Hybridization between the nearly extinct speciesDiplotaxis siettiana andBrassica juncea is prevented because of strong prefertilization barriers. Use of mentor pollen ofD. siettiana irradiated with 1000 Gy gamma radiation before the incompatible pollination led to fertilization. 5 d after pollination 17% ovules showed entry of pollen tubes, 10 d after pollination 27% ovules showed small globular embryos which grew no further. No embryos were found in control pollinations. Thus , use of irradiated mentor pollen brings about fertilization in this difficult cross and hybrids can be obtained if embryos are rescued.

The influence of increasing copper concentrations on seed germination, seedling survival and radicle length ofMinuartia hirsuta, Silene compacta, Alyssum montanum andThlaspi ochroleucum was studied. Seed germination was highly affected by the higher Cu²⁺ concentrations (80 and 160 μM), while lower Cu²⁺ concentrations seemed to be necessary for seed germination, even for the plants originated from non-Cu²⁺-rich soils (i.e. A. montanum). Nevertheless, plants originated from Cu²⁺-rich soils (M. hirsuta, S. compacta) showed a higher demand of Cu²⁺ for rapid seed germination. Cu²⁺ at higher concentrations severely reduced growth rate of radicle, especially inA. montanum andT. ochroleucum. These data clearly indicate the reduced suitability of the above mentioned plant species for reclamation on Cu²⁺ soils. Lower Cu²⁺-concentrations had no influence on seedling survival inM. hirsuta andS. compacta, but a progressive reduction of a number of survived seedlings with increasing Cu²⁺ concentration was found, that was more pronounced inA. montanum andT. ochroleucum.

Lotus corniculatus has been transformed byAgrobacterium tumefaciens harbouring therolABC, rolAB, and 35S-rolC constructs. Growth, shoot and root morphology, cytokinin and auxin concentrations in the shoots, chlorophyll content in the leaves, nodulation and nodule nitrogenase activity of clonal progenies of selected transformants, in which the transferredrol sequences were proved, were compared with control plants.
The most striking alterations were observed in the 35S-rolC transformants (dwarfism, shoot and root branching, shorter internodes, delayed nodule formation, decreased nitrogenase activity, reduced content of leaf pigments) in comparison with either therolAB, rolABC, or controls. TherolAB androlABC transformants were very similar to the control plants in their morphology as well as in most other traits measured.

Several morphological characteristics differed when wheat (Triticum aestivum L. cv. Doha 88) was grown under a cool (10 °C), warm (20 °C), and hot (30 °C) regime. Development of leaves was linearly related to shoot meristem temperature, and the time between appearance of successive leaves on the main culm was independent of growth temperature. Area and dry mass of leaves and roots increased exponentially with time, and variations between growth temperature regimes were reduced when plants were compared at a similar developmental age. In isolated thylakoids thermal stability of photosystem 2 and of whole electron transport chain was enhanced with the increase in growth temperature. Therefore this cultivar is able to acclimate to contrasting temperature regimes.

Small callus pieces excised from theAgrobacterium transformed root line D₂ ofDatura stramonium, were cultured onto solidified MS medium supplemented with a 1.0 μM kinetin and three different concentrations (0.1, 0.5 and 1.0 μM) of 2,4-dichlorophenoxyacetic acid (2,4-D), and were examined for their alkaloid productivity in relation to organization level and growth rate. Growth of transformed roots (in a MS liquid medium without plant growth regulators) was greater than that of transformed calli excised from them and cultured separately. The addition of 1.0 μM 2,4-D to the culture medium had a positive effect on callus biomass production, while it inhibited root formation by this tissue (the lower the 2,4-D concentration in the medium the greater the number of roots which emerged from the calli). Hyoscyamine production was also higher in the transformed roots than in the transformed calli, and in these tissues the production of hyoscyamine was positively correlated with organogenesis index (i.e. its ability for rooting). At the same time, the epoxidation of hyoscyamine to scopolamine only took place in the transformed calli. This occurred to a greater extent at the lower concentrations of 2,4-D in the culture medium. The mode through which the 2,4-D could control the alkaloid production of transformed callus is discussed.

Anin vitro procedure for large scale multiplication ofBoswellia serrata Roxb. has been developed using cotyledonary node segments. In average 4 shoots per node were obtained on Murashige and Skoog's (MS) medium containing 0.5 mg dm^-3 6-benzylaminopurine (BAP) and 0.05 mg dm^-3 napthaleneacetic acid (NAA) within 22 d. By repeated subculture technique 90-100 shoots per node could be obtained after 88 d of initial culture. Shoots could be rooted on MS medium containing 1/4 salts, 1% saccharose, and a combination of 0.5 mg dm^-3 indole-3-butyric acid (IBA) and 0.25 mg dm^-3 indole-3-acetic acid (IAA). Addition of antioxidants like polyvinylpyrrolidone (PVP-50 mg dm^-3) and ascorbic acid (100 mg dm^-3) in both multiplication and rooting media prevented browning of cultures. Approximately 80% of shoots rooted within 8-10 d. Rooted plantlets were kept for 15 d in culture bottles containing Soilrite^TM irrigated with a nutrient solution containing 1/4 MS salts and finally transferred to pots containing soil: Soilrite^TM (1∶1), mixture with 70% transplantation success.

Agrobacterium tumefaciens induced transgenosis by treatment of germinatingArabidopsis thaliana seed embryos has been achieved with differentAgrobacterium strains including the strain LBA4404, which was ineffective in seed transformation experiments of the other authors. The frequency of transgenosis was increased several times by application of acetosyringone to the growingA. tumefaciens suspension cultures. The DNA demethylating agent 5-azacytidine partly restored the distorted Mendelian segregation ratios in the offspring of transgenic plants.

The content of lead in greening etiolated barley leaves remained the same, regardless the time of incubation of excised leaves in the presence of lead ions (8-24 h). The lead deposits have not been detected within mesophyll cells, but were found in intercellular spaces of mesophyll, in guard cells and in cuticle covering stomata. This suggests that lead may be transported in the leavesvia transpiration stream. Lead reduced the content of chlorophyll, especially chlorophyllb content and the average number of grana, whereas in the presence of kinetin the content of chlorophyll increased. In the combined treatment (lead + kinetin) kinetin diminished the inhibitory effect of lead on the chlorophyll content. The number of chloroplasts in mesophyll cells remained unchanged after lead treatment, whereas kinetin alone or applied together with lead increased the average chloroplasts number. The thylakoids system in chloroplasts of kinetin and kinetin + lead treated plants was similar to that observed in control, although the grana number was smaller. Both lead and kinetin increased the content of condensed chromatin in nuclei.

The effect of five 3-(2-alkoxyphenylcarbamoyloxy)chinuclidium chlorides (alkoxy = butoxy-octyloxy) on survival of a wild-type strain and repair-deficient strains ofChlamydomonas reinhardtii was studied. There was a direct relationship with increased toxic effects in the algal strains as a function of the elongation of the alkyl chain of the alkoxy substituents of the phenylcarbamate acid derivatives. Repairdeficient strains were more sensitive than the wild-type strain. The recombination-deficient strain uvs10 expressed the highest sensitivity to the test agents. This suggests that a gene responsible for recombination repair is involved in an important role in DNA repair of damages induced inC. reinhardtii by the phenylcarbamic esters.

Two strains (RCR 1001 and 1044) and a commercial inoculant (Okadin) ofRhizobium leguminosarum biovarviceae were tested for their ability to survive in autoclaved clay soil for up to four months under heat, salinity and drought stress. Resistance to heat was tested by incubating rhizobia in soil at 27, 37 and 42 °C. Tolerance of rhizobia to salinity was investigated by growing rhizobia in soil salinized with 1 and 2 % NaCl (m/m). Drought resistance was tested by subjecting bacteria to soil moisture contents of 20, 10 and 5%. Strain RCR 1001 was more resistant to heat and nodulated faba bean better than other tested strains. A commercial inoculant Okadin survived more (plate count method) and nodulated faba bean (plant infectivity, most probable number, MPN) at moisture content of 5% and 2% NaCl. Although, strains RCR 1001 and 1044 resisted these stress conditions (plate count) they lost their abilities to nodulate faba bean (MPN-test). There is a possibility for selection of effective rhizobia which are more tolerant to harsh conditions.

Patchouli (Pogostemon cablin Benth.) plants grown under shade (LI) showed an increased height due to internodal elongation, leaf area, leaf area index, and chlorophyll (Chl)b, Chl (a+b) and carotenoid (Car) contents compared to the plants grown in sunlight (HI). The number of branches and green leaves decreased under LI treatment, with a marginal variation in the patchouli oil yield. A comparison between the relative contents of photosynthetic pigments indicated that Chlb and Car accumuled preferentially over Chla in the LI grown plants.

Changes in growth and phosphorus content in plants and seeds of fenugreek with increasing cadmium concentration was evaluated. Root length and shoot length ranged from 11.63 to 27.72 and from 9.70 to 54.78 cm, respectively. With the increasing Cd²⁺ concentration there was a significant decrease in root and shoot length, and fresh mass. Various phosphorus fractions of shoot decreased with increasing Cd²⁺ concentration except lipid P and nucleic acid P which increased at 65 and 95 d after sowing and protein P only increased at vegetative stage. In seeds (60 d after flowering) lipid P increased except at 2.5 μg(Cd²⁺) g^-1 (soil) while protein P decreased.

Morphactin dispensed through shoot apex induced diverse malformations of plant organs in four species ofKalanchoë. The malmorphogenetic effect was freely transmitted to newly emerging axillary branches as well as across leaf lamina to differentiating epiphyllous buds.

Chickpea (Cicer arietinum L. cv. 235) plants were grown in sand culture at moisture equal to 45-50% of sand saturation capacity under greenhouse conditions. 60 d after sowing, pots were divided into four lots, leaving one as control and sand moisture content of others was brought to 25-30% (S₁), 12-15% (S₂) and 5-6% (S₃) of sand saturation capacity, by withholding the water supply and then maintaining the required levels gravimetrically till the harvest. Relative water content of leaves and nodule water content were measured as indices of water stress. With increase in the severity and duration of water stress nitrogenase activity and nitrogen and leghemoglobin content of the nodules decreased and the ratio of leghemoglobin components I and II were changed. Nodules developed under limited water availability showed decreased branching, breakdown of the endodermis, greater compactness and decreased vacuolation of cells in the central symbiotic tissue as compared to the control.

The rate of germination, radicle and plumule length, fresh and dry mass of maize seedlings were increased as Ca²⁺ was added to the nutrient solution, which contained different levels of Cd²⁺, especially at low concentration of Ca²⁺ (5 mM) and high concentrations of Cd²⁺ (1.4 and 1.8 mM). The biosynthesis of pigments, respiration rate and content of soluble saccharides in endosperm were reduced sharply as the concentration of Cd²⁺ in the medium increased. This effects was alleviated by Ca²⁺ addition. Cd²⁺ content in seedlings was increased as the Cd²⁺ concentration in medium was increased and decreased sharply as Ca²⁺ was present in the culture medium. The study suggests liming of soil with CaCO₃ to improve the yield of many crops.

Changes in the number of protoplasts, viability, protein and chlorophyll contents and ribonucleases activity were studied in tobacco mesophyll protoplastsin vitro inoculated with tobacco mosaic virus (TMV). The number of protoplasts slowly increased during the cultivation period and the viability decreased from 95 to 67% in the control noninoculated protoplasts, and to 55% in the infected protoplasts. 30 h after inoculation the protein and chlorophyll contents strongly decreased to 25-30% and 17-19%, respectively, in comparison with contents 3 h after inoculation. The chlorophylla/b ratio decreased from 2.11 and 2.02 to 0.79 and 0.60 in healthy and infected protoplasts, respectively. The activities of ribonucleases in protoplasts quickly decreased during experiment but they were higher in infected than in noninfected protoplasts (between 20 to 30 h after inoculation they were 132 to 146% higher than that in healthy controls). These activities corresponded to the multiplication curve of TMV.

Anin vitro procedure for large scale multiplication ofBoswellia serrata Roxb. has been developed using cotyledonary node segments. In average 4 shoots per node were obtained on Murashige and Skoog's (MS) medium containing 0.5 mg dm^-3 6-benzylaminopurine (BAP) and 0.05 mg dm^-3 napthaleneacetic acid (NAA) within 22 d. By repeated subculture technique 90-100 shoots per node could be obtained after 88 d of initial culture. Shoots could be rooted on MS medium containing 1/4 salts, 1% saccharose, and a combination of 0.5 mg dm^-3 indole-3-butyric acid (IBA) and 0.25 mg dm^-3 indole-3-acetic acid (IAA). Addition of antioxidants like polyvinylpyrrolidone (PVP-50 mg dm^-3) and ascorbic acid (100 mg dm^-3) in both multiplication and rooting media prevented browning of cultures. Approximately 80% of shoots rooted within 8-10 d. Rooted plantlets were kept for 15 d in culture bottles containing Soilrite^TM irrigated with a nutrient solution containing 1/4 MS salts and finally transferred to pots containing soil: Soilrite^TM (1∶1), mixture with 70% transplantation success.

A galactose-binding lectin was isolated in electrophoretically pure form from the seeds of the snake gourd,Trichosanthes anguina, by affinity chromatography on an immobilised lactose column, as well as on a cross-linkedGuar Gum column. The lectin agglutinates native erythrocytes of human A, B and 0 phenotypes and of rabbit, rat and mouse. The molecular mass of the lectin, as estimated bySephadex G-200 gel chromatography, is 49 kDa. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis, after reduction with β-mercaptoethanol, revealed two polypeptide chains linked by disulphide bonds in the lectin molecule. It contains no covalently linked sugars. Amino acid analysis of the lectin revealed a high content of acidic amino acids, relatively lower proportion of basic amino acids and traces of cysteine and methionine. The lectin has good thermal stability, and is inactivated when oxidised by metaperiodate.

Proline content, ion accumulation, cell wall and soluble peroxidase activities were determined in control and salt-treated calli (150 nM NaCl) and whole plants (30 mM NaCl) of two rice cultivars (salt sensitive cv. IKP and salt tolerant cv. Aiwu). Under salinity, the highest accumulation of Na⁺, Cl^- and proline occurred in calli, roots and younger leaves of cv. IKP, coupled with the highest decrease in K⁺ content; accumulations of Na⁺ and Cl^- were restricted to older leaves in cv. Aiwu. Relative growth rates of calli and roots or shoots from both cultivars were not linked to peroxidase activities. High concentrations (1 M) of exogenously applied glycerol did not inhibitin vitro activities of soluble peroxidase extracted from control and salt-treated calli or plants. Conversely, 35-55% (in cv. IKP) or 60-80% (in cv. Aiwu) of soluble peroxidase activities were found in presence of isosmotic proline concentration. There were no differences between proline and glycerol effects onin vitro cell wall peroxidase activities.

The effects of nitrogen applied at increasing levels of 0, 4, 8, 16 and 32 mM N (KNO₃ or NH₄Cl) were studied in faba bean (Vicia faba) nodulated byRhizobium leguminosarum bv.viceae RCR lool. Nitrogenase activity was higher at 4 and 8 mM N than the zero N treatment (control), but 16 and 32 mM N significantly reduced the efficiency of nodule functions. Nitrate reductase activities (NRA) of leaves, stems, roots, nodules and nodule fractions (bacteroid and cytosol) were increased with rising the NO₃ ^- or NH₄ ⁺ levels. NRA decreased in the order of nodules>leaves>stems>roots. Cytosolic NR was markedly higher than that recorded in the bacteroid fractions. Nitrate levels were linearly correlated to NRA of nodules. Accumulation of NO₂ ^- within nodules suggests that NO₂ ^- inhibits nodule's activity after feeding plants with NO₃ ^- or NH₄ ⁺.

An electrophoretic investigation of the glutenin subunits and gliadin components in F₄ progenies between the hexaploid wheat (Triticum aestivum L. cv. Bezostaya 1) and the wild tetraploid wheat (Triticum turgidum var.dicoccoides Körn) is carried out. The possibility of inserting subunits and components of Glu B1, Glu B3 and Gli B1 loci fromT. dicoccoides in F₄ progenies ofT. aestivum is investigated. For this purpose parental forms with different allelic variants in these loci are chosen. It is established cytologically that the chromosomal number of progenies is 42. Genotype classes and the frequency of progenies are analyzed for which we judge by the phenotype manifestation of the allelic variants of the loci investigated. Different frequency of the transfer of subunits and components of Glu B1, Glu B3 and Gli B1 loci fromT. dicoccoides in the hexaploid wheat genome is established and it is connected with the disposition of the loci on chromosomes arms.

The effects of lead and sodium acetate treatment on the lipid composition of leaves, thylakoid membranes and cell debris of spinach were investigated. The concentration of lead in leaves and cell debris was higher than that in thylakoid membranes, probably due to a protection of photosynthetic apparatus. The lead treatment lead to decrease of contents of monogalactosyl diacylglycerols and phospholipids and to increase of the other glycolipids in the thylakoid membranes. There were no statistically significant differences between the total lipids of thylakoid membranes after incubation with lead and sodium acetate, which was an indication that in this case the effect of metal ion was not specific.

Changes in various components of photosynthetic apparatus during the 4 d dark incubation at 25°C of detached control and ultraviolet-B (UV-B) treatedVigna unguiculata L. leaves were examined. The photosynthetic apparatus was more degraded in younger control seedlings and for a longer time UV-B treated seedlings than in the older or for a shorter time UV-B treated seedlings. This was shown by determining the losses in chlorophyll (Chl) and protein contents, variable fluorescence yield, photosystem (PS) 2, PS1 and ribulose-1,5-bisphosphate carboxylase (RuBPC) activities, and photosynthetic¹⁴CO₂ fixation. In contrast, the Car/Chl ratio increased during the dark incubation due to less expressed degradation of Car.

The experiments were carried out with 96-h-old intact maize seedlings and 10 mm long coleoptile segments cut 4 mm below the tip. The electric fields were applied longitudinally along the seedlings. The electric field (15 V) caused inhibition of the elongation growth of intact seedlings which was dependent on both the polarity and the duration of the applied voltage. The growth inhibition was greater when the tip of the shoot was positive relative to the roots. The electric field also caused inhibition of indole-3-acetic acid (IAA) and fusicoccin (FC) induced growth of maize coleoptile segments excised from electrically treated seedlings. IAA-induced growth of coleoptile segments was greater when the tip of the shoot was negative to the roots (not in the case of FC-treated segments and intact seedlings). It was suggested that apart from the changes induced by electric field in transport system of auxin the electric field affected also the activity of plasmalemma proton pump.