The objective of the study was to investigate the effect of As on some physiological parameters of maize in the early growth phases. Seedlings grown in a climatic box in a Hoagland-Arnon nutrient solution were treated with 0, 2 and 5 mg(As) dm^-3 (pH 5.5). After 5 d of As treatment the changes in growth, leaf gas-exchange, chlorophyll (Chl) content, Chl fluorescence, peroxidase activity and lipid peroxidation in roots were recorded. The applied As decreased the growth, leaf area, and biomass accumulation, induced lipid peroxidation and increased peroxidase activity, especially at concentration 5 mg(As) dm^-3. It also decreased the Chl, carotenoid (Car) and protein contents. A decrease in the variable to maximum fluorescence ratio (F_v/F_m) indicated lower photosynthetic efficiency.

Identification of gene expression patterns in mangroves grown under salinity will help to reveal the molecular mechanisms of salt tolerance. Here, 10 cDNAs of genes were isolated from Kandelia candel and identified by representational difference analysis of cDNA (cDNA RDA) under different NaCl concentrations. Of five genes expressed preferentially under salt condition, two were unknown, three were two kinds of low molecular mass heat-shock proteins (sHSPs) and ADP-ribosylation factor, respectively. The expressions of other five genes were repressed under NaCl stress, two encoded cyclophilins, three were tonoplast intrinsic protein, early light-induced protein and 60S ribosomal protein, respectively.

High-frequency regeneration of shoots was achieved at root region of seedlings of Robinia pseudoacacia L. cultured from seeds on medium supplemented with thidiazuron (TDZ, 1.0 μM). The roots of intact seedlings proliferated and formed a compact callus followed by differentiation of numerous shoots. Corresponding cultures on benzylaminopurine-containing medium exhibited much weaker response. Hypocotyl segments also formed shoots at a lower concentration of TDZ (0.1 μM). The shoots formed on TDZ-containing medium were well-developed and readily rooted on hormone-free medium. The obtained plants after acclimation in culture room survived after transfer to soil.

Salt tolerant callus and cell suspension cultures of Brassica oleracea L. var. botrytis were obtained by the selection of cells from cultures growing in medium supplemented with 85, 170, and 255 mM NaCl. Salt adapted calli and cell suspensions differed in their RNA and protein concentrations. These concentrations tend to diminish in calli and increase in cell suspensions, both at one or three weeks periods of growth in NaCl. Contents of sucrose and reducing sugars, however, accumulate similarly both in calli and cell suspensions after NaCl treatments. The activity of sucrose synthase was higher in salt adapted cells than in controls. Calli exposed to 255 mM NaCl for six months synthesized a 27 kDa polypeptide, while a 13 kDa polypeptide present in control conditions was absent under salinity. Several high molecular mass polypeptides (> 200 kDa) were visualized in control calli and at moderate salt concentrations, when conditions of the gel were modified.

Wild type of Arabidopsis thaliana plants were cultivated hydroponically in Hoagland and Arnon nutrient solution and treated with copper (5 - 100 µM) for 2, 4, 7 and 14 d. A progressive decrease of the root length and biomass was observed at increasing Cu concentration in the nutrient solution. Roots accumulated higher amounts of Cu than shoots at all Cu treatments. Changes of cell and chloroplast ultrastructure of Cu-treated plants were also observed. Cu application did not induce formation of Cu-phytochelatin complexes. Changes in glutathione and glutathione disulfide content observed in roots and shoots of Cu-treated plants suggest their participation in amelioration of metal-induced oxidative stress.

Difference in the growth response to submergence between coleoptiles and roots of rice (Oryza sativa L.) was investigated in 9-d-old rice seedlings. The coleoptile length in the submergence condition was much greater than that in aerobic condition, whereas the root length in the submergence condition was less than that in the aerobic condition. Alcohol dehydrogenase (ADH) activity in the coleoptiles in the submergence condition was much greater than that in the aerobic condition, but ADH activity in the roots in the submergence condition increased slightly. These results suggest that the preferential ADH induction in rice seedlings may contribute to the difference in the growth response between the coleoptiles and roots under low oxygen conditions.

Chara tomentosa antheridial plasmodesmata are described during proliferation and spermiogenesis. In antheridial filament cells which are cycling completely synchronously, unplugged plasmodesmata are filled with light cytoplasm. The same plasmodesmata are observed after cessation of mitotic division followed by the onset of synchronous spermiogenesis. Walls separating cells at different cell cycle stages and dividing antheridial filaments into asynchronous domains are plugged with a dense osmophilic substance. Similarly plugged plasmodesmata are present between antheridial cells of different types, e.g., capitular cells and antheridial filaments. In mid spermiogenesis when abundant endoplasmic reticulum (ER) appears temporarily it penetrates into plasmodesmata enabling cell-to-cell transport via ER cisternae. In late spermiogenesis there are no cisternae in plasmodesmata.

X-rays at doses between 2.5 and 20 Gy were applied to Allium cepa L. bulbs containing either dormant root primordia (before water imbibition) or actively proliferating meristems. Irradiation of the primordia that were enriched in G₀ cells neither delayed proliferation onset nor root sprouting. Under both protocols, irradiation decreased the final length of the roots to about 60 % (at 20 Gy) of that reached by the unirradiated controls. Irradiation of the proliferating meristems increased the mitotic index at some fixation times. This could not be due to a rise in the cell entry into mitosis, as the rate of root growth decreased simultaneously. The increased mitotic index should be the consequence of a delay in the relative time taken by mitosis in the whole cycle time. Lengthened mitosis probably allows the post-replicative repair of most DNA lesions, as the frequency of interphases with micronuclei was higher in the cells which were irradiated when still dormant than in those irradiated when cycling. Thus, the mitotic delays should be the consequence of a checkpoint pathway activated by the presence of DNA damage. This feedback mechanism seems only to develop after cell proliferation is restored.

Newly synthesized derivatives of α-aminoalkanephosphonic acids (aminophosphonates) differ in the substituents at the carbon, nitrogen, and phosphorus atoms. They modified in different degree the properties of cucumber (Cucumis sativus cv. Wisconsin) cotyledon membranes, physiological activity of some enzymes (guaiacol and pyrogallol peroxidases, and catalase), chlorophyll content, and cellular membrane lipid peroxidation. Most active modifiers were those possessing sufficiently long hydrocarbon substituents at the nitrogen atom (C₁₀H₂₁) or isopropyl chain at the phosphorus atom. The branched tertbutyl group at the carbon atom enhanced slightly the activities of peroxidases in contrast to hexane ring at the same position, which decreased them.

Response of gas exchange traits to irradiance were studied in eight almond tree (Prunus amygdalus) cultivars: Desmayo Largueta, Falsa Barese, Garrigues, Lauranne, Marcona, Masbovera, Nonpareil and Ramillete, grafted on a hybrid rootstock almond × peach GF-677. From these responses cultivars can be classified from the best to the worst photosynthetic performance as follows: Falsa Barese, Masbovera, Marcona, Nonpareil, Ramillete, Desmayo Largueta, Lauranne and Garrigues. The highest net photosynthetic rate was 20.3 μmol m^-2 s^-1 in Falsa Barese. In the absence of water stress, photosynthetic rate was not limited by stomatal conductance. Consequently, non-stomatal limitations prevailed under such conditions.

The lignin content of walnut shoots did not change during in vitro shoot multiplication. Lignin content started to increase as soon as shoots were passed to a rooting medium with auxin. Exogenous auxin (applied for rooting) caused a transient elevation of the endogenous free indoleacetic acid (IAA) content with a simultaneous decrease of peroxidase activity. These events typically marked the completion of the rooting inductive phase (before any visible histological event, that is before the cell divisions beginning the rooting initiation phase). This meant that either the given exogenous auxin or the endogenous IAA has served as signal for the stimulation of lignification. Continued increase of lignification in the shoots required completion of root formation; this increase indeed was slown down when root emergence did not occur. It was further shown that lignification varied conversely to the content of the soluble phenol content, itself apparently being related to the activity of phenylalanine ammonia-lyase activity.

Adventitious roots of Primula acaulis Jacq. are characterized by broad cortex and narrow stele during the primary development. Secondary thickening of roots occurs through limited cambial growth together with secondary dilatation growth of the persisting cortex. Close to the root tip, at a distance of ca. 4 mm from the apex, Casparian bands (state I of endodermal development) within endodermal cells develop synchronously. During late, asynchronous deposition of suberin lamellae (state II of endodermal development), a positional effect is clearly expressed - suberization starts in the cells opposite to the phloem sectors of the vascular cylinder at a distance of 30 - 40 mm from the root tip. The formation of secondary walls in endodermis (state III of endodermal development) correlates with the beginning of secondary growth of the root at a distance of ca. 60 mm. Endodermis is the only cortical layer of primrose, where not only cell enlargement but also renewed cell division participate in the secondary dilatation growth. The original endodermal cells additionally divide anticlinally only once. Newly-formed radial walls acquire a typical endodermal character by forming Casparian bands and deposition of suberin lamellae. A network of endodermal Casparian bands of equal density develops during the root thickening by the tangential expansion of cells and by the formation of new radial walls with characteristic wall modifications. These data are important since little attention has been paid up till now to the density of endodermal network as a generally significant structural and functional trait of the root.

The daily dynamics of CO₂ concentration in the culture vessels and the photoautotrophic or photomixotrophic growth capacity of apple (Malus pumila hybrid MM 106 paradisiaca× Northern Spy) cultures were studied. The photoautotrophic cultures were grown on a sugar-free growth medium and submitted (0S+CO₂) or not (0S-CO₂) to periodic injections of exogenous CO₂. The photomixotrophic cultures were grown in the presence of 30 g dm^-3 sucrose, with (30S+CO₂) or without (30S-CO₂) CO₂ enrichment. The photosynthetic photon flux density applied was of 210 ± 5 μmol m^-2s^-1. In the 0S-CO₂ treatment, CO₂ showed rather uniform and narrow light-dark fluctuations throughout the culturing cycle. In the 30S-CO₂ treatment, the daily ratio between CO₂ produced during the dark period and that uptaken during the following light period, was almost always above 1 with the only exception of a few days (from the 5^th to the 9^th day) when the amount of photosynthesised CO₂ was equal to or higher than that produced during dark respiration. The 0S+CO₂ cultures needed to be enriched all days with exogenous CO₂ to avoid periods of gas deficiency while in 30S+CO₂ the CO₂ injected the first culturing day was uptaken over 5 d; thereafter, daily injections were necessary. Culture fresh and dry mass, number of newly formed shoots and number of nodes per shoot in 0S+CO₂ treatment did not statistically differ from the values obtained with 30S-CO₂. The highest growth was observed in 30S+CO₂ treatment. The increase in culture fresh mass due to 1 μmol of CO₂ added to the culture vessels was 1.54 and 1.36 mg for 30S and 0S respectively, while in terms of dry mass the increase was about 2.5 times higher in the sugar-enriched treatment. CO₂ enrichment accounted for 77.3 % and 21.2 % of the final fresh mass in 0S+CO₂ and 30S+CO₂, respectively.

Tissue-specific distribution of basic β-1,3-glucanase (Glu2), basic class II chitinase (Ch2), basic class IV chitinase (Ch4), and acidic class III chitinase (SE2) were examined both in leaves and roots of sugar beet treated with salicylic acid (SA), benzothiadiazole (BTH) and glycine betaine. Protein localization was monitored by immunohistological analysis using specific antibodies. BTH, SA as well as glycine betaine induced both Glu2 and chitinase isozymes in leaves and roots of treated plants. The enzymes were accumulated in extracellular space and cell walls. They were mostly deposited in parenchyma cells of leaves and cortex parenchyma and endodermis of roots. In leaf tissues, BTH and SA induced proteins more effectively than glycine betaine but the effect of glycine betaine in roots was as efficient as BTH and SA. Glycine betaine induced the formation of extracellular globuli containing Ch4. Induced proteins were spatially distributed over the whole plant regardless the site of the inducer application.

Explants of four F₁ hybrids (OMR 36-41/1, OMR 36-41/2, OMR 36-41/4 and OMR 36-41/5) and two cultivars (Rayong 1 and Rayong 60) of cassava (Manihot esculenta Crantz) were subjected to different combinations of 2,4-dichlorophenoxyacetic acid (2,4-D), 1-naphthaleneacetic acid (NAA), kinetin (KIN) and N⁶-benzylaminopurine (BAP) to induce somatic embryogenesis, organogenesis and micropropagation. Shoot apices of the F₁ hybrids exhibited higher frequency (62 - 74 %) of proliferation of somatic embryos than the cultivars (21 - 43 %) in Murashige and Skoog basal medium supplemented with 8 mg dm^-3 2,4-D and 0.5 mg dm^-3 NAA. Nodal explants of regenerated plantlets were rapidly micropropagated with 90 % efficiency on a medium containing 0.1 mg dm^-3 NAA and 0.05 mg dm^-3 BAP irrespective of explant source.

More than 500 isolates of bacteria were obtained from the aerial part and rhizosphere of sweet pepper (Capsicum annuum L.) plants harvested from different places in the Region of Murcia (Spain). The isolates were purified and assayed in vitro against Phytophthora capsici and Alternaria alternata. Sixty isolates (12 %) produced an inhibition zone against at least one of the pathogens, while ten had a strongly inhibitory effect on both pathogens assayed. Microscopic observation of interactions zone showed cell vacuolisation, hyphae lysis and spilling of cytoplasm content of the pathogens in the culture media. These ten isolates were then chosen for biocontrol of Phytophthora root rot and Alternaria leaf spots of pepper plants in vivo. Four of them denominated HS93, LS234, LS523 and LS674 reduced P. capsici root rot by 80, 51, 49 and 54 %, respectively, and A. alternata leaf spots by 54, 74, 62 and 53 %. HS93 belongs to the genus Bacillus and probably the species subtilis, while LS234, LS523 and LS674 belong to the genus Bacillus and probably the species licheniformis. Dry mass of plants treated with these bacteria was significantly higher than that of non-treated and inoculated plants.

Amaranthus hypochondriacus plants were grown under three photosynthetic photon flux densities (PPFD). Mature plants grown at full sunlight (38.8 mol m^-2 d^-1) had higher maximum net photosynthetic rate (P_N) and significantly higher leaf trypsin inhibitor activity than plants that developed under lower PPFD (19.4 and 12.8 mol m^-2 d^-1). In contrast, seeds collected from plants fully exposed to sunlight showed the lowest activity of trypsin inhibitor, higher rate of germination and susceptibility to infection by Aspergillus niger.

Gas exchange in paclobutrazol-treated triticale plants during water stress and rehydration was studied. Seed treatments with the retardant (1 and 25 mg dm^-3) alleviate negative effect of PEG-induced water stress. Net photosynthetic rate, transpiration rate, stomatal conductance, relative water content, and leaf water potential were higher while peroxidase activity and free proline concentration were lower in the paclobutrazol-treated plants than in control plants. This confirmed our assumption that paclobutrazol possessed a protective effect against water stress.

Primer screening and optimization for random amplified polymorphic DNA (RAPD) analysis of cashew (Anacardium occidentale L.) was investigated. Among four series (A, B, D and N) of 10-mer primers, A-series performed better amplification of fragments than other series. The maximum amplification fragments was obtained using OPA-02, OPA-03, OPA-09, OPB-06, OPB-10, OPD-03, OPD-05 and OPN-03 primers. The primers OPA-02 and OPN-03 produced maximum number of DNA fragments in Anacardium occidentale cv. H-320. Primers (OPB-08 and OPN-05 performed a least number of amplification fragments. RAPD profile also indicate that some primer did not produce good amplification. The primer OPA-02 amplified 12 number of polymorphic bands in 20 cultivars of cashew. Only one DNA fragment was produced in A. occidentale cv. Vridhachalam - 2 (M-44/3) by using the primer OPA-02.

Tortula ruralis is an important experimental system for the study of plant desiccation tolerance. EST gene discovery efforts utilizing desiccated gametophytes have identified a cDNA TrRpt2 encoding a predicted polypeptide with significant similarity to the 26S proteasome regulatory subunit IV. TrRPT2, the 446 amino acid deduced polypeptide, has a predicted molecular mass of 49.6 kDa, and a predicted pI of 8.15. Phylogenetic analysis demonstrated that previously characterized RPT2 polypeptide sequences could be reproducibly grouped into 3 major clades and that TrRPT2 forms a discrete evolutionary group. RNA blot hybridizations were used to analyze TrRpt2 expression in response to: 1) desiccation and rehydration, 2) abscisic acid-treatment, 3) increased NaCl concentration, and 4) NaCl-shock. TrRpt2 steady-state mRNA transcript levels are unchanged in response to all treatments and the gene is constitutively expressed.

Aluminium effect on the mobility of apoplast protein in root tips was studied. Two-day seedlings of soybean (Glycine max. (L.) Merr. cv. Tsurunoko) were treated with 50 μM AlCl₃ for 2 h. Using infiltration method, the apoplast protein in root tips was extracted with 20 or 100 mM MgCl₂. When 20 mM MgCl₂ was used to collect weakly bound protein to apoplast, the amount of protein extracted was reduced to be about 20 % compared with that of control and the band of 97 kDa disappeared in SDS-PAGE gel. However, the 97 kDa protein could be extracted by 100 mM MgCl₂, which were used for extraction of more tightly bound protein to apoplast, and the amount was estimated to be the same as that of control. When the protein was further developed in two-dimensional electrophoresis, three spots were found between pI 6.4 and 6.5. This is the first report of an Al effect on the mobility of apoplast protein.

A rapid micropropagation protocol through induced multiple shoots from the cotyledonary explant of mulberry (Morus alba L) is described. The highest number of shoots (20.3) was obtained when explants from 14-d-old embryos were cultured on Murashige and Skoog (MS) medium supplemented with 7 μM thidiazuron for 45 d. Of the three cultivars used, cv. S-36 was the best followed by cv. K-2 and S-1. The shoots were transferred to MS medium supplemented with 5 μM 6-benzylaminopurine for elongation. The elongated shoots were rooted on half strength MS medium containing 1 - 7 μM indole 3-butyric acid or 1-naphthalene acetic acid. The rooted plants were transplanted to soil with 90 % success. The emerged shoot primordia probably initiated from the pre-existing meristems since the shoot bud show definite vascular connection to the major vascular tissue.

Supplementary UV-B (12.2 kJ m^-2 d^-1 UV-B_BE) provided to Vigna radiata for 2 h d^-1 suppressed the length of root, shoot and whole plants, number of leaves, total leaf area, leaf area index, specific leaf mass, fresh and dry mass of leaves and shoot, relative growth rate and net productivity. In unstressed green gram plants (10 kJ m^-2 d^-1 UV-B_BE), triadimefon (TRIAD) (20 mg dm^-3) enhanced growth in all parameters over control. The growth promoting effect of TRIAD enabled the UV-B impacted plants to overcome the growth inhibitions to varying degrees indicating its protective potential against UV-B stress.

The free amino acid, protein, water and dry matter contents were determined during the seed development of Araucaria angustifolia. Soluble and insoluble proteins in the mature seed represent 4.2 % of the fresh matter. The embryonic axis stored the greatest amount of soluble proteins, while cotyledons both with the embryonic axis showed the largest quantities of insoluble proteins in the mature seed. The greatest concentration of free amino acids was detected during the stage when cotyledons start to develop. Glutamic acid, aspartic acid, alanine and serine were predominant in the whole seed while arginine, lysine and γ-aminobutyric acid were present in great amounts only in cotyledons and embryonic axis. Although megagametophyte was important as a source of free amino acids, it was not the major protein storage organ in the mature seed. In the embryogenetic process, the rise of cotyledons is closely related to physiological and biochemical changes.

Using apical and axillary nodes as explants, a rapid and efficient method for propagation of Amorpha fruticosa L. has been developed. When grown on Murashige and Skoog (MS) medium supplemented with 8 mg dm^-3 benzyladenine, 100 % explants responded with 4.94 shoots per explant after 6-weeks culture, and explants taken from the in vitro proliferated shoots subsequently produced multiple shoots when cultured on the same medium. The addition of casein hydrolysate (200 mg dm^-3) enhanced the number of shoots up to 8.77 per subculture, and coconut milk was found to promote the shoot elongation and make them grow more vigorously, 82.53 % excised shoots were rooted on half-strength MS medium containing 2.0 mg dm^-3 indoleacetic acid after 3 weeks of incubation. After acclimatization, all of the rooted plantlets established in soil, exhibiting uniform morphological and growth characteristics.