Pot Method

Pot Method

 

a laboratory method of studying plants by growing them in pots kept in greenhouses. The pot method is used to study the physiological role of nutrients and their intake by plants, the significance of the reaction of the medium (pH) and the watering rate, and the reaction of plants to the concentration of the nutrient solution, temperature (frost resistance), moisture (drought resistance), light (photoperiodism), chemical protective agents, herbicides, and so forth. The pot method is used mainly to compare different kinds of fertilizers added to soil. To determine the significance for plants of various chemical elements or their salts, the pots are filled with quartz sand or distilled water instead of soil, and the compounds under study are added.

Plants grown in pots must be protected from accidental injury and atmospheric precipitation, which disrupt the particular conditions created in the pots, and from other factors. A serious shortcoming of the pot method is that there is a limited amount of soil in which to grow the plants. Therefore, the roots are more crowded in the pots than in the field. The small amount of soil in the pots also explains why plants growing in pots respond much more sharply to a lack of one element or another than plants grown under field conditions. Therefore, the data obtained by the pot method on fertilizer requirements are often exaggerated. Another major shortcoming of the pot method is that the soil structure is destroyed when the soil is dried and sifted before it is packed into the pots. Thus, the results of pot method experiments must be regarded as preliminary and extrapolated very cautiously to field conditions.

The pot method has been most fully worked out in the studies of the Russian scientists P. S. Kossovich, D. N. Prianishnikov, and K. K. Gedroits. An enthusiastic exponent of the pot method was K. A. Timiriazev, who organized a demonstration of the method at the All-Russian Exhibition in Nizhnii Novgorod (the modern city of Gorky) in 1896.

REFERENCES

Nedokuchaev, N. K. Vegetatsionnyi metod, 4th ed. Moscow-Leningrad, 1931.
Sokolov, A. V., A. I. Akhromeiko, and V. N. Panfilov. Vegetatsionnyi metod. Moscow, 1938.
Prianishnikov, D. N. Izbr. soch., vol. 1. Moscow, 1963.
Timiriazev, K. A. Izbr. soch., vol. 2. Moscow, 1948.
Metodika polevykh i vegetatsionnykh opytov s udobreniiami i gerbitsidami. Moscow, 1967.
Zhurbitskii, Z. I. Teoriia i praktika vegetatsionnogo metoda. Moscow, 1968.

N. A. MAKSIMOV

References in periodicals archive ?
We will evaluate the method considering both in sample fit and out of sample forecast accuracy, and comparing these results with the performance of the POT method.
Instead of using only the block maxima, the POT method, as its name describes, is able to use all observations that are above a certain threshold, and is based on the following.
On a second note the POT method requires the threshold exceedances to be independent.
The PoT method is the by-product of a critical analysis of the traditional literacy campaigns that were conducted in the 1960s in the countries of the Third World .
The sensitivity and specificity of pot method were 96.
However, a comprehensive study needs to be done confirm the accuracy of the pot method for storage and transportation of sputum to microscopy centres for detection of AFB.
The sensitivity and specificity of pot method were determined using ZN method as the gold standard.
The one pot method provided a fast and convenient method for the synthesis of I and its analogs.
18 Developing Scenarios for Future Extreme Losses Using the POT Method
The present study was undertaken with the objective to stain sputum samples in their containers by 'phenol (10%) ammonium sulphate (4%) basic fuchsin (2%) solution' and to decolourize and counterstain their smears for detection of AFB- (henceforth called pot method) and to compare the smear results of pot method with the standard Ziehl-Neelsen (ZN) method.
Pot method missed 9 ZN positive smears (8 scanty and one 1+) and ZN method missed 9 pot positive smears (9 scanty) and the difference was not significant.
Students were to make a figure from the clay using the slab and pinch pot methods.