Seedlings of green gram [Vigna radiata (L.) Wilezek] cultivar KM-2 were sprayed with different concentrations of triacontanol (TRIA) (0, 0.5, 1.0, and 2.0 mg dm^-3) at 15 and 25 days after sowing. Foliar spray of 0.5 mg dm^-3 TRIA significantly promoted the plant height, fresh mass, and contents of chlorophylls, saccharides, starch, soluble proteins, amino acid and phenols. Leaf nitrate content was reduced by 0.5 and 1.0 mg dm^-3 TRIA with a corresponding increase in nitrate reductase activity. TRIA of 0.5 mg dm^-3 stimulated the onset of flowering, pod production and retention, but less number of pods and seeds per plant were observed at 2.0 mg dm^-3 treatment.

The influence of saline water (4, 8, 12 dS m^-1) irrigation on gas exchange and growth response of alfalfa genotypes Anand-2, T-9 and IL-112 was studied. T-9 and IL-112 showed a significant increase in net photosynthetic rate (P_N) at low salinity (4 dS m^-1) compared to the control whereas Anand-2 maintained an unaltered P_N. Reduction in P_N at higher salinities was primarily due to reduction of stomatal conductance. There was a greater reduction in transpiration rate as compared to P_N rate, which resulted in an increase in water use efficiency (WUE). High WUE may serve as one of the strategies of the plant to withstand saline environment. However, the slight increase in WUE in Anand-2 could not help in maintaining its growth. Increase in Na⁺ concentration in comparison to K⁺ concentration may also contribute to the inhibition in growth.

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.

Experiments were conducted to study the effect of plant type on canopy photosynthesis under field conditions. A chamber made of aluminium frame covered with clear plastic material was used to estimate canopy CO₂-exchange rates over a land area of 1.33 m². The plant type of maize "Shendan 7" [planophile type, original-type (OT)] was changed to erectophile type [altered-type (AT)] at silking stage. The rates of canopy apparent photosynthesis (CAP) were measured in both types of maize grown at five plant densities during the reproductive phase. It was shown that AT canopies had greater rates (about 17.2%) of CAP than did OT canopies and the yield increased by about 5.9-8.6% in AT canopies. The vertical distribution of photosynthetic photon flux density and CO₂ concentration in AT canopies were more uniform than those in OT ones. It was suggested that the compact architecture of maize canopy was excellent for photosynthesis and yield formation.

Soluble sugars, proline, total chlorophyll contents and electrolyte leakage were measured in two wheat (Triticum aestivum L.) cultivars KRL 1-4 and HD 2009 at different growth stages [crown root initiation (CRI), flowering, and soft dough] under short term salinity (NaCl, CaCl₂ and Na₂SO₄). In control plants sugar contents were maximum at flowering stage. Proline and sugar concentrations increased in both cultivars under salinity with a maximum increase at CRI. Electrolyte leakage increased and chlorophyll content decreased with the plant age. A sharp increase of electrolyte leakage was noticed at salinity of 10 and 15 dS m^-1 in HD 2009 and KRL 1-4, respectively. The short-term salinity at CRI stage proved more detrimental as compared to salinity at flowering and soft dough stages in term of all biochemical changes induced. In wheat, plant resistance to salinity increased with the age of plant. The cultivar KRL 1-4 performed better under salinity as compared to HD 2009.

The protein profile of cells of control somatic embryos was compared to that of embryos that have become selected and maintained on 200 mM NaCl in order to detect salt inducible proteins. Two proteins (60 and 51.5 kDa) were more abundant in the selected embryos and one protein with molecular mass 18 kDa was unique to the selected embryos. Enhanced content of 27 kDa protein was observed in all somatic embryos indicating its involvement in the embryonal state. Similar pattern of salt inducible proteins in selected somatic embryos and the plantlets regenerated from such embryos was found.

In vitro culture of long-day plant Chenopodium murale L was established. The effects of photoperiod, glucose and gibberellic acid (GA₃) on flowering and growth in vitro were investigated. Oscillatory changes of photoperiodic sensitivity were noticeable with regard to plant age. The plants induced at the phase of the 1^st and the 3^rd pair of leaves flowered to higher degree than those induced at the phase of 2^nd pair. Plants induced at the phase of the 1^st pair of leaves flowered to 17 % on 5 % glucose-containing medium and the addition of 5 mg dm^-3 GA₃ resulted in maximum flowering (43 %). Neither glucose nor GA₃ were able to compensate for photoperiodic requirements for flowering. Hypocotyl growth was decreased and the 1^st internode elongation and development of leaves were increased due to inductive photoperiodic conditions, as compared to non-inductive ones.

It is almost impossible to find a single process in plant life that is not affected by both stress and hormones directly or indirectly. This minireview is focused on the interactions between water stress and cytokinins (CKs). The attention was paid mainly to changes in endogenous CK content and composition under water stress, involvement of CK in plant responses to water stress mainly in stomatal regulation of gas exchange, water relations of transgenic plants with elevated CK content, and possibilities to ameliorate the negative effects of water stress by application of exogenous CKs.

Young maize plants, grown hydroponically, were supplied with 1/10 the optimal amount of iron (0.75 mg dm^-3). Foliar treatments with solutions, containing N⁶-benzyladenine (BA), indole-3-acetic acid (IAA) or (2-chloroethyl)-trimethylammoniumchloride (CCC) were conducted after chlorosis had been well manifested. Changes in growth, chlorophyll content, rate of photosynthesis, catalase and peroxidase activities in leaves, and the contents of Fe, Cu, Zn, Mn, and P in leaves were recorded. Growth regulators improved (CCC, IAA) or aggravated (BA) the physiological state of chlorotic plants. Their effect might be explained by changes in Fe transport towards the leaves, by increased efficiency of Fe utilization, and by effects on plant metabolism not involving Fe.

A number of nitrogen containing compounds (NCC) accumulate in plants exposed to salinity stress. The most frequently accumulating NCC include amino acids, amids, imino acids, proteins, quarternary ammonium compounds (QAC) and polyamines. The specific NCC that accumulate in saline environment vary with the plant species. Osmotic adjustment, protection of cellular macromolecules, storage form of nitrogen, maintaining cellular pH, detoxification of the cells, and scavenging of free radicals are proposed functions for these compounds under stress conditions. NCC accumulation is usually correlated with plant salt tolerance, even though this correlation is based on untested hypotheses.

A sterile mutant of pea (Pisum sativum L. line HM-6) with a number of morphological alterations was found after plant regeneration via somatic embryogenesis. Embryogenic callus was derived from the whole immature zygotic embryo on medium with 2.26 μM 2,4-dichlorophenoxyacetic acid. Morphological changes included altered leaflet shape, one pair of leaflets only, altered stipule morphology, shortened internodia, irregular or opposite leaf position on the stem, shortened flower stalk, and aborted flowers resulting in complete sterility. If the isolation of the shoot apex and axillary buds from evidently sterile plant and their culture in vitro resulted in morphologically normal and fertile regenerated plants, the chimaeric nature of R₀ mutant is considered.

The effect of calcium and zinc ions on superoxide dismutase (SOD) from four plant species (Taxus baccata, Pinus sylvestris, Medicago rigidula, and Zea mays) was followed at three temperatures: optimal (20 °C), increased (50 °C), and high, inhibiting temperature (70 - 80 °C). At 20 and 50 °C in vitro added calcium increases SOD activity, but the degree was different for the plants investigated. The effect of zinc ions at the same temperatures varied in the investigated plants from activation to inhibition. An inhibiting effect of high temperature on SOD activity was diminished in the presence of calcium or zinc ions. It was shown that calcium and zinc ions can increase activity and thermostabilize different SOD isoforms.

A Pseudomonas strain MRS16 inhibited growth of different pathogenic fungi (Aspergillus sp., Fusarium oxysporum, Pythium aphanidermatum and Rhizoctonia solani) in vitro. Larger inhibition zones were obtained on nutrient agar and King's B media compared to potato dextrose agar and pigment production media. Mutants altered in production of fluorescent pigment were derived by nitrosoguanidine mutagenesis. The pigment overproducer mutant MRS16M-1 was more inhibitory whereas nonproducer mutant MRS16M-5 was less inhibitory than parent strain on nutrient agar medium. Addition of iron (100 µM FeCl₃) in the medium decreased inhibition of fungal growth, suggesting the involvement of siderophores and other antifungal secondary metabolites. Seed bacterization of two cultivars of chickpea (Cicer arietinum cvs. H8618 and C235) differing in susceptibility to wilt caused initial root and shoot stunting at 5 d of growth followed by proliferation of secondary root growth at 10 d. Coinoculation of chickpea with Pseudomonas strain MRS16 or mutants and Rhizobium sp. Cicer strain Ca181 enhanced nodulation, nitrogen fixation and plant dry mass as compared to single inoculation with Rhizobium strain under sterile conditions.

To induce somatic embryogenesis in Quercus robur L. immature zygotic embryos at different developmental stages were collected in weekly intervals from June until September in three consecutive years from four open pollinated trees at two Vienna sites. Acorns were surface sterilised and cultured firstly on P24 medium with 5μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 μM 6-benzylaminopurine (BAP) or on hormone-free P24 medium and secondly on P24 medium with 0.9 μM BAP. The formation of white-yellow globular structures of somatic embryos started during the fourth week after the induction treatment. High induction frequencies of 30 - 80 % were achieved on 2,4-D/BAP medium, whereas rates on hormone-free medium were below 20 %. The initiation of somatic embryogenesis was favoured in the heartshaped and early cotyledonary stage of the zygotic embryo in all three years and lasted until the acorns reached maximum size in August.

Wheat plants were grown from sowing to day 18 in 26-dm³ chambers at three different CO₂ concentrations: 150 (-CO₂), 350 (C, control), 800 (+CO₂) μmol mol^-1. Afterwards, plants of the three variants were grown at the same natural CO₂ concentration. Plant characteristics were measured just before the transfer (0 days after CO₂ treatment, DAT), and at 5 - 8 DAT on the 1^st leaf, and at 12 - 22 DAT on the 4^th leaf. Decreased or increased CO₂ concentrations caused acclimations which persisted after transplantation to natural CO₂ concentration. At 5 - 8 DAT, stomatal density, stomatal conductance (g_s), CO₂ saturated net photosynthetic rate (P_Nsat0), radiation saturated net photosynthetic rate (P_Nsat1), and carboxylation efficiency (τ) were higher in -CO₂ plants and lower in +CO₂ plants than in C plants. As compared with C plants, the photochemical efficiency (α) was lower in -CO₂ and higher in -CO₂ plants, however, chlorophyll (Chl) a, Chl b, Chl a-b and carotenoid contents were lower in both -CO₂ and +CO₂ plants. On the 4^th leaf, which emerged on plant after finishing CO₂ treatments, at 12 - 22 DAT, no differences in stomatal density and g, between treatments were observed. In -CO₂ plants, pigment content and P_Nsat0 were higher, α was lower, and P_Nsat1 and τ were not different from C plants. In contrast, in +CO₂ plants, pigment content, P_Nsat1 and τ were lower, and P_Nsat0 and α were unchanged. Leaf area, dry mass, and tiller development increased in +CO₂ plants and decreased in -CO₂ plants. In the interval between 8 and 22 DAT, lower net assimilation rate in +CO₂ than in -CO₂ plants was observed.

The objective of the present study was to compare the plant morphology, water relations and photochemical efficiency of photosystem 2 in two wild. Mediterranean species Lotus creticus creticus and Lotus creticus cytisoides. L. creticus creticus showed higher density of trichomes and stomatal density on the adaxial leaf surface than L. creticus cytisoides, whereas L. creticus cytisoides showed higher stomatal density in abaxial surface than L. creticus creticus. These morphological traits promoted clear differences in leaf surface water retention and leaf reflectance. Leaf water potential and photochemical efficiency were lower in L. creticus cytisoides than in L. creticus creticus.

In six cultivars of rice (Oryza sativa L.), Pusa Basmati 1, Basmati 370, Type III, Pant Dhan 4, CSR 10 and Pokkali, embryogenic callus growth, plant regeneration, and proline and total protein contents were studied under salt stress (on agar solidified media containing 0, 0.5, 1.0, 1.5 and 2.0 % NaCl). Four weeks after inoculation the callus fresh mass decreased with increasing salt concentration in all the six cultivars. The regeneration frequency in salt stressed callus was also lower as compared to control. 15 d and 30 d after inoculation proline content increased several fold whereas total protein content decreased markedly with increase in salt concentration.

The trace metal (Fe, Mn, Zn, Cu, Ni, Pb, Cd, Sr, and Cr) contents in the most common submerged and floating aquatic plants Ceratophyllum demersum L., Myriophyllum spicatum L., and Nymphoides flava Hill. of Provala Lake were evaluated. Considerable higher contents of iron, manganese, zinc, nickel, lead and strontium were found in submerged species than in the floating ones. The presence of cadmium and lead in plant tissues points to a certain degree of lake water pollution.

Study of the effects of air pollution caused by thermal power plant emissions on some foliar traits of Ruellia tuberosa L. has shown that length and width of stomata, length of stomatal pore, stomatal density, photosynthetic rate, stomatal conductance and chlerophyll content were reduced in the polluted plants in pre-flowering, flowering as well as post-flowering phases of plant growth. Intercellular carbon dioxide concentration in the palisade tissue was increased at each stage of plant development. Stomatal index remained almost unchanged at the polluted site, except on the adaxial surface during the preflowering stage where it was higher as compared to the non-polluted plants.

The effect of lead and cadmium on biomass accumulation of cucumber seedlings (Cucumis sativus L.) as well as the contents of abscisic acid (ABA), free proline and soluble proteins in leaves were studied. Seedlings were subjected to lead nitrate or cadmium bromide in low concentrations (1 - 5 µM) for 1, 4 or 7 d, and then to the action of the same substances in high concentrations (500 - 1000 µM). The pretreatments of the seedlings with heavy metals in low concentrations enabled them to tolerate the subsequent high concentrations of cadmium and lead without injury. The plant responses to heavy metal treatment were accompanied by the accumulation of ABA, free proline and soluble proteins in leaf tissues.

The accuracy of LAI-2000 Plant Canopy Analyzer for leaf (LAI) and plant (PAI) area indexes measurements was tested in 20-year-old Norway spruce stand using the reduction of canopy biomass. Needle and branch areas were reduced progressively upward every one meter. Values of effective leaf area index (LAI_e), as an uncorrected product of LAI-2000, were compared with directly estimated LAI and PAI values after each reduction step. LAI-2000 underestimates PAI and LAI values according to LAI-2000 rings readings, and varied proportions between leaf and wood areas. The values of LAI_c have been increased with decreasing of the view angle of the relevant LAI-2000 rings. Therefore, the underestimation of LAI becomes smaller when the readings near the horizon are masked. More accurate results, for projected LAI (LAI_p) calculation, are produced by LAI-2000 when some dense grids of measurement points and the most vertical ring readings (0 -13 °) are used. Correction factor 1.6 is possible to use for unreduced canopy hemi-surface LAI estimation, when the last rings (i.e. 5^th and 4^th rings, 47 -74 °) are excluded. Correction factor of 1.25 can be used to compute LAI_p if the angle readings under 43 °are also masked.