynthesis occurred during a 2 h heat-shock at a range of temperaturesbetween 38 °C and 50 °C. Although a temperature of 50°C proved lethal, a 5 min pulse at 50 °C resulted inenhanced synthesis of heat-shock proteins which continued forseveral hours at 25 °C. After heat-shock at 50 °C for10 or 15 min, the gametophytes temporarily lost their capacityfor protein synthesis but normal protein synthesis was resumedwithin 24 h of heat-shock. A heat-shock at 38 °C precedingone at 50 °C did not have any protecting effect on the gametophytes.In vitro translation of poly(A)+ RNA isolated from heat-shockedgametophytes yielded several proteins including heat-shock proteins.The results suggest that, rather than activating genes encodingnew messages for the synthesis of stress proteins, heat-shockof gametophytes of O. sensibilis triggers a controlling systemwhich enhances the translation of certain messages that aresynthesized at normal growth temperature. Key words: Onoclea sensibilis, heat-shock response, protein synthesis, sensitive fern, in vitro translation     

Internal Root Anatomy of Maize Seedlings (Zea mays L.) as Influenced by Temperature and Genotype

The objectives of this investigation were to determine: (a)the general effect of temperature on internal root anatomy;(b) whether genotypic differences in such root traits exist;and (c) the association between internal root traits and shootgrowth, lateral root branching and cold tolerance of maize (Zeamays L.). Seedlings of 20 central European hybrids were grownunder high or low temperature (25/22·5 °C or 15/12·5°C day/night temperatures) until the third leaf was fullyexpanded. Light microscopy of cross sections revealed a largerdiameter of primary roots at low temperature which was due toa larger stele diameter and a thickening of the cortex. Concurrently,an increase in total cross sectional area of metaxylem elementswas obtained. It is assumed that the modification of the internalroot structure by temperature has an effect on both axial andradial water flow capacity. For all anatomical traits studied,variability between genotypes was apparent under both growingconditions. Furthermore, different genotypic responses to temperaturewere observed. However, basic differences between cold-tolerantand cold-sensitive genotypes did not exist. While at high temperatureroot traits and shoot growth were significantly and positivelycorrelated, at low temperature the correlation coefficient wasinsignificant. Consequently, it was not possible to characterizethe performance of the shoot at low temperature based on anatomicaltraits of the root. Moderate, positive correlation coefficientswere obtained between internal root traits and lateral rootbranching. The potential use of root anatomical traits as indirectselection criteria is discussed. Chilling tolerance, genotypes, root anatomy, Zea mays L     

Effect of Temperature and Nitrogen Supply on the Growth of Perennial Ryegrass and White Clover. 2. A Comparison of Monocultures and Mixed Swards

White clover (Trifolium repens L.) and Perennial ryegrass (Loliumperenne L.) plants were grown, in Perlite, in simulated swardsas either monocultures or mixtures of equal plant numbers. Theywere supplied with a nutrient solution either high (220 µgg^–1) or low (40 µg g^–1) in ¹⁵N-labelled nitrateand grown to ceiling yield at either high (20°C day/15°Cnight) or low (10°C day/8°C night) temperature. Temperature had little effect on the maximum rates of grosscanopy photosynthesis which were similar in High-N grass andHigh-N and Low-N clover monocultures. However these maxima werereached more slowly in clover than grass, and more slowly atlow rather than high temperature. Nitrogen supply increasedphotosynthesis in grass but not in clover. Clover had higherN contents than grass in all four treatments, although in anygiven treatment its N content was lower, and contribution ofN₂-fixation relative to nitrate uptake higher, in mixture thanin monoculture. Conversely, grass had higher N contents in mixturethan monoculture, because more nitrate was available per plantand not because of transfer of biologically fixed N from clover. Under Low-N, clover outyielded grass in mixture, particularlyat high temperature. The grass plants in the Low-N mixtureshad higher N contents and higher SLA, LAR and shoot: root ratiosthan those in monoculture. It is proposed that competition forlight is the cause of the low relative yield and negative aggressivityof grass in these swards. Under High-N, grass outyielded cloverin monoculture and mixture, at both temperatures but particularlyat low temperature when grass had a high aggressivity. Nitrogenand yield component analyses shed no light on clover's apparentlylow competitive ability and evidence is drawn from the previouspaper to demonstrate that grass grew faster than clover onlyas spaced individuals during non-com petitive growth. The relativemerits of measures of competitive ability based on final harvestdata and physiological data taken over a growth period are discussed. Trifolium repens L., white clover, Lolium perenne, perennial ryegrass, competition, temperature, nitrogen