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Isocitrate lyase (ICL) of Chlorella was induced with acetate, and induction kinetics followed in autospores and 6 h old cells of a synchronous culture. The enzyme could not be induced in illuminated cells. With both cell types 1.2 mM acetate was the optimal inducer concentration. Freeze-thawed cells and acetone powders were used for measurement of activity. With the former the time course of increase in activity was different at the two cell ages. With 6 h old cells the activity fluctuated: There was first a period of increase, then one with decrease and again one of increase. No such variation was found with freeze-thawed autospores or with acetone powders of both cell states. Darkening 6 h old cells for different periods of time before induction reduced the peak of activity, leaving the rate of the third phase unchanged. Illumination of darkened cells before induction increased the peak. Increasing the duration of both treatments increased their respective effects. Acetone extracts taken at different times after start of induction inhibited the ICL activity of a test preparation. The inhibition decreased concurrently with the variation in the ICL activity found when freeze-thawed cells were used in the enzyme assay. The inducibility, taken as the rate of the third phase, was measured at different times during the 24 h synchronous cycle. Using three different acetate concentrations and both methods of cell preparation, we found that the inducibility was constant for 17 h whereafter it increased repidly to a final level. [ABSTRACT FROM AUTHOR]

The area occupied by Polar Marine climate is almost half that occupied by ET under its current definition and covers about 6 per cent of the earth's surface. The recognition of this climate type, whether it be called "Polar Marine," retaining Köppen's somewhat misleading word "Polar," or"High Latitude Marine," or perhaps some other nomenclature, should eliminate the necessity for apology in the presentation of markedly different climates under the same classification.

In this article some important factors as shading, humidity, frost and soil, influencing the outbreak of an epidemic by Scleroderris lagerbergii plant fungi under Austrian conditions are discussed in detail. In several countries the fungus Scleroderris lagerbergii Gremmen was identified as the cause of dieback in pine. Periods characterized by large scale attacks have been alternated by years in which the disease hardly occurred. The factors giving rise to these disasters are not yet fully understood today. Apart from genetic factors which determine the susceptibility of the host plant, environmental factors may increase susceptibility to the disease. On the other hand, they may stimulate the pathogen, for example, development of the fructifications, spore discharge, germination of spores.

Thermodynamic methods are presented for calculating, from the water adsorption isotherms, the change in unfrozen water content of a partially frozen soil with temperature at a constant pressure or with pressure at a constant temperature. Then, using pertinent experimental data for Na-Wyoming bentonite, the increase in unfrozen water caused by a confining pressure of 100 atm is obtained as a function of temperature. Such information is shown to be relevant to the mechanical properties of frozen soils under stress. [ABSTRACT FROM AUTHOR]

An extended equation was derived relating the relative partial molar free energy of water in a soil to its freezing point depression and relative partial molar heat content. The equation was used to prepare a table from which each of these three quantities can be ascertained if the other two are known. The table was used with experimental data to obtain a curve of freezing point depression versus water content for Na-Wyoming bentonite. Provided the activity of the liquid water in the clay is a single-valued function of the liquid water content, and that the ice has the properties of pure bulk ice, this curve also represents the relationship between freezing point depression and unfrozen water in the partially frozen clay. An equation for the heat capacity of a partially frozen soil was also derived. This equation was employed to calculate the heat capacities of the clay at different water contents and sub-zero temperatures. A comparison of the calculated unfrozen water contents and heat capacities of the partially frozen Na-Wyoming bentonite with the available experimental data indicated satisfactory agreement, especially as regards the unfrozen water contents. [ABSTRACT FROM AUTHOR]

This small plot study shows how ground cover, furrowing, and the presence of frost in soils of the Sierra Nevada affect infiltration from prolonged simulated winter rains. A rapidly melting snowpack over soil containing dense frost may accelerate on-site runoff. The presence of stalactite soil frost promotes rapid absorption of snowmelt and reduces overland flow. Conversely, porous concrete frost usually reduces infiltration capacity and increases overland flow on burned or sparsely vegetated sites but does not impair infiltration where plant and litter cover are appreciable. Snow cover, by cooling rain water, tends to preserve soil frost and keep it visibly intact. Snow absorbs raindrop energy much as dense vegetation does. Soil losses from snow-covered plots, regardless of vegetative cover, are practically nil. Generally, plants, litter, and snow cover dissipate raindrop energy and increase infiltration, but exposed rock usually accelerates overland flow and erosion. Shallow contour furrowing seemed to facilitate infiltration and controlled overland flow adequately. [ABSTRACT FROM AUTHOR]

The article cites a study which found that biology in rural high schools correlated with farm, home and community. The early fall lessons should encompass a considerable range of plant life and animal life problems, before the frosts destroy the wealth of summer material. This wide range can serve as a medium to introduce pupils to new material, to provide the teacher with a basis for the estimation of previous experiences of the pupils, and more particularly, to make the use of perishable material in the best possible manner, because it might not be available again in living form during the school year. The teacher should make a canvass or a survey of the occupational experiences of his school district before making the course outlines. In the agricultural field, this will need a seasonal list of jobs in fruit growing, poultry raising, dairy farming, gardening, etc. The teacher of agriculture usually faces every day several vital biological problems which might refer to the teacher of biology, who should also have access to the agricultural course outline.

This article offers information about a plant named Dryopteris villarii located in Great Britain. The article begins by giving an overview of the geographical and altitudinal distribution of the native plant. It then explores the habitat of the plant, including its climatic and topographical limitations and substratum. It also discusses the response of the plant to biotic factors such as grazing and competition. In addition, the article covers the performance of the plant in various habitats and the effect of frost and drought on the plant.

The article discusses the features of Cynosurus cristasus L, an ornamental plant. It is averred that cynosurus is of low constancy in chalk grassland in southern England and demonstrates a wide range of ecotypic variation, the adaption being marked in response to biotic factor. It is indicated that C. cristasus cannot survive terrible frost and continues green over winter. In the chemical analyses of C. cristasus, the range of nutrient values was given. Moreover, its germination degenerated to about 38.0% after five years storage.

The article provides information on the British species of Silene nutans L., a perennial herb with a tough, branched, woody stock and deeply ramifying roots. It has been found that the degree of exposure to wind and drought affect the stature of the plants in Britain. It enumerates the vice-counties where the plant is well-established. Information is presented on the habitat, climatic and topographical limitations of the plant. It offers a list of various soil types on which the species occurs. It relates the effect of frost and drought on the plant.

The article discusses the presowing treatments and their relation to growth, drought, frost and heat resistance. Winter wheat grains were soaked in water at room temperature. After 30 hours, when the radicle just started to emerge, the grains were blotted and left dry under room conditions until they reached their original weight. The results of the growth experiments reveal no significant differences between the shoot or roots weights of the various pretreatments. The results of the drought tolerance tests indicate as well that no induction of a higher drought tolerance could be seen under the conditions of the experiments.

1. The cell walls of droughted soybean plants are less elastically extensible than those of nondroughted plants. This is the opposite of what would be expected from their ability to remain turgid longer. 2. The droughted plants transpire less rapidly than the nondroughted plants. But this difference is eliminated and even reversed when the protective effect of the surface is removed by cutting the leaves into strips. 3. The droughted plants possess more leaf surface lipids per unit area than the nondroughted plants. Removing some eliminates or even reverses the difference in transpiration. 4. There is no difference in dehydration hardiness between droughted and nondroughted plants. 5. The drought resistance of droughted soybean plants is solely drought avoidance, due to a deposit of more leaf surface lipids. Whether or not an increased root system could play a role in the field was not investigated, since the plants used were grown in pots. [ABSTRACT FROM AUTHOR]

The article deals with the dependence of the effect of the pholoperiodic treatments of potato on the length of the growing period. The results of photoperiodic treatment may differ, depending on the variety of potato, the treatment of the sets and growing conditions. The effect of long day on the tuber yield of potato has been chiefly positive. Relatively most positive effect of the long photoperiod on the tuber yield has manifested itself in some very frost-resistant clones resulting from the crosses between Solaniim tuberosum and S. demissum.

Presents news briefs concerning the U.S. government and politics. Appointment of New York Governor Charles E. Hughes to the Supreme Court; Efforts of the Democratic legislators to elect a majority in the U.S. House of Representatives; Occurrence of a heavy storm and killing frost in the Middle West and South of the country.

This article focuses on weather conditions in England and Wales from September 1961-February 1962. The weather of September 1961 was varied, including some very warm days, thunderstorms and widespread gales occurred at the middle and end of the month. On average, the temperatures were higher than usual and total rainfall was about normal, a few ground frosts were reported, but no air frosts. December 1961 was outstandingly cold, especially during the last two weeks when easterly winds prevailed. Rainfall was above average, chiefly falling during the early part of the month.

The article presents a description of natural aspects of farm land during the month of June. The west hills turned green with curly-top grass-quite possibly blue grama. The cows could be allowed to graze outside the pasture fence. The crops were in. After the 10th of June there was little danger of a killing frost. Now that the high water was going down and the stream clearing up there were ever so many places where a boy could drop a baited hook into a clear, cool pool. But, with a gurgling mountain stream lined with willows, birch, and spruce; a blue sky and a bright sun; the catching of fish sometimes became incidental. There were birds to wonder about and now and then a cotton-tail or woodchuck attracted attention. And there were little whirlpools which kept changing. it was fun to drop a twig into one and see it disappear only to come up again somewhere else.

The article presents a guide to determine the condition of wind and weather discussed by A. J. DeVoe at a meeting of the Farmers' Club of the American Institute held in 1881. One of the indication of storm is the decline in temperature. Cirrus clouds tend to move toward a region of fair weather. The occurrence of a heavy white frost manifests the formation of a storm.