Respiration of sugar-beet leaves during illumination, with simultaneous photosynthesis

A. S. Okanenko, D. M. Grodzinsky, V. P. Batyuk

Biologia plantarum 3:169, 1961 | DOI: 10.1007/BF02933559

The intensity of respiration and of photosynthesis were investigated simultaneously in sugar-beet leaves not detached from the plant. Several hours before the experiment the leaves had assimilated radioactive¹⁴CO2 whereafter they were placed into a normal leaf chamber for continuous gasometric estimation of the intensity of photosynthesis, according to the changes in the concentration of carbon dioxide in the passing air. At the same time, the specific activity of C0₂ was measured in the air that had passed through the assimilation chamber. From the values of the specific activity of CO₂ produced by the leaf in the...

The effect of photoperiodic régime on vernalization of winter wheat

Jan Krekule

Biologia plantarum 3:180, 1961 | DOI: 10.1007/BF02933560

1. Photoperiodic experiments with the effect of short day during vernalization of winter wheat under field conditions have shown that the short day enhances development if applied during vernalization. Short day applied after vernalization prolonged the development.2. At low intensity artificial illumination and under optimal vernalization temperatures vernalization proceeds the faster the longer the illumination. On increasing illumination intensity differences between the effect of short and long day are obliterated. Vernalization in the dark takes place only if saccharides are added.3. It is assumed that even in green plants the accumulation...

Antagonism betweenRhizoctonia solani Kühn and certain soil saprophytes: A laboratory study

K. B. Deshpande

Biologia plantarum 3:192-199, 1961 | DOI: 10.1007/BF02933561

Antagonism of three saprophytes to the pathogen,Rhizoctonia solani was studied in plate cultures under different conditions of temperature, pH, and nutrition. The antagonistsTrichoderma viride andChaetomium cochlioides were found more effective in the inhibition of the growth ofR. solani at temperatures 25 and 20° and this conforms to their growth-temperature relationship.T. viride was found more effective in acid media as reported by others, whereas other antagonists and especiallyC. cochlioides was more effective in the alkaline medium. Hence the suggestion is made that soil amendments increasing the activity...

A method of rapid examination of meiosis in fruit-trees

Jan Uhlík

Biologia plantarum 3:200, 1961 | DOI: 10.1007/BF02933562

The extent of material that had to be examined in the cytological evaluation of 40 varieties of the Czechoslovak basic assortment of pears made it necessary to work out a new, rapid method of investigation.This method makes it possible to obtain permanent sections from about 1800 anthers within three days. During the first day, a total of three series can be imbedded in paraffin wax and each of these may contain about 600 anthers. There is sufficient time during the second day to section the three series and place the sections in gallocyanin where they are left overnight. On the following day, the sections containing about 1800 anthers are imbedded...

The cytological evaluation of some pear-sorts cultivated in Czechoslovakia

Jan Uhlík

Biologia plantarum 3:205, 1961 | DOI: 10.1007/BF02933563

The author carried out a cytological evaluation of 40 varieties of the basic Czechoslovak assortment of pears. Thirty of these were diploid and ten were diploid.In addition to the chromosome number of these varieties, he determined the average dimension of the leaf stomata, to prove that it is possible to use this method in pear trees to make a reliable differentiation between diploid and triploid varieties. From a determination of the average lengths of the stomata it follows that the diploid varieties of pears can be distinguished from the triploid varieties by means of this criterion.A further, very accurate mark of difference between diploid...

Transmission ofMarmor cichorii Kvíčala toChenopodium giganteum Don

Jaroslav Brčák

Biologia plantarum 3:215-216, 1961 | DOI: 10.1007/BF02933564

The use of the quantitative ring precipitation reaction for determining the intensity of cross reactions with special reference to comparative serology

Josef Kloz

Biologia plantarum 3:217, 1961 | DOI: 10.1007/BF02933565

Practical directions and examples are given for the use of quantitative ring precipitation to determine the intensity of cross reactions. The ability of this method to reproduce objectively the intensity of an antigen-antibody reacting system under various concentrations was verified. A comparison was made between Boyden's method of "complete curves" and the quantitative ring precipitation method.The advantage of using quantitative ring precipitation is the saving of antiserum (0.05 ml. is sufficient for one determination), the smaller demand on working time and a noticeably reduced sensitivity to non-specific factors.Quantitative ring precipitation...

Wheat dwarf virus disease

Josef Vacke

Biologia plantarum 3:228-233, 1961 | DOI: 10.1007/BF02933566

Proof is given in this paper that dwarfing of wheat, which occurs in several regions of Czechoslovakia, is a virus infection. The virus was transmitted by means of naturally infected imagos of the leaf-hopperPsammotettix alienus DAHLB. to spring wheat and spring barley. It was also found that it is transmissible to a high degree by larvae grown from eggs which are then artificially infected at the source of infection. An attempt to transmit the virus by means of the aphidsBhopalosiphon oxycanthae (SCHRANK.) andSitobium granarium (KIRBY) MORDV. was negative. Nor was it possible to transmit it by soil, wheat grains or by mechanical...

On the determination of the course and termination of photoperiodic sensitivity in spring wheat (Triticum aestivum L.)

Frideta Seidlová-Blumová

Biologia plantarum 3:234-244, 1961 | DOI: 10.1007/BF02933567

Photoperiodic experiments with the spring wheat Niva were undertaken to investigate the course of photoperiodic sensitivity and localization of the dhotoperiodic reaction in the ontogeny of plants. The long-day plant used, however, was not amenable to detecting a period during which a shortened day would be completely devoid of effect on the rate of development. Some data indicate, however, that a period of increased photoperiodic sensitivity can be defined which would correspond to the period of photoperiodic reaction of short-day plants. The results also seem to indicate that this period does not terminate abruptly but gradually passes over into...

Application of the leaf-disk method to the determination of photosynthesis in cereals

Lubomír Nátr, Josef Špidla

Biologia plantarum 3:245-251, 1961 | DOI: 10.1007/BF02933568

A modification of the leaf-disk method of BARTOš, KUBíN and ŠETLíK (1960) is described for use in studying photosynthesis in cereals. In place of leaf-disks segments of 2 cm. in length are used. Two segments are cut by a punch from each leaf, one segment serving for the determination of dry weight at the beginning of the experiment, the second being exposed in a chamber under constant conditions. In view of the heterogeneity of the leaf, two segments from the opposite parts of the leaf must be used for each sample. A suitably modified support is also described for holding the segments in order to ensure their saturation with water. Dry weight increments...