Two-day-old protonemata of Funaria hygrometrica Hedw. growing in vitro were treated with 4 μM Pb (given as PbCl₂) for 48 h. After this time chloroplasts of apical cell were distributed in different way than in control. In the middle part of the cell they formed one line while in the top one, usually swollen, they were crowded and formed irregular group. The reasons of such chloroplast distribution were: 1) increase of plastid size, probably the effect of intensive accumulation of starch and appearance of characteristic protuberances, 2) decrease of cell inner space additionally intensified by thickenings of lateral walls, and 3) disturbances of microtubule number and array.

Toxic effects of aluminium are primarily root-related. This review deals with growth, morphological, and ultrastructural responses of root to aluminium, their diversity along the root axis, and in the root tissues. The cell elongation seems to be most sensitive and responsible for early inhibition of root elongation. Longer Al treatment is required to reduce cell division or to interfere with nucleic acids in the root apex. Alterations of root morphology include root thickening, disturbances of root peripheral tissues, and initiation of lateral roots closer to the root tip. Ultrastructure alterations depend strongly on position of the cells with respect to the Al source, and on their developmental stage. Cell elongation and cell ultrastructure including organisation of cytoskeleton are most sensitive within the distal part of the transition zone of the root apex. This correlates with the rate of uptake and accumulation of Al along the root apex. Recognising the diverse responses and the most sensitive sites within the root apex can help in elucidating the mechanism(s) of Al effects on plants.

Wheat (Triticum aestivum L.) cultivars GK Tiszatáj, Yubileinaya, GK Öthalom and a landrace Kobomugi were grown for 18 d in hydroponic cultures containing 0 (control), 0.1, 1.0 or 10.0 µM Cu²⁺. On a dry mass basis, cvs. Tiszatáj and Kobomugi accumulated slightly more Cu²⁺ in the root tissues than did cvs. Yubileinaya and Öthalom, but their controls also contained higher amounts of Cu²⁺. As a result of perturbation in the plasma membrane functions the K⁺ content of roots was reduced at 10 µM Cu²⁺ in all cultivars, whereas the K⁺/Na⁺ ratio decreased significantly only in the roots of cv. Öthalom. In the sensitive cultivar, Öthalom, the dry mass of the roots decreased while the cysteine content, which is a limiting factor for glutathione synthesis, did not satisfactorily increase with increasing tissue Cu²⁺ content. This suggests that in cv. Öthalom the membrane damage of the root cells at 10 µM Cu²⁺ concentration may affect the sulphur availability or metabolism. Concentrations of glutathione and hydroxymethyl-glutathione, a tripeptide which may play a similar biochemical role to glutathione, were also lower in the sensitive cultivar. In the absence of glutathione the root tissues failed to cope with the oxidative stress caused by the excessive amount of Cu²⁺. A significant accumulation of iron in the roots of the sensitive cultivar at 10 µM Cu²⁺ supply enhanced the oxidative damage.

Abscisic acid (ABA) content and relative water content (RWC) in second fully expanded leaves of cold hardened plants and in dehydrated leaves of freezing tolerant barley (Hordeum vulgare L. cv. Lunet) were compared. ABA content and RWC in leaves did not change during the first day of cold hardening. On the contrary, dehydration of leaves led to a decrease of RWC and to an increase of ABA content.

Pyruvate kinase is an important enzyme of glycolytic pathway that also functions in providing carbon skeleton for fatty acid biosynthesis. It has been purified to near homogeneity from Ricinus communis, Selenastrum minutum, Cynodon dactylon, Brassica campestris and B. napus, and characterised. Partially purified preparations are reported from several other sources. A phosphoenolpyruvate (PEP) phosphatase accompanies pyruvate kinase. In plants, two isozymes of pyruvate kinase are reported, namely cytosolic and plastidic. Isoforms of cytosolic pyruvate kinase have also been reported from spinach. In most cases pyruvate kinase is a tetrameric protein and the molecular mass lies between 200 to 250 kDa. The pH optimum is in the range of 6.2 to 7.5. It requires both Mg²⁺ and K⁺ for maximum activity. ATP, citrate, and oxalate inhibit pyruvate kinase in most cases. A sequential compulsory ordered mechanism of binding of substrates to the enzyme has been proposed.

Heat shock (HS) reduced total lipid and phospholipid contents and their synthesis in germinating seeds of pigeonpea [Cajanus cajan (L.) Millspaugh]. Lipid peroxidation was also enhanced with increasing temperature and HS duration. HS influenced lipid metabolism to a higher extent at 45°C than at 40°C. This altered lipid metabolism and lipid peroxidation was associated with the loss of various solutes from the germinating seeds, and modification of growth and development. Pretreatment of germinating seeds at 40°C for 1 h or at 45°C for 10 min followed by incubation at 28°C for 3 h prior to 45°C for 2 h ameliorated solute leakage due to reduced lipid peroxidation and improvement in lipid content and membrane function.

Influence of increased K supply on growth and nutrient content in pearl millet (Pennisetum glaucum) under severe water stress was assessed in a pot experiment under glasshouse conditions. Nineteen-day-old plants of two lines, ICMV94133 and WCA-78 were subjected for 30 d to 235, 352.5, and 470 mg(K) kg^-1(soil) and two water regimes (100 and 30% field capacity). Increasing soil K supply did not alleviate the adverse effect of water deficit on the growth of two lines of pearl millet. Accumulation of N and K in the shoots of both lines was higher under water deficit than that under well-watered conditions, but such effect was not observed for P or Ca.

The effect of storage conditions on the serological activity of two isolates of potato virus Y^NTN strain (PVY^NTN) was studied by ELISA. Purified virus, intact and homogenized infected leaves stored freeze-dried and frozen at various temperatures were tested. Purified virus was the most stable at +4 °C and non-purified virus was best preserved as a freeze-dried leaf homogenate at -20 °C. Their serological activity did not change after three months of storage.

Callus induction was obtained on Murashige and Skogg agar medium with 45 μM 2,4-dichlorophenoxyacetic acid under dark at 25°C. Among the four explant types investigated, the best callus induction was obtained from two-week old fronds to which a surgical incision was applied in the basal (meristematic) region. This treatment resulted in 89.11% of fronds producing callus which continued to proliferate for another 24 months. To obtain plant regeneration pieces of calluses were transferred onto Murashige and Skoog agar medium containing 22 μM indole-3-acetic acid and 4.6 μM kinetin and maintained under 16-h photoperiod (irradiance of 30 μmol m^-2 s^-1) at 23°C. Green fronds formed on all callus pieces. The regenerated fronds were later transferred onto Wang medium where they formed roots. The regenerated Lemna minor L. plants obtained through indirect organogenesis did not differ morphologically from individuals forming the stock collection.

The effect of salinity on leaf superoxide dismutase (SOD) activity of lemon trees of different rootstock-scion combinations was studied. In leaves from Citrus limonum cv.Verna scions on Citrus macrophylla and C. reticulata rootstocks, salinity treatment clearly caused a significant depression in both Fe-SOD and Mn-SOD activities and an increase in Cu,Zn-SOD activity. However, in leaves from Citrus limonum on Citrus aurantium rootstook, the reduction observed in the activity values of Fe-SODs and Mn-SODs was not statistically significant. Salt stress also produced a decrease in the content of soluble proteins and chlorophylls. However, this drop was greater in C. limonum leaves on C. macrophylla than for other combinations.

All seeds of Aeluropus lagopoides and Urochondra setulosa germinated under non-saline conditions except for Sporobolus ioclados which showed only 40 % germination. Increase in salinity substantially inhibited germination and few seeds germinated at 400 mM NaCl. Germination at 200 mM NaCl was alleviated in U. setulosa by the application of gibberellic acid and fusicoccin, in A. lagopoides by thiourea, betaine, kinetin, fusicoccin and ethephon, and in S. ioclados by gibberellin and ethephon. High salinity (400 mM NaCl) induced germination inhibition was alleviated by proline, kinetin, fusicoccin and ethephon only in A. lagopoides.

Artichoke (Cynara scolymus L.) leaf size and shape, glandular and covering trichomes, stomatal density, stomata shape, pore area and epicuticular waxes during micropropagation stages were studied by scanning electron microscopy (SEM) and morphometric analysis with the aim to improve the survival rate after transfer to greenhouse conditions. Leaves from in vitro shoots at the proliferation stage showed a spatular shape, ring-shaped stomata, a large number of glandular trichomes and juvenile covering hairs, but failed to show any epicuticular waxes. Leaves from in vitro plants at the root elongation stage showed a lanceolated elliptic shape with a serrated border, elliptical stomata, decreased pore area percentage, stomatal density, and mature covering trichomes. One week after transfer to ex vitro conditions, epicuticular waxes appeared on the leaf surface and stomata and pore area were smaller as compared to in vitro plants. Artichoke acclimatization may be improved by hormonal stimulation of root development, since useful morphological changes on leaves occurred during root elongation.

Pot culture experiments were conducted using different NaCl concentrations to assess their impact on the growth and metabolic changes in senna (Cassia angustifolia Vahl.). Five treatments (0, 40, 80, 120, and 160 mM NaCl) were given to the plants at three phenological stages, i.e. at pre-flowering, (45 days after sowing, DAS); flowering (75 DAS) and post-flowering (90 DAS) stages. A significant reduction in the biomass and length of the roots and shoots, photosynthetic rate, stomatal conductance, the total chlorophyll content, protein content, nitrate reductase activity, and reduced nitrogen content of the leaves was observed at each phenological stage with each salt concentration applied. Contrary to this, proline and nitrate contents of the leaves increased markedly. The post-flowering stage was most sensitive to NaCl treatment.

The contents of several photosynthetic metabolites - 3-phosphoglyceric acid (3-PGA), pyruvate, nicotinamide adenine dinucleotide phosphate (NADP) and adenosine triphosphate (ATP) - were determined in leaves of cotton plants (Gossypium hirsutum L. cv. H-777) subjected to waterlogging at vegetative stage, and/or drought at the reproductive stage. In controls, soil moisture contents was kept at field capacity. One day prior to stress, the plant shoots were sprayed with 5 μM aqueous solution of indole-3-acetic acid (IAA), gibberellic acid (GA₃), benzylaminopurine (BAP), abscisic acid, and ethrel. In control plants, various growth regulators reduced contents of 3-PGA and ATP while increased contents of NADP and pyruvate. During waterlogging IAA promoted 3-PGA content, and BAP enhanced pyruvate content. During drought, GA₃ enhanced ATP and 3-PGA contents, while IAA enhanced pyruvate content.

Electrophoretic patterns of malate dehydrogenase (Mdh), alcohol dehydrogenase (Adh), and 6-phosphogluconate dehydrogenase (Pgd) of Zea mays L. × Tripsacum dactyloides L. hybrids and their parents were compared. The components of enzymes specific to T. dactyloides may be used as markers to identify the following T. dactyloides chromosomes in the hybrids: Tr 16 (Mdh 2 and Pdg 1), Tr 7, and/or Tr 13 (Adh 2). The isozymes of Mdh 2 are supposed as a possible biochemical marker to evaluate the introgression of genes, determining an apomictic mode of reproduction from T. dactyloides (localized on Tripsacum 16 chromosome) into Z. mays. The isozymes may be used as markers for the identification of maize chromosomes 1 and 6 in the hybrids as well. Chromosome count taken on the examined hybrids showed the addition of 9 to 13 chromosomes of T. dactyloides to maize chromosome complement.

Effects of NaCl (150 mM), proline (10 mM) and their combination on growth and contents of chlorophyll, proline and protein of bean (Phaseolus vulgaris cv. Kizilhaç) seedlings in vitro were investigated. NaCl decreased seedling growth. Proline added to control seedlings did not change seedling growth but decreased chlorophyll and increased protein contents. When proline added to NaCl-treated seedlings growth was increased in comparison with NaCl-treated only. Thus, proline alleviated salinity stress in bean seedlings.

The possibility of improving the recovery of plant photosynthesis after water stress by cytokinin-induced stimulation of stomatal opening or delay of leaf senescence was tested. The 6-benzylaminopurine (BAP) in concentrations 1 and 10 μM was applied to the substrate (sand + nutrient solution) or sprayed on primary leaves of 14-d-old Phaseolus vulgaris L. plants sufficiently supplied with water or water-stressed for 4 d. The later ones having relative water content decreased to 69 % were fully rehydrated during the following three days. Parameters of photosynthesis and water relations were measured in primary leaves of 7-, 10-, 14-, and 17-d-old plants. Application of 1 μM BAP slightly delayed leaf senescence: in 17-d-old control plants, net photosynthetic rate (P_N) and chlorophyll (Chl) content, and when sprayed on leaves also some of Chl a fluorescence kinetic parameters of BAP-treated leaves were slightly higher than those of untreated leaves. Both types of application of 1 μM BAP slightly improved recovery of plants during rehydration after water stress in terms of increased g_ad, g_ab and P_N, i.e., parameters which were markedly decreased by mild water stress. However, contents of Chl a, Chl b and carotenoids and parameters of Chl a fluorescence kinetic were not markedly affected by mild water stress and after rehydration were not stimulated by 1 μM BAP. 10 μM BAP had mostly negative effects on the parameters measured.

The effect of benzyladenine (BA) and ascorbic acid (AA) on relative water content, proline accumulation, net photosynthetic rate (P_N), chlorophyll (Chl) content and nitrate reductase (NR) activity, under sufficient water supply and moisture stress was studied in senna (Cassia angustifolia Vahl.) at seedling, vegetative, flowering and pod formation stages. AA treatment resulted in a higher accumulation of proline at all the stages of growth. Both BA and AA enhanced P_N, Chl content and NR activity, and ameliorate the negative effect of water stress.

The major objective of the research is to identify and locate quantitative trait loci (QTL_s) in the Yugoslav maize population. The plants (F2) were selected for the analysis at seedling stage and were selfed to obtain F3 generation. The analysis covered about 15 enzymes controlled by about 30 loci. The seeds of F3 family planted in the greenhouse for measuring some quantitative traits, recorded tasselling and silking during vegetation. At the end of vegetation grain yield, and some other quantitative traits of grain in F3 family were assessed. The relationship between marker loci and the loci for quantitative traits (QTL_s) were estimated by computerized statistical method.

Cabbage (Brassica oleracea, var. capitata, cv. Hercules) seedlings were inoculated with vesicular-arbuscular mycorrhizal (VAM) fungi Glomus fasciculatum, G. aggregatum, and G. mosseae. Differential efficiency in mycorrhizal colonization and the specificity of fungal symbiont to stimulate the growth and nutrient uptake of the host were observed. In addition, there was an increase in phenol, protein, reducing sugar contents, and peroxidase activity in the VAM inoculated seedlings. Since these compounds are known to confer resistance against fungal pathogens, the use of VAM as a biological control agent to protect cabbage against several root diseases is suggested.