A floating sterile mutant of Ulva pertusa, which grows faster than the wild type and also during summer periods, was grown in the laboratory under "white light" (WR as reference), broad band isoquantic red (600 - 700 nm, RR) and blue (400 - 500 nm, BR) radiation. The observed specific growth rates at WR, BR, and RR were 8.6, 2.15, and 1.2 %, respectively. A stimulatory effect of BR on the growth at low irradiance (60 μmol m-2 s-1) was observed during the 15 d of culture. Around 42.1 % of total nitrogen was used by Ulva mutant in WR, but under BR and RR it was around 27.0 and 16.7 %, respectively. However, the utilization of nitrogen under BR was significantly higher than under RR. Considerable CO2 fluctuation in the light and dark periods was observed in all the cultures, and it was higher under WR, followed by BR and RR. The possible growth promoting effect of BR includes nitrogen uptake and the consumption of HCO3- which in turn leads to reduced air CO2 concentration in the medium.

The role of proline in imparting tolerance to salinity was investigated in Hydrilla verticillata, Najas indica and Najas gramenia. The plants were exposed to different concentrations of NaCl and artificial sea water (SWS) separately. The chlorophyll (Chl) a/b ratio decreased significantly in all the three plant species in both NaCl and SWS treatments, comparatively more in former than the latter. NaCl resulted in drastic decrease in this ratio in salt sensitive H. verticillata and N. indica, but in somewhat lesser decrease in salt resistant N. gramenia. Proline content increased at both NaCl and SWS treatments, especially at the latter. However, in H. verticillata proline content at 1.5 and 2.5 % NaCl decreased. It was concluded that proline cannot be used as a biochemical marker of salt tolerance in aquatic plants, however, the decrease in Chl a/b ratio in response to NaCl may be used as an index of salt sensitivity in this ecological group of plants.

Expression of the β-glucuronidase (GUS) reporter gene driven by the CaMV 35S, rolC, nos and mas promoters was assessed in the tips of 12 independent clones of transgenic sugar beet (Beta vulgaris) roots. Three questions were addressed: 1) expression pattern specific for a given promoter, 2) expression pattern variability, and 3) relationship between gene expression and cell differentiation. Characteristic patterns of tissue-specific expression were distinguished for each promoter. Striking differences, however, were found between some clones, bearing the same construct. Statistical analysis of the pattern variability proved that the variability is significantly lower within the construct than between constructs. rolC-GUS clones exhibited the lowest and CaMV 35S clones the highest pattern variability. Comparisons between the four promoters showed consistent GUS activity in areas playing a key role in tissue determination (the elongation zone) where cells switch from frequent mitosis and mostly isodiametrical growth, typical for the promeristem, to rapid elongation and differentiation. All of the clones were highly GUS-positive in the elongation zone of stele. Activity was commonly localised in the stele of the maturation zone for CaMV 35S, rolC and mas-GUS clones. CaMV 35S-GUS clones were highly active in the promeristem.

Transfer of chloroplasts from Solanum tuberosum into S. nigrum cell resulted in an atrazine sensitive cybrid plant. The shoots of this cybrid were bleached under atrazine stress. The cybrid displayed identical isoenzyme patterns that have been found in S. nigrum, and thus nuclei of the cybrid plant cells did not integrate any chromosomes or chromosome fragments from S. tuberosum nuclei. Under atrazine stress, differences in the isoenzyme expression were found in both the cybrid and original plants. In the peroxidase patterns, POX-4 was detected while POX-1 disappeared. Esterase patterns were less influenced, EST-4 was expressed in both plants under the influence of atrazine. Atrazine treatment of both cybrid and original plant shoots had specific effects on carbonic anhydrase, malate dehydrogenase, and glutamate oxaloacetate transaminase. The number and/or the staining intensity of bands corresponding to these isoenzymes decreased under atrazine stress more in cybrid plants (atrazine sensitive) than in S. nigrum (atrazine resistant).

Adventitious root formation in vitro in 1-mm stem slices cut from microshoots of apple cv. Jork 9 was studied using light and electron microscopy. When indole-3-butyric acid (IBA) had been added to the medium, starch grains accumulated during the first 24 h of culture in cells of the cambial region and in cells in the vicinity of vascular tissue and in the primary rays. This accumulation occurred only in the basal part of explants. After that, the nuclei in these cells were activated, and the density of the cytoplasm and the number of cell organelles increased, whereas starch was broken down. Cambium cells started to divide transversely and at 96 h, after several divisions, a continuous ring of isodiametric cytoplasmic cells had appeared around the xylem near the basal cutting surface. The cells in this ring were rich in cell structures, and did not contain large starch grains and a central vacuole. Root meristemoids regenerated from the portions of the ring that were localized in the primary rays. From the other cells in the ring, callus developed. The meristemoids did not grow into the direction of the epidermis as in shoots, but along the vascular bundles. After emergence from the cutting surface, the meristemoids were transformed into small, dome-like primordia. They developed a typical root apex with root cap, root ground meristem and tracheid connection with shoot vascular tissue.

We studied the influence of ethephon (2-chloroethylphosphonic acid) on the first stages of development of the main apex of Liatris spicata cv. Callilepis and its relation to the mobilization of soluble saccharides in the corm. Ethephon enhanced cell expansion during the first weeks of cultivation but did not affect the timing of flower initiation. Soluble saccharide concentration in the corm reached a maximum after sprouting, probably due to rapid growth of the shoot. There was no change in the concentrations of soluble saccharides immediately prior to flower initiation, which suggested that quantitative changes in these saccharides were not responsible for activating flower initiation. When corms were treated with ethephon there was a greater degree of soluble saccharide mobilization during the first weeks of cultivation than in untreated corms. However, this did not seem to be the direct result of the addition of this phytohormone and was more probably the consequence of cell growth being encouraged.

The content of cytokinins especially zeatin nucleotide decreased in shoots as a result of temperature increase. Simultaneously the cytokinins accumulated in roots. The changes in cytokinins distribution were followed by a decline of evapotranspiration after its initial temperature-induced uprising.

Developing fruits on lower nodes were major reproductive sink for photosynthates in bell pepper (Capsicum annuum L.). The removal of these fruits resulted in faster growth of other fruits on upper nodes. Sink manipulated plants have the higher rate of net photosynthetic rate at the later stages of plant development.

Four clones of Malus domestica Borkh. cv. Golden Delicious - namely Smoothee, Crielaard, Reinders and Golden B - were cultured in vitro from single-node microcuttings placed on solid medium under irradiance (PPFD) of 50 µmol m-2 s-1. After 9 months an average shoot proliferation of 5.3 was achieved; Crielaard showed the highest rate (7.1), followed by Golden B(5.4), Smoothee and Reinders (4.4). Proliferating shoots were then exposed to higher PPFD (80 µmol m-2 s-1) and different spectral composition of radiation using PMMA-B and PMMA-R/FR filters. High PPFD decreased the average proliferation rate to 4.5, in particular in Crielaard and Golden B, while it increased proliferation in Reinders. When a PMMA-R/FR filter was interposed, the mean proliferation rate slightly increased. PMMA-B filters decreased the overall proliferation rate to 3.0; only in Crielaard it was increased, but shoots were very small. Thus PPFD and spectral composition influenced in vitro shoot proliferation and growth and the responses were different among the clones.

The uptake of K⁺ by the leafy shoots of four submersed higher aquatic plants (Elodea canadensis, Ranunculus aquatilis, R. trichophyllus, and Callitriche hamulata) with different HCO₃ ^- affinity was measured in successive 2-h periods under the conditions of high or low photosynthetic rates (i.e. at pH 7.5 or 10). At pH 7.5 the uptake of K⁺ by species with the higher HCO₃ ^- affinity (E. canadensis, R. trichophyllus) was significantly faster than that by species with a lower HCO₃ ^- affinity (R. aquatilis, C. hamulata). In the former group of species, the K⁺ uptake rate at pH 7.5 was 1.7 - 3.5 times higher than at pH 10. At pH 10, the soft-water species, R. aquatilis, had the lowest net photosynthetic rate (PN) of the three HCO₃ ^- users but, in contrast to the relative hard-water species, R. trichophyllus, showed a small K⁺ efflux (47 nmol kg^-1 s^-1). Thus, K⁺ uptake by shoots was not strictly correlated with PN. A significant K⁺ efflux (73 - 86 nmol kg^-1 s^-1) occurred from all HCO₃ ^- users in darkness. The relatively low K⁺ uptake by the strict CO₂ user, C. hamulata, was quite independent of PN and light or darkness. It may be suggested that uptake of K⁺ by shoots of submersed plants depends on their HCO₃ ^- affinity.

Forty-one accessions belonging to ten genera of the tribe Triticeae representing both wild and cultivated species were analyzed by polymerase chain reaction (PCR). Of two consensus tRNA primers tested, one primer revealed characteristic amplification products for all of the species. A total of 35 tRNA markers were scored across all accessions. Five genus-specific and three species-specific markers were obtained. Genomic fingerprints were largely conserved within a genus. The phylogram obtained using parsimony has separated most of the accessions into their prevailing taxonomic species and genus groups. The phylogram showed close association among the three genera Secale, Triticum and Hordeum as expected. The Triticum-Secale relationship was closer than the Triticum-Hordeum or the Secale-Hordeum relationships. The tree also reflected the close associations among the forage grass species belonging to Leymus and Elymus. Thus tDNA-PCR helped to identify species and genera.

Plant regeneration was achieved from coleoptile tissue of wheat (Triticum aestivum L. cv. Kharachia-65). Coleoptiles (1.0 - 3.5 cm long) were excised from 2- to 5-d-old seedlings and cultured on Murashige and Skoog's (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D - 0.5, 2.5, and 5.0 mg dm^-3). Cream, friable callus was obtained after 6 weeks of inoculation. This callus was sub-cultured on MS medium supplemented with 2,4-D (2.5 mg dm^-3) and 5 % coconut water. After 6 weeks of sub-culturing white, cream or pale, friable, nodular callus was obtained. Plant regeneration occurred when this callus was sub-cultured on MS medium supplemented with 0.2 mg dm^-3 1-naphthalene acetic acid + 1.0 mg dm^-3 6-benzylaminopurine. For rooting, regenerated shoots or plantlets were transferred on MS medium supplemented with 0.5 mg dm^-3 indole-3-acetic acid. Rooted plantlets were directly transferred into pots and grown under field conditions. Seed setting invariably occurred in all plants.

Plants of teak (Tectona grandis L.f.) growing after transplantation to fertile soil for 5 - 6 months were subjected to water stress by withholding watering continuously for 3 weeks. The growth rates of both plants in height and developing leaves in length were unaffected during the first week after withholding watering, but they were decreased by about 50 % during the second week and became negligible during the third week of water stress treatment. The rate of leaf production and internodal elongation were also decreased in plants experienced 2 weeks of water stress. However, after rewatering, these plants regained growth potential and exhibited high rates of leaf expansion and plant growth comparable to those of well-watered plants. Diurnal course of net photosynthetic rate (PN) of plants subjected to water stress for 2 weeks was similar as that of well-watered plants. However, PN of plants subjected to water stress for 3 weeks was reduced in the afternoon. Similarly, stomatal conductance (gs) and transpiration rate (E) of plants experiencing 3-week water stress were decreased in the afternoon. Soon after rewatering, PN, gs and E reached similar values to those of well-watered plants.

Shoot tips, cotyledonary nodes and hypocotyls of chickpea (Cicer arietinum L.) were grown on 3 media: plant induction medium (PIM), callus induction medium (CIM), and shoot induction medium (SIM). Maximum growth and differentiation was seen in PIM, whereas minimum was observed in CIM. Shoot tips which differentiated to multiple shoots evolved negligible amounts of ethylene. Maximum ethylene evolution was recorded by hypocotyls in PIM. Ethylene appears to have stimulatory effect on shoot bud differentiation in cotyledonary nodes. But in hypocotyls, increased ethylene inhibited growth and differentiation. Calli on media containing only auxin (PIM) evolved significantly more ethylene, whereas those on media with cytokinin (SIM) evolved more methane. Callus forming explants like cotyledonary nodes and hypocotyls evolve more ethylene than shoot tips.

Habituated sugar beet calli have been characterized as having a deficiency in some tetrapyrrole containing compounds. However, peroxidases might be dissociated from the other tetrapyrrole containing compounds. When light-cultured normal and habituated calli were transferred to darkness their peroxidase activity reduced and increased, respectively, indicating that habituation could not strictly be characterized by a deficiency in peroxidase content but rather by a different regulation of its activity. This regulation could be mediated through soluble effectors which act as potential peroxidase inhibitors and/or by a differential expression of the peroxidase isoenzyme patterns which were present in these tissues in both light and darkness. The different peroxidase activity and the nature of acidic and basic peroxidase isoenzymes in normal and habituated tissues could explain the different features of both types of cultures.

Rice (Oryza sativa L.) seedlings were grown under NaCl stress. The leaf growth of resistant cv. Damodar was less affected than that of the susceptible cv. Jaya. The leaf protein content showed no distinct cultivar or age dependent differences under NaCl salinity. There was a significant increase in chlorophyll (Chl) and carotenoid (Car) contents of 25-d-oldseedlings of both cv. Jaya and cv. Damodar. However, Chl and Car content of 15-d-old seedlings of cv. Jaya decreased and that of cv. Damodar increased, under NaCl stress.

Excised embrya and subsequently divided embrya of Podophyllum peltatum were cultured on the Murashige and Skoog medium supplemented with different growth regulators, because traditional methods of breaking seed dormancy failed. The growth of excised embrya was stimulated by 1 or 0.1 mg dm-3gibberellic acid (GA3), 0.1 mg dm-3 GA3 + 0.2 mg dm-3 kinetin (kin), or 0.2mg dm-3 kin. GA3 (1 mg dm-3) showed the best effect; after 5 weeks the plantlets had 1.5 - 2 cm long cotyledons, 5 - 6 cm long roots, 88 % of embrya germinated and developed further. The addition of 0.5 mg dm-3 zeatin + 0.2 mg dm-3 naphtaleneacetic acid (NAA), 0.2 mg dm-3 NAA, and 1 mg dm-3 kinetin inhibited the growth of embrya. 1 mg dm-3 kinetin + 0.1 mg dm-3 NAA, 0.1 mg dm-3 zeatin and 0.2 mg dm-3 6-benzylaminopurine resulted in a compact appearance of plantlets and a lower germination rate. Divided embryo cultures produced plantlets via somatic embryogenesis which occurred only on the 2,4-dichlorophenoxyacetic acid containing media. The maturation of somatic embrya was observed on media without any auxin.

Changes in growth and anatomical structure of vascular tissues in stem, root and leaf of safflower plants grown in NaCl and CaCl2 solutions having different osmotic potentials (ΨS from 0 to -0.9 MPa) with addition of 0, 10 and 20 mg dm-3 zinc were studied. Shoot and root lengths, fresh and dry masses and fresh/dry mass ratio were lower in salt-stressed plants compared to unstressed plants. Salinity induced structural changes in stem, root and leaf tissues; few xylem vessels with smaller size were noticed in stressed plants. The higher concentration of Zn improved growth especially in roots and enhanced xylem formation in comparison to stressed plants grown at the same osmotic potential without Zn. Zn also protected xylem distructure by salinity in leaves.

We present a simple and rapid technique for the double staining of plant peroxidase and other proteins in the same polyacrylamide gel using the principle of iodide oxidation followed by Coomassie Blue counterstain. The colored bands of peroxidase isozymes and proteins are easily distinguishable. An additional benefit of the method is the use of the low cost chemicals, as well as it eliminates the need for a potentially hazardous reagents frequently used in the detection of peroxidase isozymes.

Electrophoretic seed protein patterns of 18 samples belonging to 14 species and 4 sections of Lathyrus are treated by principle component analysis (PCA). The morphological ground and karyological structure data of these samples are also discussed in the light of sectional and groups delimitation. The species under study of section Cicercula are separated into 3 groups and L. hirsutus referred to the most primitive species within Lathyrus species. This agrees with their previous grouping delimination based on morphological characters and with chromosomal features such as karyotype structure. L. aphaca referred to the most advanced species in this genus, which agrees with the modification of this morphological characteristics and reduction in chromosome criteria. Section Nissolia hasan intermediate position between section Cicercula and section Aphaca.

Protocols were developed for plant regeneration from callus induced in mature embryos of rice. Somaclonal variation was scored by genome mutation, chromosome mutation and plasmon mutation in R₀, R₁ and R₂ plant progenies. The frequency of haploids and diploids appeared in the ratio of 20:33. Variation in the chromosome number in callus cells was found to be high and age dependent. Different types of chlorophyll deficient mutants including albinos appeared in R₂ plant progeny where gene mutation frequency was the highest (52.4 %). The results revealed that a high frequency of somaclonal variation is possible to generate by tissue culture techniques.

Wounding-induced extracellular pH shifts were characterized previously in excised segments of maize (Zea mays L.) coleoptiles. In the present study it is demonstrated that similar pH shifts also occur in Triticum aestivum L., Secale cereale L., Hordeum vulgare L., Avena sativa L., Sorghum durra (Forsk.) Stapf, and Setaria italica (L.) Beauv., with characteristic quantitative differences between the species. Indole-acetic acid induces pronounced drops of the medium pH in all species except Setaria italica.

A non-destructive method of total vertical projections for estimating the length of rigid root systems, not introduced yet in plant sciences, is described. It is demonstrated on measuring less and more dense root systems of seedlings of Zea mays grown at hypoxic or control conditions. Photographs of six vertical projections (30° apart) of each root system were taken and evaluated. The method being based on proved mathematical formula offers unbiased estimation of the length of a rigid root system, curved in three-dimensional space, by non-destructive means. Thus, it is applicable during ongoing experimentation on plants grown in a solution culture. It was shown that less than 120 intersections between the root projection and test lines in one photograph ensured sufficient precision of the method and that the observer subjectivity could be overcome by presented instructions.

Cadmium-treated pea plants exhibited PEPC and NADP-ME activities, titratable acidity, and malate concentration in the leaves similar to controls. The PEPC activity in the roots of Cd-treated plants decreased by about 40 %, and NADP-ME increased more than twice. The titratable acidity remained similar as in the leaves, but the malate content diminished by about 30 %. The application of 500 g(d.m.) m-3 biomin and a combination of biomin and algae suspensions to Cd-treated plants brought about an increase in the titratable acidity and in the malate concentrations in the leaves and the roots.