Different NaCl concentrations in a nutrient medium ofGossypium hirsutum L. induced a different decrease in the rates of photosynthesis and photorespiration in two cultivars.

Cultures of isolated mesophyll protoplasts ofBrassica napus L.have shown a positive reaction with the acidic phloroglucinol test for lignin (Wiesner reagent) 30 h after the beginning of the culture period. The reaction was observed in protoplasts and in a very early stage connected with divisions, in which acidic phloroglucinol positive material was primarily deposited like a girdle surrounding the division plane. Brown exudates, which are a serious problem even in young cultures derived from isolated protoplasts, have been secreted into the medium by cells, and also showed a positive reaction. The same staining pattern has been found with toluidine blue 0.

Ethylene production and growth of callus cultures of lavandin (Lavandula offidnalis Cham x Lavandula latifolia Villars) cv. Grosso were examined. Callus lines, derived from various kinds of primary expiants (shoot tip, leaf and calyx), exhibited differences in ethylene production patterns independent of callus growth. Moreover these differences could not be ascribed to the expiant source. Within a line, ethylene pattern paralleled callus growth curve. Variations in ethylene evolution were induced in shoot tip callus by means of ACC, AVG and varied amounts of 2,4-D in the culture medium. Following all these treatments callus growth was not altered. Hie decrease in 2,4-D concentration caused changes in Chl a and water content of the tissues.

Effects of phorate (Thimet-10 G) on the activities of enzymes of nitrogen metabolism,viz., glutamine synthetase (GS), glutamate dehydrogenase (GDH), and glutamate synthase (GOGAT) in the primary leaves, nitrogenase (N₂-ase) in detached root nodules, and protein concentration in the primary leaves ofVigna mungo (L.) Hepper have been studied. Phorate stimulated the activities of these enzymes and protein concentration in primary leaves at lower concentrations (50 to 200 mg per pot), but inhibited at higher concentrations (400 to 600 mg per pot). Although, the V_max for each enzyme with different treatments varied, the K_m value of each enzyme in the control and the treated plants remained unaltered.

Protein and RNA contents and synthesis were evaluated in the course of wheat grain (T. durum cv. Cappelli) development. Embryos and endosperms were considered separately during five phases from the 20th day after anthests until full ripenes was reached. No clean-cut changes were observed in the pattern of soluble proteins of the embryos. In the endosperms protein synthesis continues till the later phases and appears to be due to the albumin + globulin component. Screening of bands of endosperm proteins from electrophoresis indicates that the gliadins are synthesized early, with the exception of a Ω - gliadin. Glutelins with high relative molecular mass also appear to be synthesized when the grain approaches full ripeness.
The RNA content of the embryo and the endosperm is high in the early stages, when high cell proliferation occurs, and declines later on. The synthesis of RNA during in vitro imbibition is, however, higher in the later phases of ripening. Most of RNA synthesized in the embryos was ribosomal.

We have studied the effect of glucose on different enzyme activities in callus cultures of N.plumbaginifolia. We provided evidence that the increase in glucose concentration represses the synthesis of GDH, AcPh and MDH whereas ADH and LDH are unaffected. When glucose repressed cultures were transferred to the low glucose concentration medium the activity of GDH and AcPh resumed to the level shown by non repressed cultures. Sucrose and fructose were as effective as glucose in repressing GDH activity. These results support the hypothesis of the existence of a catabolite dependent regulation of enzyme synthesis in higher plants.

The accumulation of nitrogen and potassium by plant cells at undesirable concentrations manifests itself in changes in the osmotic phenomenon and finally in the transport process. Temperature gradient is another factor influencing the transport phenomenon. We have followed the changes in the electric diffusion potential and the heat transfer under the influence of these two factors on transport properties of roots of plants grown under conditions of either salinity or nutrient deficiency on the transport of KG solution through segments of the first node roots and of the primary root. Physical causes of the accumulation of the above mentioned ions were then studied by means of a mathematical model. The results obtained showed that high KNO₃ concentration in nutrient solution caused an inhibition of volume and heat flows, stimulated osmotic flow, and reduced electrical polarization of root cells. Cell polarization was slowed down when temperature gradient was increasing and enhanced when temperature gradient was decreasing. This indicates that the pressure difference between the exterior and the interior of root cells was levelled off by osmotic water flow but not by potassium ion flow.

Physiological regions of yam tubers were morphologically defined in different specie into 'Head', 'Middle' and 'Tail', while the limits of these regions were studied using phosphorylase activity. Variation in enzyme activity, pH and protein concentration was found in different regions of the tubers. Old yam tubers had significantly higher activities of saccharide degrading enzymes, hexokinase, phosphorylase, glucose-6-phosphate dehydrogenase, phosphofructokinase and pyruvate kinase, than the new tubers. However, activity of phosphofructokinase in newD. rotundata was higher than that of old tuber. The high activity of phosphorylase in different regions of all the yam tubers examined indicates a very important role of this enzyme in starch degradation inDioscorea species. The measured pH and protein concentration were also higher in old yam tubers. Except for phosphorylase, these enzymes had alkaline pH optima.

Five independent tobacco regenerant clones obtained after transformation withAgrobdcterium rhizogenes strain TR101 (four clones of the T phenotype, clone 5 a mixture of plants of the T and T' phenotypes) and untransformed plants cultivatedin vitro were gradually acclimated to the atmosphere and transferred to the soil substrate in pots. During 28 d after transplanting the increase of the leaf area was in T phenotype plants greater than in untransformed plants, but 14 d later no significant differences were observed between T phenotype and untransformed plants in leaf area and dry matter. T'phenotype plants, however, had significantly lower values in all growth parameters than T phenotype and control plants. Abaxial net photosynthetic CO₂ uptake (PN) was in both T (clones 1-4) and T' plants significantly lower than that in control and clone 5T plants. Nevertheless, due to the relatively higher adaxial PN in T plants, the total PN through both leaf surfaces was significantly lower only in clone 4 and clone 5' plants. The tendency to higher transpiration rates (E) in clones 1 - 4 in comparison with the control resulted in significant differences in water use efficiency (W.U.E.). Relatively higher E in T plants of clones 1 - 4 was connected most probably with their more developed root system (greater root dry-matter) than in untransformed plants, because no influence of the differences in stornata density on E was found.

The pattern of the activity of arginine decarboxylase (ADC) and omithine decarboxylase (ODC) involved in polyamine synthesis in ripening wheat seeds was examined. The aim was to study the polyamines and the activity of the two enzymes in correlation with the growth processes occurring in the developing wheat seeds. The results obtained showed a very different pattern of polyamine content in the two organs of caryopsis, and that the two enzymes in the embryos have a higher activity than in the endosperms. Moreover, while in the embryos the ADC exhibits higher activity than the ODC, in the endosperms the activity of ODC is about similar to that of ADC. This pattern is discussed in relation to the different histological characteristics of embryo and endosperm tissues during seed development.

The influence of light of different spectral composition and levels of irradiance (2-40 Wm-²) on adventitious root formation (ARF) in birch shoot segments was investigated. Spontaneous rooting of shoot segments occurred in segments with intact apical or axillary meristems. Concerning ARF shoot meristems could be substituted by application of auxin. The very low rooting percentage of shoot segments in darkness was improved considerably by auxin application. Irradiation of cuttings was a requirement for a high percentage of spontaneous rooting. The promoting effect of light was dependent on its spectral composition and was the highest under red followed by white and blue light. The low rooting response under blue light was enhanced almost to the red light level by shielding the root-forming cutting base from light.

Soil drenches containing 250 μg of paclobutrazol or uniconazol (50 ml of a 17 μM solution) reduced the height of both corn (Zea mays L. cv. How.Sweet It Is) and soybean (Glycine max (L.) Merr. cv. A2) seedlings. With corn, uniconazol was considerably more active than paclobutrazol in reducing height whereas with soybean both compounds had similar dwarfing effects. The compounds increased foliar chlorophyll content and leaf thickness in soybean but had no effect on these parameters in corn. The increase in leaf thickness with soybean was due primarily to an increase in the thickness of the palisade cell layer. Chloroplast size and ultrastructure of both species were unaffected by the compounds. The growth regulators increased root diameter in both corn and soybean because of increased size of cortical parenchyma cells and particularly in soybean because of radial rather than longitudinal growth of the first few layers of the cortical parenchyma.

Cytochemical investigations on peroxidase localization during microsporogenesis inLarix europaea D.C.,Taxus baccata L. andPinus sylvestris L. have revealed striking differences in the localization and activity level of this enzyme linked with the developmental stage.
The localization and level of activity of peroxidase, typical of each stage, changed in the course of microsporogenesis in a strictly orderly way, giving a characteristic and stable pattern. The pattern of intracellular peroxidase localization proved to be the same for microsporogenesis of all the gymnosperms in question.
It is suggested that the identity of that pattern in plants so phylogenetically distant asTaxus baccata L. andPinus sylvestris L. indicates that peroxidase activity in gymnosperms' microsporogenesis is connected with the fundamental and genetically well stabilized processes of meiotic cytodifferentiation.
Moreover, enhanced peroxidase activity has been found in the sites of callose walls synthesis of dyads and tetrads, which suggests the participation of this enzyme in callose synthesis.

Studies on exogenous application of phenolic compoundsviz: p-hydroxybenzoic acid, resorcinol and chlorogenic acid each with concentration of 10^-4 M are done on the legume (Cajanus cajan (L.)Millsp.) AL-15. The effect of applied phenolic compounds as well as of structural differences in phenols indicate a marked influence of phenolic compounds in regulating growth processes in plants. Fresh and dry mass of various plant parts increased after foliar spray with phenols resulting in an improved harvest index. It is seen that phenols also play an important role in the initiation and development of nodules.

The cotyledons ofXanthium strumarium plants are of low sensitivity to photoperiodic treatment and contain only trace amounts of ABA under long-day conditions. The first pair of leaves, very sensitive to photoperiodic treatment, contains a higher level ofABA, decreasing with age of the plant. Prolonged short-day photoperiodic treatment increases the ABA level in the cotyledons but this is still 10times lower than in the first two leaves. Exogenous 10^-4M ABA increases the ABA level in the cotyledons to the level corresponding to that in the first leaves, and enhances the photoperiodic sensitivity of cotyledons. In contrast to cotyledons, the photoperiodic treatment affects the ABA level in the first pair of leaves only slightly. The authors propose that a high ABA level supports the transition of plants to flowering, while a low ABA level may be responsible for a low photoperiodic sensitivity of cotyledons inXanthium plants.

Electrophysiological processes were investigated in reception organs of photoperiodism in a model short-day plant,Chenopodium rubrum L. (selection 374), within the inductive cycle for flowering. Transorgan (surface) electric potential (E_tr) was measured as a potential difference between the first leaf surface and the roots of an intact plant, and between the surface of an excised leaf and the petiole base. The time-course of E_tr in intact plants showed irregular, or partially regular, oscillations within both phases of the inductive cycle and under continuous light. The highest amplitudes were during the postinductive light period. E_tr in excised leaves behaved practically in the same way as in intact plants. The E_tr oscillations were localized in leaves. In general, no electrophysiological changes were found in the reception organs within the inductive cycle which could be correlated with the formation and transport of floral stimulus, or with the attainment of an induced state. The results indirectly support the idea that the floral stimulus is chemical in nature.

A fertile plant with altered phenotype of oilseed rape (Brassica napus) spring cultivar HM-81 was regenerated from hairy root tumors incited by Agrobacterium rhizogenes 15834. Southern blot hybridization analysis revealed several copies of T_l and T_r-DNA of Ri plasmid.

Immature embryo and root meristem expiants of wheat were cultured on modified medium of Murashige and Skoog and Gamborg's medium supplemented with 2,4-dichlorophenoxy acetic acid. Morphogeriic callus cultures were obtained from both the expiants. The frequency of shoot formation varied from 22% to 48% from callus obtained from embryos while only root formation could be induced from root meristem expiants. Cultures from young and old non-differentiating calli, and calli with shoot and/or root formation at different intervals were analysed for isozymes of esterase, peroxidase and acid phosphatase for studying the morphogenic capacity. With the development of shoot and/or root from callus, some conspicuous isozymes appeared which indicates the involvement of these isozymes in root/shoot development rather than in the induction of morphogenesis in callus. Basic isozyme pattern of each enzyme for the callus was retained in all the callus stages.

An analysis of flows through primary root and first node root tissues of plants grown under conditions of salinity and nutrient deficiency induced by temperature gradients was carried out using. a mathematical model. The results obtained show that high KNO₃ concentration in Knop's nutrient solution (salinity) causes an inhibition of volume and heat flows and that the omission of KNO₃ from Knop's nutrient solution (deficiency) stimulates these flows. The causes of the inhibition lay in the fact that salinity reduced hydraulic, electric, and osmotic conductivity when compared with the control (Knop's solution), but relative to nutrient deficiency, it increased osmotic conductivity, electrodiffusion, diffusion, and filtration of heat flow induced by the electric and heat power. The causes of the stimulation were that deficiency partially decreased conductivities, similarly as salinity when compared with the control, and also decreased osmotic abilities of the system. By contrast, it increased heat conductivity and corresponding filtrations (diffusion-thermal, thermoosmotic). In first node root tissues, it increased all conductivities with the exception of electric conductivity, then osmotic, electroosmotic, diffusion, electrodiffusion, and filtration of heat flow and current flow, that is the number of possible ways of solution transport through root tissues increased.

Shoot multiplication of Larixdecidua was achieved using axillary and adventitious buds. The formation of axillary buds was stimulated on shoot tips soaked in a cytokinin solution (BAP 10-50 mg 1^-1 for 2-4 h. Adventitious buds were induced on cotyledons, needles and vegetative buds cultured on WPM or QL medium supplemented with cytokinin (BAP 1-3 mg 1^-1). The shoot formation from induced axillary and adventitious buds was promoted on WPM or QL medium containing a low concentration of auxin (IBA 0.1 mg 1^-1). Shoot multiplication of Pinussylvestris was stimulated on WPM, MS, and QL media supplemented with a low concentration of cytokinin (BAP 0.2 mg 1^-1) and auxin (IBA 0.1 mg 1^-1). Shoot segments produced 2-5 new axillary shoots within 4-5 weeks. Root initiation was stimulated on larch and pine shoots cultured first on WPM supplemented with auxins (NAA and IBA) and later transferred to auxin-free medium.

The mode of transport and regulative properties of phenylacetic acid (PAA) were studied in 11-cm long segments of pea epicotyls capable of growth. The transport of PAA m both the basipetal and aeropetal direction was limited to tissues situated immediately below and/or above the site of its application. PAA was able to promote the flow of¹⁴C-ABA in the acropetal direction. PAA-initiated thickening growth was probably the cause of this promotion.

Changes in free IAA level were studied in the leaves of the central stem zone of short-day tobacco (Mcotianatabacum, cv. Maryland Mammoth) and long-day tobacco(Nicotiana silvestris) in inductive photoperiodic regime after 10, 20, 30 and 40 d, respectively. The leaves of SD tobacco Mammoth showed a high free IAA level in vegetative plants kept under long days but it significantly decreased (by ca. 50 %) after 10, 30 and 40 short days, respectively. After 20 short days the IAA level was as high as in the leaves of plants at the beginning of inductive treatment. The changes of freeIAA level in the leaves of LD tobacco N.silvestris were similar to those of SD Mammoth, but the IAA level in this species was significantly lower than that of Mammoth throughout the investigated period. Consequently, the changes observed in N. silvestris were much less pronounced. Plants of both tobacco species were fully induced to flowering by 30 inductive days and this was associated with differentiation of the flower organs.
Application of 10 -4 M IAA during the last 10 d of the inductive treatment of 30 d significantly reduced flowering in SD tobacco Mammoth without changing the stem length and apex width. Apex length was slightly reduced. IAA application elicited almost no effect inN. silvestris. The results are discussed with respect to the possible role of IAA in flower induction in SD and LD plants.

Flag leaf removal at any stage of grain growth hastened senescence (reduction in chlorophyll content) of the sterile glumes whereas a removal of the latter did not alter senescence of the former. Kernel mass, grain mass per ear, harvest index and sink activity reduced more conspicuously by the removal of glumes than by the flag leaf removal. Removal of grains hastened senescence of the glumes only, although protein content increased at a later grain removal in the majority of source organs. Moisture contents of the developing grains were mostly reduced by the removal of either the flag leaf or the glumes, though flag leaf removal at anthesis affected it the most. Protein levels of the developing grains reduced at harvest only when the glumes were removed at anthesis but sugar levels in later phases always decreased irrespective of the time of removal and nature of the source organs.

Differently positioned seeds in the mature pod of winged bean (Psophocarpus tetragonolobus (L.) DC) differ in mass and content of total protein and phosphorus and starch.

Growth of Dunaliella tertiolecta was retarded when the alga was exposed to high boron (B) concentrations between 50 and 200 g m-³. Photosynthetic oxygen evolution as well as respiratory oxygen uptake were significantly suppressed with the rise of B concentration. Similarly the contents of chlorophyll, glycerol, lipid and proteins were lowered, while that of saccharides was raised.