Vegetative growth and reproductive growth strongly competes with each other during panicle development in litchi (Litchi chinensis Sonn.). We herein investigated the roles of hydrogen peroxide and nitric oxide in the competition between growth of rudimentary leaves and panicle development. The results show that the chilling-induced flowering increased H₂O₂ and NO contents in the mixed buds. Treatments with sodium nitroprusside (SNP), the NO donor, and methyl viologen dichloride hydrate (MV), the superoxide generator, increased NO and H₂O₂ contents in the mixed buds. MV and SNP treatments promoted abscission of rudimentary leaves and encouraged panicle development before or at the stage of panicle emergence. The nitric oxide synthase inhibitor N ^ω -nitro-L-arginine methyl ester (L-NAME) and the H₂O₂ trapper dimethylthiourea (DMTU) inhibited a chilling-induced flowering. SNP promoted the expression of litchi LEAFY homolog (LcLFY). These promotive effects were suppressed by the NO scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl3-oxide (PTIO) and the H₂O₂ trapper, DMTU. The results suggest that H₂O₂ and NO promote reproductive growth by inhibiting the growth of rudimentary leaves as well as by promoting the expression of the flower related gene, LcLFY.

Large-scale gene expression analyses were conducted during embryonic development of Capsella bursa-pastoris using the cDNA-AFLP technique, and 231 differentially expressed genes were identified. Most of the transcript-derived fragments (TDFs) were identified against Arabidopsis sequences and a minority against other plant sequences by searching in NCBI database. A total of 128 TDFs, homologous to genes with known functions, were classified into 13 functional categories, and many of them were involved in transcription, metabolism, disease defense and protein binding. Expression profiles of 90 C. bursa-pastoris genes were compared with those of the corresponding Arabidopsis genes and 64 genes showed similar expression profiles and the expression profiles of the rest 26 TDFs were different from those of the relevant Arabidopsis genes. Besides, some genes related to oxidative stress and ABA response were fiercely up-regulated during embryogenesis of C. bursa-pastoris according to RT-PCR.

Chalcone isomerase (CHI, EC 5.5.1.6) is an entrance enzyme in the flavonoid biosynthesis, which catalyzes the conversion of chalcones to flavanones. In this study, the full-length CHI cDNA from grape vine (Vitis vinifera L.) was cloned, the recombinant protein was purified and the polyclonal antibody was prepared. Using these tools, the expression and tissue localization of CHI in developing grape berry was analyzed by RT-PCR, gel blot hybridization and immunohistochemical techniques. The expression of CHI was dependent on developmental stage, and CHI protein was mainly distributed in vascular bundles throughout all the stages of berry development, which suggested that flavonoids in the berry might have been partially synthesized in situ.

Zinc finger proteins are encoded by the genes chiefly involved in stress resistance hormone signal transduction of plants. In this study, a cDNA encoding a zinc finger transcription factor was isolated by the yeast one-hybrid system from Gossypium arboreum using the MYB-box element of the universal stress gene (GUSP1) promoter as bait. The corresponding protein (named GaZnF) can bind specifically to a 13 bp MYB-box region. The GaZnF cDNA is 1093 bp in length, including a 510 bp open reading frame. The predicted GaZnF protein contains ANI-A20 motifs and shares a high sequence similarity with zinc finger proteins from other plants. Spatial expression pattern of GaZnF was studied under drought, heavy metals and salt stresses through real-time PCR. The gene showed enhanced expression under each stress treatment with maximum transcript abundance in root tissues. The results support the hypothesis that G. arboreum zinc finger proteins are involved in plant response to drought, salt and heavy metal stresses.

Effects of putrescine (Put) on responses of wheat (Triticum aestivum) seedlings or detached tillers at mid-milky stage to high temperature (HT) stress were investigated. The heat tolerant cv. PBW 343 exhibited higher content of antioxidants and activities of antioxidative enzymes, while lower content of lipid peroxides as compared to the heat-sensitive cv. HD 2329. HT elevated peroxidase (POX) and superoxide dismutase (SOD) activities, while diamine oxidase (DAO) and polyamine oxidase (PAO) activities were reduced in roots, shoots and developing grains. Application of Put under HT further enhanced POX and SOD activities along with increased content of ascorbate and tocophereol in grains. Invariably POX and SOD revealed higher activities in roots while CAT, DAO and PAO activities were higher in shoots. The content of lipid peroxides was increased in roots and shoots of HT stressed seedlings but less in Put-treated cv. PBW 343.

To gain a comprehensive understanding of plant response to Cd, physiological and proteomic changes in wheat (Triticum aestivum L.) leaves exposed to a range of Cd concentrations (10, 100 and 200 μM) were investigated. Leaf elongation was decreased, whereas the H₂O₂ and malondialdehyde content increased significantly at higher Cd concentrations. Changes in protein profiles were analyzed by two-dimensional electrophoresis. Twenty-one proteins which showed 1.5-fold change in protein abundance in response to Cd were identified. These proteins can be functionally grouped into three groups: 1) oxidative stress response, 2) photosynthesis and sugar metabolism and 3) protein metabolism and others. These results provide a new insight into our understanding of the molecular basis of heavy metal response in plants.

To uncover the potential antioxidative role of anthocyanins in vivo in protecting photosynthetic tissues from photoinhibition, the effects of high irradiance [HI, 1300 μmol(photon) m^-2 s^-1] were studied using detached leaves derived from Arabidopsis wild-type (WT) and the mutant deficient in anthocyanin biosynthesis (tt3tt4). HI stress caused decreased chlorophyll content and photochemical efficiency, but increased cell-membrane leakage and contents of hydrogen peroxide and superoxide radical in the leaves of both Arabidopsis phenotypes, but the WT plants showed better HI tolerance than tt3tt4 mutant. HI caused a significant increase in the 1,1-diphenyl-2-picrylhydrazyl scavenging capacity in WT but not in the tt3tt4 mutant. The anthocyanins could not contribute substantially to light-shielding during the periods of HI stress, because the anthocyanin content in WT was very low and the colour of leaves was the same as in the tt3tt4 mutant. Thus, it was assumed that the better HI tolerance in WT was mostly related to the potential antioxidative role of anthocyanins.

A micropropagation protocol for Bacopa monniera (L.) Wettst., a medicinally important plant, has been developed. Direct organogenesis without callus formation was induced by culturing node, internode and leaf explants on growth regulator free Murashige and Skoog (MS) medium. MS medium supplemented with an antibiotic trimethoprim (TMP) and a fungicide bavistin (BVN) produced axillary shoots from node and adventitious shoot buds on the surface of all explants. The combination of 200 mg dm^-3 TMP and 200 mg dm^-3 BVN induced the optimum frequency of shoot formation as well as shoot number. Presence of both TMP and BVN induced multiple axillary shoot formation from the nodal segments and this ability was maintained for four subcultures.

To investigate a possible involvement of nitric oxide in gene regulation of glutathione and flavonoid synthesis pathways, maize seedlings were treated with sodium nitroprusside (SNP), a NO donor, and apocynin (APO), an inducer of NO production. After 12-h treatment, the transcripts of γ-glutamylcysteine synthetase (γ-ecs), glutathione synthetase (gsh-s), chalcone synthase (chs), phenylalanine ammonia lyase (pal.1), myb-related protein P (P1) and actin 1 (act) genes were quantified in maize leaves by real time PCR, using α-tubulin as standard transcript. The level of γ-ecs and gsh-s transcripts in maize leaves were increased 9-fold and 12-fold, respectively, following SNP treatment, while after APO treatment, those transcripts were not significantly different from control plants. SNP-treated maize leaves did not show significant changes in pal.1 and chs expression. NO content in maize leaves was increased in SNP and APO treated plants in comparison to control plants. In conclusion, our experiments suggested that genes involved in glutathione synthesis could be modulated by SNP in maize leaves. On the other hand, APO had no effect on γ-ecs and gshs gene expression.

We investigated the drought resistance of a wheat (Triticum aestivum L.) stay-green mutant tasg1 and its wild-type (WT) in field experiments conducted for two years. Drought stress was imposed by controlling irrigation and sheltering the plants from rain. Compared with the WT, tasg1 exhibited a distinct delayed senescence under both normal and drought stress conditions, as indicated by slower degradation of chlorophyll and decrease in net photosynthetic rate than in WT. At the same time, tasg1 mutants maintained more integrated chloroplasts and thylakoid ultrastructure than did WT plants under drought stress. Lower malondialdehyde content and higher antioxidative enzyme activities in tasg1, compared to WT, may be involved in the stay-green phenotype and drought resistance of tasg1.

The leaf structure and chloroplast ultrastructure of kidney tea (Orthosiphon stamineus Benth.) was studied in in vitro culture on standard MS medium supplemented with or without plant growth regulators (PGRs). The cytokinin N⁶-benzyladenine (BA) negatively affected the structure of the palisade parenchyma and chloroplast ultrastructure and increased the stomatal frequency of the adaxial epidermis. The auxin indole-3-butyric acid (IBA) did not modify the morphology of regenerated leaf tissues as well as the chloroplast ultrastructure. The effect of both PGRs applied in combination was manifested in well-differentiated mesophyll parenchyma, typical chloroplast ultrastructure and increased stomatal frequency on both leaf surfaces. This protocol can be suggested for further ex vitro propagation.

The aim of this study was to analyse the relationship between root growth inhibition and alterations in catalase (CAT) and ascorbate peroxidase (APX) contents and activities in barley root tips during the recovery after short-term Cd stress. Significant root growth inhibition was observed after a relatively short-term (30 min) exposure of barley roots to low 15 μM Cd concentration. In seedlings treated with 30 μM Cd root growth was renewed 8-9 h after Cd treatment. By contrast, seedlings exposed to 60 μM Cd failed to restore root growth. The CAT activity increased after 15 μM Cd treatment, whereas, higher Cd concentrations inhibited CAT activity. However, APX activity was not affected by Cd treatment. The content of APX1 transcript increased while content of APX2 decreased 3 h after short-term treatment in a concentration dependent manner. While the expression of CAT1 was upregulated after 15 and 30 μM Cd treatment, it was strongly downregulated by 60 μM Cd. By contrast, CAT2 was upregulated in a concentration dependent manner. These results suggest that increased CAT activity is crucial for restoration of root growth after moderate Cd stress while at severe Cd stress its inhibition may lead to the irreversible damages.

Marker-free transgenic cucumber (Cucumis sativus L.) cv. Poinsett 76 SR plants were produced by Agrobacterium mediated transformation. A transformation efficiency of 1.62 was observed on using Agrobacterium tumefaciens strain LBA4404 harbouring Arabidopsis cbf1 gene driven by the inducible promoter RD29A in a binary vector system pCAMBIA. Transgene integration and single copy insert in transgenic cucumber was confirmed by polymerase chain reaction (PCR) and Southern blot analysis in T₀ lines and also confirmed marker-free status in T₁ generation. Transgene expression was confirmed by reverse transcription (RT)-PCR in T₁ generation transgenic cucumber and advanced to T₂ generation. Upon exposure to chilling stress (4 °C), the T₂ generation transgenic plants survived up to 36 h; however, wild-type plants could not survive and gradually died. A significant decrease in membrane injury index (MII), increase in activities of antioxidant enzymes (SOD and CAT), free proline content and relative water content (RWC) in the leaves were observed in transgenic cucumber as compared to wild-type under chilling stress. Thus, the transgenic cucumber plants expressing Arabidopsis cbf1 gene conferred protection against chilling stress.

The influence of abscisic acid (ABA) on plastidial and cytosolic terpenoids and on two key enzymes for terpenoid biosynthesis was determined in vegetative stage of Cannabis sativa L. Low concentration of ABA (1 μM) increased 1-deoxy-D-xylulose 5-phosphate synthase (DXS) activity in treated plants in comparison to control plants. The amounts of chlorophyll a and carotenoids increased in response to ABA treatment but chlorophyll b content declined. The accumulation of α-tocopherol was stimulated only by 10 μM ABA. The ABA-treated plants showed a decline in 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity which was followed by a decrease in squalene and phytosterol content. ABA also decreased tetrahydrocannabinol (THC) and cannabidiol (CBD) contents. The essential oil had higher ratios of monoterpenes to sesquiterpenes as ABA-treated plants had less numbers of sesquiterpenes in comparison with control plants. Influence of ABA on the amounts of sesquiterpenes was different, some of them showed decrease of content and others increase of content.

The aim of this work was to characterize a nucleotide sequence MK14 that originated from a plasmid library obtained via degenerate oligonucleotide primed polymerase chain reaction (DOP-PCR) amplification of laser microdissected Y-chromosomes of Silene latifolia. This sequence showed significant similarity to parts of two adjoining genes from bacterial representatives of the genus Ralstonia. MK14 sequence contains a part of a conserved domain, and phylogenetic analysis based on this region confirmed its relationship to Ralstonia-derived sequences. Genomic Southern blot analysis proved the presence of this fragment in the genome of S. latifolia. We hypothesize that this insertion is of bacterial origin, and was probably gained via horizontal gene transfer. Moreover, MK14 insertion is shared by some closely related Silene species, suggesting an ancient spontaneous transformation by an ancestor of bacteria from the genus Ralstonia.

In Pinus peuce zygotic embryo culture grown on Gresshoff and Doy (1972; GD) basal medium, 2.22 μM benzyladenine (BA) was superior in promoting adventitious bud induction during 4 weeks comparing to kinetin or BA + kinetin. Shoot elongation was achieved on half-strength GD medium devoid of plant growth regulators and containing activated charcoal. Pulse treatment with 1 mM indole-3-butyric acid (IBA) for 2 h, followed by transfer to half-strength GD medium, produced the most efficient rooting. Rooted shoots were transplanted to the greenhouse and plantlets continued to grow and developed into phenotypically normal plants. Up to 10 plants per explant can be obtained within 36 weeks from culture initiation.

Rosaceae is a large family, however, our understanding of its phylogeny is based largely on morphological observations. To understand the relationship between subfamilies Rosoideae, Amygdaloideae, Maloideae and Spiraeoideae at a molecular level, we isolated and compared the plant phosphatidyl ethanolamine-binding protein-like genes TERMINAL FLOWER1 (TFL1)-like and CENTRORADIALIS (CEN)-like, which are involved in the control of shoot meristem identity and flowering time. A comparison of gene structures and phylogenetic tree analyses by the Neighbor-Joining method showed that each of the two TFL1-like (MdTFL1-1 and MdTFL1-2) and CEN-like genes (MdCENa and MdCENb) in Maloideae were classified into two distinct clades. The TFL1-like and CEN-like genes of Gillenia in Spiraeoideae belonged to monophyletic Maloideae groups, suggesting that Gillenia and Maloideae have a common near ancestor. However, the Gillenia TFL1-like gene does not contain the insertion sequence of the third intron that is found in MdTFL1-2-like genes of the members of Maloideae such as apple, Korean whitebeam, quince, and Siberian mountain ash. Therefore, after the Maloideae ancestor genome became polyploid through hybridization between Gillenia-like species or genome doubling, an insertion sequence of the third intron of MdTFL1-2-like genes was generated.

Poplar hybrid 741 [Populus alba × (P. davidiana + P. simonii) × P. tomentosa] leaves were rooted within 8 d when cultured in vitro on 1/2 Murashige and Skoog (MS) medium. The spatial distribution of endogenous indole-3-acetic acid (IAA) in the rhizogenesis was investigated, using an immunohistochemical approach. In addition, the effect of 2,3,5-triiodobenzoic acid (TIBA) on IAA distribution was also analyzed. The results showed that a strong IAA signal was detected in the vascular bundles of the basal regions of the petioles 3 d after root induction. Furthermore, the signal in vascular bundles of the basal regions of the petioles was stronger than that of the middle regions of the petioles. Application of TIBA on lamina delayed both the accumulation of IAA in the vascular bundles and rhizogenesis. These data indicate that an endogenous IAA rise in vascular bundles is among the first signals leading to the rhizogenesis, and that it results from transportation of the hormone from the lamina of the leaf to the base of the petiole, rather than by in situ IAA generation.

The transcript levels and activities of the superoxide dismutase isoenzyme (Cu/ZnSOD) were assessed in winter (Tarm-92) and spring (Zafer-160) barley cultivars during cold acclimation, freezing stress and after rewarming. Leaf Cu/ZnSOD activity and Cu/ZnSOD expression level were not significantly changed during cold acclimation. The Cu/ZnSOD expression increased evidently at mild freezing stress (-3 °C; F1), while Cu/ZnSOD1 activity did not show any response and Cu/ZnSOD2 activity decreased continuously during F1 and F2 (-7 °C) in Tarm-92. On the other hand, root Cu/ZnSOD2 activity was in accordance with Cu/ZnSOD expression in Zafer-160 after F2 treatment. Rewarming periods did not cause any significant changes in the Cu/ZnSOD activity and expression of Cu/ZnSOD in both cultivars when compared to freezing stresses. These results showed that freezing stress can regulate differently Cu/ZnSOD transcription and enzyme activity.

During the period of senescence of desert plant Alhagi sparsifolia Shap. the maximum photochemical quantum yield measured as variable to maximum fluorescence ratio (F_v/F_m) remained relatively high, although the number of active reaction centres per cross section (RCs) decreased significantly. The efficiency of electron acceptors beyond the primary quinone acceptor (Q_A) decreased. The effect of temperature and irradiance on photosystem activity was maximum after 6 d. Our results suggest that: 1) the down-regulation of photosystem activity was due to the decline of both RCs and electron acceptance between plastoquinone (PQ) and cytochrome (cyt) b6/f; 2) photosystem activity presented negative correlation with daily mean temperature, and 3) reduction of daily sunshine period and increase of temperature at noon can stimulate the speed of senescence.

The anatomic and functional leaf characteristics related to photosynthetic performance of Castanea sativa growing in vitro and in nursery were compared. The irradiance saturated photosynthesis in in vitro grown plantlets was significantly lower compared to nursery plants (65 vs. 722 μmol m^-2 s^-1). The maximum photosynthetic rate (P_Nmax) was 4.0 and 10.0 μmol(CO₂) m^-2 s^-1 in in vitro microshoots and nursery plant leaves, respectively. Carboxylation efficiency (C_E) and electron transport rate (ETR) were three-folds higher in nursery plants than in microshoots. The nonphotochemical quenching (NPQ) was saturated at 80 μmol m^-2 s^-1 in microshoots suggesting limited photoprotection by thermal dissipation. The microshoots had wide open, spherical stomata and higher stomatal density than nursery plants and they had almost no epicuticular wax. Consequently, the microshoots had high stomatal conductance and high transpiration rate. These anatomic and functional leaf characteristics are likely major causes of the low survival rates of plantlets after ex vitro transfer.

A cDNA encoding γ-tocopherol methyltransferase from Brassica napus (BnTMT) was overexpressed in soybean [Glycine max (L.) Merr.] under the control of seed-specific promoter of Arabidopsis fatty acid elongase 1 (FAE1) or soybean glycinin G1. Two and three transgenic plants were selected, respectively, after Agrobacterium-mediated transformation. Polymerase chain reaction (PCR) and Southern blots confirmed that BnTMT was single-copy integrated into the genome of transgenic plants. RT-PCR analysis showed that the expression of BnTMT was higher in the immature cotyledons than in the mature cotyledons, while no expression was detected in the leaves. Moreover, the expression level under the control of FAE1 was higher than that of G1. HPLC analysis indicated that the seed-specific expression of BnTMT resulted in 11.1-fold and 18.9-fold increase in α- and β-tocopherol content, respectively, in T₂ seed. These results suggested that introducing BnTMT into soybean can be used to increase the vitamin E composition in seeds.

Branching is an important step in higher plant development, which not only determines the configuration of the plant directly, but also affects its adaptability to the environment. The interactions between hormones, genes, environmental and other factors subtly regulate the process of branching. Strigolactone is a newly recognized phytohormone and its content and distribution might be a key factor affecting branching. This review is focused on the genes related to synthesis and transduction pathway of strigolactone, and summarizes the inhibitory role of strigolactone in plant branching. Discussions about the issues to be clarified and prospects of the future research were also proposed.

Antioxidative responses and proline accumulation induced by exogenous H₂O₂ were investigated in the callus from halophyte Nitraria tangutorum Bobr. H₂O₂-treated callus exhibited higher H₂O₂ content than untreated callus. The activities of catalase (CAT) and peroxidase (POD) significantly increased in the callus treated with H₂O₂, while ascorbate peroxidase (APX) activity decreased. In addition, significantly enhanced proline content was observed in the callus treated by H₂O₂, which could be alleviated by H₂O₂ scavenger dimethylthiourea and calcium (Ca) chelator ethylene glycol bis-(β-aminoethyl ether)-N,N,N',N'-tetra-acetic acid (EGTA). Moreover, γ-glutamyl kinase (GK) activity increased in H₂O₂-treated callus, but proline dehydrogenase (PDH) activity decreased significantly, and the reduction was partly abolished by EGTA or Ca channel blocker verapamil. Assays using a scanning electron microscope showed significantly enhanced Ca content in H₂O₂-treated callus.

Glucose-6-phosphate dehydrogenase (G6PDH) has been implicated in supplying reduced nicotine amide cofactors for biochemical reactions and in modulating the redox state of cells. In this study, the role of G6PDH in thermotolerance of the calli from Przewalskia tangutica and tobacco (Nicotiana tabacum L.) was investigated. Results showed that Przewalskia tangutica callus was more sensitive to heat stress than tobacco callus. The activity of G6PDH and antioxidant enzymes (ascorbate peroxidase, catalase, peroxidase and superoxide dismutase) in calli from Przewalskia tangutica and tobacco increased after 40 °C treatment, although two calli exhibited a difference in the degree and timing of response to heat stress. When G6PDH was partially inhibited by glucosamine pretreatment, the antioxidant enzyme activities and thermotolerance in both calli significantly decreased. Simultaneously, the heat-induced H₂O₂ content and the plasma membrane NADPH oxidase activity were also reduced. Application of H₂O₂ increased the activity of G6PDH and antioxidant enzymes in both calli. Diphenylene iodonium, a NADPH oxidase inhibitor, counteracted heatinduced H₂O₂ accumulation and reduced the heat-induced activity of G6PDH and antioxidant enzymes. Moreover, exogenous H₂O₂ was effective in restoring the activity of G6PDH and antioxidant enzymes after glucosamine pretreatment. Western blot analysis showed that G6PDH gene expression in both calli was also stimulated by heat and H₂O₂, and blocked by DPI and glucosamine under heat stress. Taken together, under heat stress G6PDH promoted H₂O₂ accumulation via NADPH oxidase and the elevated H₂O₂ was involved in regulating the activity of antioxidant enzymes, which in turn facilitate to maintain the steady-state H₂O₂ level and protect plants from the oxidative damage.

The leaf apoplast is a dynamic compartment in contact with plant pathogenic bacteria after infection. Among the very first interaction events is the receptor-mediated perception of bacterial surface molecules such as flagellin or other conserved microbe-associated molecular patterns (MAMPs). Apoplast proteins likely play a role in basal resistance (BR) or pattern-triggered immunity (PTI). Here, a proteomic approach was carried out on water soluble - potentially the most mobile - apoplast proteins from flagellin-treated tobacco (Nicotiana tabacum) leaves. As the quickness of BR/PTI seems crucial for its efficacy, samples were taken as early as 2.5 and 7 h post inoculation. Proteins were separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and identified by liquid chromatography tandem mass spectrometry (LC-MS/MS). Forty-nine different proteins from 28 protein spots changed in their density compared to the water-inoculated control. Eleven protein spots appeared de novo in response to EBR induction. There are glycohydrolases and redox-active proteins besides pathogenesis-related proteins among them, predicting plant cell wall structural modifications and more direct antimicrobial effectors as earliest changes related to BR/PTI.

Small heat shock proteins (sHSPs) are crucial components of the plant response to heat shock. We identified and analyzed eight sHSP genes of Capsella bursa-pastoris to better understand the ability of this species to adapt. Eight genes were initially cloned and sequenced from the mature embryo cDNA pool. They belong to the cytosolic I (CI), cytosolic II (CII), and cytosolic III (CIII) subfamilies. One CI sHSP gene was homologous to that of C. rubella. Sequence analysis using 3' RACE revealed that there are two or more variable 3'-untranslated regions (UTRs) in these sHSP transcripts. The transcriptional levels of the eight sHSP genes were analyzed in different organs and developmental stages via qRT-PCR. Eight genes were significantly up-regulated in young leaves exposed to heat stress at 42 °C, and also showed differential responses to ABA treatment. We also compared expression of these genes with corresponding Arabidopsis sHSP genes and found some differences between the two species.

Grapevine rootstocks belonging to different species of Vitis differ in their response to stress. Vines of rootstocks 110R and 1613C were subjected to different salt and water stresses individually and in combination. Expression of VvNHX1, a Na⁺/H⁺ antiporter gene, was analyzed at 7 and 21 d of stress treatment. In 110R, the expression of VvNHX1 gene increased in response to both salinity and water stress already after 7 d. Under salinity and combined stress enhanced expression of this gene was observed also after 21 d whereas expression decreased under water stress. In 1613C, expression of this gene did not increase under salinity stress. There was delayed response to water and combined stress and expression increased several fold after 21 d of stress. The stressed vines of 110R maintained lower sodium content and higher K⁺/Na⁺ ratio as compared to rootstock 1613C.

Lipoxygenase (LOX) from opium poppy (Papaver somniferum L.) chloroplasts was isolated and 126.1-fold purified to electrophoretic homogeneity by combination of ion-exchange chromatography on HA-Ultragel column and affinity chromatography on a linoleyl-aminopropyl agarose column. The relative molecular mass of the LOX determined by SDS-PAGE was 92 kDa. Kinetic properties of purified LOX were determined in spectrophotometric assay by using of linoleic acid (K_M = 1.78 mM and V_max = 11.4 μmol mg^-1 min^-1) and linolenic acid (K_M = 1.27 mM and V_max = 10.2 μmol mg^-1 min^-1). The optimum pH was 6.0 for both linoleic and linolenic acid dioxygenation catalyzed by LOX. HPLC analysis of the products revealed a dual positional specificity of linoleic acid dioxygenation at pH 6.0 with ratio of 9- and 13-hydroperoxide products being about 1:1. The activity of purified LOX was stimulated by Mg²⁺ and Ca²⁺.