A study was conducted to generate fingerprints of thirty-two Indian potato cultivars using capillary electrophoresis based semi-automated simple sequence repeat analysis. Five fluorescent-tagged primer pairs (STPOACUTR, LEGAST1, STPOAC58, STM0030 and STM0031) used in this study yielded 43 alleles at 16 different loci, showing multi-loci resolving character. The estimated similarity between the cultivars was in the range of 0.72 to 0.98 indicating narrow genetic relationship. None of the primer set alone could differentiate all 32 cultivars included in this study. However, two primer sets STM-0031 and STPOAC58 amplifying 12 and 9 polymorphic alleles, respectively, could together distinguish all of them. The results indicated usefulness of semi-automated capillary electrophoresis in quick and reproducible SSR genotyping of potato cultivars.

The purpose of this research is micropropagation of Ginkgo biloba L. Apical and nodal meristems removed from plantlets or apical buds from a tree were used as explants. Meristems produced an extensive callus and single or rare multiple shoots on Murashige and Skoog medium with different growth regulators and endosperm extract (En) obtained from mature seeds of the same species. For successful root production it was necessary to transfer the shoots to a rooting medium with En.

Five different methods for measuring transpiration, which include gravimetric analysis (control), heat pulse velocity (HPV), time domain reflectometry (TDR), single leaf and whole plant infrared gas-exchange measurements, have been tested on two cultivars (Redcort and Empire) of young apple trees (Malus communis L.). The objective was to compare these methods and establish the most affordable one to be used in greenhouse conditions in order to determine and/or estimate the amount of water for an efficient irrigation management. Results obtained with TDR were particularly accurate and not statistically different with respect to the control (-4.2 %) and this was supported by the correlation coefficient (r = 0.94) found. The HPV method was sufficiently accurate and reliable for small stems, however, in our conditions this method generally underestimated the transpiration (-32.4 %). Single leaf and particularly whole plant infrared gas-exchange measurements suffered an overestimation of the transpiration with respect to the control.

A simple protocol for mass multiplication of Crataeva nurvala, a medicinal tree, from seedling-derived explants is described. Six different types of explants (cotyledonary nodes, epicotyl nodes, hypocotyl segments, first pair of leaves, cotyledons, and root segments) developed shoots on Murashige and Skoog's (MS) basal medium or the same supplemented with different concentrations of 6-benzylaminopurine (BAP). Among the explants tested for caulogenic potential, only the epicotyl and cotyledonary nodal explants developed shoots on MS basal medium, while on BAP (0 - 2.0 mg dm^-3) adjuvated media all the explants exhibited caulogenesis. The optimum concentration of BAP varied for these explants. The shoots could be rooted on half strength MS with 0.02 mg dm^-3 α-naphthalene acetic acid to get plants, which have been transferred to soil. The explants from in vitro regenerated shoots also possessed a similar caulogenic potential.

We measured the stable deuterium isotopic composition of xylem sap, the shoot predawn and midday water potentials, and the leaf δ¹³C of Mediterranean shrubs Pistacia lentiscus, Globularia alypum and Rosmarinus officinalis in a south-oriented transect from a large (12 m tall) Aleppo pine tree, Pinus halepensis. We aimed to study the possibility of hydraulic lift from the deep roots of this pine tree to the shallow soil layers and its influence on these neighbour shrubs. These same traits were also studied in several individuals of the shrub Pistacia lentiscus growing with different types of neighbours: just shrubs, a small (3 - 4 m) pine tree, and the above mentioned large pine tree. The greater the distance from P. halepensis the plants grew, the higher xylem water δD, the lower the soil water content, and, the lower the predawn and midday water potentials were found. These results suggest the existence of an hydraulic lift from deep roots to shallow soil in this big tree. Further indication of this existence is provided by the improved water status of P. lentiscus (higher water potentials and δD, and lower δ¹³C and, therefore, lower water use efficiencies) when growing close to the big pine in comparison with the same shrub species growing close to small pines or just surrounded by other shrubs. Moreover, all these trends occurred in the dry summer season, but disappeared in the wet spring season.

The effect of an extended drought (from 1992 to 1995) on water relations was assessed on evergreen oak (Quercus ilex L.) in a dehesa ecosystem (Seville, Southern Spain). Diurnal and seasonal transpiration patterns were analysed at leaf (porometry) and whole-tree level (sap flow), focusing on the relationship between tree transpiration rates (E_t) and potential evapotranspiration rates (PET). Daily maximum E_t varied over the year, becoming higher between May and August, and lower between November and April. Annual E_t (169 - 205 mm y^-1) accounted for less than 40 % of annual rainfall. The prolonged drought did not affect the water relations of the Q. ilex, mainly due to strong stomatal regulation avoiding the loss of water. Stomatal control was found in all seasons, although it was stronger in summer. This behaviour leads to low water consumption and low E_t/PET ratios throughout the year (0.05 to 0.27).

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.

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.

The effect of triadimefon (TDM) on various biochemical parameters was studied in NaCl stressed radish (Raphanus sativus L.). Stress imposed by 80 mM NaCl decreased the protein content and proline oxidase activity, and increased the proline and glycine betaine contents, and protease, γ-glutamyl kinase and ATPase activities. The TDM treatment alleviated the stress by increasing protein, and glycine betaine contents, and by decreasing proline accumulation, and proline oxidase and ATPase activities.

Plant dormancy and dormancy breaking depend, at least partially, on close relationships between buds and tissues underlying bud (bud stands). In Prunus persica, the dormancy was related to high nutrient absorption in bud stands linked to high plasmalemma ATPase (EC 3.6.1.3) activity. Two plasmalemma fractions was isolated from peach vegetative buds and bud stands using aqueous phase partitioning and ultracentrifugation. Results of markers enzyme assays indicated that both plasmalemma enriched fractions obtained were highly purified. During the dormancy period plasma membrane ATPase amount and activity were higher in bud stands than in buds. Moreover, assays performed at different temperatures (4, 18, 30 °C) indicated modifications of kinetic parameters (K_m, V_m) in both tissues during dormancy release. In buds, from November to February, K_m declined at 4°C and increased at 30 °C whereas no changes was measured at 18 °C and V_m increased at all temperature. In bud stands, no changes of K_m was measured at 4 °C and 18 °C whereas an increase occurred at 30 °C and V_m decreased at all temperature. According to the results, it can be postulated that dormancy release in peach-tree could be related to modifications of plasma membrane ATPase properties, in buds and bud stands, during winter time.

A severe drought that took place in Spain and other Mediterranean countries in 1994 produced a dieback of Quercus ilex trees on south-facing conglomerates but only minor defoliations in trees on north-facing schists. The foliar Δ¹³C of damaged trees continued to decrease in the next two wet years probably indicating increasing water use efficiency, and their δ¹⁵N continued to increase indicating progressive ecosystem N saturation and/or N losses whereas there were no significant changes in undamaged trees. Pre-drought Δ¹³C values were reached in the third year after the drought, but δ¹⁵N values did not yet recover. Another co-occurring small tree, Phyllyrea latifolia, did not show any damage and gained dominance in the most affected stands.

Direct differentiation of shoot buds from hypocotyl segments of 12-d-old seedlings of Tamarindus indica was obtained on Murashige and Skoog (MS) medium with or without growth regulators. The highest regeneration (66 %) and the maximum number of shoots (3 - 4) per explant were obtained from the explants on MS medium containing 6-benzylaminopurine (5 × 10-6 M). A maximum roots per shoot were produced on medium containing 3-indole butyric acid (5 × 10-6 M). The resulting plantlets were hardened and transferred to soil in pots where 75 % of them survived and resumed growth. Histological examination of explants suggests that the shoots were of de novo origin which would make this system suitable for transformation experiments.

The specificity of a monoclonal antibody IgG1, raised against trans-zeatin riboside-keyhole limpet hemocyanin conjugate, was investigated by means of inhibition experiments with soluble competing antigens. A competitive enzyme immunoassay was set up, with immobilized antigen. The analysis of the cross reaction profile enabled a study of the specificity of the antigen-antibody interaction. The antibody was able to distinguish the trans form of zeatin riboside from the cis form (cross reaction index = 1 %); cross reactions with ribose, adenine, adenosine and other related heterologous antigens were not detectable over the range of concetration tested. The recognition centres for the antibody seem to be the purine ring and the R substituent, especially in its hydroxymethyl group. Employment of this monoclonal antibody to localize cytokinins in control and shedding affected fruits of Malus domestica Borkh. evidenced high content of trans-zeatin riboside in developing seeds, differences in its content in embryo and endosperm, and a strong reduction of its content in the tissues of drop fruits. This decrease may be an important component responsible for early fruit abscission.

The effects of modifying local source-sink relations on fruit and leaf characteristics of young pear trees were evaluated during the 1997 - 1998 growing season. The following treatments were applied: early spur ringing (ESR) from 27 days after full bloom (DAFB), late spur ringing (LSR) from 97 DAFB, early 15 % spur leaf area removal (ELAR) and late 15 % spur leaf area removal (LLAR). ESR and LSR significantly inhibited fruit growth, suggesting that the fruiting spurs were not fully autonomous in their carbon economy. ELAR and LLAR had little effect on fruit size; sink strength was demonstrated here, since the presence of the fruit caused an efficient transfer of photoassimilates. ESR treatment decreased specific leaf mass (SLM) by 23.84 % when measured 94 DAFB. ELAR did not significantly influence SLM. Treatments had no marked influence on fruit quality.

This work describes in vitro morphogenesis and plantlet regeneration from seeds of the naturally polyembryonic tree Syzgium alternifolium. The basal medium (BM) comprised half strength Murashige and Skoog's (MS) salts, B₅ vitamins, 2 mg dm^-3 glycine, 250 mg dm^-3 ascorbic acid and 20 g dm^-3 sucrose. Addition of auxins like indole-3-acetic acid (IAA), 1-naphthalene acetic acid or 2,4-dichlorophenoxyacetic acid to the basal medium induced formation of roots or callus from the dicotyledonous as well as tricotyledonous seeds. In contrast, cytokinins like N⁶-benzyladenine (BA), kinetin, 2-isopentenyl adenine, thidiazuron alone or a combination of BA and auxins induced development of adventitious shoots. The medium containing 3.0 mg dm^-3 BA and 0.5 mg dm^-3 IAA induced the highest number of adventitious shoots (32 - 33) from dicotyledonous seed with an average length of 4.1 cm within 6 weeks of incubation. Rooting of 80 % adventitious shoots was achieved by dipping the shoots in 100 mg dm^-3 IAA for 15 min. About 70 % of the rooted shoots were successfully established in pots after hardening.

The mechanisms of saccharose and sorbitol transport in Prunus persica leaves were investigated in plasma membrane vesicles purified by aqueous 2-phase partitioning and equilibrated in pH 7.5 buffer containing K+. The imposition of an artificial proton motive force energized an active uptake of both saccharose and sorbitol. The maximum uptake rate of saccharose was 2.5 times higher than that of sorbitol. Saccharose and sorbitol uptake exhibited saturation kinetics suggesting they were carrier-mediated. Apparent Km for the saccharose and the sorbitol uptake were 0.36 and 0.67 mM, respectively. Active absorption of saccharose was completely inhibited by a non-permeant thiol reagent, PCMBS, contrary to sorbitol absorption. These results suggested that saccharose and sorbitol were transported at least by two different carriers.

Random amplified polymorphic DNAs (RAPD) analysis has been adapted to assess the degree of RAPD polymorphism within the genus Hordeum to determine if this approach can distinguish wild and cultivated species. Nineteen wild and seven cultivated accessions were evaluated using 4 random 10-mer primers. The potential of the RAPD assay was further increased by combining two primers in a single polymerase chain reaction (PCR). RAPD fragments generated by two pairs of arbitrary 10-mer primers discriminated six wild species and one cultivated species by banding profiles. The size of the amplified DNA fragments ranged from 150 to 2300 base pairs. 33 %percent of the fragments were common to both wild and cultivated species; 67% were specific to either wild or cultivated species. The average difference in fragments was less within the species than among the species. By comparing RAPD fingerprints of wild and cultivated barley, markers were identified among the set of amplified DNA fragments which could be used to distinguish wild and cultivated Hordeum species.

Leaf bearing stems ofCuratella americana L. were very susceptible to induced cavitation: embolisms began at a pressure of 0.5 MPa (15 %) and at 2.0 MPa most of the conductivity was lost (85 %). Nevertheless, in nature similar leaf specific conductivities, of about 90 x 10^-5 kg m^-2 s^-1 MPa^-1 during both wet and dry seasons indicated absence of drought induced embolisms. Leaf water potentials were neither very negative or considerably different between seasons but stomatal conductance decreased from 236 mmol m^-2 s^-1 measured during wet period to 100 mmol m^-2 s^-1 during drought season. Therefore, it was concluded thatCuratella had an accurate homeostatic balance of leaf water status to keep up xylem integrity.

The results of long-term investigations of variations of rates of water transport through the trunk xylem, its diameter, the leaf water potential and the transpiration rate of the apple tree showed that the daily rhythm of the relative rate of moisture flow in the trunk xylem is an obvious index of the state of the apple tree water exchange. This enables us to determine the period of its unbalance at intensive transpiration as well as the level of the forming water deficit with high accuracy and operativeness. Moreover, by the daily curve of the relative rate of xylem flow one can judge the role of contribution of the trunk reservoir to transpiration.

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.

A method for micropropagation ofDalbergia sissoo has been developed. Single node segments obtained from coppice shoots of a mature tree (20 - 25 year old) produced 3-4 shoots per explant on Murashige and Skoog (MS) medium containing 4.4 x 10^-6 M benzylaminopurine (BAP) and 4.4 × 10^-7 M of Β-naphthoxy acetic acid (NOA) (shoot multiplication medium) within 4 weeks. Thein vitro regenerated shoots were 3 - 4 cm in length and provided 2 to 3 culturable nodal segments which on shoot multiplication medium again produced 3-4 shoots. Following this procedure 18-24 shoots were produced from single nodal segment within 60 d. 80 % of the shoots directly produced five roots when they were firstly treated with MS medium supplemented with 10^-5 M indole-3-butyric acid (IBA) and subsequently transferred to half strength liquid MS medium containing 1 % activated charcoal followed by half strength liquid MS free hormones, vitamins and activated charcoal. Thein vitro raised plants were hardened for survival after transplantation to soil by exposing them to various humidity conditions, gradually from higher to low, with nearly 100 % transplant success.

Net photosynthetic rate (P_N), ribulose-1,5-bisphosphate carboxylase (RuBPC) activity, chlorophyll (Chl) content and biomass production were estimated at monthly intervals inChukrasia tabularis, Dolichandrone atrovirens, Eugenia jambolana, Gmelina arborea, Lannea coromandelica, Terminalia arjuna andTerminalia bellerica from September 1990 to August 1991. The leaves of all the seven tree species showed significantly higher P_N during summer than in winter and these rates differed from one species to the other. A positive correlation was found between P_N of different tree species and their Chl content or biomass production. There was no significant correlation between ribulose-1,5-bisphosphate carboxylase activity and P_N when these were expressed on leaf area basis.

In seedlings of the tropical tree speciesErythrina variegata Lam. andHardwickia binata Roxb. exposed to different acidic mist (H₂SO₄, pH 5, 3 and 2) for 5 d significant reduction in seedling growth, biomass accumulation and¹⁴CO₂ fixation were determined. In isolated chloroplasts a decrease in the activities of photosystem 2 and whole electron transport chain was observed only at pH 3 and 2, but no significant change in photosystem 1 activity was observed. SDS-PAGE analysis of crude leaf extracts of ribulose 1,5-bisphosphate carboxylase (RuBPC) indicated a significant loss of 55 and 15 kDa polypeptides at pH 2 inErythrina. The reduction in the RuBPC activity in seedlings grown under acidic mists correlated well with CO₂ fixation.

Regeneration abilities of buds on shoot segment explants isolated from adult trees of oak (Quercus robur), aspen (Populus tremula), black locust (Robinia pseudacacia), Japan pagoda tree (Sophora japonica), and English walnut (Ailanthus glandulosa) were studied during the growing season. Optimum BAP concentrations for the regeneration of oak bud meristems were dependent on the date of sampling. Axillary shoots could be induced from winter and summer buds of oak and aspen on Dustan and Short media supplemented with activated charcoal and BAP at concentrations from 0.5 to 2 mg 1^-1. More intensive rooting of segments of newly formed shoots was observed on MS medium diluted to one half and supplemented with 2 % sucrose and 0.2 mg 1^-1 of IBA.Populus tremula formed longer axillary shoots on DS media supplemented with 0.5 mg 1^-1 of BAP and 1 mg 1^-1 of GA₃.
Regeneration capacities of black locust, Japan pagoda tree, and English walnut were higher. In addition to the induction of multiple shoots from buds, shoots could also be obtained from calluses formed on basal segment parts. Asparagine and glutamine at a concentration of 25 mg 1^-1 stimulated the percentage of differentiated stems on callus surface. Inhibitory effects of substances which accumulated in buds in the second half of the growing season could be reduced by means of pulse treatments in 50 mg 1^-1 BAP solutions or using short-term dipping into 0.1 % AgNO₃ solution.

Net photosynthetic rate (P_N), ribulose-1,5-bisphosphate carboxylase (RuBPC) activity, chlorophyll (Chl) content and biomass production were estimated at monthly intervals inChukrasia tabularis, Dolichandrone atrovirens, Eugenia jambolana, Gmelina arborea, Lannea coromandelica, Terminalia arjuna andTerminalia bellerica from September 1990 to August 1991. The leaves of all the seven tree species showed significantly higher P_N during summer than in winter and these rates differed from one species to the other. A positive correlation was found between P_N of different tree species and their Chl content or biomass production. There was no significant correlation between ribulose-1,5-bisphosphate carboxylase activity and P_N when these were expressed on leaf area basis.

Multiple shoots (16-20 shoots per expiant) were induced from cotyledonary node region ofAnogeissus acuminata (Roxb. ex DC.) Guill. & Perr. on Murashige and Skoog's (MS) medium containing IAA 0.1 mg 1^-1 + BAP 1.5 mg 1^-1 and ascorbic acid 50 mg 1^-1, citric acid 25.0 mg 1^-1, arginine 25 mg 1^-1 and adenine sulphate 25 mg 1^-1. From the first node of seedling only 4-6 shoots per expiant were proliferated. Segments ofin vitro produced shoots were used as expiants for further multiplication of shoots upto 16 successive cultures at an interval of 4 week on MS medium with IAA 0.1 mg 1^-1 + BAP 1.0 mg 1^-1 and additives. The original cotyledonary expiant was repeatedly subcultured upto 4 times after harvesting crop of shoots, each time.In vitro produced shoots were rooted on half strength MS medium containing 0.5 mg 1^-1 IBA. Plantlets were transferred to pots. Other expiants (cotyledons, hypocotyl, and leaf) produced callus on medium containing auxins and cytokinins. The calluses differentiated into embryo like structures or roots on MS medium.

Phytotoxic micromycetes appear to be responsible for the apple replant disease (ARD). This was suppressed by the inoculation of apple-tree seedlings with some species of vesicular-arbuscular mycorrhizal (VAM) fungi-Glomus fasciculatum andG. macrocarpum. After the inoculation, growth of apple-tree seedlings improved in dependence on the type of soil, on VAM fungus species and on the ARD appearance. After 12-month cultivation, plant biomass (height, shoot and root dry masses) was markedly increased by inoculation withG. fasciculatum. Similarly, the numbers of colony forming units per unit soil (CFU) of phytotoxic micromycetes and of diazotroph bacteria (associative dinitrogen-fixing bacteria) in the rhizosphere was affected; CFU of phytotoxic micromycetes decreased, whereas CFU of the genusAzospirillum was higher. These bacteria could also serve as antagonists against phytotoxic micromycetes. It is also suggested that the ratio of CFU of diazotroph bacteria to CFU of phytotoxic micromycetes can be used as an indicator of the degree of ARD. It may be assumed that the use of some VAM fungi can replace the chemcial treatment of the soil with ARD.

The responses of seedlings of three fast growing tree species,Eucalyptus hybrid(E. camaldulensis × E. teriticornis), Casuarina equisetifolia andMelia azedarach, to different levels of soil moisture in controlled glasshouse conditions were compared. The survival percentage, height of plants, number of leaves per plant, number of branches, fresh mass and dry mass of roots, stems, branches and leaves decreased in the three species with increasing water stress. Stomatal frequency and length of stomata inEucalyptus andMelia also decreased with increasing water stress. However, no significant difference was obtained in the width of stomata and the ratio of number of open stomata to total number of stomata per unit area. The leaf thickness decreased, but the thickness of palisade parenchyma increased with increasing water stress inEucalyptus hybrid andCasuarina. Leaf thickness ofMelia did not show any significant variation due to water stress.