Kamila Vágnerová

Rhizosphere microflora of wheat

SummaryThe composition and some properties of bacterial flora isolated from root surface, from the rhizosphere and control soil during the initial stages of wheat growth were studied. Isolated bacteria were divided into groups according to their morphological properties, their nutritional requirements and growth intensity and according to some biochemical properties.It was found that the bacterial flora of the root surface, of the rhizosphere and control soil during the initial stages of wheat development differ in the occurrence of morphological types, nutritional requirements and growth activity. The rhizosphere effect was also quite marked in the percentage of bacterial genera in the above three zones.It was shown by comparing the properties of bacterial flora of seeds and of soil in which the wheat was grown that the seed bacteria, in common with the soil bacteria, can move over to the roots but that the physiologically more active soil bacteria become predominant and markedly affect the composition of the rhizosphere population.AbstractИзуались состав и некотоые свойства бактериальной ϕлоры, выделенной с поверхности корней, из ризосϕеры и из свободной ночвы в начальных ϕазах роста ншепицы.. Выделевные бактерии были разделены на групиы по своим морϕологическим свойствам, по требованиям кпитанию, по интенсивности роста и по некоторым биохимическим свойствам.Было установлено, что существуют различия между представителями бактериальной ϕлоры с поверхности корпей, из ризосϕеры и из свободной почвы в начальных ϕазх развития пшепицы, что касается морϕологических тиов, требований к литанию и активности роста. И что касается родов бактерий, представленных в этих трех зонах, заметно проявился эϕϕект ризосϕеры.Сравнение свойств бактериальной ϕлоры семян и почвы, в которой лшенида выращивалась, показало, что бактерии семян так же, как и бактерии почвы, могут переходит на корни, но ϕизиологически более активные почвенные бактерии получают преимущество и оказывают главное влияние на соств популяции ризосϕеры.

Rhizosphere microflora of wheat. I. Composition and properties of bacterial flora during the first stages of wheat growth, II. Composition and properties of bacterial flora during the vegetation period of wheat.

SummaryThe composition and some properties of bacterial flora isolated from root surface, from the rhizosphere and control soil during the initial stages of wheat growth were studied. Isolated bacteria were divided into groups according to their morphological properties, their nutritional requirements and growth intensity and according to some biochemical properties.It was found that the bacterial flora of the root surface, of the rhizosphere and control soil during the initial stages of wheat development differ in the occurrence of morphological types, nutritional requirements and growth activity. The rhizosphere effect was also quite marked in the percentage of bacterial genera in the above three zones.It was shown by comparing the properties of bacterial flora of seeds and of soil in which the wheat was grown that the seed bacteria, in common with the soil bacteria, can move over to the roots but that the physiologically more active soil bacteria become predominant and markedly affect the composition of the rhizosphere population.AbstractИзуались состав и некотоые свойства бактериальной ϕлоры, выделенной с поверхности корней, из ризосϕеры и из свободной ночвы в начальных ϕазах роста ншепицы.. Выделевные бактерии были разделены на групиы по своим морϕологическим свойствам, по требованиям кпитанию, по интенсивности роста и по некоторым биохимическим свойствам.Было установлено, что существуют различия между представителями бактериальной ϕлоры с поверхности корпей, из ризосϕеры и из свободной почвы в начальных ϕазх развития пшепицы, что касается морϕологических тиов, требований к литанию и активности роста. И что касается родов бактерий, представленных в этих трех зонах, заметно проявился эϕϕект ризосϕеры.Сравнение свойств бактериальной ϕлоры семян и почвы, в которой лшенида выращивалась, показало, что бактерии семян так же, как и бактерии почвы, могут переходит на корни, но ϕизиологически более активные почвенные бактерии получают преимущество и оказывают главное влияние на соств популяции ризосϕеры.

Rhizosphere microflora of wheat. III. Fungal flora of wheat rhizosphere.

SummaryAn investigation was made of the extent to which the rhizosphere effect is reflected in the composition of mycoflora in the wheat rhizosphere during the initial stages of growth and during the vegetation period. It was found that during the initial phases of wheat growth no marked change took place in fungal counts in the rhizosphere and in control soil or on the roots. The fungal count in the course of the vegetation period was markedly lower in the rhizosphere and in fallow soil than on the roots.The qualitative composition of fungal flora differs both in the individual zones, i.e. on the roots, in the rhizosphere and in control soil, as well as during the vegetation period. The incidence of genera of the familyMucoraceae increased on the roots during the initial stages of development; during the vegetation period the number of genera of the familyTuberculariaceae, Dematiaceae and of fungi with dark sterile mycelium rose gradually. The familyMucoraceae was represented more abundantly during the initial stages of development on the roots than in soil, the familyMoniliaceae occurred during the entire period of vegetation principally in soil. It was found that during colonization of roots the fungi originating from soil assert themselves more pronouncedly than those from seeds.Different methods of isolation of soil, rhizosphere and root fungi were compared in order to find out to what extent the results concerning fungi isolated from the rhizosphere of wheat are affected by the application of different methods. By using the common dilution method only 15 genera were detected, while 21 could be identified by the soil plate method and 23 by the washing method.AbstractИзуался вопрос, до какой степени эϕϕект ризосϕеры проявляется в составе микоϕлоры в ризосϕере пшеницы в начальных ϕазах роста и в течение периода вегетации. Было установлено, уто происходит выразительных изменений в количестве грибов ни в ризосϕере В течение периода вагетации количе-ство грибов на корнях бывало вше, чем в ризосϕере и в свободной почве.Качественный состав грибной ϕлоры колеблется как в отдельных зонах, т.е.на корнях, в ризосϕере и в свободной Число представитей родов семейства Мucoraceae на корнях увелчивалось в начальных ϕазах развития. В хоце вегетации на корнях увеличивалось число родов семйств Tuberculariaceae, Dematiaceae и грибов с темным стерильным мицелием. Семейство Мucoraceae в начальных ϕазах разви тия было представлено более значительным числом родов на корнях, чем в почве, семейство Moniliaceae встречалось в течение всего периода вегтации, главным образом в почве. Было установлено, что при заселении корней грибы почвы имеют большее значение, чем грибы, бышие на семенах.Путем сравнения различных методов выделения грибов из почвы, из ризосϕеры и с корней было установлено, докакй степни результы выделения было найдено только 15 родов, с помощью метода пластинок почвы -21 род, а методом смывов – 23 рода.

The effect of microorganisms and sorption on the protease activity of plant roots

The protease activity of sterile roots of wheat was zero or very low, so that the determined values did not exceed limits of the experimental error. Roots colonized by microorganisms had a significant protease activity. The activity of protease on seeds and roots of the plants growing in a medium inoculated with the soil microflora was higher than in cases when only the epiphytic microflora of seeds served as a source of microorganisms. Sterile roots inoculated with three different strains of bacteria isolated from the rhizosphere and producing protease exhibited a considerable protease activity. The protease activity of non-sterile roots of plants growing in the dark was higher than that of plants growing under normal illumination. Crystalline proteinase was adsorbed on sterile roots and the activity of the enzyme was decreased in this adsorbed state. The adsorption of the enzyme was only slightly higher in the presence of calcium ions. Treatment of roots with a sodum chloride solution, with dextran and ethanol increased the adsorption of the proteinase by roots.

Production and utilization of aminoacids by various species of Rhizosphere Bacteria

SummaryRoot surface and rhizosphere soil of wheat were used for the isolation and identification of 11 species of microorganisms growing in the basic medium and releasing different amino acids into the medium. Asparagine, serine, aspartic acid, α-alanine and methionine (valine) were found to be most abundant. In selected filtrates, qualitatively different with respect to their amino acid content, the above amino acids were utilized by a majority of the microorganisms tested for their growth. The authors are of the opinion that the microorganisms of root surface and rhizosphere growing in the basic medium only and liberating amino acids can have a certain significance for the ecology of rhizosphere microbial associations.AbstractБыло выделено с поверхности корней и из почвы ризосϕеры пшеницы и идентиϕицировано 11 видов микроорганизмов, растущих в минеральной среде с глюкозой и выделяющих в среду различные аминокислоты. Наиболее часто в ϕильтратах находились аспрагин, серин, аспарагиновая кислота, α-аланин и метионин (валин). В подобранных ϕильтратах, качественно различных по содержанию аминокислот, большая часть исследуемых микроорганизмов использовала эти амниокислоты для своего роста. Авторы полагают, что микроорганизмы споверхности корней и ризосϕеры, растущие только в минеральной средес глюкозой и выделяюощие аминокислоты, могут иметь определенное значение в экологии микробных сообществ ризосϕеры.

Relationships between plant roots, proteolytic organisms and activity of protease

Proteolytic bacteria represented 18–58% of the bacterial population isolated from the rhizoplane of different crops. The activity of protease was considerably higher on roots of wheat growing in the soil than in the rhizosphere or free soil. However, only a slightly positive rhizosphere effect in the relative occurrence of casein-hydrolyzing bacteria could be observed. An indirect relationship between numbers of bacteria hydrolyzing casein and the activity of the enzyme could be found. The activity of protease related to a unit of culturable proteolytic bacteria was considerably higher on the root than in the rhizosphere and in the soil. A relationship between characteristics of the production of the enzyme by proteolytic bacteria and the protease activity on the surface of roots was demonstrated. The resulting enzyme activity on the surface of roots depended apparently on growth conditions of the plant and nature of root exudates and was influenced both by inactivation and protection due to adsorption of the enzyme by roots.

Rhizosphere microflora of wheat@@@МИКРОФЛОРА РИЗОСФЕРЫ ПШЕНИЦЫ: II. Composition and properties of bacterial flora during the vegetation period of wheat@@@II. Состав и особенности бактериальной ϕлоры в течение периода вегетации пшеницы

SummaryThe composition and some properties of bacterial flora of the root surface, of the rhizosphere and of control soil during the vegetation period of wheat (earing, flowering, maturity and 5 weeks after harvesting) were studied. The morphology of isolated bacteria was examined and nutritional requirements and growth intensity determined.It was found that the bacterial flora isolated from these three zones differs in its composition and properties. Gramnegative rods are characteristic for the roots; bacteria of this zone require amino acids for growth and possess a high growth activity. Gram-positive coccoid forms and sporulating bacteria are typical for control soil; in this zone there is a higher incidence of bacteria with simple nutritional requirements. Bacteria of this zone also display a high growth intensity but in their composition they differ markedly from the bacterial flora of root surface. In the rhizosphere zone the effect of root flora and bacterial flora of control soil blend.An analysis of nutritional requirements and growth properties of the morphological groups of bacteria revealed differences depending on the zone from which the bacteria had been isolated. Among Gramnegative bacteria which are characteristic for the roots, the highest incidence of growth-active types was observed in root isolates; among Gram-positive cocci which are characteristic for soil, it was observed in soil isolates. The data obtained confirm the assumption of the selective influence of plant roots on the accumulation of certain groups or species of bacteria on the roots and in their vicinity.AbstractИсследовались состав и некоторые особенности бактенности бактериальной ϕлоры поверхности корней, ризосϕерной и свободной почвы в течение периода вегетации пшеницы (ϕазы колошения, цветения, восковой зрелости и через 5 недель после уборки). Определялись морϕология выделенных бактерий, их требования к питанию и интенсивность их роста.Было установлено, что бактериальная ϕлора, выделенная из этих трех зон, различна по своему составу и свойствам. Для корней характерны грам-отрицательные палочки; бакерии этой зонынуждаются для роста в аминокислотах и отличаются высокой активностью роста. для свободной почвы характерны грам-положительные кокки и спороборазующие разующие бактерии; в зтой зоне встречаетя больше бактерий со скромными требованиями к нитанию; бактерии этойзоны также отличаются большой интенсивностью роста, но по своему составу отчетливо разнятся от бактериальной ϕлоры поврхности корней. В эоне ризосϕеры перемешивается влияние ϕлоры корней и бактерий свободной иочвы.Анализ требований к питанию и особенностей роста морϕологических групп бактерий показал их различия в зависимости от тго, откуда были данные бактерии выделены. Среди грам-отрицательных бактерий, характерктерных для корней, наибольшая встречаемость типов с активным ростом наблюдалась в изолятах с корней; среди грам-положительных кокков, характерных для свободной почвы, - в изолятах из почвы. Полученные нами данные подтверждают наличие селективнго действия корней растений на скопление определенных групп или видов бактерий на корнях и вблизи корней.

Determination of protease activity of plant roots

The colorimetric method described by Charney and Tomarelli (1974) for the assay of the proteolytic activity in the duodenal juice was adapted to measuring protease activity of roots. Diazotized casein served as substrate and the amount of degraded azocasein was measured colorimetrically. A linear relationship between the incubation time or concentration of the enzyme (roots) and the amount of the hydrolyzed substrate was found. The rate increase of the enzyme reaction was proportional to enzyme concentration up to 1 g roots and incubation time of 3 h, and up to 0.5 g of roots and incubation time of 4 h. The optimum of the protease activity was at pH 8.2–8.6.