Sensitization of three strains of chlorococcal algae for UV- effects by 5- bromodeoxyuridine

J. Nečas

Biologia plantarum 18:1-12, 1976 | DOI: 10.1007/BF02922325

The sensitization of chlorococcal algae by 5-BdU for the purpose of UV-light mutagenesis was studied. The results obtained were compared with our earlier findings on the sensitization of the same algal strains by 5-BU. No shielding effect of the 5-BdU molecules against UV-light was observed. Probably, the uptake of them from the liquid medium did not result in such excess as compared with the treatment by 5-BU, even if the cells were long enough (24 h) exposed to the concentration of 5-BdU. Likewise, neither stimulating nor inhibiting growth effects on the growing cell colonies were observed after treatment with 5-BdU. The sensitization of the algal...

Anatomical characteristics of the epidermis in some cultivars ofBrassica oleracea L. distribution and structure of stomata in the cotyledons

Jarmila Novotná

Biologia plantarum 18:13-18, 1976 | DOI: 10.1007/BF02922326

The blade area and the number of stomata were studied in the cotyledons of five cultivars ofBrassica oleracea L., cultivated in a growth chamber and in the greenhouse, respectively. Characteristic differences between different varieties were found in the number of stomata per unit area as well as in their occurrence on both the adaxial and abaxial surfaces.

Growth correlations and rna synthesis in different parts of the shoot apical meristem ofChenopodium rubrunt L. induced to flowering

Frideta Seidlová

Biologia plantarum 18:19-25, 1976 | DOI: 10.1007/BF02922327

Uridine-³H incorporation and RNA concentration were investigated in different parts of the shoot apical meristem ofChenopodium rubrum using autoradiography and cytophotometry. A single inductive cycle was sufficient to bring about postinductive first events in the shoot apex but not for complete flower differentiation. The initial activation of RNA synthesis manifested itself in all zones of the apex. The first increase was more conspicuous in the peripheral than in the central zone. The indications of the first events in the apices after a single inductive cycle disappear prior to morphological reversal to the vegetative state. Induction...

Effect of calcium and sucrose concentration on pollen germination invitro of sixRosa species

Marie N. Končalová, Dagmar Jičínská, Olga Sýkorová

Biologia plantarum 18:26-30, 1976 | DOI: 10.1007/BF02922328

The germination of the pollen from11 individuals of six wildRosa species was studied. The presence of calcium resulted in increased pollen germination, longer pollen tubes, and in a decrease of the requirement of sucrose concentration in cultivation media. Pollen germination in the medium with Ca reached the values of pollen viability estimated by tetrazolium test in all cases except with roses with balanced heterogamy, of the sectionCaninae. The stimulating effect of calcium was generally most pronounced in the pollen from roses of hybrid nature, such asR. jundzillii, R. canina, and especially in the case of the calciphilous...

Book Review

Ingrid Tichá

Biologia plantarum 18:30, 1976 | DOI: 10.1007/BF02922329

Radioresistance of kohlrabi (Brassica oleracea L, var.gongylodes L.) seeds in relation to the metabolism of indoles, auxins and gibberellins

Květa Vackova, M. Kutáček

Biologia plantarum 18:31-35, 1976 | DOI: 10.1007/BF02922330

Irradiation of the seeds of radioresistant kohlrabi with gamma-rays causes at doses SO to 300 kR a decrease in growth and a drop in tryptophan (Try) level in seven-day-old plants. The level of glucobrassicin (GLUBR), 3-indolylacetonitrile (IAN) and gibberellic acid (GA3) in these plants increases up to a maximum with a dose of about 150-200 kR, afterwards it decreases. We assume that the specific system of auxin synthesis inBrassicaceae plants takes an important part in the reparation processes and thus in the radioresistance of these plants as well. In contrast to the divergent systems of auxin biosynthesis in other plants which are damaged...

Cytochrome oxidase and ascorbic acid oxidase activities in cereal plants

Naděía Růžičková-Skřipská

Biologia plantarum 18:36-43, 1976 | DOI: 10.1007/BF02922331

Cytochrome oxidase and ascorbic acid oxidase activities were investigated in rye, wheat, barley and oat plants. The variations in the activity of both enzymes was followed in the course of the initial 28 days of growth, as well as at the phase of milk ripeness, namely in the cytoplasmic and mitochondrial cell fractions of roots, leaves and spikes.Both enzymes were active in all measurements. Cytochrome oxidase mostly exhibited a higher activity than ascorbio acid oxidase. The activity of the former enzyme was substantially higher in the mitochondrial fraction of leaves, roots and spikes of the four experimental plants in comparison with the cytoplasmic...

Book Review

Ingrid Tichá

Biologia plantarum 18:43, 1976 | DOI: 10.1007/BF02922332

The evaluation of the root system of mustard by means of its dielectric characters with respect to the yield

O. Chloupek

Biologia plantarum 18:44-49, 1976 | DOI: 10.1007/BF02922333

When examining plants of white mustard (Sinapis alba L.), a significant relationship between the size of the roots and the yield was found, both in a pot experiment and in a field one. The yield was influenced by the size of the root system during and after flowering time. Especially the number of seeds has increased, and the average weight of seeds showed the same tendencies after the flowering time. The productivity of plants with an above-average yield was increasing more quickly than the size of their root system. From the beginning of the vegetation till the end of flowering these most efficient plants showed the lowest permitivity dispersion...

Book Review

J. Tupý

Biologia plantarum 18:49, 1976 | DOI: 10.1007/BF02922334

Nucleic acid synthesis and effect of glucose on its kinetics in cotyledons ofChenopodium rubrum l. during photoperiodic induction

Lola Teltscherová, Dagmar Pleskotová

Biologia plantarum 18:50-57, 1976 | DOI: 10.1007/BF02922335

In cotyledons ofChenopodium rubrum L. polydisperse RNA is synthesized in the region of the low molecular weight RNAs during photoperiodic induction. After short-time labelling the rate of 4s RNA synthesis was always higher in induced plants than in plants having obtained a light-break in the middle of the dark period. When glucose was added to the nutrient medium during the dark period of a single photoperiodic cycle the rate of nucleic acid (NA) synthesis was higher in non-induced plants than in induced ones at the termination of the dark period. In plants induced by two cycles in the absence of glucose the rate of NA synthesis at the termination...

Nonrelatedness between symptoms and cucumber virus 4 content in different cucumber cultivars

M. Čech, Hana Branišová

Biologia plantarum 18:58-62, 1976 | DOI: 10.1007/BF02922336

The virus replication capacity (determined by density gradient centrifugation and spectrophotometric virus assay) and severity of symptoms were compared in ten cucumber(Cucumis sativus L.) cultivars infected by cucumber virus 4. Except the expected resistant susceptible and symptomless virus carrier plants a new paradoxial group of cultivars was found. This group is characterized by low virus reproduction rate but simultaneously associated with severe symptoms and is responsible for difficulties in the virus transmission and purification. It is concluded that the critical evaluation of the resistance against viruses of TMV-group must include...

Book Review

Jana Pospíšilová

Biologia plantarum 18:62, 1976 | DOI: 10.1007/BF02922337

Finding of lettuce big vein virus in Czechoslovakia

J. Chod, J. Polák, V. Kůdela, M. Jokeš

Biologia plantarum 18:63-66, 1976 | DOI: 10.1007/BF02922338

Big vein disease occurring on lettuce plants cv. 'Pražan' was identified and the susceptibility to this disease was tested on 9 lettuce cultivars of foreign origin. Lettuce big vein virus was confirmed to be the cause of the disease. The transmission of the LBVV by the fungusOlpidium brassicae (Wor.)Dang., the sporangia of which were found by microscopy in the cells of surface tissues of lettuce roots, was experimentally proved. Rod-like particles, the average length of which was estimated at 244 nm, were found in the roots of diseased plants. LBW transmission by mechanical inoculation and by aphids could not be proved.

Uptake of potassium by rice plants at different stages of growth

N. K. Fageria

Biologia plantarum 18:67-71, 1976 | DOI: 10.1007/BF02922339

Uptake of potassium by rice plants at different stages of growth can be described by a biphasic isotherm in the range of 5 × 10^-5 M and is probably mediated bya multiphasic mechanism in the plasmalemma.

Book Review

Ingrid Tichá

Biologia plantarum 18:71, 1976 | DOI: 10.1007/BF02922340

Germination of the seeds of Chenopodium bonus-henricus. mechanism of germinating inability in seeds collected at high altitudes

A.- J. Dorne, D. Côme

Biologia plantarum 18:72-77, 1976 | DOI: 10.1007/BF02922341

A decreased germination capacity of the seeds ofChenopodium bonus- henricut collected at high altitude is not due to an embryo dormancy. It is caused by a seed coat inhibition. The seed coats contain large amount of strongly oxidisable phenolic compounds which deprive the embryo of oxygen.

The occurrence of auxins in the old leaves of apple trees

R. Bulgakov, L. Chvojka

Biologia plantarum 18:78-80, 1976 | DOI: 10.1007/BF02922342

A relatively high auxin level was found in old leaves from the lower part of long shoots of young apple trees using the straight growth bioassay on wheat coleoptile segments. The auxin level remains almost constant during summer and autumn.