Reproductive biology of Mystus vittatus (Bloch) (Bagridae: Siluriformes) from Guntur,Andhra Pradesh

Maturation, minimum length at first maturity, spawning season, spawning periodicity, sex-ratio and absolute fecundity of Mystus vittatus, a common bagrid catfish, have been investigated. The observations show that spawning takes place during September and October. Each individual spawns only once in the season as evidenced by the study of the intraovarian ova. Females dominate the catches, and absolute fecundity (F) can be expressed by% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaaiaacaqabeaadaqaaqaaaOabaeqabaGaciiBai% aac+gacaGGNbGaaeiiaiaabAeacaqGGaGaaeypaiaabccacaqGTaGa% ae4maiaab6cacaqGYaGaaeyoaiaabkdacaqGGaGaae4kaiaabccaca% qG0aGaaeOlaiaabgdacaqG3aGaaeymaiaabgdacaqGGaGaaeiBaiaa% b+gacaqGNbGaaeiiaiaabYeaaeaacaqGHbGaaeOBaiaabsgacaqGGa% GaaeOraiaabccacaqG9aGaaeiiaiaab2cacaqGXaGaaeOlaiaabwda% caqG0aGaaeinaiaabwdacaqGGaGaae4kaiaabccacaqGWaGaaeOlai% aabMdacaqG0aGaae4naiaabkdacaqGGaGaae4vaaaaaa!5FCC!\[\begin{gathered} \log {\text{ F = - 3}}{\text{.292 + 4}}{\text{.1711 log L}} \hfill \\ {\text{and F = - 1}}{\text{.5445 + 0}}{\text{.9472 W}} \hfill \\ \end{gathered} \]     

Manganese toxicity: The significance of magnesium for the sensitivity of wheat plants

The tolerance of wheat to manganese was investigated in soil and solution culture. Although no critical toxicity concentration could be identified, growth was reduced when the ratio of magnesium to manganese in the shoots (R_p) fell below 20:1 (mgg^–1/mgg^–1). In soil, plant growth relative to unstressed plants (Y) could be described by the empirical equation: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaeywaiabg2% da9iaaicdacaGGUaGaaGyoaiaaiwdacqGHsislcaaIWaGaaiOlaiaa% iMdacaaI1aGaaeyzaiaabIhacaqGWbGaaiikaiabgkHiTiaaicdaca% GGUaGaaGymaiaaiodacaaI5aGaaeOuamaaBaaaleaacaqGWbaabeaa% kiaacMcaaaa!4959!\[{\text{Y}} = 0.95 - 0.95{\text{exp}}( - 0.139{\text{R}}_{\text{p}} )\]In solution culture the value of R_p was related to the ratio of the two ions in the nutrient solution (R_s) according to the expression: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaeysaiaab6% gacaqGGaGaaeOuamaaBaaaleaacaqGWbaabeaakiabg2da9iaaicda% caGGUaGaaGinaiaaikdacqGHRaWkcaaIWaGaaiOlaiaaisdacaaI4a% GaaeiiaiaabMeacaqGUbGaaeiiaiaabkfadaWgaaWcbaGaae4Caaqa% baGccaGGPaaaaa!47B6!\[{\text{In R}}_{\text{p}} = 0.42 + 0.48{\text{ In R}}_{\text{s}}\]The magnesium concentration in the nutrient solution for optimum growth at a given concentration of manganese was given by: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaeysaiaab6% gacaqGGaGaae4waiaab2eacaqGNbGaaeyxaiabg2da9iaaikdacaGG% UaGaaGioaiaaiMdacqGHRaWkcaaIWaGaaiOlaiaaiwdacaaI0aGaae% iiaiaabMeacaqGUbGaaeiiaiaabUfacaqGnbGaaeOBaiaab2faaaa!4A0B!\[{\text{In [Mg]}} = 2.89 + 0.54{\text{ In [Mn]}}\]Magnesium increased the tolerance of plants to high concentrations of manganese in shoot tissue and also increased the ability of the plant to discriminate against manganese ions in translocation of nutrients from roots to shoots.     

The effect of micro-aerobic conditions on continuous ethanol production by Saccharomyces cerevisiae

Summary The effect of trace amounts of oxygen on the degree of ethanol inhibition in a continuous anaerobic culture of Saccharomyces cerevisiae was studied at the 100 gl ^–1 feed glucose concentration level. Results showed that the use of micro-aerobic conditions (0,5% of saturation) enhanced the utilisation of substrate by increasing the ethanol tolerance of the yeast without any significant decrease in the ethanol yield per unit substrate consumed. When the results were fitted to an equation of the form % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaqcLbyacaqG8o% GaaeypaiqabY7agaqcaiaab6cadaWcaaGcbaqcLbyacaqGdbWaaSba% aSqaaKqzagGaae4CaaWcbeaaaOqaaKqzagGaae4qamaaBaaaleaaju% gGbiaabohaaSqabaqcLbyacqGHRaWkcaqGlbWaaSbaaSqaaKqzagGa% ae4CaaWcbeaaaaqcLbyacaGGUaWaaSaaaOqaaKqzagGaae4samaaBa% aaleaajugGbiaabchaaSqabaaakeaajugGbiaabUeadaWgaaWcbaqc% LbyacaqGWbaaleqaaKqzagGaey4kaSIaaeywamaaBaaaleaajugGbi% aabchacaqGZbaaleqaaKqzagGaaiOlaiaacIcacaqGdbWaaSbaaSqa% aKqzagGaae4CaiaabAgaaSqabaqcLbyacqGHsislcaqGdbWaaSbaaS% qaaKqzagGaae4CaaWcbeaajugGbiaacMcaaaaaaa!6301!\[{\text{\mu = \hat \mu }}{\text{.}}\frac{{{\text{C}}_{\text{s}} }}{{{\text{C}}_{\text{s}} + {\text{K}}_{\text{s}} }}.\frac{{{\text{K}}_{\text{p}} }}{{{\text{K}}_{\text{p}} + {\text{Y}}_{{\text{ps}}} .({\text{C}}_{{\text{sf}}} - {\text{C}}_{\text{s}} )}}\]it was found that the values for % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabeiVdyaaja% aaaa!373F!\[{\text{\hat \mu }}\], K_s and Y_ps were the same as for the non-aerobic case while the ethanol inhibition constant, K_p , had increased from 5,2 to 14,0 gl ^–1.Notation C_sf feed substrate concentration - gl ^–1 - C_s substrate concentration gl ^–1 - C_p product concentration - gl ^–1 - C_x cell concentration - gl ^–1 - D dilution rate - h^-1 - K_s substrate saturation constant - gl ^–1 - K_p product inhibition constant - gl ^–1 - m maintenance coefficient - h^–1 - Y_ps product yield coefficient - g EtOH/g glucose - Y_xs cell yield coefficient - g cells/g glucose - specific growth rate - h^–1 - % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabeiVdyaaja% aaaa!373F!\[{\text{\hat \mu }}\] maximum specific growth rate - h^–1     

Dynamics of electron transfer within and between PS II reaction center complexes indicated by the light-saturation curve of in vivo variable chlorophyll fluorescence emission

The dynamics of light-induced closure of the PS II reaction centers was studied in intact, dark-adapted leaves by measuring the light-irradiance (I) dependence of the relative variable chlorophyll fluorescence V which is the ratio between the amplitude of the variable fluorescence induced by a pulse of actinic light and the maximal variable fluorescence amplitude obtained with an intense, supersaturating light pulse. It is shown that the light-saturation curve of V is a hyperbola of order n. The experimental values of n ranged from around 0.75 to around 2, depending on the plant material and the environmental conditions. A simple theoretical analysis confirmed this hyperbolic relationship between V and I and suggested that n could represent the apparent number of photons necessary to close one reaction center. Thus, experimental conditions leading to n values higher than 1 could indicate that, from a macroscopic viewpoint, more than one photon is necessary to close one PS II center, possibly due to changes in the relative concentrations of the different redox states of the PS II reaction center complexes at the quasi-steady state induced by the actinic light. On the other hand, the existence of environmental conditions resulting in n noticeably lower than 1 suggests the possibility of an electron flow between PS II reaction center complexes.Abbreviations F₀ and F_m minimal and maximal levels of chlorophyll fluorescence emission, respectively - F_p peak fluorescence induced by a pulse of actinic light - I incident light irradiance (in W m^-2) - PS II Photosystem II - P₆₈₀ PS II reaction center - Q_A and Q_B primary and secondary (stable) electron acceptors of PS II - V relative variable chlorophyll fluorescence % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0Jf9crFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaiikaiaadA% facqGH9aqpcaGGOaGaaeOramaaBaaaleaacaqGWbaabeaakiabgkHi% TiaabAeadaWgaaWcbaGaaeimaaqabaGccaGGPaGaai4laiaacIcaca% qGgbWaaSbaaSqaaiaab2gaaeqaaOGaeyOeI0IaaeOramaaBaaaleaa% caqGWaaabeaakiaacMcacaGGPaaaaa!47BD!\[(V = ({\text{F}}_{\text{p}} - {\text{F}}_{\text{0}} )/({\text{F}}_{\text{m}} - {\text{F}}_{\text{0}} ))\]     

Organic matter transformations in soils

Summary The kinetics of carbon and nitrogen mineralization in soils amended with different organic materials was investigated at different periods of incubation lasting for 30 weeks. The data indicated that the decomposition of organic matter in soils is controlled by two simultaneously occurring superimposed first-order kinetic reactions. Based on cumulative C or N mineralization-t^1/2 relationships, the carbon or nitrogen mineralization potentials of the soils amended with different organic materials were derived on the premise that the rate of C or N mineralization is proportional to the amount of potentially mineralizable substrate as defined by the equation: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiaado% eacaGGVaGaamizaiaadshacqGH9aqpcqGHsislcaWGlbGaam4qaiaa% bccacaqGVbGaaeOCaiaabccacaqGSbGaae4BaiaabEgacaqGGaGaai% ikaiaaboeacaqGVbGaeyOeI0IaaeiiaiaaboeacaqG0bGaaeykaiaa% bccacaqG9aGaaeiiaiaabYgacaqGVbGaae4zaiaabccacaqGdbGaae% 4BaiaabccacqGHsislcaqGGaGaae4saiaab+cacaqGYaGaaeOlaiaa% bodacaqGWaGaae4maiaabccacaqGOaGaamiDaiaacMcaaaa!5C0E!\[dC/dt = - KC{\text{ or log }}({\text{Co}} - {\text{ Ct) = log Co }} - {\text{ K/2}}{\text{.303 (}}t)\]where Co is the C mineralization potential, Ct is the cumulative amount of CO₂ evolved at time t, and K is the mineralization rate constant. The estimates of C or N mineralization potential, mineralization rate constants and half-time for C or N mineralization are reported for the organic matter amended soils. The relative enrichment of conventional humus fractions after a 30 week period of incubation indicated that the soils could be ranked in the following order of encouraging humification of the organic materials: Haplustults>Haplaquents>Calciorthents.re]19751007     

Measurement of amount of nitrogen fixed by a legume crop

Summary The amount of nitrogen fixed by a legume crop can be calculated from the relationship % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGceaqabeaacaqGbb% GaaeyBaiaab+gacaqG1bGaaeOBaiaabshacaqGGaGaae4BaiaabAga% caqGGaGaaeOzaiaabMgacaqG4bGaaeyzaiaabsgacaqGGaGaaeOtai% aabccacaqG9aaabaGaaeypaiaabccadaqadaqaaiaaigdacqGHsisl% daWcaaqaaiGacggacaGG0bGaai4Baiaac2gacaGGGaGaaiyjaiaacc% cacaGGobGaaiylaiaacgdacaGG1aGaaiiiaiaacwgacaGG4bGaai4y% aiaacwgacaGGZbGaai4CaiaacccacaGGPbGaaiOBaiaacccacaGGSb% GaaiyzaiaacEgacaGG1bGaaiyBaiaacwgacaGGGaGaai4yaiaackha% caGGVbGaaiiCaaqaaiGacggacaGG0bGaai4Baiaac2gacaGGGaGaai% yjaiaacccacaGGobGaaiylaiaacgdacaGG1aGaaiiiaiaacwgacaGG% 4bGaai4yaiaacwgacaGGZbGaai4CaiaacccacaGGPbGaaiOBaiaacc% cacaqGYbGaaeyzaiaabAgacaqGLbGaaeOCaiaabwgacaqGUbGaae4y% aiaabwgacaGGGaGaai4yaiaackhacaGGVbGaaiiCaaaaaiaawIcaca% GLPaaacaqI4bGaaKiiaiaabshacaqGVbGaaeiDaiaabggacaqGSbGa% aeiiaiaab6eacaqGGaGaaeyAaiaab6gacaqGGaGaaeiBaiaabwgaca% qGNbGaaeyDaiaab2gacaqGLbGaaeiiaiaabogacaqGYbGaae4Baiaa% bchaaaaa!9A78!\[\begin{gathered} {\text{Amount of fixed N = }} \hfill \\ {\text{ = }}\left( {1 - \frac{{\operatorname{atom} \% N - 15 excess in legume crop}}{{\operatorname{atom} \% N - 15 excess in {\text{reference}} crop}}} \right)\user1{x }{\text{total N in legume crop}} \hfill \\ \end{gathered} \]when a suitable reference crop is chosen. The implications and interpretation of this method of measurement are described.     

Plant regeneration from explant and protoplast derived calluses of Medicago littoralis

Plant regeneration from explant and protoplast derived callus has been achieved in Medicago littoralis cv. Harbinger 1886, an annual legume resistant to the fungus Pseudopeziza medicaginis. Callus was induced from different tissue explants and the fastest growth rate was observed for hypocotyls in B5 medium with 2 mg l^–1 2,4-dichlorophenoxyacetic acid and 0.5 mg l^–1 N⁶-benzyladenine. Protoplasts were isolated from cotyledons and leaves of sterile plants and from callus; the first two kinds of protoplasts showed a plating efficiency of 5.6% and 5%, respectively, when embedded in agarose. Plant regeneration occurred on media containing % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9qq-f0-yqaqVeLsFr0-vr% 0-vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaqGobWaaW% baaSqabeaacaqG2aaaaOGaaeOVfiaabs5adaahaaWcbeqaaiaaikda% aaGccaqG+waaaa!3F97!\[{\text{N}}^{\text{6}} {\text{\Delta }}^2 {\text{}}\]isopentenyl-adenine combined with indole-3-acetic acid or 1,2-benzisoxazole-3-acetic acid, and on media with N⁶-benzyladenine plus -naphtaleneacetic acid; a cytokinin/auxin ratio higher than 1 induced embryos while a ratio around 1 stimulated shoot formation. Embryo development and rooting of shoots were performed in RL medium without growth regulators.Abbreviations NAA -naphthaleneacetic acid - BA N⁶-benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - 2iP % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9qq-f0-yqaqVeLsFr0-vr% 0-vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaqGobWaaW% baaSqabeaacaqG2aaaaOGaaeOVfiaabs5adaahaaWcbeqaaiaaikda% aaGccaqG+waaaa!3F97!\[{\text{N}}^{\text{6}} {\text{\Delta }}^2 {\text{}}\]isopentenyl-adenine - IAA indole-3-acetic acid - BOA 1,2-benzisoxazole-3-acetic acid - KIN kinetin - MS Murashige & Skoog (1962) - GRFMS growth regulator free MS medium - B5 Gamborg et al. (1968) - RL Phillips & Collins (1979) - KM8 KM8P Kao & Michayluk (1975) - CPW Frearson et al. (1973) - f. wt fresh weight - FDA fluorescoin diacetate     

Sequences of colonization,diversity, biomass,and productivity of macroinvertebrates on artificial substrates in a freshwater canal

The sequence of colonization, species diversity (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% qGKbaaaaaa!36E5!\[\overline {\text{d}} \]), biomass, and productivity of macroinvertebrates on artificial substrates was determined in a relatively constant environment freshwater canal. Three substrates were removed weekly during a 16 week test period. Community structure of benthic macroinvertebrates was determined at the onset and end of the test period and compared with substrate community structure. Calopsectra sp. was the dominant early colonizing organism; Dicrotendipes sp. and Dicrotendipes modestus were also abundant. In late collections other chironomids, ephemeropterans, gastropods, oligochaetes, amphipods, and trichopterans occurred. Trichopterans were generally dominant in numbers and biomass in later collections. A total of 104 were collected on the substrates.Collection diversity (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% qGKbaaaaaa!36E5!\[\overline {\text{d}} \]) began at 3.42 (week 1), decreased to 2.72 in the third week, and then continually increased for the remainder of the test period to 4.43. Cumulative diversity had a similar trend, decreasing from 3.42 (week 1) to 3.06 in the fourth week, and then increasing to 4.05. Neither collection % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% qGKbaaaaaa!36E5!\[\overline {\text{d}} \] or cumulative % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% qGKbaaaaaa!36E5!\[\overline {\text{d}} \] reached an asymptote in the 16 week period.Collection biomass began at 0.0867 g/0.26 m² for week one and was 1.0575 g/0.26 m² at the end of the test period. Biomass increased linearly for seven weeks, fluctuated widely until week 14, then increased sharply for the remainder of the test period. Productivity ranged from –3.42 g/m²/wk in the eighth week to 5.10 g/m²/wk in the last collection. Biomass and productivity were greatly affected by the presences or absences of a relatively few large organisms.One hundred two taxa were collected from the benthic samples, 34 not being present on the substrates. Limodrilus hoffmeisteri was the dominant benthic organism, while Calopsectra sp. and Polypedilum sp. were also abundant. The February benthic diversity % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% qGKbaaaaaa!36E5!\[\overline {\text{d}} \] was 4.54 and the June % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% qGKbaaaaaa!36E5!\[\overline {\text{d}} \] was 4.05.     

Response by macrozoobenthos biomass to water level regulation in some Finnish lake littoral zones

The relationship of the macrozoobenthos biomass in the littoral area to the yearly fluctuation in water level and the characteristics of the area or lake are studied using data collected from sheltered bays in regulated and natural waters. Most of the lakes were clear and oligotrophic. The benthos biomass at all depths in the littoral decreased with increased water level fluctuation, provided that the transparency of the water was uniform.The macrozoobenthos biomass in the 0–3 m depth zone could be predicted fromlog macrozoobenthos biomass (mg ODW) m^-2=4.25-1.33 (log Biomass Index) in which the Biomass Index is calculated as% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaeOqaiaabM% gacaqGVbGaaeyBaiaabggacaqGZbGaae4CaiaabccacaqGjbGaaeOB% aiaabsgacaqGLbGaaeiEaiaab2dacaqGGaGaaeiiaiaabccacaqGGa% GaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiai% aabccadaWcaaabaeqabaGaae4DaiaabggacaqG0bGaaeyzaiaabkha% caqGGaGaaeiBaiaabwgacaqG2bGaaeyzaiaabYgacaqGGaGaaeOzai% aabYgacaqG1bGaae4yaiaabshacaqG1bGaaeyyaiaabshacaqGPbGa% ae4Baiaab6gacaqGGaGaaeyAaiaab6gacaqGGaGaaeiDaiaabIgaca% qGLbGaaeiiaiaabchacaqGYbGaaeyzaiaabAhacaqGPbGaae4Baiaa% bwhacaqGZbGaaeiiaiaabMhacaqGLbGaaeyyaiaabkhaaeaacaqGOa% GaaeyBaiaabUdacaqGGaGaae4yaiaabggacaqGSbGaae4yaiaabwha% caqGSbGaaeyyaiaabshacaqGLbGaaeizaiaabccacaqGMbGaaeOCai% aab+gacaqGTbGaaeiiaiaab2gacaqGVbGaaeOBaiaabshacaqGObGa% aeiBaiaabMhacaqGGaGaaeyBaiaabwgacaqGHbGaaeOBaiaabccaca% qG2bGaaeyyaiaabYgacaqG1bGaaeyzaiaabohacaqGPaaaaeaacaqG% tbGaaeyzaiaabogacaqGJbGaaeiAaiaabMgacaqGGaGaaeizaiaabM% gacaqGZbGaae4AaiaabccacaqG2bGaaeyyaiaabYgacaqG1bGaaeyz% aiaabccacaqGPbGaaeOBaiaabccacaqG0bGaaeiAaiaabwgacaqGGa% Gaae4CaiaabggacaqGTbGaaeyzaiaabccacaqGVbGaaeiCaiaabwga% caqGUbGaaeiiaiaabEhacaqGHbGaaeiDaiaabwgacaqGYbGaaeiiai% aabohacaqGLbGaaeyyaiaabohacaqGVbGaaeOBaiaabccacaqGOaGa% aeyBaiaabMcaaaaccaGae8hiaaIaaKiEaiab-bcaGiaaigdacaaIWa% GaaGimaiaac6caaaa!CBD8!\[{\text{Biomass Index = }}\frac{\begin{gathered} {\text{water level fluctuation in the previous year}} \hfill \\ {\text{(m; calculated from monthly mean values)}} \hfill \\ \end{gathered} }{{{\text{Secchi disk value in the same open water season (m)}}}} \user1{x} 100.\]The whole illuminated littoral shifts due to water level fluctuation, which disturbs the zonation of the benthos. Such an increase or decrease in benthic biomass has been observed after one year of disturbance due to water level fluctuation. It need, however, a study based on the carefully planned and collected data, in which it can be taken account by a multivariate statistical analysis also the interactions between the important factors affected the littoral benthos.     

Indole-3-acetic acid transport in apical dominance: a quantitative approach. Influence of endogenous and exogenous IAA apical source on inhibitory power of IAA transport

The relationship between the amount of indole-3-acetic acid transported (IAA transport) through the second node of 7-day-old pea seedlings and the degree of inhibition of axillary bud outgrowth at the same node was studied. For both the endogenous apical IAA source (leaves of apical bud) and the exogenous one (lanolin paste containing 0.25–1.0 mg mL^–1 IAA) the slope of linear dependence between inhibition and IAA transport was similar. However, the same IAA transport induced different inhibitions, which were higher for the endogenous source. Moreover, the apical bud induced higher inhibition at the same level of IAA transport when the 4th leaf was present than when it was absent. Apparently, the source of IAA also may regulate the inhibitory power of IAA transported from it. IAA transport appears to consists of active and slightly active one moving along different pathways.Abbreviations a and b coefficients of linear regression of the type y = a+bx; - confidence level of t-test - ELISA enzyme linked immunosorbent assay - GR_1,2 ^e/d growth rate of the lateral bud of experimental/decapitated (control) pea plants at the first and second days after treatment or decapitation - I degree of inhibition of lateral bud outgrowth - IAA indole-3-acetic acid - L_1,2,3 the lengths of lateral bud at 1, 2 or 3rd day after treatment or decapitation of pea plants - n data number - r correlation coefficient - T amount of IAA transported through the second node of pea plant for 3 hours - TIBA 2, 3, 5-triiodobenzoic acid - t-test statistical test used here to compare slopes of linear regressions (y = a+bx) calculated as % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaeiDaiaabc% cacaqG9aGaaeiiaiaadkgadaWgaaWcbaGaaGymaaqabaGccaqGGaGa% aeylaiaabccacaWGIbWaaSbaaSqaaiaaikdaaeqaaOGaaeiiaiaab+% cacaqGGaWaaOaaaeaacaqGBbaaleqaaOGaaeikaiaabohacaqGLbGa% aeiiaiaadkgadaWgaaWcbaGaaGymaaqabaGccaqGPaWaaWbaaSqabe% aacaqGYaaaaOGaaeiiaiaabUcacaqGGaGaaeikaiaabohacaqGLbGa% aeiiaiaadkgadaWgaaWcbaGaaGOmaaqabaGccaqGPaWaaWbaaSqabe% aacaqGYaaaaOGaaeyxaiaab6caaaa!524A!\[{\text{t = }}b_1 {\text{ - }}b_2 {\text{ / }}\sqrt {\text{[}} {\text{(se }}b_1 {\text{)}}^{\text{2}} {\text{ + (se }}b_2 {\text{)}}^{\text{2}} {\text{]}}{\text{.}}\]     

Vegetation gradient on the shores of Lake Nasser in Egypt

The paper, a synthesis based on data generated by our own investigation on Stipa baicalensis steppe for the period 1986–1988, deals with the relationships among biotic and abiotic factors at community ecology level. Analysis is placed on aboveground net primary production (ANPP), the energy source for livestock production process, and on accumulated temperature (5°C) (X₁), rainfall during the growing season of the steppe plants (X₂), and content of organic matter of surface soil (X₃), the abiotic variables most often used to explain variation in ANPP.The models predicting ANPP in Stipa baicalensis steppe were structured in terms of X₁, X₂, and X₃. The predictive power of the models was found to be very high, and the models were successfully validated in three cases with an independent data set.The prediction model that gave the best fitting in Stipa baicalensis steppe was% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbqfgBHr% xAU9gimLMBVrxEWvgarmWu51MyVXgaruWqVvNCPvMCG4uz3bqefqvA% Tv2CG4uz3bIuV1wyUbqee0evGueE0jxyaibaieYlf9irVeeu0dXdh9% vqqj-hEeeu0xXdbba9frFf0-OqFfea0dXdd9vqaq-JfrVkFHe9pgea% 0dXdar-Jb9hs0dXdbPYxe9vr0-vr0-vqpWqaaeaabiGaciaacaqabe% aadaabauaaaOabaeqabaGaaeywaiaabIcacaWG4bGaaiykaiabg2da% 9iaaiwdacaaIYaGaaGioaiaac6cacaaIXaGaaG4maiaaikdacaaI4a% Gaey4kaSIaaGymaiaaikdacaGGUaGaaGymaiaaiMdacaaI0aGaaGio% aiaadIhadaWgaaWcbaGaaGymaaqabaGccqGHRaWkcaaI4aGaaGOmai% aac6cacaaI1aGaaG4naiaaicdacaaIXaGaaGimaiaaicdacaaIXaGa% amiEamaaBaaaleaacaaIYaaabeaakiabgUcaRiaaiwdacaaI3aGaai% OlaiaaigdacaaI5aGaaGioaiaaiEdacaWG4bWaaSbaaSqaaiaaioda% aeqaaOGaey4kaSIaaGymaiaaikdacaGGUaGaaGOnaiaaiodacaaI3a% GaaGynaiaadIhadaWgaaWcbaGaaGymaaqabaGccaWG4bWaaSbaaSqa% aiaaikdaaeqaaOGaeyOeI0IaaGOnaiaac6cacaaIXaGaaGOmaiaaiA% dacaaI1aGaamiEamaaBaaaleaacaaIXaaabeaakiaadIhadaWgaaWc% baGaaG4maaqabaaakeaacaqGGaGaaeiiaiaabccacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGa% aeOmaiaabIdacaqGUaGaaeimaiaabIdacaqG3aGaaeynaiaadIhada% WgaaWcbaGaaGOmaaqabaGccaWG4bWaaSbaaSqaaiaaiodaaeqaaOGa% aeylaiaabodacaqG2aGaaeOlaiaabgdacaqG3aGaae4naiaabsdaca% WG4bWaa0baaSqaaiaaigdaaeaacaaIYaaaaOGaaeylaiaabccacaqG% ZaGaaeymaiaab6cacaqG0aGaaeinaiaabkdacaqG5aGaamiEamaaDa% aaleaacaaIYaaabaGaaGOmaaaakiaab2cacaqGYaGaaeOnaiaab6ca% caqGYaGaaeOnaiaabodacaqGZaGaamiEamaaDaaaleaacaaIZaaaba% GaaGOmaaaaaaaa!9ED0!\[\begin{gathered} {\text{Y(}}x) = 528.1328 + 12.1948x_1 + 82.5701001x_2 + 57.1987x_3 + 12.6375x_1 x_2 - 6.1265x_1 x_3 \hfill \\ {\text{ + 28}}{\text{.0875}}x_2 x_3 {\text{ - 36}}{\text{.1774}}x_1^2 {\text{ - 31}}{\text{.4429}}x_2^2 {\text{ - 26}}{\text{.2633}}x_3^2 \hfill \\ \end{gathered} \]We have also made, in detail, the analysis of the relationships among ANPP and 3 ecological factors above variables. ANPP was responsive to all of 3 ecological factors discussed in the paper. Action intensity, which has an effect upon ANPP, can be indicated by a contribution rate. The contribution rates of X₁, X₂, and X₃ were 1.069, 2.0513 and 1.8889, respectively.This paper not only discussed profoundly the relationships among ANPP and X₁, X₂, and X₃, but also studied exhaustively effects of the interactions X₁, X₂, and X₃, on ANPP.     

Limnology and plankton periodicity of Jos Plateau water reservoir,Nigeria, West Africa

Limnological data (Dec. 1980–Jan. 1982) on the plankton and water chemistry of Lamingo Dam, located within the Jos biotite granite area of the Plateau State (Nigeria) are presented. The water-body falls in Beadle's (1981) category I of African lakes (conductivity < 40 µS cm^–1). Alkalinity (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0Jf9crFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3914!\[\bar x\] = 0.3 meq l^–1), principally composed of bicarbonates, dominated the anions % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0Jf9crFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaK4waiaajI% eacaqIdbGaaK4tamaaxababaGaeyOeI0caleaacaaIZaaabeaakiaa% b6dacaqIdbGaaKiBaiaaj2cacaqG+aGaaK4uaiaaj+eadaqhaaWcba% GaaKinaaqaaiaajkdacaqITaaaaOGaaKyxaaaa!4657!\[\user1{[HCO}\mathop -\limits_3 {\text{ > }}\user1{Cl - }{\text{ > }}\user1{SO}_\user1{4}^{\user1{2 - }} \user1{]}\]The plankton were characterized by a moderate standing crop of phytoplankton, and zooplankton were, generally, very limited in species and abundance. The order of dominance for the categories of phyto and zooplankton was: [Bacillariophyceae > Chlorophyceae > Dinophyceae] and [Rotifera > Crustacea] respectively. A diel cycle was characterized by nocturnal upward migration of the zooplankton, and the reverse behaviour in the phytoplankton.Interrelations between the biotic assemblages of plankters and various physical and chemical variables are discussed.     

Seasonal variation of water extractable aluminium forms in acidified forest organic soils under different vegetation cover

The Jizera Mountains area is affected by natural and anthropogenic acidification processes. The effect of acidification is reflected by presence of elevated amount of different Al forms in soil horizons. Changes of water extractable forms of Al (total $ {\text{Al}}_{{{\text{H}}_{2} {\text{O}}}} $ , species: Al(X)¹⁺, Al(Y)²⁺ and Al³⁺) and other soil characteristics (e.g. DOC, pH) were investigated in forest soils from April to October 2008. Seasonal changes of Al forms were identified in organic F and H soil horizons. No significant effect of the soil type on Al forms was documented. Nevertheless, influence of vegetation cover (beech and spruce forest, clear-cut area) on Al(X)¹⁺, Al(Y)²⁺ forms was proved. The results show that binding and mobility of Al forms are controlled mostly by pH and dissolved organic carbon (DOC).     

Influence of media composition on lactic acid production rate from whey by Lactobacillus helveticus

Summary The effect of preculture and culture media formulation on Lactobacillus helveticus lactic acid production rate was investigated in batch fermentations. Maximum lactic acid productivity of 5.5 g/l.h. was obtained from hydrolyzed whey. Clarified whey ultrafiltrate gave 4.4 g/l.h. at less expense.Nomenclature % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9qq-f0-yqaqVeLsFr0-vr% 0-vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaadaqdaaqaai% aab2eacaqGxbaaaaaa!3AF8!\[\overline {{\text{MW}}} \] peptides average molar weight - N_TK, N_NH2 total and primary -amino nitrogen concentrations (g/l) - p lactic acid concentration (g/l) - % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9qq-f0-yqaqVeLsFr0-vr% 0-vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaadaqdaaqaai% aabAfacaqGqbaaaaaa!3AFA!\[\overline {{\text{VP}}} \] lactic acid mean volumetric productivity (g/l.h.) - x total cell mass concentration (g/l)     

Electronic and utermöhl comparative techniques in quantitative analysis of freshwater particulates

The Coulter Counter Model B and the Millipore Particle Measurement Computer System were compared with the Utermöhl technique in counting and sizing test objects and suspended freshwater particulate matter. Replicate samples of lake water and pulp mill effluent were analyzed with the electronic instruments for an estimate of counting error % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaeWaaeaada% WcaaqaaiGacofaciGGfbGaaiOlaiaacshacaGGUaGaaiymaiaaccda% caGGWaaabaGabiiEayaaraaaaaGaayjkaiaawMcaaaaa!3EB7!\[\left( {\frac{{\operatorname{S} \operatorname{E} .t.100}}{{\bar x}}} \right)\] Coulter Counter error for determinations of number, volume, and diameter of homogeneous particles was less than io%, and for natural populations of freshwater particles, less than 2o%. Millipore errors of number, area, and horizontal chord were roughly twice these values. Precision was least at low concentration of particles. In practical applications, pulp mill effluent analyses were characterized by close correlation between electronic methods of counting, but lake water particle determinations failed to relate. Microscope counts and sizes of freshwater particles were generally unrelated to electronic measurements. A definite electronic instrument specificity for homogeneous particles was apparent. Wide variations in determinations of characteristics by electronic and manual methods existed. The greatest problem in the. estimation of freshwater biomass is the determination of the unknown detrital fraction.     

An assessment of the meiobenthos from nine mountain lakes in Western Canada

The numbers and biomass of meiobenthic invertebrates of nine representative mountain lakes were assessed relative to the macrobenthic invertebrates retained on 0.425 mm mesh. The meiobenthos accounted for an average of % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSGaaeaaca% aIXaaabaGaaG4maaaaaaa!3777!\[{\raise0.7ex\hbox{$1$} \!\mathord{\left/{\vphantom {1 3}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$3$}}\]of the total biomass and 97% of total numbers retained on 0.045 mm mesh. In general surveys in these lakes, the use of 0.250 mm mesh instead of 0.425 mm mesh would be unlikely to improve estimates of total numbers and biomass enough to justify the additional effort needed. Accepting the meiobenthic turnover rate to be three to five times that of the macrobenthos, meiobenthic production is probably close to or much higher than the macrobenthic production in these lakes.     

Metazoans from a sandy aquifer: dynamics across a physically and chemically heterogeneous groundwater system

We investigated the relationship between groundwater metazoans and their physical and chemical environment in a shallow Atlantic Coastal Plain aquifer adjacent to the Chesapeake Bay, Maryland, USA. Average abundance of the groundwater organisms over a 1 % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSGaaeaaca% aIXaaabaGaaGOmaaaaaaa!3776!\[{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}\] year period were large (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% WG4baaaaaa!36FB!\[\overline x \] = 471⁻¹; range = 0–10001⁻¹) and included a wide range of taxa (nematodes, rotifers, copepods, oligochaetes, and others). Highest meiofaunal abundances occurred in the summer and fall with considerable variation across a study site that spanned hundreds of meters. We found that over 70% of the variability in the abundance of total meiofauna at Wye Island could be explained by date, sampling location, and conductivity. Additional physical and chemical factors (e.g., dissolved oxygen, nitrate, dissolved organic carbon) which were significantly related to faunal abundances, differed among taxa. Nematode abundances were negatively related to nitrate concentrations. Copepod and oligochaete abundances were highest at intermediate pH values (4–6). Copepods also occurred in higher abundances at higher conductivity (> 0.25 dS m ⁻¹). Rotifers were most abundant at higher oxygen values (> 6 mg l⁻¹). The high faunal abundances found in this sandy aquifer, and the degree to which such habitats are understudied (especially in North America), suggest a great need for additional research to elucidate factors that control faunal dynamics.     

Energy expenditure and cardiorespiratory responses at the transition between walking and running

We investigated whether the spontaneous transition between walking and running during moving with increasing speed corresponds to the speed at which walking becomes less economical than running. Seven active male subjects [mean age, 23.7 (SEM 0.7) years, mean maximal oxygen uptake ( ), 57.5 (SEM 3.3) ml·kg ^–1·min ^–1, mean ventilatory threshold (VTh), 37.5 (SEM 3) ml·kg ^–1 ·min ^–1] participated in this study. Each subject performed four exercise tests separated by 1-week intervals: test 1, and VTh were determined; test 2, the speed at which the transition between walking and running spontaneously occurs (ST) during increasing speed (increases of 0.5 km·h ^–1 every 4 min from 5 km·h ^–1) was determined; test 3, the subjects were constrained to walk for 4 min at ST, at ST ± 0.5 km·h ^–1 and at ST ± 1 km·h ^–1; and test 4, the subjects were constrained to run for 4 min at ST, at ST±0.5 km·-h ^–1 and at ST±1 km·h ^–1. During exercise, oxygen uptake ( ), heart rate (HR), ventilation ( ), ventilatory equivalents for oxygen and carbon dioxide (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmOvayaaca% WaaSbaaSqaaiaabweaaeqaaOGaai4laiqadAfagaGaamaaBaaaleaa% caqGYaaabeaakiaacYcacaqGGaGaaeiiaiqadAfagaGaamaaBaaale% aacaqGfbaabeaakiaac+caceWGwbGbaiaacaqGdbGaae4tamaaBaaa% leaacaaIYaaabeaaaaa!4240!\[\dot V_{\text{E}} /\dot V_{\text{2}} ,{\text{ }}\dot V_{\text{E}} /\dot V{\text{CO}}_2 \]), respiratory exchange ratio (R), stride length (SL), and stride frequency (SF) were measured. The results showed that: ST occurred at 2.16 (SEM 0.04) m·s ^–1; , HR and speed at ST were significantly lower than the values measured at VTh (P< 0.001, P< 0.001 and P< 0.05, respectively); changed significantly with speed (P< 0.001) but was greater during running than walking below ST (ST minus 1 km·h ^–1, P< 0.001; ST minus 0.5 km·h ^–1, P< 0.05) with the converse above ST (ST.plus 1 km·h ^–1, P<0.05), whereas at ST the values of were very close [23.9 (SEM 1.1) vs 23.7 (SEM 0.8) ml·kg ^–1 · min ^–1 not significant, respectively, for walking and running]; SL was significantly greater during walking than running (P<0.001) and SF lower (P<0.001); and HR and were significantly greater during running than walking below ST (ST minus 1 km·h ^–1, P<0.01; ST minus 0.5 km·h ^–1, P{<0.05) with the converse above ST (ST plus 1 km·h ^–1, P·< 0.05), whereas no difference appeared for and R between the two types of locomotion. We concluded from this study that ST corresponded to the speed at which the energy expenditure of running became lower than the energy expenditure of walking but that the mechanism of the link needed further investigation.     

Interêts du dosage des adénosines 5′-phosphate pour l'étude de la dynamique des populations phytoplanctoniques lacustres (le Pavin - France)

A study on A.T.P., A.D.P. and A.M.P. in the phytoplankton of Lake Pavin was carried out from November 1976 to December 1977. Samples were collected at nine depths, between the surface and 50 m.A.T.P., A.D.P. and ( = A.T.P.+ A.D.P. + A.M.P.) show a similar behaviour in space and time but A.M.P. behaves independently. The A.M.P. concentration is high only when primary production of phytoplankton is high.The energy charge [CE = (ATP + % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSGaaeaaca% aIXaaabaGaaGOmaaaaaaa!3776!\[{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}\]ADP)/(ATP + ADP + AMP)] could be used as measure of adaptation in algal populations. Indeed, the energy charge increases as algal cells experience difficulty in maintaining themselves in the biotope.

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Interêts du dosage des adénosines 5-phosphate pour l'étude de la dynamique des populations phytoplanctoniques lacustres (le Pavin - France)

     

Distribution of stream macroalgae in the eastern Atlantic Rainforest of São Paulo State, southeastern Brazil

Fifty-two stream segments were sampled from 16 August to 13 September in 1993 in the eastern Atlantic Rainforest of S?o Paulo State, southeastern Brazil (22°55′–25°00′S, 44°48′–48°03′W). Forty-two macroalgal subgeneric taxa were found and the most widespread species were Audouinella pygmaea (21% of sites), Compsopogon leptoclados and Microcoleus subtorulosus (19%). Macroalgal species number per sampling site ranged from 0 to six (2.6 ± 1.7) and was positively correlated to species abundance, whereas species cover ranged from 0 to 70% of the stream bed (15.5 ± 20.8%). No significant correlation was found among macroalgal species number and abundance with any physical or chemical variable analyzed. Most sites were dominated by one or few macroalgal species, mainly, Audouinella macrospora, C. leptoclados and M. subtorulosus. No significant difference was found between the frequency distribution of variables measured for streams and for total macroalgae but the most widespread species (A. pygmaea) differed significantly for current velocity, specific conductance, turbidity and pH. Overall means for macroalgal occurrence include the following values: temperature (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiwaaaa!36CA!\[X\] = 19.9°C), current velocity (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiwaaaa!36CA!\[X\] = 45 cm s⁻¹), oxygen saturation (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiwaaaa!36CA!\[X\] = 66%), specific conductance (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiwaaaa!36CA!\[X\] = 59.6 μS cm⁻¹), turbidity (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiwaaaa!36CA!\[X\] = 5 NTU) and pH (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiwaaaa!36CA!\[X\] = 7.1). This pattern of patchy distribution and dominance by few species has been suggested as typical of stream macroalgal communities and has been ascribed to the rapid fluctuation of physical and chemical conditions. Total macroalgal species richness as well as mean species number per sampling site were considerably lower than found in similar studies of other regions. The Intermediate Disturbance Hypothesis was applied to explain these results: the same factor (high precipitation) responsible for the maintainance of the high species diversity in the surrounding forest can be, paradoxically, a constraint to the development of a more diverse macroalgal flora in streams.