Chlorophyll (Chl) a, b and (a+b) contents were measured in eleven cultivated and wild species of Lamiaceae collected from different environments. In nine of these eleven species, belonging to the subfamily Nepetoidea, the Chl a/b ratio was low. This suggests a prevailing shade aspect, regardless of collection sites and cultivated or wild origin.

The emissions of volatile organic compounds, VOC, from plants have strong relevance for plant physiology, plant ecology, and atmospheric chemistry. We report here on the current knowledge of the many internal (genetic and biochemical) and external (abiotic - temperature, light, water availability, wind, ozone, and biotic - animal, plant and microorganisms interactions) factors that control emission rates of different VOC by altering their synthesis, vapour pressure or diffusion to the atmosphere. The complex net of these factors, their interactions and the different responses of the different VOC produces the large qualitative and quantitative, spatial and temporal variability of emissions and the frequent deviations from current standard emission models. The need for a co-operative multidisciplinary multiscale research to disentangle this complex and important issue of plant VOC emissions is reminded.

NaCl-stress induced a pronounced suppression in growth of wheat seedlings. The most abundant amino acids (cysteine, arginine, methionine) constituting about 55 % of total free amino acid content in control wheat were reduced in 100 mM NaCl-treated plants. However, valine, isoleucine, aspartic acid and proline accumulated in response to NaCl stress and NaCl-treated wheat seedlings showed 1.6 fold increase in total free amino acids compared to the control. Addition of 2 [micro ]M thiamine alleviated the effects of NaCl on the amino acid composition and the amount of total free amino acids decreased to that in the control. Content of 26 kDa protein increased in NaCl-treated plants, stimulation was more pronounced in roots than in shoots. In contrast, the contents of 13 and 20 kDa proteins decreased. After addition of thiamine, the 24 kDa protein, which disappeared with NaCl treatment, has been initiated again. Moreover, thiamine treatment stimulated the accumulation of the 20 kDa protein.

We examined the effects of simultaneous treatments with Cd and Ni on the phytochelatin (PC) biosynthesis in suspension-cultured tobacco (Nicotiana tobacum cv. Bright Yellow-2) cells. The induction of PC biosynthesis in response to Cd was not affected by the coexistence of Ni. Cd and Ni formed complexes with different compounds in cells.

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.

Germinating seeds of spring wheat (Triticum aestivum L.) were tolerant to dehydration up to the 4^th day following imbibition and from the 5^th day the seedling survival decreased. Dehydration also inhibited the rate of seed dry mass depletion and seedling dry matter accumulation and increased the content of soluble sugars both in grain and seedlings. Glucose supplied either to dry seeds or to 4-d-old seedlings increased survival of dehydrated seedlings. In contrast, exogenously supplied non-readily metabolizable sorbose and mannose suppressed seedling survival.

In a field experiment with a mangrove species Suaeda maritima L. grown under ambient and supplementary UV-B radiation corresponding to 20 % ozone depletion, changes in growth and contents of photosynthetic and UV-absorbing pigments were determined. Supplemental UV-B irradiation for 9 d significantly reduced the growth and concentration of photosynthetic pigments. However, anthocyanin and flavonoid contents were significantly increased in UV-treated plants and which could be reduce the UV-B penetration and damage to the underlying tissues.

Using bean seedlings, the effects of benzyladenine (BA) on stomatal conductance (g_s), transpiration rate (E), and net photosynthetic rate (P_N) were examined in order to find out dose and time responses. In bean seedlings, BA appli roots in concentrations of 1, 5, 10, and 20 µM increased g_s and P_N of leaves already 1 h after application. E was not markedly affected and water use efficiency (WUE) was increased. However, the effects were mostly transient and after 24 h P_N only at 1 and 5 µM BA was increased, and other parameters were not affected or even decreased. In sugar beet seedlings, the effects of hydroxybenzyladenosine (HBA) in addition to those of BA on the same parameters were determined. The both cytokinins were applied in 1, 5, 10, and 20 µM concentrations either to roots or sprayed on leaves However, the effects were inconsistent and the positive effect was observed only after 24 h on P_N in plants with roots immersed in 5 and 10 µM BA, or 10 µM HBA, and on E in plants sprayed with 5 µM BA or 10 µM HBA. Thus the stimulation of gas exchange by exogenously applied cytokinins is rather exceptional than general.

The in vitro studies with Cardiospermum halicacabum indicated that the different explants, i.e cotyledon, hypocotyl, cotyledonary node, leaf, internode and node had the potential to produce calli on Murashige and Skoog (MS) medium supplemented with benzylaminopurine (BAP) and napthalene acetic acid (NAA). Calli of different explant origin showed variable growth responses on different BAP concentrations. The shoots were favourably formed from the calli of leaf and cotyledon explants. The maximum number of shoots were produced from calli subcultured on MS + BAP (17.8 µM). The roots were initiated on growth regulator free MS medium.

Carob (Ceratonia siliqua L.) has compound pinnate leaves consisting of 4 - 6 pairs of leaflets. However, in conditions of in vitro culture only one pair of leaflets develops. With increasing irradiance from 9.3 to 74.1 µmol m^-2 s^-1, leaf area increased 5-fold. Sucrose also significantly increased leaf area and the maxima were at concentration 147 mM at high irradiance and 233.6 mM at low irradiance. Sucrose was superior to fructose, glucose and combination of both in increasing leaf area. Decreasing concentration of KNO₃ and NH₄NO₃ caused a 3-fold decline of leaf area.

The allelopathic potential of Ageratum conyzoides, which is one of the most dominant weeds in upland-crop areas of Southeast Asia, was investigated under laboratory conditions. The residue obtained from an aqueous acetone extract of the plant shoots inhibited the germination and the growth of roots and shoots of Amaranthus caudatus, Digitaria sanguinalis and Lactuca sativa. The concentration-dependent responses of the test plants suggest that the residue of Ageratum conyzoides might contain allelochemical(s).

Effects of high temperature on the activity of photosynthetic enzymes and leaf proteins were studied in mulberry (Morus alba L. cv. BC2-59). A series of experiments were conducted at regular intervals (120, 240 and 360 min) to characterize changes in activities of ribulose-1,5-bisphosphate carboxylase (RuBPC) and sucrose phosphate synthase (SPS), photosystem 2 (PS 2) activity, chlorophyll (Chl), carotenoid (Car), starch, sucrose (Suc), amino acid, free proline, protein and nucleic acid contents in leaves under high temperature (40 °C) treatments. High temperature markedly reduced the activities of RuBPC and SPS in leaf extracts. Chl content and PS 2 activity in isolated chloroplasts were also affected by high temperature, particularly over 360 min treatment. Increased leaf temperature affected sugar metabolism through reductions in leaf starch content and sucrose-starch balance. While total soluble protein content decreased under heat, total amino acid content increased. Proline accumulation (1.5-fold) was noticed in high temperature-stressed leaves. A reduction in the contents of foliar nitrogen and nucleic acids (DNA and RNA) was also noticed. SDS-PAGE protein profile showed few additional proteins (68 and 85 kDa) in mulberry plants under heat stress compared to control plants. Our results clearly suggest that mulberry plants are very sensitive to high temperature with particular reference to the photosynthetic carbon metabolism.

Three clones of tobacco transformed with the T-DNA of Agrobacterium rhizogenes Ri plasmid A4b cultivated in vitro on a solid agar medium neither showed pronounced morphological diversity nor significantly differed in chlorophyll (Chl) contents from control plants. However, the transformation caused a 27 to 83 % decay in leaf oxygen evolution and in both ribulose-1,5-bisphosphate carboxylase (RuBPC) and phosphoenolpyruvate carboxylase (PEPC) activities. Therefore, the transformation brought about a reduction of active PEPC as well as activable RuBPC amounts in plant tissues. Individual clones did not mutually differ. In tobacco transformed with A. rhizogenes strain TR101 and grown in soil only the mean leaf area tended to reduce. Chl contents, Chl a/b ratio, oxygen evolution, and activities of both RuBPC and PEPC were insignificantly affected by the transformation.

Frequency of safflower (Carthamus tinctorius L.) somatic embryogenesis, number of somatic embryos per responding explant and somatic embryo maturation and germination were affected by genotype, explant age, carbon source, and ethylene. Among 8 cultivars tested, 7 were embryogenic with varying frequencies. The best response was obtained with cv. Girna. Whole cotyledonary explant from 10-d-old plants was best responding compared to 5- or 15-d-old ones. Among different carbon sources, sucrose at 87.6 mM concentration was most suitable for embryo induction, maturation and germination. Of the different ethylene inhibitors, silver nitrate at 50 [micro ]M concentration significantly increased the embryogenic frequency and also the number of embryos per responding explant. Silver nitrate has pronounced effect on embryo maturation but had no effect on germination.

Season-dependent fluctuation of hop latent viroid in meristem tips enabled selection of viroid-free cultures from Osvald's clone 31, 72, 114, and cv. Premiant. These mericlones were used to evaluate effect of viroid infection on the composition of hop resins and essential oils in the first production year. Healthy plants were compared with naturally re-infected individuals under field conditions. On average, viroid infection decreased content of α-bitter acids by 40 %. The content of β-bitter acids, as well as the ratios of humulone/cohumulone and lupulone/colupulone was not influenced by viroid infection. The content of all monoterpenes was for 29, 37.4 and 41.6 % higher for myrcene, α- and β-pinene, respectively, in infected plants compared with the healthy controls. The contents of sesquiterpenes like β-caryophyllen α-humulene, α-copaene, γ-muurolene, β-bisabolene, γ-cadinene, and δ-cadinene decreased by 13.7, 13, 14, 18.5, 29, 21.7 and 18.5 %, respectively, due to viroid infection. The possible influence of some oxidative-reduction processes activated by viroid-caused pathogenesis was assumed to be involved in the accumulation of terpenes alcohols like geraniol and methylgeranate, and in the reduction of the contents of the majority of ketones detected in the spectra of essential oils.

Photosynthetic parameters were measured in triticale and its parents wheat and rye. Soluble protein content in leaves, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) content per fresh mass, total chlorophyll content, biomass yield, leaf area, leaf mass and specific leaf mass were higher but Rubisco content expressed as percentage of soluble protein, carboxylase activity, photosynthetic rate and stomatal conductance were significantly lower in rye than in wheat. Native-PAGE of Rubisco revealed that rye carboxylase was different from that of wheat. The difference was not related to either the small or large subunit of Rubisco but, may be, to the ionic and/or other properties of the Rubisco protein moiety. Triticale Rubisco was similar to wheat. For most of the studied physiological parameters, triticale showed much more similarity with wheat than with rye.