Showing papers in "Acta Physiologiae Plantarum in 2000"
TL;DR: New insights into the function of H2O2 are discussed, proposed to be involved in the signal transduction pathways leading to acclimation and protection from abiotic stresses.
Abstract: The role of reactive oxygen species, especially H2O2, in plant response to stresses has been the focus of much attention. Hydrogen peroxide has been postulated to play multiple functions in plant defence against pathogens. (1) H2O2 may possess direct microbicidal activity at the sites of pathogen invasion. (2) It is used for cell-wall reinforcing processes: lignification and oxidative cross-linking of hydroxyproline-rich proteins and other cell-wall polymers. (3) It was found to be necessary for phytoalexin synthesis. (4) H2O2 may trigger programmed plant cell death during the hypersensitive response that restricts the spread of infection. (5) H2O2 has been suggested to act as a signal in the induction of systemic acquired resistance and (6) it induces defence genes. Recently H2O2 has been proposed to be involved in the signal transduction pathways leading to acclimation and protection from abiotic stresses. The present review discusses new insights into the function of H2O2 in plant responses to biotic and abiotic stresses.
155 citations
TL;DR: It was found that in drought stressed plants a higher ability to accumulate proline positively correlates with lower membrane injury, and in osmotically stressed plants the highest proline accumulation in the leaves was noticed in genotype with the largest membrane injury.
Abstract: The aim of this work was to examine the relationship between proline accumulation and membrane injury in barley leaves suffering from the effects of water deficit. Water deficit stress was induced by water withholding or by immersing the roots in polyethylene glycol (PEG 6000) solution of osmotic potential −1.5 MPa. The effect of water stress on proline accumulation and on membrane injury was evaluated in leaf blades of several barley genotypes. Substantial differences in proline accumulation and membrane injury indices among most of the genotypes investigated were observed. It was found that in drought stressed plants a higher ability to accumulate proline positively correlates with lower membrane injury. Whereas, in osmotically stressed plants the highest proline accumulation in the leaves was noticed in genotype with the largest membrane injury. The possible role of proline in membrane protection under conditions of slow-acting drought or shock-acting osmotic stress is discussed.
86 citations
TL;DR: The most important advantages of Agro-based system include relatively high transformation efficiency, integration of defined piece of DNA (transgene) frequently as a single copy, Mendelian transmission to the next generation, simple transformation procedure and lower cost of equipment than biolistic.
Abstract: Agrobacterium tumefaciens is a very useful vector to transfer foreign genes into dicotyledonous cells. Monocotyledonous, especially cereals, were considered outside the host range of the bacteria. The main, alternative technique of transformation developed for them was delivery of naked DNA (e.g. microprojectile bombardment, electroporation of protoplasts). The results of Agrobacterium-mediated transformation of cereals accumulated during the last few years confirmed that the method was reliable and repeatable also for this group of plants. The most important advantages of Agro-based system include relatively high transformation efficiency, integration of defined piece of DNA (transgene) frequently as a single copy, Mendelian transmission to the next generation, simple transformation procedure and lower cost of equipment than biolistic.
38 citations
TL;DR: Dose response experiments showed that, when putrescine and spermidine was administered at 0.75 mM concentration, it resulted in maximum biomass and production of beta-laine and thiophene in B. vulgaris and T. patula respectively as compared to the control and the media treated with double and triple strength of nitrates.
Abstract: Growth of hairy roots of Beta vulgaris, which produces betalaines, and of Tagetes patula, which produces thiophenes, was studied under the influence of externally treated polyamines. Of the three polyamines, viz. putrescine, spermidine and spermine, administered singly at 1.5 mM concentration, putrescine and spermidine at 0.75 mM concentration influenced increase in the accumulation of biomass of B. vulgaris and T. patula hairy roots by 1.42 and 1.30 fold over the control. Whereas, the treatment of spermine (1.5 mM) alone resulted in decrease in the biomass in both the systems. Combined administration of putrescine (0.75 mM) and spermidine (0.75 mM) enhanced growth in both B. vulgaris and T. patula than that observed in individual treatments. Polyamines administered alone or in combination did alter production of betalaine and thiophene content. Dose response experiments showed that, when putrescine and spermidine was administered at 0.75 mM concentration, it resulted in maximum biomass and production of beta-laine and thiophene in B. vulgaris and T. patula respectively as compared to the control and the media treated with double and triple strength of nitrates and in combination with putrescine and spermidine at equimolar concentration. In B. vulgaris and T. patula hairy root cultures, endogenous spermine titers were maximum in putrescine and spermidine 0.75 mM each treated, cultures, which was 1.63 and 2.0 fold higher than in control on 28th and 35th days respectively.
36 citations
TL;DR: Plants of 25 wild Lycopersicon accessions were screened in the greenhouse for resistance to the whitefly-borne tomato yellow leaf curl virus (TYLCV); plants of accession CIAS 27 (L. pimpinellifolium) showed moderate resistance to TYLCV.
Abstract: Plants of 25 wild Lycopersicon accessions were screened in the greenhouse for resistance to the whitefly-borne tomato yellow leaf curl virus (TYLCV). High levels of resistance were detected in 7 of 9 accessions of L. peruvianum and in all 5 accessions of L. chilense tested. In contrast, plants of 7 accessions of L. hirsutum and 3 of 4 accessions of L. pimpinellifolium were highly susceptible. Plants of accession CIAS 27 (L. pimpinellifolium) showed moderate resistance to TYLCV.
33 citations
TL;DR: In this paper, the seasonal changes of ascorbate and thiol content were observed in each needle class and population, with the maximum in the winter and minimum in the summer.
Abstract: Current and previous year needles from three 16 years-old populations of Scots pine (Pinus sylvestris L.) trees were seasonally collected at the three experimental areas: Lubon- close to the phosphate fertiliser factory, Glogow — close to the copper foundry and Kornik — control site. Glogow is the most polluted site, where at 1998 monthly mean daily concentrations of different pollutants were: SO2 - 17 µg·m−3, NOx - 12 µg·m−3 and dust containing heavy metals as Cu, Pb, Cd - 29 µg·m−3. Trees growing in Lubon were influenced for many years by high concentration of SO2 and fluor compounds. A few years ago emissions were markedly reduced, but low pH of soil and high concentration of aluminium ions still influence the growth of trees. Seasonal changes of ascorbate and thiol content were observed in each needle class and population, with the maximum in the winter and minimum in the summer. In needles from trees growing on polluted sites higher level of ascorbic acid and thiols comparing to control site was observed. Significant differences appeared in each population of Scots pine growing under higher pollution stress in the Glogow site. In needles from trees growing in Lubon significant differences in ascorbic acid and thiols content were evidently less numerous. Needles from polluted sites in some seasons contained significantly more malondialdehyde (MDA) and those was more frequent in Glogow than in Lubon. The results indicated that in the Glogow site trees are more influenced by pollution stress than in Lubon and the defense reaction measured as an increase of the antioxidant level is more evident.
29 citations
TL;DR: Several new resistant sources to TYLCV are identified within a extraordinarily variable wild Lycopersicon gene pool, collected in semidesert areas of Ecuador and Peru changed into wet by “El Nińo” by using Agrobacterium-mediated inoculation.
Abstract: The high variability found among Tomato yellow leaf curl virus (TYLCV) isolates from different geographical areas makes progress in breeding for TYLCV resistance slow. By using Agrobacterium-mediated inoculation, we have identified several new resistant sources to TYLCV within a extraordinarily variable wild Lycopersicon gene pool, collected in semidesert areas of Ecuador and Peru changed into wet by “El Nino”. This screening assay revealed a high susceptibility within L. esculentum and L. pennellii, but different levels of resistance within L. pimpinellifolium and L. hirsutum. Resistance level was related to the collection place, being concentrated in accessions collected in Northern Peru (Piura province). Agroinoculation allowed the selection of 4 Lycopersicon pimpinellifolium and 2 Lycopersicon hirsutum accessions with higher level of resistance than accessions of these species previously reported, avoiding interference due to vector resistance mechanisms reported in both species. These new resistance sources will be included in pyramiding strategies aimed at obtaining durable resistance to TYLCV.
29 citations
TL;DR: Changes in gibberellin (GAs) activities were determined in tea shoots during winter dormancy and subsequent to dormancy release and the possible role of free and conjugated GAs in dormancies and following its release is discussed.
Abstract: Changes in gibberellin (GAs) activities were determined in tea shoots during winter dormancy and subsequent to dormancy release. Free GA-like activity was extremely low at the initiation of dormancy and remained so during the dormancy period. Conjugated GA-like activity (ficin hydrolyzable and β-glucosidase hydrolyzable compounds) remained high during the dormancy period. With an increase in free GA activity, conjugated GA activity decreased in tea shoots prior to dormancy release. The possible role of free and conjugated GAs in dormancy and following its release is discussed in relation to winter dormancy in tea shoots.
28 citations
TL;DR: Assessment for resistance of the leaflet and stem in six tomato cultivars, 44 wild tomato accessions and a Solanum lycopersicoides accession found L. peruvianum LA2745 to be a promising material for breeding gray-mold resistant cultivars.
Abstract: Tomato gray mold (Botrytis cinerea Pers.) is a common disease worldwide, and often causes serious production loss by infecting leaves, stems, flowers and fruits. Presently, no resistant cultivars are available. To find new breeding materials for gray mold resistance, assessment for resistance of the leaflet and stem in six tomato cultivars, 44 wild tomato accessions and a Solanum lycopersicoides accession was performed. Although no correlation was observed (r=−0.127ns) between resistance of the leaflet and the stem, L. peruvianum LA2745, L. hirsutum LA2314 and L. pimpinellifolium LA1246 showed high resistance both in the leaflet and in the stem. Particularly, in the leaves of LA2745, no lesions were observed even more than two weeks after the inoculation with conidia, and F1s between a cultivated tomato and LA2745 also showed high resistance as observed in LA2745. From these results, LA2745 is thought to be a promising material for breeding gray-mold resistant cultivars.
28 citations
TL;DR: It could be concluded that Vicia faba trypsin inhibitor belongs to Bowman-Birk type of inhibitors, as it has molecular weight lower than generally observed for Kunitz type inhibitors.
Abstract: A trypsin inhibitor from seeds of faba bean (Vicia faba L.) was purified to near homogeneity as judged by native-PAGE with about 11 % recovery using ammonium sulphate fractionation, ion-exchange chromatography on DEAE-cellulose and gel filtration through Sephadex G-100. The inhibitor had a molecular weight of 18 kD as determined by SDS-PAGE and Sephadex G-100. The inhibitor inhibited trypsin and chymotrypsin to the extent of 48 and 12 %, respectively. The inhibtion was of non-competitive type with dissociation constant for the enzyme inhibitor complex in the region of 0.07 mg·ml−1. The inhibtor was stable between pH 4 and 5. It completely lost its activity when heated at 125 °C for 1 h or at 100 °C for 2 h. The inhibitor also lost its activity on exposure to 2-mercaptoethanol. Based on these properties, it could be concluded that Vicia faba trypsin inhibitor belongs to Bowman-Birk type of inhibitors, as it has molecular weight lower than generally observed for Kunitz type inhibitors.
22 citations
TL;DR: The involvement of enzymic antioxidant system, superoxide dismutase, guaiacol peroxidase, and ascorbate peroxideidase in defense reaction to environmental stress evoked by air and soil pollution, was seasonally studied on three populations of Scots pine (Pinus sylvestris L.) growing on experimental areas close two industrial objects in Poland as discussed by the authors.
Abstract: The involvement of enzymic antioxidant system, superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase in defense reaction to environmental stress evoked by air and soil pollution, was seasonally studied on three populations of Scots pine (Pinus sylvestris L.) growing on experimental areas close two industrial objects in Poland. The first of them (Luboon) is localised near a phosphate fertiliser factory, the second (Glogow) near a copper foundry, and control stand is placed in Kornik. Glogow is the most polluted site, where in 1998 monthly mean daily concentrations was: SO2 - 17 µg·m−3, NOx- 12 µg·m−3 and dust containing heavy metals (Cu, Pb, Cd) - 29 µg·m−3. Trees in Lubon were influenced for many years by high concentration of SO2 and fluor compounds. Few years ago emissions were markedly reduced, but changes in the soil (low pH and high concentration of aluminium ions) still influence the growth of trees. In needles of two populations: 3 (Russia) and 8 (Poland), from the polluted sites Glogow and Lubon, activities of superoxide dismutase (SOD) and guaiacol peroxidase (PO) were significantly higher compared to Kornik. However, in one population (16 - Slovakia), such dependance was not evident. Activity of ascorbate peroxidase (AP) measured in winter was also higher in needles from polluted sites. The results indicated that the sensitivity of free radical scavenging system in Scots pine needles differs among populations.
TL;DR: In this paper, the authors investigated the uptake ofulic acid by soybean root in nutrient culture at different concentrations, temperatures and pH, and found that soybean roots absorbed this compound at greater rates in the concentrations between 0.05mM and 1.0mM.
Abstract: Ferulic acid uptake by soybean root in nutrient culture was investigated by the depletion method at different concentrations, temperatures and pH. Results showed that soybean roots absorbed this compound at greater rates in the concentrations between 0.05-mM and 1.0-mM and it was concentration dependent. Ferulic acid uptake was unaffected at pH 4.5 or 6.0 but reduced at pH 7.0. At pH 6.0, uptake rates decreased significantly with increasing temperature of nutrient solution.
TL;DR: The results of the determination of starch and soluble sugar content could show that chilling impaired sucrose translocation, and the increase in invertase activity seems to confirm that tomato is a plant which is not a plant genetically adapted to low temperatures.
Abstract: The effects of chilling stress on leaf photosynthesis and sucrose metabolism were investigated in tomato plants (Lycopersicon esculentum Mill. cultivar Marmande). Twenty-one-day-old seedlings were grown in a growth chamber at 25/23 °C (day/night) (control) and at 10/8 °C (day/night) (chilled) for 7 days. The most evident effect of chilling was the marked reduction of plant growth and of CO2 assimilation as measured after 7 days, the latter being associated with a decrease in stomatal closure and an increase in Ci. The inhibition in photosynthetic rate was also related to an impairment of photochemistry of photosystem II (PSII), as seen from the slight, but significant change in the ratio of Fv/Fm. The capacity of chilled leaves to maintain higher qP values with respect to the controls suggests that some protection mechanism prevented excess reduction of PSII acceptors. The results of the determination of starch and soluble sugar content could show that chilling impaired sucrose translocation. The activity of leaf invertase increased significantly in chilled plants, while that of other sucrose-metabolizing enzymes was not affected by growing temperature. Furthermore, the increase in invertase (neutral and acid) activity, which is typical of senescent tissue characterized by reduced growth, seems to confirm that tomato is a plant which is not a plant genetically adapted to low temperatures.
TL;DR: The inheritance was studied of two texture parameters with an effect of mealiness and pleasantness of taste: BFp and EBp of the cross tomato cv Moneymaker x L. pimpinellifolium.
Abstract: Components of tomato taste can be modeled from a set of instrumentally measured parameters. The inheritance was studied of two texture parameters with an effect of mealiness and pleasantness of taste: BFp and EBp. A recombinant inbred line population (F6) of the cross tomato cv Moneymaker x L. pimpinellifolium was analyzed for these parameters, and a molecular linkage map was developed for this population. A single QTL region on chromosome 9 was found with an effect on both BFp and EBp. The QTL explained 18.2 and 18.8% of the population variances, and 19.5 and 39.0% of the parental differences respectively for BFp and EBp.
TL;DR: A lead-depended increase in activities of superoxide dismutase and peroxidase was observed, whereas catalase activity was maintained at relatively constant values at lower lead concentrations and then decreased markedly below control level.
Abstract: Duckweed Lemna minor L. was grown on Wang culture medium supplemented with lead ions for 24 hours. Metal was tested at 1.5, 3 and 6 mg·dm−3 concentrations. The response of antioxidant enzymes, such as superoxide dismutase, catalase and peroxidase in lead-treated roots of duckweed was investigated. Lead ions had no effect on the spectrum of catalase and peroxidase isoenzymes while a new isoform of superoxide dismutase appeared on the Pb treated roots. A lead-depended increase in activities of superoxide dismutase and peroxidase was observed, whereas catalase activity was maintained at relatively constant values at lower lead concentrations and then decreased markedly below control level.
TL;DR: It was concluded that the application of one of these types of sterility, (ps 2) in practice, showed the functional male sterility in tomato was a potential not to be underestimated in developing approaches that aimed at reducting the time and cost associated with hybrid seed production.
Abstract: Advantages and disadvantages in using functional male sterility (positional sterile — ps, positional sterile 2 — ps 2, and excerted stigma — ex) in tomato hybrid seed production and attempts to elaborate systems for their more efficacious use in breeding were discussed in this review. It was concluded that the application of one of these types of sterility, (ps 2) in practice, although in a limited number of countries, showed the functional male sterility in tomato was a potential not to be underestimated in developing approaches that aimed at reducting the time and cost associated with hybrid seed production.
TL;DR: The influence of triacontanol in a form of Tomatex preparation on basic indices of chlorophyll fluorescence in tomato leaves, yield of fruits, and dry matter content in fruits was evaluated in a pot experiment situated in vegetation hall in 1999 as mentioned in this paper.
Abstract: The influence of triacontanol in a form of Tomatex preparation on basic indices of chlorophyll fluorescence in tomato leaves (Delfina cv.), yield of fruits, and dry matter content in fruits was evaluated in a pot experiment situated in vegetation hall in 1999. Tomatex was applied into roots at seedling stage (6–7 leaves) or at the stage of seedling and flowering of the 2nd inflorescence bunch. Plants were given by 0.3, 3.0, and 30 µg triacontanol per pot at a single dosage. Results obtained have shown that triacontanol regardless of the dose applied, significantly increased the maximal efficiency of PSII photochemistry in the dark (Fv/Fm), the efficiency of excitation capture by open PSII reaction centers (Fv’/Fm’), the actual quantum yield of PSII electron transport in the light-adapted state (ΦPSII), the photochemical quenching coefficient (Qp). However, nonphotochemical quenching coefficient (Qn) and non-radiative dissipation (NPQ) were decreased. Plants treated with triacontanol at the doses of 0.3 and 3.0 µg had significantly higher yields of fruits than control. No differences were found between plants treated once and twice with the growth regulator. Triacontanol did not show univocal effects on dry matter content in fruits either.
TL;DR: In this paper, the effects of Cd2+ toxicity on the photochemistry of primary leaves at two different growth stages of runner bean plants were taken into consideration to study whether Cc2+ can use Ca2+ channels to get into chloroplasts.
Abstract: Effects of Cd2+ toxicity on the photochemistry of primary leaves at two different growth stages of runner bean plants were taken into consideration to study whether Cd2+ can use Ca2+ channels to get into chloroplasts. Different concentrations of Cd2+, ionophore A 23187 and Ca2+ were vacuum infiltrated into leaf discs. Toxicity of Cd2+ at the donor side of PSII depending on the metal concentration and age of the plants was confirmed. Application of ionophore caused an increase in the sensitivity of the PSII donor side to low Cd2+ concentrations. Additional supply of Ca2+ in the infiltration medium abolished toxic effect of Cd2+ on photochemical activity, except for older plants, where it was not observed for the highest Cd2+ concentration. In our opinion it is possible that Cd2+ penetrates into chloroplasts via Ca2+ channels. Age-dependent Ca2+ content in the primary leaves seems to be a very important factor protecting photochemical activity from the toxic action of Cd2+.
TL;DR: The growth of Lemna minor was inhibited by lead ions, but the dry to fresh weight ratio increased as the concentration of Pb2+ in the medium increased, and the contents of chlorophyll a andchlorophyll b in roots and fronds were correspondingly lower in comparision with the control.
Abstract: Duckweed Lemna minor L. was grown on Wang culture medium supplemented with lead ions for 24 hours. Metal was tested at 1.5, 3 and 6 mg·dm−3 concentrations. The growth of Lemna minor was inhibited by lead ions, but the dry to fresh weight ratio increased as the concentration of Pb2+ in the medium increased. With increased concentrations of Pb ions, the contents of chlorophyll a and chlorophyll b in roots and fronds were correspondingly lower in comparision with the control. The effect of lead upon activities of some glycolitic and fermentative enzymes in roots of duckweed was examined. The activity of pyruvate kinase decreased with increasing lead concentrations, but cytosolic malate dehydrogenase behaved in an opposite manner. The lowest concentration of Pb stimulated alcohol dehydrogenase; phosphoenolopyruvate carboxylase activity was maintained at relatively constant values at all tested lead concentrations.
TL;DR: The expression of a bacterial cytokinin biosynthesis gene (PI-II-ipt) in Nicotiana plumbaginifolia Viviani plants has been correlated with enhanced resistance to Manduca sexta and Myzus persicae and the activity appears to be associated with oxygen-containing aliphatic compounds, possibly diterpenes, as analyzed by TLC, UV absorption and fragmentation with EIMS.
Abstract: The expression of a bacterial cytokinin biosynthesis gene (PI-II-ipt) in Nicotiana plumbaginifolia Viviani plants has been correlated with enhanced resistance to Manduca sexta and Myzus persicae. We expressed the PI-II-ipt gene in N. tabacum and Lycopersicon esculentum and observed similar antifeedent effects with the transgenic tobacco but not tomato. A 30 to 50 % reduction in larval weight gain was observed with some of the tomato plants but these results could not be repeated consistently. Leaf surface extracts from transgenic N. plumbaginifolia leaves killed 100 % of M. sexta second instars at concentrations of 0.05 % (w/v) whereas the N. tabacum extracts were at least 20 times less active. Extract suspensions were stable for up to 2 days at ambient temperatures below 42 °C and for at least 3 months at 4 °C when stored in the dark. HPLC analysis of the N. plumbaginifolia extracts yielded an active fraction that reduced hatching of M. sexta eggs by 30 % and killed first, second and third instars within 24, 48 and 72 hours of exposure, respectively. The activity appears to be associated with oxygen-containing aliphatic compounds, possibly diterpenes, as analyzed by TLC, UV absorption and fragmentation with EIMS. Based on the partial characterization of this activity, the production, secretion or accumulation of secondary metabolites in leaves of cytokinin producing PI-II-ipt N. plumbagini-folia plants appears to be responsible for the observed insect resistance.
TL;DR: RAPD analysis was carried out on three forms of TSWV resistant individuals with the use of 271 primers and 5 primers enabling us to distinguish between resistant and susceptible forms were detected.
Abstract: The selection of TSWV resistant individuals can be facilitated by molecular markers RAPD analysis was carried out on three forms (Stevens × Rodade — resistant; Rey de los Tempranos — moderately tolerant; Potentat — susceptible) with the use of 271 primers Out of 271 primers 28 generated stable polymorphism and so they were tested for linkage to resistance gene Bulk segregant analysis (BSA) was applied to F2 segregating progeny developed from resistant × susceptible parents As a result, 5 primers enabling us to distinguish between resistant and susceptible forms were detected Only one of them had previously been reported by Chague et al (1996) The analysis should be repeated on a larger population to confirm the results obtained
TL;DR: Results suggest that in the conditions of sucrose starvation glutamate dehydrogenase may be responsible for the increase of glutamate oxidation by mitochondria of pea embryos.
Abstract: Embryos of pea (Pisum sativum L. cv Sol) deprived of cotyledons were cultured for 3 days in medium with or without sucrose. Respiratory activity of embryos (intact) as well as the ability to oxidize glutamate by mitochondria isolated from embryos were studied. Respiration of intact embryos grown in sucrose supplemented medium was more intensive than in the starved ones. Transfer of the starved embryos to the sucrose-containing medium induced the increase in the intensity of O2 consumption. Mitochondria isolated from both starved and control embryos exhibited respiratory control. Mitochondria isolated from embryos cultured in the absence of sucrose showed higher (about 60 %) ability to oxidize glutamate and α-ketoglutarate than mitochondria from embryos grown in sucrose containing medium. The absence of sucrose in the medium led to a rapid increase in the specific activity of glutamate dehydrogenase (NADH-GDH and NAD-GDH) and it was accompanied by changes in izoenzymatic pattern of enzyme. These results suggest that in the conditions of sucrose starvation glutamate dehydrogenase may be responsible for the increase of glutamate oxidation by mitochondria of pea embryos. Electrophoretic separation of glutamate dehydrogenase isolated from embryos cultured in medium without sucrose showed the presence of ca. 17 isoenzymes while in non-starved embryos only 7 isoenzymes were identified. However, the addition of sucrose to starved embryos after 24 hours of cultivation led to a decrease in glutamate dehydrogenase activity (up to 40 %) but it did not cause the changes in isoenzymatic pattern. These results suggest that in the conditions of sucrose starvation glutamate dehydrogenase maybe responsible for the increase of glutamate oxidation by mitochondria of pea embryos. The posibility of glutamate dehydrogenase regulation by sucrose is discussed.
TL;DR: In this article, a procedure for regenerating plants of Lupinus mutabilis from shoot apices, from which the leaf primordia and initial cell layer(s) of the apical meristem were removed, has been used to generate transgenic plants following Agrobacterium tumefaciens-mediated gene delivery.
Abstract: A procedure for regenerating plants of Lupinus mutabilis from shoot apices, from which the leaf primordia and initial cell layer(s) of the apical meristem were removed, has been used to generate transgenic plants following Agrobacterium tumefaciens-mediated gene delivery. Transformation competent cells, from which buds developed, were located at the periphery of the apical meristem. Kanamycin resistant plants were obtained which expressed β-glucuronidase activity. Integration of the neomycin phosphotransferase II and β-glucuronidase genes into the genomes of transgenic plants was confirmed by non-radioactive DNA-DNA hybridisation. This is the first report of the generation of transgenic plants in L. mutabilis.
TL;DR: In this article, the role of water content and wall components in determination of staple length in cotton genotypes is discussed, which shows that water content shows inverse correlation with fiber elongation.
Abstract: Fibers of three cotton cultivars (Gossypium hirsutum L.) H-4, H-8 and (G. arboreum) G. Cot-15, which shows variation in staple length were analyzed for growth in terms of fiber length and fresh and dry mass. From the growth analysis cotton fiber development is divided in four distinct phases i.e. (i) initiation (ii) elongation (iii) secondary thickening and (iv) maturation. Rate of fiber elongation and rate of water content shows close parallelism. Highly esterified and less esterified pectic fraction along with high and low molecular weight xyloglucan fractions were estimated from fiber walls of all the three cotton genotypes. Xyloglucans were fractioned in to high and low molecular weight by alkali treatment, 1 M and 4 M KOH respectively. Xyloglucan content shows inverse correlation with fiber elongation. Role of water content and wall components in determination of staple length in cotton genotypes is discussed.
TL;DR: During the last years several new resistances were identified and breeders are introducing these in modern varieties cumulating various resistances and particular qualities now required by specific markets, notably fruit long life and good taste.
Abstract: Tomato crops are parasitised by a large and ever increasing number of pathogens. For tomato, the genetic control of pathogens is very used in practice. The sources of resistance occur monogenic and dominant. Their sources are the wild species closely related to the cultivated form.
TL;DR: The results indicate that the large increase in putrescine content that derives from cytokinin treatment cotyledons is not essential for cytokin in-induced expansion of cotYledons, and polyamines may play an important role in gene expression during cytokinIn-stimulated expansion of cucumber cotygledons.
Abstract: The cucumber cotyledon expansion test was used as a model system to study a possible relationship between cytokinin and polyamines. When kinetin was applied to excised cotyledons incubated in the dark it caused a marked increase in the activity of arginine decarboxylase. As a result of ADC action, putrescine content also rose markedly, whereas the level of spermidine and spermine decreased. However, inhibition of putrescine biosynthesis with D-arginine did not affect cytokinin promotion growth. Applied alone, putrescine had no significant effect on growth. These results indicate that the large increase in putrescine content that derives from cytokinin treatment cotyledons is not essential for cytokinin-induced expansion of cotyledons. Addition of K+ and Ca2+ ions to the cotyledons incubated with cytokinin caused a marked reduction in the putrescine level and ADC activity. The higher level of putrescine (35 %) and spermine (62 %) bound to chromatin and the large increase (174 %) in spermidine content bound to ribosomes which derive from cytokinintreated cotyledons in relation to literature data can indicate that these polyamines may play an important role in gene expression during cytokinin-stimulated expansion of cucumber cotyledons. The inhibition of cytokinin effect, viz. enlargement of the cotyledons by inhibitors of spermidine biosynthesis, additionally suggessted a possible involvement of polyamines in cytokinin action.
TL;DR: Results of the study proved that advantageous effect of foliar tomato nutrion grown in eat substrate was observed only in treatments with restricted supply of fertilizers to the growing medium, and did not change dry matter and vitamin C content and increased total and reducing sugars accumulation in tomato fruits.
Abstract: Tomatoes grown in traditional mediums such as peat moss are usually supplied with essential nutrients by preplant fertilization and in the later growth stages by top dressing application to the root zone. According to the data from literature the efficient method of nutrient supply during the intensive stage of growth may be estimated as by foliar spraying.
TL;DR: The obtained results indicate the importance of consistent and favorable conditions for disease development in screening of tomato resistance to bacterial speck.
Abstract: Two genotypes of tomato A 100 and Ontario 7710 which were inoculated separately with four strains of Pseudomonas syringae pv. tomato differed significantly in disease severity (susceptibility) to bacterial speck. At both concentrations of inoculum of each strain used (107 and 108 cfu/ml) A 100 appeared to be highly susceptible whereas Ontario 7710 showed very low or no susceptibility. The significant differences in virulence between strains and in response of tomato plants in three replicate experiments were found. Generally, concentration of inoculum 107 cfu/ml was too low to induce consistent level of disease severity. The obtained results indicate the importance of consistent and favorable conditions for disease development in screening of tomato resistance to bacterial speck.
TL;DR: Methyl jasmonate at a concentration of 0.5 % induced the formation of secondary abscission zone and senescence in several types of stem explants of Bryophyllum calycinum when it was applied in various places of the stem or the debladed petiole as lanolin paste.
Abstract: Methyl jasmonate (JA-Me) at a concentration of 0.5 % induced the formation of secondary abscission zone and senescence in several types of stem explants (only internode segment, internode segment with nodes and without leaves, internode segment with nodes and debladed petioles) of Bryophyllum calycinum when it was applied in various places of the stem or the debladed petiole as lanolin paste. In the presence of small leaves in stem explants methyl jasmonate also induced the formation of secondary abscission zone and senescence but the presence of larger leaves completely inhibited methyl jasmonate-induced processes. Auxin, (indole-3-acetic acid, IAA), at a concentration of 0.1 % extremely prevented the formation of secondary abscission zones and senescence in the stem tissues induced by methyl jasmonate. Similar relationship between auxin and methyl jasmonate to induce the formation of secondary abscission zone and senescence was found in decapitated shoot of the intact plant. Mechanisms of the formation of secondary abscission zone are also discussed in terms of the interaction of methyl jasmonate with auxin.
TL;DR: Two PVY tomato strains, arising from the same natural isolate, and a strain originating from a wild Solanaceous host, Solanum nigrum, were compared for host range and symptomatology, suggesting that Lye 84.2 has probably derived from LYE 84, that both strains have very similar sequences and that the capsid protein does not play a direct role in the resistance-breaking capacity of LYE84.2.
Abstract: Two PVY tomato strains (LYE 84 and LYE 84.2), arising from the same natural isolate, and a strain originating from a wild Solanaceous host, Solanum nigrum (SON 41.2), were compared for host range and symptomatology. All strains induced mosaic without necrosis on tobacco as PVYO strains. The two tomato strains behaved similarly on pepper, infecting only susceptible pepper cultivars (pathotype 0), whereas SON 41.2 was able to overcome the two alleles of the recessive resistance gene pvr2 (pathotype 1.2). On the other hand, only LYE 84.2 was virulent on tomato and broke the resistance of the wild genitor Lycopersicon hirsutum PI 247087. Sequence determination of the capsid gene and the 3′ non-coding region of LYE 84 and LYE 84.2 showed a total homology at both nucleic acid and amino acid levels. This suggests that LYE 84.2 has probably derived from LYE 84, that both strains have very similar sequences and that the capsid protein does not play a direct role in the resistance-breaking capacity of LYE 84.2.