Monoculture Research Articles

Comparison of rotifer culture quality with yeast plus oil and algal-based cultivation diets

The culture quality of rotifers, Brachionus plicatilis, was compared for yeast and algal-based cultivation diets. The rotifer quality was evaluated based on factors which may affect survival and growth of marine fish larvae, including individual length and biomass, nutritional value, bacterial content, and rotifer viability. The diets used were monocultures of Tetraselmis sp., Isochrysis galbana, Pavlova lutheri, and baker's yeast plus capelin oil. Rotifers grown to early stationary phase with equal food rations exhibited equal length distribution, but the rotifer individual biomass was 10–25% higher for yeast-grown rotifers than for algal-grown rotifers. All diets gave equal protein content of individual rotifers. The lipid content was slightly higher and the ratio of protein to lipid was slightly lower with yeast plus capelin oil than with algae. The fatty acid composition of the rotifers was closely related to that of their dietary lipids and the Ω3 fatty acid content was not systematically different for the two types of diets. Use of yeast plus capelin oil resulted in considerably higher numbers of both suspended and rotifer-associated bacteria than with use of algal diets. No differences were found for the algal species involved. The viability of the rotifers in a temperature and salinity test was far better in groups fed algae than in groups fed yeast plus capelin oil. The results indicated an overall better quality of rotifers cultivated with algae than for rotifers cultivated with yeast and oil. Questions related to proteins and the microflora of rotifers should be further emphasized in future research.

Monocultures of the mind: perspectives on biodiversity and biotechnology

Monocultures of the mind: perspectives on biodiversity and biotechnology

Hormonal modulation of the interactions of cultured rat testicular Sertoli and peritubular myoid cells. Effects on glycosaminoglycan synthesis.

Previous investigators have suggested metabolic cooperation between Sertoli and peritubular cells. This study concerns Sertoli cell and peritubular myoid cell interactions in terms of synthesis of one of the main testicular extracellular matrix (ECM) constituents, glycosaminoglycans (GAG). We have tested the effect of hormones and other regulatory agents such as a combination of FSH, insulin, retinol, and testosterone (FIRT) on monocultures of Sertoli and peritubular myoid cells, and have examined whether or not coculture of Sertoli and peritubular myoid cells substitutes for the stimulation by FIRT. Cocultures of Sertoli and testicular peritubular myoid cells showed significant increases in the levels of secreted protein and sulfoprotein, as well as in cell-associated GAG synthesis in untreated cultures. This indicates cell-cell cooperation between Sertoli and peritubular myoid cells in the testis in terms of sulfated protein and GAG synthesis. Addition of the hormone mixture and retinol (FIRT) stimulated cell-associated and ECM-associated GAG in peritubular myoid cells, suggesting a role of circulating hormones in ECM production by peritubular myoid cells in vivo. Cocultures of Sertoli and myoid cells substituted for the stimulatory response of FIRT on peritubular myoid cells, predominantly in terms of cell-associated GAG synthesis, which again emphasizes that the paracrine regulation of testicular ECM synthesis is dependent on Sertoli-myoid cell cooperation.

All in the Family: Railroads and Henequen Monoculture in Porfirian Yucatan

All in the Family: Railroads and Henequen Monoculture in Porfirian Yucatan

A replacement series evaluation of competition between velvetleaf (Abutilon theophrasti) and soybean (Glycine max)

Summary:We examined relative competition abilities of velvetleaf (Abutilon theophrasti) and soybean (Glycine max) grown in a replacement series near Ames, Iowa, U.S.A. in 1986 and 1987. Relative above ground dry weight of soybean in mixtures was higher than expected from mono culture values early in the growing season but lower than expected later in the season, whereas velvetleaf had higher than expected values later in the season. Velvetleaf depressed seed yield of soybean in all mixtures; relative seed yield of velvetleaf was greater in all mixtures than in monoculture. Relative growth rate (RGR), leaf area ratio (LAR) and net assimilation rate (NAR) of soybean did not differ significantly among mixtures and generally decreased over the growing season. Velvetleaf exhibited no consistent differences among mixtures in RGR, LAR, and NAR. Net assimilation rate of velvetleaf was constant over most of the growing season. Relative growth rate and LAR of velvetleaf were highest early in the season and then progressively declined. Velvetleaf had higher NAR and higher RGR than soybean early in the season; LAR of velvetleaf was lower than LAR of soybean over most of the season. Velvetleaf and soybean did not significantly interfere with each other early in the growing season, but velvetleaf gained resources at the expense of soybean during the middle and later parts of the season.

An Investigation into the effect of monocultural plantation of eucalyptus camaldulensis on soil fertility status

The effect of Eucalyptus camaldulensis monoculture on soil fertility statusin the dry zone was studied comparatively with another monoculture of Tectonagrandis and a naturalforest located in the same area over a period of 5 months. Total litter production of Eucalyptus was 370.68 kglha as compared with1349.07 kglha in Tectona grandis (study period overlapped the leaf senescence)and 217.75 kglha in the natural forest. Litter decomposition was 40.22% inEucalyptus while it was 40.27% and 44.95% in naturalforest, and Tectona respectively.Nutrient release to litter at the time of fall did not differ between thevegetation types. However, it differed between the tree components and nutrients,the orders being leaves>twigs>bark and N>P>K>Ca. Significant differences (p;;;::0.05)were seen in moisture content, pH, organicmatter content, total nitrogen percentage, available potassium and calcium betweenthe soils in the vegetation types.

Production of transferable neuronotrophic factor(s) by human midgut carcinoid tumour cells; studies using cultures of rat fetal cholinergic neurons.

A co-culture system was established between human midgut carcinoid tumour cells and rat fetal cholinergic neurons. In monocultures in serum-free media, only tumour cells survived, while neurons deteriorated. In serum-free co-cultures, neurons displayed outgrowth of neuritic processes. Neurons of neuronal serum-free monocultures thrived if supplemented with conditioned media from tumour cell cultures grown serum-free. This indicates that tumour cells produce transferable growth factor(s) with potent neuronotrophic actions. Immunocytochemical studies indicate that this growth factor resembles nerve growth factor immunologically, since tumour cells were strongly immunoreactive after incubation with a rabbit anti-nerve growth factor antiserum, and furthermore expressed immunoreactive nerve growth factor receptors.

Competition Experiments for Light in a Plant Monoculture: An Analysis Based on Two-Dimensional Spectra

Les effets spatiaux de la competition entre plantes sont examines dans une serie d'experimentations ou des plants de Tagetes patula sont cultives en lattice triangulaire

SYMPOSIUM: FRUIT GROWING REGIONS IN THE EASTERN JAPAN

Fruit farming of decidous tree has developed in the Eastern Japan. Furthermore, the Tsugaru Plain is the largest apple producing region in Japan. In Hirosaki City, the center of the Tsugaru Plain, we had a symposium concerning the fruit farming, during the fall meeting of the Association. The summary of papers presented by reporters are in the following. (I) Norio Natsumura (Chiba Shoka Univ.): Apple cultivation in Tohoku District was started when the seedings had been supplied by the Home Ministry, while pioneers of the cultivation were landlords. Since they wanted to have marketable crops, they chose apple cultivation. (2) Yuzo Ishikawa (Akita Kita High-school): Fruit growing regions in Akita Prefecture are divided into the Yokote Basin and the Hanawa Basin. In the Yokote Basin, where farmers adopted cooperative production system, there has been an increasing fruit production. On the contrary, in the Hanawa Basin, there has been a decline in it. (3) Hiroyasu Aoki (Nakano Primary-school in Nagano Prefecture): The Nagano Basin is also an apple producing region. Since 1965, multi-fruit cultivation has been intro duced to produce pears and grapes as well as apples, replacing the traditional mono culture of apples. (4) Hiroshi Sasaki (Tsukuba Univ.): Vineyards in the Kofu Basin have intensively been cultivated in order to get fresh eating grapes. However, as grapes cultivation in Germany is different in the purpose to make wine, the same types of grapes can be produced in the small scale farms in the Kofu Basin. Here the consolidation of arable lands has been promoted to increase the production. Comments and discussions Studies on the relationships among fruit farming and paddy field farming, problem of circulation system of fruits, infuence of urbanization and industrialization on friuit farming, connection about technique of fruit cultivation and formation of the place of production are important. These are the conclusions which we have reached in this symposium.

Cultural diversity in central America and Panama: its relationship to conservation and planning.

The most frequently overlooked aspect of conservation of natural resources and economic development is human cultural diversity. However, conservation and development of natural resources are basically human-oriented endeavors and all conservation and developmental efforts ought to start with a clear understanding of the varied needs of the people. In addition, cultural diversity is a natural resource that ought to be protected along with all the more commonly recognized resources of the ecosystems of which humans form an integral part. Cultural diversity in a large measure is an ecological phenomenon because such diversity includes variations in the ways different people perceive and utilize the environments in which they live. Thus, cultural diversity, in large measure, equates with ecological diversity. It has been well established that a high degree of ecological diversity (including taxonomic, niche, biogeochemical and other measures of diversity) is a necessary attribute of humid tropical ecosystems if such ecosystems are to remain viable over long periods of time. The current land-use trends in Central America and Panama are leading toward ever larger areas being devoted to monocultural use with sharply reduced ecological diversity that poses great dangers for the near and long terms. In addition, the resultant removal of people from rural areas results in growing social, economic and political problems, that are not being successfully met by developing nations. Not only is there a growing wastage of human resources, a weakening of the social structures, and an increasing and dangerous dependence upon monocultures oriented toward export markets, but the ecological diversity of the previous existing land-use systems are being lost. This kind of diversity is probably no less valuable to the ecological health of a nation's agriculture, forestry, and general resource utilization than is the genetic diversity of "primitive" crop plant varieties which biologists now recognize and increasingly seek to preserve as "modern" crop plant varieties become ever more simple genetically and hence ever more vulnerable to disease and other perturbations.

Growth of tropical and temperate grasses at Palmerston North

Warm-season yields of 14 C4-photosynthetic pathway tropical grasses were compared with yields of 6 C3-pathway temperate grasses, and observations were made on the extent of flowering and on frost sensitivity. Plants were grown in mono culture in small swards at Palmerston North for two seasons. Plant spacing, cutting frequency and height, fertiliser dressings, and disease and pest control measures were selected to encourage each variety to express its growth potential both with and without irrigation. During the first season Setaria introductions produced the highest dry matter yields (14–16000 kg/ha); the temperate grasses yielded 8 500–12 000 kg/ha. : In the second summer Digitaria decumbens, Cynodon dactylon, Paspalum dilatatum, and Setaria splendida produced 16 000–18 000 kg/ha without irrigation and the temperate grasses 4 250–12 400 kg/ha. Tropical grasses yielded as well as or better than the temperate grasses during the warm season. Irrigation did not increase yields in the first summer. ...

Iron nutrition of sunflower and corn plants in mono and mixed culture

Sunflower (Helianthus annuus L. var. Giganteus) and corn plants (Zea mays L. var. Velox) were grownin mono and mixed culture for 11 days in nutrient solution containing no iron, inorganic Fe3+ and FeEDTA (2 ppm Fe each) respectively to evaluate the interaction between both plant species on their ability for iron uptake. Both plant species developed chlorosis under iron stress (no iron, inorganic Fe3+); however, due to the ability of sunflower plants to lower the pH of the nutrient solution under iron stress conditions, in presence of inorganic Fe3+ the pH lowering was followed by regreening of sunflower in mono and mixed culture. In mixed culture but not in mono culture corn plants also regreened under these conditions. With respect to iron accumulation, therefore, the sunflower plants promoted the uptake and translocation of iron to the shoot of corn plants, i.e. an ‘Fe-efficient’ species can improve the iron nutrition of an ‘Fe-inefficient’ one. In contrast to this corn plants had little or no effect on the iron nutrition of sunflower plants. The corn variety used in this experiment developed chlorosis even in presence of 2 ppm Fe in form of EDTA. This high susceptibility to iron chlorosis was related to the P/Fe ratio in the shoot rather than to the capacity of the plants for absorption and translocation of iron, because sunflower plants with the same or even lower iron content but lower phosphorus content were green.