Vlasta Čatská

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 micro-organisms in relation to the apple replant problem

SummaryOne of the factors giving rise to soil sickness in apple orchards is the rhizosphere microflora. The composition of the microbial coenosis in the rhizosphere changes with increasing age of the apple trees. An increase in the counts of micromycetes and actinomycetes and a decrease in bacterial counts was found in agreement with the decreasing pH of the rhizosphere soil. The presence of fluorescent pseudomonads in the rhizosphere of old apple trees was rare, but the planting of apple seedling into sick soil induced their proliferation. The relative proportion of individual genera of micromycetes changed according to the tree age; fungi of the genus Mucor were more often found in the rhizosphere of younger trees than in that of older ones while fungi of the genus Penicillium had an opposite trend. Biological tests showed that Penicillium fungi form the majority of the phytotoxic microflora. The amount of phytotoxic micromycetes was higher in ‘sick’ soil as compared with control soil in which apple trees had not been grown for at least 15 years. Higher numbers of phytotoxic micromycetes were isolated also from the rhizosphere of apple seedlings grown in ‘sick’ soil as compared with those growing in control soil. An increase in the amount of phytotoxic micromycetes in apple tree rhizosphere could be induced by mere addition of 5% (w/w) ‘sick’ soil to the soil in which apple trees were grown for the first time. By adding sterilized ‘sick’ soil, the amount of phytotoxic micromycetes in the apple seedling rhizosphere was not affected. Increased numbers of phytotoxic micromycetes affected negatively the growth of apple trees and the morphology of apple tree roots. This demonstrated the possibility of transfer of a factor participating in the etiology of soil sickness in apple orchards.

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 volatile and gaseous metabolites of swelling seeds on germination of fungal spores

Effects of volatile and gaseous metabolites of swelling seeds of pea, bean, wheat, corn, cucumber, tomato, lentil, carrot, red pepper and lettuce on germination of spores of five genera of fungi were found to depend rather on the fungal than on the plant genus. Germination of spores ofBotrytis cinerea, Mucor racemosus andTrichoderma viride was most severely inhibited. Spores ofVerticillium dahliae were less sensitive and germination of spores ofFusarium oxysporum was inhibited only in two cases. On the other hand, exudates of pea and bean stimulated germination of spores ofFusarium oxysporum. Also spores ofTrichoderma viride germinated better in an atmosphere enriched with exuded metabolites of swelling lettuce seeds. When carbon dioxide produced by the swelling seeds was absorbed in potassium hydroxide, spores ofTrichoderma viride andVerticillium dahliae did not germinate at all, the inhibitory effects of volatile and gaseous exudates on germination of spores ofMucor racemosus were accentuated, and also the percentage of germinated spores ofFusarium oxysporum decreased. Germination of spores ofBotrytis cinerea was not influenced. Absorption of volatile and gaseous metabolites in a solution of potassium permanganate decreased in most cases their inhibitory effects, particularly inBotrytis cinerea.

Rhizosphere mycoflora of wheat after foliar application of chlorocholine chloride, urea and 4-chloro-2-methylphenoxyacetic acid

A single-step spraying of wheat during shooting under field conditions with solutions of CCC (chlorocholine chloride), CCC and urea, CCC and Aminex (ammonium salt of 4-chloro-2-methylphenoxyacetic acid), or CCC, urea and Aminex caused changes both in numbers and composition of the rhizosphere mycoflora. The numbers both in the rhizosphere of differently treated plants and in the free soil decreased during vegetation. A more pronounced effect in the number of fungi was demonstrated in plants treated only with CCC. The difference was more considerable during first 10 days after the spray. As far as the relative occurrence of individual genera in the rhizosphere soil is concerned, fungi of the generaPenicillium Link ex Fr.,Fusarium Link ex Fr.,Verticillium Nees andTrichoderma Pers were most influenced after the treatment with the used agents.

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.

Volatile and gaseous metabolites released by germinating seeds of lentil and maize cultivars with different susceptibilities to fusariosis and smut

The effect of volatile and gaseous metabolites released by germinating seeds of lentil cultivars more and less susceptible to fusariosis on the germination of spores ofMucor racemosus, Trichoderma viride, Verticillium dahliae andBotrytis cinerea was found to depend rather on the fungal genus than on the lentil cultivar. However, spores ofFusarium oxysporum reacted more sensitively during germination to the presence of exudates of both cultivars, when the more susceptible lentil displayed a stimulation, the less susceptible one an inhibition of spore germination. The greatest difference in the effect of exudates was observed in the more and less susceptible maize cultivars with respect to the germination of chlamydospores ofUstilago maydis, especially during the first hours of seed germination. Analysis of the exudates of germinating seeds showed the release of a greater amount of ethanol and methanol with acetaldehyde by the more susceptible cultivars of lentil and particularly maize.

Effect of volatile and gaseous metabolites of germinating pea seeds on micromycetes

Differences in the effect of volatile and gaseous metabolites of germinating pea seeds on the germination of spores ofMucor racemosus and macroconidia ofFusarium oxysporum are described. Germination of spores ofM. racemosus was inhibited by seed metabolites whereas germination of macroconidia ofF. oxysporum was stimulated during the first two days and inhibition occurred only after further two days of germination of the seeds. A pronounced inhibition of germination of spores of both micromycetes took place due to absorption of CO2 from volatile and gaseous metabolites. Absorption of some components of seed metabolites in a KMnO4 solution led to a decrease of the inhibitory effect on germination of spores ofM. racemosus and stimulatory effect on germination of macroconidia ofF. oxysporum.

Bodenmüdigkeit in Apfelanlagen

Summary Composition of microbial population in the rhizosphere of apple trees changed with the increasing age of the trees. The total number of bacteria, including fluorescent pseudomonads, decreased and that of micromycetes increased, fungi of the Mucor genus disappeared, while Altemaria and Penicillium spp. proliferated. Alternatia tenuis, Penicillium expansum, Penicillium griseofulvum, and Penicillium claviforme predominated in the rhizosphere of 70-year-old apple trees. These genera produced in vitro the phytotoxins griseofulvin, methyl-salicyl acid, and patulin. It was possible to induce “soil sickness” by inoculating the roots of apple seedlings with Penicillium claviforme (the microbial pattern of the rhizosphere changed thereafter). Fluorescent pseudomonads occurred rarely in the rhizosphere of the 70-year-old apple trees, however, after planting apple seedlings in the “sick” soil, the proliferetion of these pseudomonads was stimulated. Inoculation of apple seedlings with Pseudomonas putida increased the occurrence of fluorescent pseudomonads in the rhizosphere and inhibited the growth of seedlings. The growth of apple seedlings in the “sick” soil was stimulated by the inoculation of their roots with another Pseudomonas sp., which exhibited in vitro mycolytical properties and in pot experiments decreased the amount of phytotoxic micromycetes in the rhizosphere. The repeated urea treatment of seedling leaves and of the soil did not affect the growth of seedlings in the “sick” soil, while in normal control soil a significant positive effect was observed. The growth and yield of wheat, that was grown in the “apple-sick soil” in the following year, was not affected; wheat grown in “sick” soil responded positively to urea treatment of leaves and soil. It is assumed that in the rhizosphere of apple trees Penicillium spp. and other phytotoxic microorganisms produce continously a certain amount of phytotoxins which affect the growth of trees and probably also the fruit yields. The introduction of suitable antagonistic microorganisms into the rhizosphere could decrease the number of phytotoxic micromycetes and improve the growth of apple seedlings.