Equal Environmental Conditions Research Articles

Traditional nature management as a way to prevent the loss of wildlife species in a changing environment

Wildlife species of tundra and sub-arctic boreal regions are facing an immediate threat to its existence owning to environmental changes. This paper highlights how traditional nature management in northwestern Russia and northeastern Canada is able to reduce threats to the environment, focusing on vulnerability of biodiversity to changing climatic conditions. The goal of this study is to identify key areas of wildlife species loss during a changing climate by exploring the ability of traditional nature management to support environmentally sustainable habitats for the existence of the most typical biomes of tundra and sub-arctic boreal landscapes. The differentiating biodiversity method was used to determinate presence of rare species as a criterion of non-disturbed areas. This research is based on statistical data on biodiversity dynamics, meteorological data, reports on environmental conditions, cartographic materials, satellite images collected from open sources, and fieldworks. The author indicates non-disturbed sites in terms of biological resources protection in the studied regions. Obtained results confirm that on territories where traditional nature management is carried out, the reduction of biodiversity is much lower than on areas located in equal environmental conditions.

Practical Design of Hybrid Photobioreactor System for Economic Feasibility and Environmental Sustainability

Modern photobioreactors for microalgae-based biofuel production face various budgetary challenges in comparison to its competitor design, the traditional open pond system. Herein, a novel design of a double-chamber hybrid photobioreactor is proposed, featuring low-cost components including a 3-W centrifugal pump and recyclable plastic modules for its solar flank, as well as derivatives from tubular and membrane photobioreactors. The hybrid photobioreactor exhibits reasonable hydrodynamic performance with a circulation time of 120 seconds and a mixing time of 38 seconds. A side-by-side runthrough of Chlorella vulgaris cultivation with the novel hybrid photobioreactor and a standard open pond system was done to compare growth rates and system performance under equal environmental conditions. Resulting measurements show that the hybrid photobioreactor produced a 34.87% comparatively greater amount of C. vulgaris by the tenth day of cultivation, demonstrating a significantly higher growth rate (P < 0.05). In contrast, wet-sludge lipid extraction processes show that the C. vulgaris culture grown in the open pond system held a substantially larger lipid accumulation than that of the hybrid photobioreactor, although the difference was not statistically significant (P > 0.05). The pilot-scale photobioreactor not only costed as little as the open pond system but also incurred 88.6% less expenses compared to a similarly designed bioreactor made of clear PVC material. Consequently, this project demonstrates the candidacy of the proposed low-cost hybrid photobioreactor design for microalgal biofuel production.

Carcass Traits of Geese (Anser anser) as Affected by Age, Gender and Their Interactions

Background: The geese have several advantages over chickens. These birds are highly valued for its meat, also used to get rid of weeds as it was released in the fields, which the cost of raising it was low. In recent years, despite of interest in geese production, it is important to take cognisance of the fact that there is a dearth of information on carcass traits, and the different effects of age, gender and their interactions on carcass characteristics of geese. Therefore, the objective of the current study aimed to investigate effect of age, gender and their interactions on the carcass traits of geese (Anser anser). Methods: A number of geese parents at the end of the third season and their gosling hatched reared until 10 weeks of age and each stock contain equal number of sexes for assessing carcass traits. All geese were reared under equal managerial, environmental and hygienic conditions. Result: Parent stock was significantly (p≥0.0001) higher body weight, dressing percentage and edible meat parts compared to the young geese. Males’ geese had approximately a 17% significantly higher live weight, a 4.6% higher dressed carcass percentage and 5.2% higher edible meat parts percentage than females. The intestine and neck percentages were significantly affected only by age, whereas blood and feather percentages were significantly affected only by gender. Moreover, abdominal fat and gizzard fat percentages were affected by all observed factors. The young geese had approximately a 24.7% higher non-edible meat percentage than the parent’s geese. Females’ geese had approximately 8.7% higher non-edible meat percentage than males. Abdominal and gizzard fat (%) were significantly affected by interaction between age and gender. A significant positive correlation coefficient was detected between live body weight and all edible parts of carcass characteristics weights for goose males. In conclusion, the increase of age had a positive effect on the carcass traits of geese (Anser anser). Males’ geese had a better carcass characteristics compared to females; in addition, the females were significantly higher than males for the abdominal fat and gizzard fat percentages.

Experimentally Discharged Spent Engine Oil (An Environmental Pollutant) on Soil Reduced the Growth, Yield, and Seed Proximate Content of Arachis hypogea L Under Equal Environmental Conditions

ABSTRACT Spent engine oil (SOE) has been indiscriminately disposed into the environment; yet, fewer records have focused on exposing the effect of the oil on food production. We investigated the effect of the oil (pollutant) on vegetative growth, yield, and proximate content of the seeds of an economic crop (Arachis hypogea). The upper layer of sandy-loam soil was collected in an area prone to indiscriminate emptying of the spent engine oil, mixed with poultry manure (4:1 kg), then transferred into polythene bags. Using a completely randomized design (CRD) consisting of four treatments, Arachis hypogea were sown at a depth of 4 cm in the soil. After germination, vegetative parameters of the seedlings were measured before pollution. After pollution, vegetative parameters, including yield and proximate content of the plant were measured. Results indicate that vegetative indices of the control (0 ml SEO) group and the other treated groups T1 (100 ml SEO), T2 (200 ml SEO) and T3 (300 ml SEO) were not significantly (p ≤ 0.05) different before pollution. After pollution, there was a decline in plant height, yield (number of pods), number of leaves, stem circumference, and the leaf area. The moisture, ash, fat, carbohydrate, crude protein, and fiber of the plant were also reduced when compared with the control group. Indiscriminate discharge of spent engine oil could be hazardous to plants of the environment and food production.

Biological responses of Sri Lankan rice (Oryza sativa L.) varieties to rhythmic sound patterns (music and religious chants)

Abstract. Munasinghe DSP, Weerakoon SR, Somaratne S. 2020. Biological responses of Sri Lankan rice (Oryza sativa L.) varieties to rhythmic sound patterns (music and religious chants). Nusantara Bioscience 12: 154-161. Influences of music cause either promoting or restricting the growth of plants. The effects of Pirith chanting and rhythmic sound patterns (Western classical music, Eastern classical music, Rock music) were focused in the present study. Seeds of Two (02) rice varieties (Bg 300 and Kuruluthuda) in f0 and f1 generations were subjected to dormancy break treatment, kept in a soundproof confined chamber, and arranged in Randomized Complete Block Design (RCBD) with two (02) replicates and 10 seeds per replicate. Seeds were germinated under the three sound rhythms, Pirith chanting, and silence. Plants kept under silence served as the control. Sound rhythms and Pirith were played separately for an hour, at 30 cm distance away from the seeds with an intensity of 55-60 dB for seven (07) days continuously, maintaining equal environmental conditions. Following seven (07) days, the percentile germination rate was recorded. Germinated seeds were planted in plastic pots filled with paddy soil, up to ¾ of the total depth, and pots were arranged in Randomized Complete Block Design (RCBD) with five (05) replicates and three (03) plants per replicate. Following one week, plants were subjected to sound rhythm treatments and silence for three (03) months continuously. Measurement of growth and yield performance were recorded every fortnight. Significantly different (p < 0.05) growth and yield performances in both generations were observed under Pirith, Eastern Classical and Western Classical music. Higher rates of growth were observed for rice varieties exposed to Pirith, Eastern and Western classical music. Similarly, yield was also higher compared to rice varieties exposed to rock music. The findings suggest that soft rhythmic sounds are the most appropriate type of music which improved growth and yield performance of rice varieties, Bg 300, and Kuruluthuda. However, further studies are needed to confirm present results and to elucidate the mechanism of responses to Pirith chanting and other rhythmic sound patterns using phytochemical and biochemical analyses.

The Consequence of Aqueous Extract of Tobacco Leaves (Nicotiana tabacum. L) on Feed Intake, Body Mass, and Hematological Indices of Male Wistar Rats fed under Equal Environmental Conditions

Objective While the dangers of consuming tobacco by smoking has been of concern, the hazardous effect of other forms of tobacco consumption (in smokeless form) on health indices are less well explored. In this paper, we explored the effect of different doses of aqueous extract of tobacco leaves on feed intake, body mass, and hematological indices of male Wistar rats under equal environmental conditions. Method Using an oral route of administration, the rats (n = 24; w = 65–85 g; 2–3 weeks old) were administered at different doses of 100, 200, 400, 0 mg/kg body weight (b.w.) per day to group A, B, C, and D for 42 days, after phytochemical and acute toxicity testing of the tobacco leaves. Results Compared to the negative control group (D), packed cell volume, hemoglobin concentration, red blood cells, and lymphocytes reduced dose-dependently in contrast to the white blood cells, neutrophils, mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, and mean corpuscular volume. As body mass and feed intake in relation to the different doses of aqueous extract of tobacco leaves reduced significantly (p < 0.05), the reverse was observed for body mass and feed intake in relation to room temperature. Conclusions By influencing hematological indices, feed intake, and body mass, the extract of tobacco leaves can be hazardous to health. However, to assess safety and to come up with a conscious conclusion, future studies should explore the effect of the extract on organs histopathology, biochemical parameters, and lipid profile of the body.

Experimental and numerical investigations on the thermal performance of a modified evacuated tube solar collector: Effect of the bypass tube

Many factors impact the thermal efficiency of the evacuated tube solar collectors (ETSCs) and numerous studies have been carried out to increase the efficiency of ETSCs. In this study, the stagnant region at the bottom of the evacuated tube has been removed using a bypass tube to connect the storage tank to the bottom of the modified evacuated tube. The thermal performance of a modified evacuated tube solar collector (METSC) has been investigated experimentally and numerically. The thermal characteristics of the METSC were compared to those of a commercial sample under equal environmental conditions. Furthermore, the impact of the diameter of the bypass pipe on the velocity profile, and temperature distribution of the fluid inside the modified collector has been investigated numerically to achieve the optimum diameter. The results demonstrate that this structure modification improves the collector performance due to removing the stagnant region at the bottom of the evacuated tube and the storage tank. This modification made the temperature distribution inside the pipe and tank more uniform, and increased the efficiency up to 11%. Moreover, useful gain of the solar collector in the modified model was 25% more than that of the typical model over a one-hour period. In addition, for the same duration, the average temperature of water inside the tank enhanced by 1.5 °C in the METSC in comparison to the typical model under equal environmental conditions.

The effect of Buddhist pirith chanting and Western pop music on growth performance of “Pranajeewa”, &lt;i&gt;Codariocalyx&lt;/i&gt; &lt;i&gt;motorius&lt;/i&gt; (Houtt.) H. Ohashi

Response of Codariocalyx motorius to Western pop music and Pirith chanting was examined by conducting an experiment with three months old C. motorius saplings, kept in a sound proof confined chamber. Completely Randomized Design (CRD) was used with five replicates. One week after planting, plants were exposed to three treatments; Western pop music, Pirith and silence. Music and Pirith were played separately for an hour, 30 cm distance away from plants with a sound level of 58 – 63 dB for two months continuously, maintaining equal environmental conditions. Measurements on growth performance were taken once in a fortnight. Percentage difference of parameters was calculated and data were analysed using ANOVA. Significant differences (p < 0.05) between the treatment of Pirith and Western pop music were observed for plant height, leaf width, leaf area, and chlorophyll content and leaflet length. However,thin layer chromatographic profiles observed under UV light and Anisaldehyde spray reagent exhibited no difference in chemical components. Magnitudes of the percentage difference between measured parameters of C. motorius under Pirith chanting and Western pop music indicated that there was discernible effect of Pirith chanting on the measured plant parameters in the study implying that rhythmic chanting of Pirith is the most appropriate type of music which improved the growth performance of C. motorius.

A preliminary study on effect of buddhist pirith chanting and pop music on the growth and yield performance in rice (&lt;em&gt;Oryza sativa&lt;/em&gt; L.)

Music influences the growth of plants through either promoting or restricting the growth of plants. The effects of Pirith chanting and pop music were focused in the present study. Seeds of Two (02) rice varieties (Bg300 and Kaluheenati) were subjected to dormancy break treatment, kept in a soundproof confined chamber and arranged in Completely Randomized Design (CRD) with two (02) replicates and 10 seeds per replicate. Seeds were allowed to germinate under the sound rhythms; pop music, Pirith chanting and silence separately in sound proof chamber. A set of pop songs and Thunsuthra in Pirith chanting were chosen as the two (02) sound rhythms. Seeds were kept under silence served as the control. Music and Pirith were played separately for an hour, at 30cm distance away from the seeds with an intensity of 55-60 dB for seven (07) days continuously, maintaining equal environmental conditions. Following seven (07) days, the percent germination was recorded. The same germinated seeds were planted in plastic pots filled with paddy soil, up to ¾ of the total depth and pots were arranged in Completely Randomized Design (CRD) with two (02) replicates and five (05) plants per replicate. Following one week, plants were subjected to the sound rhythm treatments and silence separately for three (03) months continuously. Measurement on growth and yield performance were recorded every fortnight. Significantly different (p &lt; 0.05) in growth and yield performances were observed under Pirith and pop music. Considerably higher rates of growth and yield were observed for varieties exposed to Pirith and comparatively, the effect of Pirith on growth and yield performance was higher with respect to pop music thus implying that the rhythmic chanting of Pirith is the most appropriate type music that improved the growth performance of Oryza sativa.

Morpho-physiological variation and essential oil content of Iranian populations in Thymus kotschyanus Boiss. &amp; Hohen grown under similar condition

Thymus kotschyanus Boiss. & Hohen is one of the medicinal herbs native of Iran. According to the economic importance of thyme, identify of morphological characteristics and essential oil content is important in different populations. We studied the pattern of variation of 33 morphological and physiological characteristics of T. kotschyanus in 15 Iranian populations experimentally grown under similar conditions. The results showed that in important traits, the highest mean of flowering stem length was related to Zanjan-I population, the most number of shoots pre plant was in Azarbayejangharbi-IV population, the highest leaf’s length and width respectively, belonged to Tehran and Lorestan population, the highest plant height was in Zanjan-I population, the most fresh and dry weight was related to Azarbayejangharbi-II population and the longest inflorescence was observed in Qazvin-II population. Cluster analysis of quantitative traits divided three main groups in thymus populations and Azarbayejangharbi populations were separated partially. Based on the qualitative traits, populations were classified in five main groups. As such, Zanjan and Qazvin populations were in separate groups. The results showed that the most content of essential oil and the highest mean of the most morphological traits were belonged to Azarbayejangharbi-I, IV and Tehran populations. Therefore, the morphophysiological characteristics of medicinal plants have many effects on essential oil’s content. Thus, the planting of diverse population in the equal environmental conditions will reduce the environmental impacts on incidence of vegetative traits, also better reveals the diversity of genetical differences between populations.

Bayesian modeling of bacterial growth for multiple populations

Bacterial growth models are commonly used for the prediction of microbial safety and the shelf life of perishable foods. Growth is affected by several environmental factors such as temperature, acidity level and salt concentration. In this study, we develop two models to describe bacterial growth for multiple populations under both equal and different environmental conditions. First, a semi-parametric model based on the Gompertz equation is proposed. Assuming that the parameters of the Gompertz equation may vary in relation to the running conditions under which the experiment is performed, we use feedforward neural networks to model the influence of these environmental factors on the growth parameters. Second, we propose a more general model which does not assume any underlying parametric form for the growth function. Thus, we consider a neural network as a primary growth model which includes the influencing environmental factors as inputs to the network. One of the main disadvantages of neural networks models is that they are often very difficult to tune, which complicates fitting procedures. Here, we show that a simple Bayesian approach to fitting these models can be implemented via the software package WinBugs. Our approach is illustrated using real experimental Listeria monocytogenes growth data.

A Survey of Aquatic Invertebrate Communities in Nebraska Sandhill Lakes Reveals Potential Alternative Ecosystem States

Abstract Aquatic invertebrate communities are important to shallow lake ecosystem form and function, providing vital components to the food web and thereby important to achieving lake management goals. We characterized lake invertebrate communities and physicochemical variables in six Nebraska Sandhill lakes and examined these characteristics within an alternative stable state framework. Surveys were conducted during 2005 within each of these lakes by sampling aquatic macroinvertebrate abundance, zooplankton abundance and biomass, phytoplankton biomass, and physicochemical variables. When placed within an alternative stable state framework, the response variables exhibited a gradient of different ecosystem states. Two lakes appeared congruent with the clear water state (dense submergent vegetation, high invertebrate abundance and diversity, and low phytoplankton), two lakes were congruent with the turbid water state (high phytoplankton, low vegetation coverage, and low invertebrate abundance and diversity), and two lakes were intermediate, likely in a state of hysteresis (i.e., multiple states under equal environmental conditions). Principal component groupings further supported these findings by following similar lake-specific patterns with attributes of each stable state grouping meaningfully according to the observed lake states. The lakes contained varied fish communities, potentially influencing many measured metrics, through a top-down mechanism. Generally, lakes dominated by piscivorous fish displayed the clear water state, whereas lakes with abundant planktivores displayed the turbid water state. Shallow lakes containing dense invertebrate communities likely provide a rich food base to important fauna (migratory waterfowl) that aid in reaching desired management objectives for these systems. Multiple small lakes, in proximity, displaying divergent ecosystem states invites the opportunity for more in-depth analyses of driving mechanisms that will undoubtedly add to our ability to effectively manage these systems in the future.

Sulfate radical-initiated formation of isoprene-derived organosulfates in atmospheric aerosols

Recent studies show that isoprene-derived organosulfates are an important fraction of ambient secondary organic aerosol (SOA), adding up to 20% to the organic mass. Organosulfates with m/z of 199 and 183 relating to C4 compounds are found in ambient and laboratory generated SOA and a sulfate radical induced oxidation of methacrolein (MACR) and methyl vinyl ketone (MVK) has been shown to be a possible formation mechanism. In the present study, experiments on the sulfate radical-induced oxidation of methacrolein and methyl vinyl ketone were performed in bulk aqueous phase, as well as in an aerosol chamber, and finally compared with ambient PM10 samples collected at a rural East German village during the summer 2008, to investigate their relevance in aqueous phase SOA formation. Samples from aqueous phase experiments and extracts from filters were analysed with UPLC/(-)ESI-IMS-QTOFMS. All the samples showed the abundance of highly oxidised organosulfates with m/z 153, 155, 167, 183 and 199 corresponding to the species found in ambient particle samples. In the bulk phase studies with laser-induced sulfate radical formation, the signal intensities increased with increasing number of laser pulses, indicating the sulfate radical-induced formation of these organosulfates. Additionally, the chamber experiments showed a particle mass growth of about 10 microg m(-3) and 4 microg m(-3) for experiments on the reactive uptake of MACR and MVK with a sulfate radical precursor (K2S2O8) in the seed particles. Correlations of the C2 to C5 organosulfate species (including the m/z 215, C5H11O7S-), detected in the ambient samples were found to be very strong (r > 0.8), indicating that these compounds are formed from similar mechanisms and under equal environmental conditions. This study shows that sulfate radical-induced oxidation in the aqueous particle phase provides a reasonable explanation for the formation of these organosulfates from methacrolein and methyl vinyl ketone.

Conventional and pulse cathodic protection of reinforced concrete: Electrochemical behavior of the steel reinforcement after corrosion and protection

AbstractThe applicability and efficiency of an alternative for impressed current cathodic protection (CP) for reinforced concrete, based on pulse technology, was investigated. The technique, denoted as pulse CP (pCP), was evaluated on the basis of a comparative analysis to reference (non‐corroding), corroding, and conventional CP conditions, in terms of long‐term monitoring of electrochemical parameters for the embedded steel with time of corrosion and protection. The hereby reported results are for the total duration of the experiment, i.e., 460 days of conditioning, also presented in comparison with earlier stages. Protection was applied after corrosion was initiated (using corrosion medium of 5% NaCl), at different time intervals (here reported are starting points 60 and 150 days of age). Both CP regimes used current density of 5 or 20 mA/m2 steel surface. The pulse CP was applied as a pulse‐shaped block current (square wave) with the current itself being the feedback control signal, using 12.5–50% duty cycle at 500 Hz to 1 kHz frequency. Under equal environmental conditions and for a comparatively long period of application, the pulse CP was found to perform as effectively as the conventional CP with regard to electrochemical behavior of the steel reinforcement. Furthermore, the pulse CP technique was found to achieve more rapidly the so called “open circuit potential (OCP) passivity” as a result of an enhanced ion transport (chloride withdrawal) and more favorable cement chemistry (increased alkalinity around the steel reinforcement).

Differences in life-cycle traits of Calanus finmarchicus originating from 60°N and 69°N, when reared in mesocosms at 69°N

Two different Calanus finmarchicus (Gunnerus) cohorts originating from 60°N (Bergen) and 69°N (Tromso) were investigated in equal environmental conditions to study their different physiological responses to the same environment. A two-plus-two-bag mesocosm study was carried out between March and July 1998, in Hakoybotn, Tromso, in order to determine development and mortality rates of the two parallel cohorts of C. finmarchicus. For practical reasons, the cohort from Bergen was incubated 10 days earlier than the Tromso cohort. Consequently, they were exposed to elevated food conditions as compared to the Tromso cohort. A high initial mortality among the Bergen cohort could clearly be ascribed, by genetic discrimination, to "contamination" with C. helgolandicus. After this initial mass mortality, the mortality was constantly 0.03–0.04 day−1. In cohorts starting from naupliar stage I, there was no significant difference in development or growth, the median development time (NI–CIV) differing by only 7 days (~6%). The difference in development time can be explained to a large extent (~4 days) by temperature differences. This is substantiated with model simulations using a physiological model developed for C. finmarchicus. There was a time lag in incubation between the two cohorts, resulting in elevated temperature during incubation of the Tromso cohort. A fraction of both cohorts differentiated sexually at stage CV, with males differentiating before females. Females from both cohorts produced eggs, but specific egg production differed significantly (P>0.001, t-test). This was supported by elevated RNA:DNA ratio in females from the Bergen cohort. Both cohorts demonstrated quite similar development and physiological growth rates and, consequently, are considered to belong to the same genetic population inhabiting the Norwegian Shelf. The study demonstrates that C. finmarchicus is capable of adaptation to changes in environment and, thereby, demonstrates a significant physiological plasticity.

A genetic analysis of body weight and length in rainbow trout reared in seawater for 18 months

Data from four year-classes of raibow trout was analysed. The brood fish originally came from different Norwegian fish farms, but all are considered to belong to the same population. During the freshwater period each full-sib family was reared separately and each group was given as equal environmental conditions as possible. Fingerlings from each fullsib family were sampled and freeze-branded. At an age of one year fingerlings from each family were sampled and transported to different fish farms along the Norwegian coast. This paper deals with the traits body weight and length at slaughter after about 18 months in net cages in the sea. Fish farm × sire interaction was significant, but accounted for a relatively small part of the total phenotypic variance. It is concluded that genotype × farm interaction can be ignored when planning a selection programme for rainbow trout under Norwegian farming conditions. A significant interaction was found between sire and dam, implying the presence of non-additive genetic variation. The heritabilities for body weight and length estimated from sire components (year-class 1973, 1974 and 1975) were 0.17 and 0.23, respectively. The genetic correlation between body weight and length was close to unity. Genetic variation in body weight of rainbow trout is high, about three times as high as for body length. The heritabilities estimated for condition factor were small and none of the sire components were significant. It is concluded that the combination of weight and length used to calculate the K-factor has little genetic basis.

Selection experiments with salmon: IV. Growth of Atlantic salmon during two years in the sea

Brood stock of Atlantic salmon were sampled from 37 rivers or riversystems (strains) for three consecutive years. Each strain was represented by several full- and half-sib families. During the freshwater period each full-sib family was reared separately and each group was given as equal environmental conditions as possible. Fingerlings large enough to become 1-year-old smolt were freeze-branded and smolts from the different strains were sampled and transported to five salmon farms along the Norwegian coast. This paper deals with body weight and length of Atlantic salmon after a growth period of 2 years in the sea. Significant differences between strains were found for all three year classes. The interaction farm × strain was significant but accounted for only a small part of the total variation. It is concluded that genotype × environment interaction can be ignored when planning a selection programme for Altantic salmon for Norwegian farming conditions. A significant interaction sire × dam was found for the 1972 year-class, implying the presence of non-additive genetic variation. The heritabilities for body weight and length estimated from sire components (year-class 1973 and 1974) were quite high: 0.31 and 0.28, respectively. Genetic correlations between body weight and length were close to unity. The heritabilities for condition factor ( K= weight in g (length in cm) 3 ·100 were small and none of the sire components were significant. It is concluded that the combination of weight and length used in calculating the K-factor has minor genetic basis. Genetic variation in body weight of Atlantic salmon is high, and about three times as high as for body length.

Factors Affecting the Shift in Predominance from Eurasian Perch (Perca fluviatilis) to Roach (Rutilus rutilus) in the Kličava Reservoir, Czechoslovakia

A shift in predominance from Eurasian perch (Perca fluviatilis) to roach (Rutilus rutilus) in the Kličava Reservoir in 1964, 10 yr after filling, was attributed mainly to a marked decline in the ratio of female to male perch spawners. The ratio was about 1:4 for perch and unity for roach. Fecundity of perch was about 25% that of roach which, together with the decline in spawning females, probably contributed to smaller year-classes. The decline in growth rate of perch in response to increasing abundance was greater than that for roach. Under equal environmental conditions, roach is also more productive than perch. Key words: Percidae, Perca, Rutilus, Kličava Reservoir, Czechoslovakia, shift in predominance, fecundity, sex ratio, methodology, growth–abundance relationships

Polyploids are More Variable than their Original Diploids

STUDYING the modification of a large number of experimentally produced polyploid plants of various species and families (Solanaceae, Gramineae, Compositae, etc.) within the single plants and in the polyploid lines in respect to the modification of their diploid forms, when the plants grew in equal environmental conditions, I found the following regularities. Cell dimensions showed in the majority of the cases studied a greater modification in the tetraploid than in the diploid plants. Cell dimensions of the experimentally produced octoploids were more variable than the cell dimensions of tetraploid and diploid forms. The numbers of chloroplasts per pair of stomatal cells were more variable in the tetraploids than in the diploids and much more variable in the octoploids than in the tetraploids and diploids. Counting, for example, the chloroplasts1 in 100 pairs of stomatal cells of each form of Nicotiana alata—diploid, tetraploid and octoploid, the following values for the standard deviations were respectively found: σ2n = 1·81, σ4n = 4·70, and σ8n = 7·03. (It was found that polyploidy does not affect the size of the chloroplasts1 2. It also does not significantly affect the variability of the chloroplast diameter.) The modification of the cell dimensions decreases somewhat gradually in the subsequent polyploid generations, that is, it decreases with the increase of the polyploid generations. But in the cases studied tetraploids still had more variable cell dimensions in the fifth generation than the corresponding diploids.

葡萄の挿木に於ける榮養の場についで

The author of this paper tried to find whether equal masses of cuttings produce in equal time and under equal environmental conditions, equal quantities of shoots and roots unconditionaly with grape vine (Vitis vinifera Chasselas dore) and he found that the quantity of new shoots and roots approximately proportionates to that of cuttings.He noticed however this mass relation law is adaptable only within a limit contrarily to Loeb's results. The increase ratio of shoots and roots is. not proportional to the cutting mass, it diminishes little by little at first, rapidly later as the cutting mass grows larger and it ceases when cutting mass reaches to some dimention. The author then considers that the reserved food is available for new shoots and roots except when it is within a morphological distance and outside of this limit it is not usable.By this fact the author believes that there must be field of nutrition in grape cuttings.