Gas exchange in Gossypium hirsutum L. cv. H-777 as affected by water deficit and growth regulators (IAA, GA₃, BAP, ABA, ethrel) was examined. Sixty days after sowing, growth regulators in concentration 50 µM were applied as foliar spray and irrigation was withheld to get desired (moderate and severe) water deficit. All the parameters were measured on the third leaf from the top between 10:00 and 11:00. Net photosynthetic rate (P_N), transpiration rate (E), stomatal conductance (g_s), carboxylation efficiency (CE), and water potential (ψ_w) decreased significantly with the increasing water stress, however, water use efficiency (WUE) was unaffected. Foliar spray with IAA, GA₃ and BAP partially counteracted the effect of water deficit on the above parameters except ψ_w, which became more negative. ABA and up to some extent ethrel increased WUE and maintained higher ψ_w, however, caused further decrease in P_N, E, and g_s.

The results demonstrate the benefits of using filter-paper-based system for cultivation the germinating barley seeds for Al toxicity or Al tolerance analyses. Due to the high affinity of filter paper to Al monomeric forms, milimolar Al concentrations were required to cause similar Al toxicity symptoms of roots as micromolar Al concentrations in hydroponics: 1 mM Al had no effects on the emerging barley roots, 2 mM Al was moderately toxic but roots showed good recovery, 4 mM Al was highly toxic and 8 mM Al even lethal. Screening of eight barley cultivars revealed different rank of their tolerance to Al. The root growth inhibition positively correlated with the Al concentration in root tips.

Susceptibility of Mexican cacti to Agrobacterium rhizogenes was evaluated in 65 species of 22 genera. Stem discs taken from in vitro cultured plants were inoculated with Agrobacterium rhizogenes A4 agropine-type strain that contains the wild RiA4 plasmid and the binary vector pESC4 with the nptII and gus genes. Hairy roots were produced directly from wounds, or starting from calli generated on the wounded surface, in 34 of the evaluated species. The frequency of hairy roots formation, the number of roots per explant and its growth rates were variable among the tested species. In the 31 remaining species the production of transformed roots was not observed under the conditions used in these experiments. Histochemical detection of β-glucuronidase (GUS) activity demonstrated the expression of this foreign gene in the hairy roots. PCR analyses demonstrated the presence of the rolB and nptII genes in the DNA of the transformed roots. The patterns of alkaloid-like compounds obtained by thin layer chromatography in some of the tested species were qualitatively similar between the transformed and non-transformed roots.

NaCl salt stress induced changes in growth and enzyme activities in blackgram (Phaseolus mungo L.) seeds during germination were studied. A decrease in germination percentage, root length, shoot length, and fresh mass was noticed with an increase in NaCl concentration. With the increase in NaCl concentration and duration of stress proline content increased and catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) activities decreased.

Explants taken from the mature vigorous tree of wild cherry (Prunus avium L.) were assayed for their organogenic capacity under various phytohormonal treatments. The highest rate of adventitious shoot multiplication was recorded at a combination of 0.5 mg dm^-3 6-benzylaminopurine (BAP) and 0.05 mg dm^-3 thidiazuron (6.83 shoots per explant). No differences in multiplication rates were found among media supplemented with BAP, BAP + α-naphthaleneacetic acid (NAA) or BAP + indole-3-butyric acid (IBA). Shoot elongation was significantly affected by the concentration of BAP, regardless of auxin addition to medium. Up to 73 % of microshoots rooted after using 0.3 mg dm^-3 IBA, otherwise the adventitious rooting occurred at reasonable frequencies in all auxin treatments. Regenerated plantlets were successfully hardened ex vitro and continued to grow after the transfer to soil. No morphological aberrations were observed in the regenerates.

Multiple shoots were induced by culturing nodal explants excised from 1-month-old aseptic seedlings of red pepper (Capsicum annuum L. cv. Pusa Jwala) on Murashige and Skoog (MS) medium supplemented with (0.1-10 μM) thidiazuron (TDZ). The rate of multiple shoot induction per explant was maximum (14.4 ± 0.06) on MS medium supplemented with 1.0 μM TDZ. Regenerated shoots were elongated well on growth regulator free MS medium. Adventitious roots were induced two weeks after transfer of elongated shoots to MS medium supplemented with auxins (IAA, IBA or NAA) in different concentrations. Optimum root formation frequency was obtained in medium containing 1.0 μM IBA. Ex-vitro rooting was also achieved by pulse treatment with 300 μM IBA for 10 min. Rooted shoots were transplanted in plastic pots containing garden soil (with 90 % survival rate), where they grew well and attained maturity. Regenerated plants were phenotypically and cytologically normal.

Acacia ampliceps Maslin and Eucalyptus camaldulensis Dehnh. were grown for one year in lysimeters at three soil moisture regimes: 100 % (well-watered), 75 % (medium-watered) and 50 % (low-watered) of total plant available water. Biomass yield of both species increased with increase in soil moisture. Water-use efficiency (WUE) of E. camaldulensis decreased and that of A. ampliceps increased markedly with decrease in available soil moisture. A. ampliceps showed 4 - 5 times more biomass yield than E. camaldulensis grown at similar soil moisture. A. ampliceps showed almost 5, 9 and 12 times higher WUE than E. camaldulensis under low-, medium- and well-watered treatments, respectively. Significant negative correlation of δ¹³C with WUE (r = -0.99) was observed in A. ampliceps. In contrast, δ¹³C of E. camaldulensis showed a significant positive correlation with WUE (r = 0.82).

Multiple shoot buds could be induced directly from internode explants of Celastrus paniculatus inoculated on Murashige and Skoog's (MS) medium containing different growth regulators. The best response was obtained when 4.44 μM 6-benzylaminopurine (BAP) was incorporated in the medium. Incorporation of indole-3-acetic acid (IAA) and α-naphthalene acetic acid (NAA) did not improve response, rather promoted callusing. Adventitious shoot buds could be multiplied and elongated on MS medium containing 2.22 μM BAP. Rooting of shoots (80 %) was obtained when their bases were dipped in pre-autoclaved indole-3-butyric acid (IBA) solution (2.45 mM) for 10 min followed by their implantation on medium containing 1/4 MS salts, 1.0 % sucrose and 0.6 % agar. Out of 500 plantlets subjected to hardening, 410 were successfully hardened under greenhouse conditions. Twenty plants were established in field while remaining of them were transferred to nursery conditions without any mortality.

Although it is well accepted that cytokinins (CKs) regulate processes such as leaf senescence and stomatal conductance, data on CKs in the canopy of mature trees are lacking in the literature. Here we report the first in situ sampling for determination of CKs in mature sugar maple (Acer saccharum) canopy layers. The upper canopy showed a distinct seasonal pattern in total CK content, while the lower canopy remained relatively unchanged.

The physiological responses of alfalfa (Medicago sativa L. cv. Gilboa) to salinity (100 mM NaCl) and some inorganic nutrients (K+, Ca2+ and N as NO3-) were investigated. Salinity caused a substantial reduction in biomass, carbon assimilation rate, stomatal conductance, water use efficiency, leaf area, relative growth rate, NO3- content and nitrate reductase activity, whereas, transpiration rate was slightly affected. Inclusion of K+, Ca2+ and N as NO3- in plant nutrient medium in combination or alone brought about a marked stimulation in control plants and moderated the salinity caused reductions in NaCl treated plants. In addition, plants also exhibited differences in these parameters at two growth stages.

Nitrate and total nitrogen contents, and nitrate reductase (NR) activity of the excised maize roots in buffered or unbuffered nitrate solution (at pH 6.5 or 4.5) as affected by putrescine (PUT), abscisic acid (ABA) and salicylic acid (SA) were investigated. In unbufferred solution, the NR activity was lower at pH 4.5 as compared to that at pH 6.5, but in bufferred solution the activity was higher at lower pH. Supply of 100 µM PUT or 500 µM SA, promoted NR activity and 50 µM ABA inhibited the activity at pH 6.5. However, at pH 4.5, PUT and SA inhibited NR activity and ABA had no effect. In most cases, the increase in NR activity was positively correlated with total organic nitrogen and a negatively with nitrate content. A reverse situation was found when NR activity was inhibited by the growth regulators.

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.

In roots of Pisum sativum seedlings, the average lag-time required for initiation of the gravitropic response was reduced proportionally to the concentration of 24-epibrassinolide (EBL) added to the root solution (range of 10^-13 to 10^-8 M concentrations). A treatment with clotrimazole, a compound inhibiting steroid synthesis, prevents initiation of the gravitropic response. This effect was partly reverted by addition of EBL. From analysis of variability in the populations, it is suggested that BR conditions the root curvature through a gravitropic-induced change in sensitivity to the PGRs regulating cell elongation.

Erythrina variegata Lam. seedlings were grown under low (100 mM NaCl) and high (250 mM NaCl) salinity. Seedlings exposed to high salinity for 10 d showed significant reduction in growth rate and biomass production while the root/shoot ratio increased. In contrast to pigment and protein contents, starch and saccharide contents increased in salt stressed seedlings. When the seedlings were subsequently sprayed with triacontanol (1 mg kg^-1) the salinity effect was partially ameliorated and growth, biomass, chlorophyll and carotenoid contents increased.

Changes in the content of soluble sugars and starch were determined during the first phase of de novo organogenesis in stem internode segments (SIS), taken either from control plants or from the plants grown on medium with 10^-8 M paclobutrazol (PBZ). Transient accumulation of soluble sugars was observed in both variants during the first two days. Control SIS accumulated higher amount [22.0 mg g^-1(f.m.)] of soluble sugars than the PBZ pretreated SIS [15.2 mg g^-1(f.m.)]. PBZ variant showed four times higher starch content at the start of experiment in comparison with the control. Both variants accumulated starch during cultivation until the beginning of regeneration.

Interspecific competition between four soybean cultivars (PI471938, Stressland, Essex and Forrest) and the weed, common waterhemp was investigated under increasing weed densities (i.e. 0, 1, 4 and 16 plants per pot). Soybean height and leaflet number were measured over a 45-d period and used to calculate relative growth rates (RGR). Trigonelline (TRG) concentration was determined within the V1 leaf of 45-d-old soybean plants. Soybean leaflet number (P[lt ]0.05), soybean height (P[lt ]0.05) and soybean RGR_h (expressed in terms of height) differed significantly (P[lt ]0.05) according to waterhemp density. At each waterhemp density Stressland matured at a significantly faster rate whereas the maturation rate of Essex decreased in the presence of waterhemp. Final TRG concentrations were affected by the interaction between soybean cultivar and waterhemp density. Under no competition, TRG concentration was significantly lower in Forrest relative to PI471938, Stressland and Essex. TRG concentrations in Essex declined in higher waterhemp densities.

Establishment of salt tolerant rice plants was examined by single step or step up NaCl treatments of shoot bud clumps in vitro, and variation among in vitro salt tolerant plants were examined by rapid amplified polymorphic DNA (RAPD). Shoot bud clumps were necrotic, stubbed or dead when subjected to single step treatment with 1.5 or 2.0 % NaCl. Conversely all the clumps could grow vigorously when subjected to step up salt treatment with 0.5, 1.0, 1.5 and 2.0 % NaCl at 3 week intervals and 2 % NaCl tolerant plants were established. RAPD revealed shoot bud clumps with and without different NaCl treatments, seedlings from field and grown in vitro, and regenerants from callus were genetically close to one another. Conversely, callus cultures were genetically isolated. Growth under different salt stress conditions was not correlated with the genetic variation, suggesting that 2.0 % NaCl tolerant plants might not result from genetic mutation but were due to adaptation of plants by step up NaCl treatment in vitro.

To determine the allelopathic potential of root exudate from early developmental stage of rice (Oryza sativa L), 6-d-old seedlings of eight cultivars were grown with 3-d-old alfalfa (Medicago sativa L.), cress (Lepidium sativum L.) or lettuce (Lactuca sativa L.) seedlings in Petri dishes under controlled condition. All rice cultivars (cv. Norin 8, Kamenoo, Nipponbare, Kinuhikari, Koshihikari, Sasanishiki, Yukihikari and Hinohikari) inhibited growth of roots, shoots and fresh mass of alfalfa, cress and lettuce seedlings. Effectiveness of cv. Koshihikari was the greatest and more than 60% inhibition was recorded in all bioassays, followed by that of cv. Norin 8 of which effectiveness was more than 40%.

rRNA was labelled with RNase-gold complexes applied to ultrathin Lowicryl sections of excised Cucurbita pepo L. (zucchini) cotyledons grown in darkness. Benzylaminopurine-caused stimulation of cotyledon growth decreases the density of ribosomes in palisade cells despite stimulating rRNA synthesis. Abscisic acid inhibits RNA synthesis and transport, but does not visibly affect the number of pre-existing ribosomes in retarded growth cells. The amount of rRNA in the cells of 24 h treated cotyledons is rather consequence of the growth rate than its leading factor.

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 effect of the methyl ester of jasmonic acid (MeJA) in 10 μM concentration was studied on the development of the bacterial contaminants and on the content of some metabolites in Scenedesmus incrassulatus cultivated at temperatures 15, 20, 25, 30, and 36 °C. The number of bacteria on algae cells increased with the rise in temperature. Application of MeJA into nutrient medium inhibited the development of bacterial pathogens more than 3 times at 20 °C, 2.3 times at 30 °C, and 2.6 times at 36 °C without changing the species composition. MeJA caused an increase of the protein content in algae cells. The contents of palmitic and linoleic acids increased with the rise of temperature from 15 to 36 °C. At the same time the contents of linolenic and oleic acid decreased. At low temperatures, cultivation with MeJA induced more significant changes in the composition of C18 acids while at high temperature the changes were more pronounced in C16 acids. Treatment with MeJA decreased the activity of glutamate dehydrogenase at optimal and suboptimal temperatures and increased it at superoptimal temperature. Hence MeJA jasmonate had a positive effect on the tolerance of S. incrassulatus to stress temperatures, which was also demonstrated by better growth.

Significant amounts of lepidine was detected in mature and juvenile explants from both in vivo and in vitro grown plants. The yield, however, was variable depending upon the source and type of explant used. Mature in vivo plants at vegetative stage exhibited highest yield. Among all the explants, maximum lepidine was detected after 8 weeks in shoot apex callus on MS medium supplemented with 2 mg dm^-3 naphthaleneacetic acid and 5 mg dm^-3 benzylaminopurine. Addition of 900 μM Zn^2- or 100 μM Cu^2- further enhanced the yield of lepidine.

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.

The responses of barley and wheat seedlings to lead and cadmium ions in relation to the concentration and duration of treatment were studied. Both metals inhibited seed germination and growth of roots and shoots, but the toxic effect of cadmium was observed at lower concentrations. Inhibition of seedling growth was already recorded already within a day after the beginning of the treatment, and then increased further. The sensitivity of the processes studied to both the metals decreased in the order: root growth, shoot growth and seed germination. The resistance of barley and wheat to lead was similar, whereas the resistance to cadmium was higher in barley

Lavandin (Lavandula dentata) axillary buds were grown in Linsmaier-Skoog (LS) medium solidified with 10 % bactoagar (control) and supplemented with 0.1 mg dm^-3 benzyladenine (BA), 0.1 mg dm^-3 indolebutyric acid (IBA) or both plant growth regulators. In the studied conditions the axillary buds developed into plantlets. The addition of BA inhibited the formation of glands by 44 % as compared with the control plantlets and also inhibited their development: these plantlets had the highest number of unbroken glands (in pre-secretory state) when compared with plantlets grown in the other conditions. The presence of BA stimulated chloroplast formation, and increased the content of essential oils by 150 % with respect to the control plantlets. It also increased their secretion, and the number of lipid droplets in the chloroplasts, cytosol and plasmalemma. On the contrary, the presence of IBA decreased the essential oil concentration in plantlets by 31 % when compared with the control ones and inhibited their secretion capacity.

Biomass growth and ginsenoside production in cell suspension and adventitious roots of Panax ginseng C.A. Meyer cultures cultivated both in Erlenmayer flasks and a 3 dm³ bioreactor were studied. The maximum content of ginsenosides was found in the suspension culture cultivated in the bioreactor (4.34 % dry mass), however the saponin content was limited to two major ginsenosides, Rb₁ and Rg₁. The production of ginsenosides in adventitious roots was lower (1.45 or 1.72 % dry mass), nevertheless, the full range of ginsenosides was detected.

The effects of salt stress on the growth, photosynthesis, and antioxidative ability of the rice (Oryza sativa L.) plants raising from γ-irradiated seeds were investigated using two cultivars, Ilpumbyeo and Sanghaehyanghyella. The 50 and 100 mM NaCl solutions caused a remarkable decrease of the early germination rate and seedling growth. However, the salt stress-induced inhibition of the growth was significantly alleviated in the γ -irradiated plants. The chlorophyll contents and the effective quantum yield of photosystem 2 (Φ _{PS 2}) were lower in the NaCl-treated plants than in the control ones, while the non-photochemical quenching was higher in the former ones. Activities of the antioxidant enzymes such as superoxide dismutase (SOD) and ascorbate peroxidase (APX) increased with increasing NaCl concentrations, and the irradiated groups had even higher SOD and APX activities than the non-irradiated ones. These alleviation effects were observed similarly in both the cultivars tested.

In vitro culture of Chenopodium murale L. (ecotype 197) green and herbicide SAN 9789 - treated "white" plants was established and the effects of benzylaminopurine (BAP), indole-3-acetic acid (IAA) and gibberellic acid (GA₃) on growth and flowering were tested. Green plants did not flower on glucose free media, while 17 % of plants flowered on 5 % glucose-containing medium. SAN 9789 (10^-5 M) inhibited growth and flowering. BAP and IAA (0.1 - 5 mg dm^-3) also inhibited growth and flowering of green and "white" plants. GA₃ (10 mg dm^-3) stimulated leaf development in green plants, but had no significant effect on "white" plants, and stimulated flowering of green (41 %) and "white" (33 %) plants.

Lead nitrate at concentration of 150 mg dm^-3 inhibits root growth of Lupinus luteus seedlings by bout 20 %, which is accompanied by an increase of K⁺ leakage from the root cells. Non-denaturing isoelectric focusing in polyacrylamide slab gel has shown that lead stimulates the activity of most lipoxygenase isoenzymes and induces one additional isoenzyme with pI 6.9.

An efficient and reproducible protocol for regeneration of plantlets at a high frequency was developed by using sugar cane buds. Disinfected buds were firstly submerged in ethanol sodium hypochlorite solution with 0.1 % polyvinylpyrrolidone, 1.5 % ascorbic acid and 1.75 % citric acid as antioxidants and subsequently treated with solution of agrimicin:captan (1:1). The upper stalk segment was better to obtain bud in vitro culture compared to lower segments. The medium for induction of multiple shoots consisted of Murashige and Skoog basal medium (MS) supplemented with 2 mg dm^-3 thidiazuron and 1 mg dm^-3 naphthalene acetic acid. An average of 24 shoots per bud was obtained for cv. Mex 68-P23 within four weeks and 29 shoots for cv. MY 55-14 within six weeks. Indole-3-butyric acid induced more roots in both cultivars compared to the untreated plantlets. Plantlets transferred to soil showed normal growth with up to four axilliary buds in each node. It was concluded that the germplasm obtained through the above mentioned technique generated stalks with more buds in each node which would give farmers more vegetative material for plantations in field with 100 % germination.