chlorophyll Content

The effect of spent engine oil on the height, leaf number, leaf area, stem girth, chlorophyll, and moisture contents of Corchorus olitorius grown on 0, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 2.0%, and 3.0% (v/w oil/soil) oil-contaminated soil was investigated. The engine oil at all concentrations delayed the germination of C. olitorius by 2 days (compared to control) and there was a general significant reduction in all the growth parameters in plants grown on contaminated soil compared to control plants. The highest leaf area of 26.8 cm 2 was found in the control plant and least was found in the 0.6% soil (0.11 cm 2) after 3 weeks while no values were recorded on the 0.8-3.0% engine-oil-contaminated soil after 5 weeks of experiment. The highest chlorophyll content was also found in the control plant (11.5 mg/l). This showed that spent engine oil has an adverse effect on the growth of C. olitorius plant.

Disponible en: http://redalyc.uaemex.mx/src/inicio/ArtPdfRed.jsp?iCve=57313040004 ... Redalyc Sistema de Información Científica Red de Revistas Científicas de América Latina, el Caribe, España y Portugal ... González-Torres, Anselmo; Figueroa-Viramontes, Uriel; Delgado, ...

For Tunisian olive tree orchards, nitrogen deficiency is an important nutritional problem, in addition to the availability of water. Establishment of relationships between nutrients such as nitrogen and ecophysiological parameters is a promising method to manage fertilisation at orchard level. Therefore, a nitrogen stress experiment with one-year-old olive trees (Olea europaea L. 'Koroneiki' and 'Meski') was conducted with trees respectively subjected to four nitrogen supply regimes (23.96 meq l-1 , 9.58 meq l-1 , 4.79 meq l-1 and 0 meq l-1 NO 3-). The current paper focuses on the use of the SPAD-502 portable chlorophyll (Chl) meter, a nondestructive method for fertilisation management under nitrogen stress conditions of olive trees. Maximum net photosynthetic assimilation rates, chlorophyll fluorescence parameters and the SPAD Chl index were therefore measured simultaneously and the Chl and nitrogen content of the leaves were analysed. Significant correlations were established in the olive tree leaves between SPAD-502 readings on the one hand and Chl content, nitrogen content, photosynthetic assimilation rate, and Chl fluorescence parameters (Φ PSII and ETR) on the other hand.

Improved understanding of the impact of leafing phenology and soil water supplies on the gas exchange and water use efficiency (WUE) of trees in agroforestry systems in the semi-arid tropics is essential to optimise tree/crop interactions and the use of scarce natural resources, particularly in view of recent initiatives to use carbon credits to reward subsistence farmers who plant and manage trees effectively. Understanding of the relationships between photosynthetic and transpiration rates and chlorophyll content may help to explain variation in growth rate, productivity and WUE between species and growth environments. Such information is lacking for the species examined here, the evergreen Grevillea robusta (A. Cunn), semi-deciduous Alnus acuminata (HBK) and deciduous Paulownia fortunei (Hemsl.). Although differences in leafing phenology influence the extent of competition or complementarity between trees and crops in agroforestry systems, and hence crop yield, farmers may deliberately plant fast-growing, competitive tree species if they provide attractive economic returns or carbon credit subsidies. The objectives were to characterise: (1) the extent of variation in foliar gas exchange and instantaneous water use efficiency (WUE i) between trees with contrasting leafing phenologies; (2) the influence of leaf age and available soil moisture on gas exchange and WUE i of trees; and (3) chlorophyll and foliar nitrogen (N) concentrations and gas exchange parameters for maize in agroforestry and sole crop systems. Foliar chlorophyll and N concentrations, assimilation (A) and transpiration rate (E) were much greater in P. fortunei than in A. acuminata or G. robusta. A, E and WUE i were greatest in young mature leaves of all three species but declined as they senesced. WUE i increased as soil moisture content declined and was similar in all species, suggesting their differing leafing phenologies were responsible for observed differences in long-term water use and growth. A and WUE i were greater in maize than in tree species, consistent with its C4 photosynthetic pathway. The implications for tree and crop growth, yield and acceptability to subsistence farmers in the semi-arid tropics are discussed.

The functional state of the photosynthetic apparatus of Xowering homoiochlorophyllous desiccation tolerant plant Haberlea rhodopensis during dehydration and subsequent rehydration was investigated in order to characterize some of the mechanisms by which resurrection plants survive drought stress. The changes in the CO 2 assimilation rate, chlorophyll Xuorescence parameters, thermoluminescence, Xuorescence imaging and electrophoretic characteristics of the chloroplast proteins were measured in control, moderately dehydrated (50% water content), desiccated (5% water content) and rehydrated plants. During the Wrst phase of desiccation the net CO 2 assimilation decline was inXuenced by stomatal closure. Further lowering of net CO 2 assimilation was caused by both the decrease in stomatal conductance and in the photochemical activity of photosystem II. Severe dehydration caused inhibition of quantum yield of PSII electron transport, disappearance of thermoluminescence B band and mainly charge recombination related to S 2 Q A ¡ takes place. The blue and green Xuorescence emission in desiccated leaves strongly increased. It could be suggested that unchanged chlorophyll content and amounts of chlorophyll-proteins, reversible modi-Wcations in PSII electron transport and enhanced probability for non-radiative energy dissipation as well as increased polyphenolic synthesis during desiccation of Haberlea contribute to drought resistance and fast recovery after rehydration.

The effects of five different N-sources (KNO 3 + NH 4 NO 3 = control, KNO 3 , NH 4 NO 3 , NH 4 H 2 PO 4 , L-alanine) on growth, nutritional status, chlorophyll (Chl) content, and photosynthetic parameters of the apple rootstock MM 106 shoots cultured in vitro were investigated. In comparison to all the other treatments, control explants grown on a MS medium containing KNO 3 + NH 4 NO 3 had the highest fresh mass, Chl content, net photosynthetic rate, transpiration rate, and stomatal conductance.

The effects of carbendazim, captan, thiram, and mancozeb, on plant vitality, chlorophyll content, N uptake, protein content, nodulation, and seed yield in chickpea (Cicer arietinum) were assessed in a controlled environment. Seeds treated with fungicides at 1 and 1.5 g. a.i./kg seed had no significant adverse effect on plant vigor, seed yield, and N and protein contents. In contrast, fungicides applied at 2 g. a.i./kg of captan, thiram and mancozeb, significantly reduced the measured parameters. In general, the toxicity of fungicides in terms of seed yield increased in the following order: Control ¼ carbendazim > thiram > captan > mancozeb. Total chlorophyll content in foliage declined consistently with fungicides dose rates and application days. Seeds treated with lower rates of fungicides significantly increased nodulation (nodule number per plant and its dry mass) and were compatible with chickpea inoculum used in this study. Although carbendazim at 2 g a.i./kg seed had no phytotoxic effect assessed under greenhouse conditions, it significantly reduced the chlorophyll content, nodulation (60 d) and N content in shoots.

Two cherry tomato plant cultivars (Lycopersicon esculentum Miller, cultivars 'Koko' and 'Pepe') were supplied with high (395 ppm), medium (266 ppm) and low (199 ppm) concentrations of nitrogen to determine the influence of nitrogen fertilization on development, cultivar preference and honeydew production by greenhouse whiteflies, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae). The nitrogen, protein, and chlorophyll contents of tomato leaves were higher in the high nitrogen supplied plants than in the medium or low nitrogen supplied plants, but the sugar content showed an inverse relationship. The developmental times of eggs and nymphs decreased as the nitrogen concentrations increased in both cultivars. The preference of T. vaporariorum was compared by counting the number of eggs deposited on leaves in choice and non-choice tests. In the non-choice test, no significant nitrogen treatment effects were observed but the upper plant stratum was preferred for egg laying. In the choice test, there were significant main effects of cultivar and nitrogen concentration. T. vaporariorum laid eggs more on leaves of plants with higher nitrogen at the upper stratum. In both experiments, T. vaporariorum preferred the 'Koko' cultivar to the 'Pepe' cultivar. The honeydew production of T. vaporariorum nymphs increased with decreasing nitrogen treatment concentrations. The largest honeydew production was detected in the 'Pepe' cultivar grown at low nitrogen concentration. It is concluded that cultivar 'Pepe' had an advantage over 'Koko' in term of T. vaporariorum management program in tomato greenhouses.

Nitrogen is a crucial macronutrient needed in the greatest amount of all mineral elements required by plants. Development of crop varieties with high nitrogen use efficiency (NUE) is imperative for sustainable agriculture. Understanding how plant genes respond to different nitrogen conditions is essential for formulating approaches, for manipulating genes, for improving NUE. In the present study we analyzed the activity of three different enzymes involved in nitrogen assimilation viz., GS, GOGAT and GDH along with physiological parameters like chlorophyll variable yield (Fv/Fmax), photosynthesis rate and total chlorophyll content at four different growth stages of wheat plant development under different nitrogen treatments. For this study two different wheat varieties UP-2644 and Raj-4097 having high and low protein content, respectively in the grains were chosen. Gene expression profile of a Dof transcription factor (TaDof1 of wheat) was also included in the study to assess its role in nitrogen metabolism. Densitometry analysis at S 2 and S 3 stage of wheat spikes of both the wheat varieties grown at different nitrogen treatments showed that TaDof1 expression was up-regulated in low nitrogen treatment. In S 3 stage, in high protein content wheat variety UP-2644, TaDof1 expression was elevated in low and normal nitrogen treatment as compared to high nitrogen treatment. The gene expression profile of Dof 1 was found to coincide with the enzyme activities of GS, GOGAT at the S 3 stage. The activities of these enzymes were prolonged in the high protein content variety. Since, Dof transcription factor(s) have been previously reported to control the expression of genes involved nitrogen assimilation i.e., GS and GOGAT and may be the elevated expression of Dof 1 at the grain filling stage over expresses the GS and GOGAT genes thereby prolonging their activities.

Row aquatic vegetation is characterized by distinctive features as inundated habitats and individuals arranged in
rows. However, current radiative transfer models have not yet taken into account both the water background and
the row structure. To address this problem, we developed a hybrid radiative transfer and geometric optical model
(Aquatic Vegetation Row Model, AVRM) for row vegetation and taken rice at early growth stages as a typical
example. We verified the model through field experiment and an independently developed Monte Carlo simu
lation model (Aquatic Vegetation Row Monte Carlo model, AVMC), and found that they could better simulate the
canopy reflectance characteristics of rice before canopy closure than existing models: PROSAIL model for uni
form terrestrial vegetation, AVRT model for uniform aquatic vegetation, and Kimes model for row terrestrial
vegetation, respectively. The effects of row structure, leaf area index, and water background on the bidirectional
reflectance spectra of rice canopies were investigated. Our models could be used as virtual laboratory to simulate
the reflectance characteristics of rice at early growth stages, which may benefit rice condition monitoring and
growth management.

A persistent front, in large part generated by the confluence of western tropical North Atlantic (WTNA) surface waters with the massive freshwater plumes of the Orinoco and Amazon Rivers, separates waters of the Caribbean Sea from those of the adjacent WTNA. We characterized physical and biogeochemical properties across this front in order to elucidate the processes leading to enhanced near surface phytoplankton biomass within the front. Although chlorophyll content of the water column to either side of the front is similar, phytoplankton in waters within this “Caribbean‐Atlantic front” resides for the most part above the pycnocline and sustains large production rates in comparison with the lower rates of deep, sub‐pycnocline WTNA phytoplankton. Nitrogen budgets indicate that a substantial fraction of the production within the front may arise from biological nutrient recycling while the deeper WTNA communities rely to a greater extent on nutrients from below the nutricline.

ABSTRACT To evaluate the expression of drought tolerance for bread wheat, six parents diverse in their response to drought i.e., Giza 171 (P1), Sakha 95 (P2), Bohouth 6 (P3), Cham 8 (P4), Gemmiza 12 (P5) and Masr 3 (P6) and their 15 F1 crosses at 100% water requirements, and 70% water requirements sown in randomized complete blocks design season 2023/24 to estimate some genetic parameters for day to heading, days to maturity, chlorophyll pigments, superoxide dismutase activity, the activity of ascorbate peroxidase, proline content, number of spikes/plant, number of grains/spike, 100-kernel weight, and grain yield/plant. slightly significant differences were shown for most studied traits across all water regimes. The ratios of general combining ability to specific combining ability exceeded one for the examined traits, with some exceptions, signifying the influence of additive gene effects on the inheritance. The parental genotypes as good combiners, for earliness were P1 under both treatments, as well as P1, P2, and P3 at 70% water requirements, for physiologic and agronomic traits. The crosses P3 × P4 and P4 × P6 were the best combinations across the two treatments depending on physiological response and yield attributes. Most hybrids had significant heterotic values for agronomic and bio-physiological traits. The genotypic and phenotypic coefficients of variation varied from 1.71% for days to maturity to 14.83% for proline content, and from 1.90% for days to maturity to 16.64% for the activity of ascorbate peroxidase under well-watered, respectively; likewise, from 2.03% and 1.80% for days to maturity to 14.69% and 14.05% for chlorophyll a, respectively under water deficit.

Este experimento foi desenvolvido com o objetivo de estudar o crescimento de mudas de Bombacopsis glabra (Pasq.) A. Robyns (castanha-do-maranhão) sob diferentes intensidades luminosas. A capacidade de emergência das plântulas foi determinada pela porcentagem e pelo índice de velocidade de emergência, utilizando quatro repetições de 100 sementes (1 semente/saco). Após 40 dias, 75 mudas foram transferidas para condições de 30 e 50% de sombreamento e para pleno sol. O desenvolvimento das mudas foi conduzido em delineamento de blocos casualizados, com três repetições de cinco mudas, nas quais foram avaliados a altura do caule e o diâmetro do colo aos 61, 82, 103 e 124 dias após a emergência das plântulas; o teor de clorofila a, b, total e a razão a/b; a massa seca da planta (MS); a área foliar (AF); a taxa de crescimento relativo (TCR); a razão de área foliar (RAF); a taxa assimilatória líquida (TAL); e a sobrevivência aos 103 e 124 dias após a emergência, quando o experimento foi encer...

Portulaca oleracea Linn., commonly known as purslane, is a C4 succulent and salt tolerant weed. The present work was focused on the seed germination of purslane under different levels of NaCl and Na2SO4 (25, 50, 100 and 200 mM) salinity along with continuous dark and light conditions. Results indicated that both salinity treatments had negative impact on seed germination under both light conditions. Interestingly, seed germination percentage of purslane was high under both salinity treatments and continuous light conditions as compared to dark conditions. The differential response of purslane’s seed germination under NaCl and Na2SO4 salinity and light conditions suggests weediness of this plant under adverse environmental conditions. The present work might be helpful for agricultural practices dealing with the problem of this weed.

The reactions of substituted furo[3,2-b]pyrrole-5-carboxhydrazides 1 with 5arylfuran-2-carboxaldehydes 2, 4,5-disubstituted furan-2-carboxaldehydes 3 and thiophene-2carboxaldehyde 4 has been studied. The advantage of microwave irradiation on some of these reactions was reflected in the reduced reaction time and increased yields. Reactions of 1 with 4-substituted 1,3-oxazol-5(4H)-ones 11 led to diacylhydrazines 13 or to imidazole derivatives 14 depending on the temperature. 1,2,4-Triazole-3-thione 17 was synthesized by two-step reaction of 1 with phenylisothiocyanate and subsequent base-catalyzed cyclization of thiosemicarbazide 16. The effects of hydrazones 5-10 on inhibition of photosynthetic electron transport in spinach chloroplasts and chlorophyll content in the antialgal suspensions of Chlorella vulgaris were investigated.

The purpose of this study was to describe and compare the spectral response of common beans desiccated with diquat and glufosinate-ammonium (GLA) using a hyperspectral terrestrial sensor and report how the desiccants influence dry bean visual appearance. Bean plants were desiccated with two different types of diquat and GLA desiccants. After the measurements of the spectral curves were carried out, from these values the indices of vegetation and derivatives were calculated, the chlorophyll content of the leaves on the days of the campaign was also measured. After harvesting the grains, some qualitative variables of the grains, such as cooking time and color, were evaluated Vegetation indices (VIs) in the near-infrared and mid-infrared regions of the spectrum (wavelength locations of 705, 750, 860, and 1240 nm) were significantly different between desiccant treatments (p≤0.05) two days after application (DAA). Desiccant application caused chlorophyll degradation as detected at the wavelength of 650 and 800 nm at DAA 1. The red edge and first derivatives showed that crop injury was higher in the diquat treatment because peak magnitude for this treatment became smaller over time. The desiccant application negatively affected seed quality, resulting in smaller Hue values and longer cooking time (CT). Hue angle correlated negatively with plant water content variation and CT Our results suggest that hyperespectral terrestrial sensing can differentiate the effects caused by the desiccants, showing that ammonium glufosinate causes less damage to seed quality and the water loss is like the control group.

Two arbuscular mycorrhizal fungi, Glomus mosseae and Acaulospora laevis either alone or in combination with Trichoderma viride showed the dependence of Rauwolfia serpentina on endomycorrhizal fungi. After 60 days, G. mosseae singly or in combination with Trichoderma viride showed enhanced height increment compared to control plants. Maximum phosphorus content was shown by plants treated with G. mosseae plus T. viride (0.444 ± 2.62) in roots and (0.437 ± 4.71) in shoots. Phosphorus content in roots was more than that in shoots. Chlorophyll content and stomatal conductivity also showed similar trend.

Disturbance of forest ecosystems, an important component of the terrestrial carbon cycle, has become a focus of research over recent years, as global warming is about to increase the frequency and severity of natural disturbance events. Remote sensing offers unique opportunities for detection of forest disturbance at multiple scales; however, spatially and temporally continuous mapping of non-stand replacing disturbance remains challenging. First, most high spatial resolution satellite sensors have relatively broad spectral ranges with bandwidths unsuitable for detection of subtle, stress induced, features in canopy reflectance. Second, directional and background reflectance effects, induced by the interactions between the sun-sensor geometry and the observed canopy surface, make up-scaling of empirically derived relationships between changes in spectral reflectance and vegetation conditions difficult. Using an automated tower based spectroradiometer, we analyse the interactions between canopy level reflectance and different stages of disturbance occurring in a mountain pine beetle infested lodgepole pine stand in northern interior British Columbia, Canada, during the 2007 growing season. Directional reflectance effects were modelled using a bidirectional reflectance distribution function (BRDF) acquired from high frequency multi-angular spectral observations. Key wavebands for observing changes in directionally corrected canopy spectra were identified using discriminant analysis and highly significant correlations between canopy reflectance and field measured disturbance levels were found for several broad and narrow waveband vegetation indices (for instance, r 2 NDVI = 0.90; r 2 CHL3 = 0.85; p b 0.05). Results indicate that multi-angular observations are useful for extraction of disturbance related changes in canopy reflectance, in particular the temporally and spectrally dense data detected changes in chlorophyll content well. This study will help guide and inform future efforts to map forest health conditions at landscape and over increasingly coarse scales.

Plantlets propagated in temporary immersion bioreactors (TIB) have better performance than those propagated by conventional methods such as micropropagation. This is as a result of a better handling of the in vitro atmosphere and the nutrition. The object of this study was to further improve the cultivation conditions by introducing photomixotrophism as an intermediate link of photoautotrophic growth during ex vitro acclimatization. For this purpose the effects of light were evaluated by different parameters such as photosynthetic photon flux density (PPF), sucrose concentration, and CO 2 enrichment levels on CO 2 evolution inside the culture vessels. It was observed that CO 2 diminished upon light exposure and increased in the dark according to the photoperiod during each cycle of immersion. With this approach it was possible to increase the photomixotrophism in the pineapple plantlets propagated in TIB. It was demonstrated that light is the factor with more influence on plant quality, although under these conditions they seem to use more of the nutrients of the medium than their photoassimilates. The propagation of pineapple in TIB involves three phases: proliferation, pre-elongation, and final growth of the buds. In each phase the cultivation conditions were determined to substitute for sterilization by autoclaving, to improve the quality of the plants, to elevate the efficiency of the process, and to reduce production costs. The buds that grew in the temporary immersion bioreactor with the presence of Vitrofural (G-1) achieved the best indicators of growth. Significant increases were observed in the leaf area, dry mass of the buds, and chlorophyll contents.

The mechanisms affecting the heat sensitivity of chickpea are largely unknown. Heat-tolerant (ICCV07110, ICCV92944) and heat-sensitive (ICC14183, ICC5912) chickpea genotypes were sown in February in the soil-filled pots. At the time of flowering, these were subjected to varying day/night temperatures of 30/20, 35/25, 40/30 and 45/358C in the growth chambers (12 h light/12 h dark; light intensity, 250 mmol m 72 s 71 , 80% relative humidity). The pollen viability, pollen germination, tube growth, pollen load and stigma receptivity decreased with increases in temperatures to 45/358C. The heat-tolerant genotypes experienced significantly less damage to pollen and stigma function. Membrane integrity, chlorophyll content, photochemical efficiency and cellular oxidizing ability were inhibited by the increase in temperature, with greater impacts on the sensitive genotypes. Oxidative injury as lipid peroxidation and hydrogen peroxide content was significantly greater in sensitive genotypes at 40/30 and 45/358C. Enzymatic and non-enzymatic antioxidants showed increased levels at 40/308C, but decreased considerably at 45/358C. Heat-tolerant genotypes possessed greater activity of ascorbate peroxidase and glutathione reductase, along with higher levels of ascorbate and reduced glutathione at 40/30 and 45/ 358C. Biomass, pod set and yield were not affected significantly at 35/258C, but began to decrease at 40/308C and were lowest at 45/358C. The sensitive genotypes were not able to set any pods at 45/358C, whereas the tolerant genotypes produced only few fertile pods at this temperature. It was concluded that heat stress leads to loss of pollen as well as stigma function and induces oxidative stress in the leaves that cause failure of fertilization and damage to the leaves, respectively.

The phylogenetic analysis of bacterial communities in environments receiving anthropogenic impact could help us to understand its effects and might be useful in the development of monitoring or management strategies. A study of the composition of 16S rDNA clone libraries prepared from bacterial communities in water samples from a marina and a beach on the coast of Mallorca (W. Mediterranean) was undertaken at two time points, corresponding to periods of maximum and minimum anthropogenic use of this area for nautical and recreational activities. Libraries generated from the marina were significantly different from those from the beach and a non-impacted, bay sample. In the marina, a predominance of sequence types was observed related to bacterioplankton from nutrient-enriched environments or typically associated with phytoplankton, such as certain phylotypes of the Roseobacter clade, OM60 clade and Bacteroidetes. Similar results were found in the summer beach library but not in the winter one, in which there was an increase in the number of clones from oligotrophic groups, in agreement with lower chlorophyll content and bacterial counts. Therefore, nutrient enrichment seemed to be an important driver of the composition of bacterial communities in sites receiving direct human impact. Interesting sequence types from the Cryomorphaceae and group agg58 (Bacteroidetes) were exclusively found in beach libraries, and the reasons for this distribution deserve further study. Clones related to putative hydrocarbon-degrading bacteria of the genus Acinetobacter were observed in the marina, in agreement with a certain degree of pollution at this site. Non-marine sequences belonging to the Actinobacteria predominated over marine groups in the summer library from the marina and, therefore, unusual communities might be transiently present in this enclosed environment. Overall, the composition of the bacterial communities in these environments agreed well with the defining characteristics of the environments sampled.

The fruticose lichen Ramalina duriaei is generally considered to be sensitive to air pollution. In the present study we sought to determine whether thalli of this lichen collected in a remote unpolluted site (the HaZorea Forest, northeast Israel) and transplanted to the Ashdod region (southwest Israel) could provide information on the quality of the air in this area. For this purpose, the concentrations of Pb, Cu, Cd, Ni, Mn, Fe, S, Ca, Mg, Na, and K were determined in in situ thalli collected in the HaZorea Forest in March 1993 and in in situ and transplanted thalli retrieved in June 1993. The concentration of these elements in R. duriaei thalli was analyzed in comparison with physiological parameters such as the integrity of cell membranes, chlorophyll content, and alterations in reflectance responses from lichen thalli. Thalli transplanted to several industrial sites in the town of Ashdod for a period of 100 d accumulated high concentrations of Pb, Cd, Ni, Fe, S, Mg, Na, Ca, and ...

Lilium 9 formolongi was genetically engineered by Agrobacterium-mediated transformation with the plasmid pCrtZW-N8idi-crtEBIY, which contains seven enzyme genes under the regulation of the CaMV 35S promoter. In the transformants, ketocarotenoids were detected in both calli and leaves, which showed a strong orange color. In transgenic calli, the total amount of carotenoids [133.3 lg/g fresh weight (FW)] was 26.1-fold higher than in wild-type calli. The chlorophyll content and photosynthetic efficiency in transgenic orange plantlets were significantly lowered; however, after several months of subculture, they had turned into plantlets with green leaves that showed significant increases in chlorophyll and photosynthetic efficiency. The total carotenoid contents in leaves of transgenic orange and green plantlets were quantified at 102.9 and 135.2 lg/g FW, respectively, corresponding to 5.6-and 7.4-fold increases over the levels in the wild-type. Ketocarotenoids such as echinenone, canthaxanthin, 3 0-hydroxyechinenone, 3-hydroxyechinenone, and astaxanthin were detected in both transgenic calli and orange leaves. A significant change in the type and composition of ketocarotenoids was observed during the transition from orange transgenic plantlets to green plantlets. Although 3 0-hydroxyechinenone, 3-hydroxyechinenone, astaxanthin, and adonirubin were absent, and echinenone and canthaxanthin were present at lower levels, interestingly, the upregulation of carotenoid biosynthesis led to an increase in the total carotenoid concentration (?31.4%) in leaves of the transgenic green plantlets. Keywords Carotenoid Á Ketocarotenoid Á Agrobacteriummediated transformation Á Lilium 9 formolongi Á Metabolic engineering Á Multi-gene construct Electronic supplementary material The online version of this article (

SummarySeveral novel allelic groups of tomato (Solanum lycopersicum L.) mutants with impaired photomorphogenesis have been identified after γ‐ray mutagenesis of phyA phyB1 double‐mutant seed. Recessive mutants in one allelic group are characterized by retarded hook opening, increased hypocotyl elongation and reduced hypocotyl chlorophyll content under white light (WL). These mutants showed a specific impairment in response to blue light (BL) resulting from lesions in the gene encoding the BL receptor cryptochrome 1 (cry1). Phytochrome A and cry1 are identified as the major photoreceptors mediating BL‐induced de‐etiolation in tomato, and act under low and high irradiances, respectively. Phytochromes B1 and B2 also contribute to BL sensing, and the relative contribution of each of these four photoreceptors differs according to the light conditions and the specific process examined. Development of the phyA phyB1 phyB2 cry1 quadruple mutant under WL is severely impaired, and seedlings d...

The rate and sensitivity to inhibitors (KCN and salicylhydroxamic acidISHAMI) of respiratory oxygen uptake has been investigated in photosynthetic organs of several freshwater aquatic plant species: six angiosperms, two bryophytes, and an alga. The oxygen uptake rates on a dry weight basis of angiosperm leaves were generally higher than those of the corresponding stems. Leaves also had a higher chlorophyll content than stems. Respiration of leaves and stems of aquatic angiosperms was generally cyanide-resistant, the percentage of resistance being higher than 50% with very few exceptions. The cyanide resistance of respiration of whole shoots of two aquatic bryophytes and an alga was lower and ranged between 25 and 50%. These results suggested that the photosynthetic tissues of aquatic plants have a considerable alternative pathway capacity. The angiosperm leaves generally showed the largest alternative path capacity. In all cases, the respiration rate of the aquatic plants studied was inhibited by SHAM alone by about 13 to 31%. These results were used for calculating the actual activities of the cytochrome and alternative pathways. These activities were generally higher in the leaves of angiosperms. The basal oxygen uptake rate of Myriophyllum spicatum leaves was not stimulated by sucrose, malate or glycine in the absence of the uncoupler carbonylcyanide-m-chlorophenylhydrazone (CCCP), but was greatly increased by CCCP, either in the presence or in the absence of substrates. These results suggest that respiration was limited by the adenylate system, and not by substrate availability. The increase in the respiratory rate by CCCP was due to a large increase in the activities of both the cytochrome and alternative pathways. The respiration rate of M. spicatum leaves in the presence of substrates was little inhibited by SHAM alone, but the SHAM-resistant rate (that is, the cytochrome path) was greatly stimulated by the further addition of CCCP. Similarly, the cyanide-resistant rate of 02 uptake was also increased by the uncoupler.

This study aimed at assessing the toxic effects of industrial effluents using duckweed (Lemna minor L.) plants as a test system. Growth inhibition test according to standardized protocol (ISO 20079) was performed. The suitability of the Comet assay (indicates DNA damage) and certain parameters such as peroxidase activity and lipid peroxidation level, as biomarkers for environmental monitoring was evaluated. The water samples were collected monthly over a 3-month period from the stream near the industrial estate of Savski Marof, Croatia. All samples caused inhibition of growth rates based on frond number and biomass as well as decrease of chlorophylls content. In contrast, peroxidase activity, malondialdehyde content and tail extent moment (measure of DNA strand breaks) markedly increased. Obtained data demonstrate the relevance of duckweed as sensitive indicators of water quality as well as the significance of selected biological parameters in the reliable assessment of phyto-and genotoxic potential of complex wastewaters.

plants is initiated by its activation, and the reaction is catalyzed by the enzyme ATP sulfurylase (ATP S) and finally leads to the formation of cysteine (Cys) [1, 3]. Cys serves as a precursor for a range of further reduced S containing compounds, including glu tathione (GSH). GSH represents a major S storage capacity in plants and performs several essential func tions within the plant cell, serving as a redox regulator and antioxidant [4-6]. As a component of the ascor bate-GSH cycle, it takes part in the removal of H 2 O 2 excess, in a reaction, in which GSH is oxidized to glu tathione disulfide (GSSG). The high ratio of GSH to its oxidized form, GSSG, occurring under optimal growth conditions can be restored by means of higher glutathione reductase (GR) activity, increased GSH synthesis, decreased GSH degradation, or the trans port of GSH and GSSG [7]. In addition, by affecting

Seagrass distribution is controlled by light availability, especially at the deepest edge of the meadow. Light attenuation due to both natural and anthropogenically-driven processes leads to reduced photosynthesis. Adaptation allows seagrasses to exist under these sub-optimal conditions. Understanding the minimum quantum requirements for growth (MQR) is revealed when light conditions are insufficient to maintain a positive carbon balance, leading to a decline in seagrass growth and distribution. Respiratory demands of photosynthetic and non-photosynthetic tissues strongly influence the carbon balance, as do resource allocations between above-and below-ground biomass. Seagrass light acclimation occurs on varying temporal scales, as well as across spatial scales, from the position along a single leaf blade to within the canopy and finally across the meadow. Leaf absorptance is regulated by factors such as pigment content, morphology and physical properties. Chlorophyll content and morphological characteristics of leaves such as leaf thickness change at the deepest edge. We present a series of conceptual models describing the factors driving the light climate and seagrass responses under current and future conditions, with special attention on the deepest edge of the meadow.

Effects of short-term ozone (O3) fumigation on radish (Raphanus sativus L.) plants were examined in growth chambers under controlled environment conditions. Plants were exposed to 0 μg/m3 (reference), 80 μg/m3, 160 μg/m3 and 240 μg/m3 O3 concentrations for 7 h per day for five days. Day/night temperature was 21°C/14°C and photoperiod 16 h. Chlorophyll content was evaluated spectrophotometrically. Chromatographic analysis of saccharides was also undertaken. The results showed that elevated O3 inhibited the growth of radish rhizocarps, net assimilation rate and biomass accumulation. O3 induced leaf desiccation, necrosis and premature senescence, but a typical reaction of plants to O3 stress was the rapid regeneration of new leaves. O3 inhibited accumulation of carotenoids more than chlorophylls. The higher photosynthetic pigment content in newly generated radish leaves may be regarded as an adaptation of the photosynthetic system to O3. Leaf saccharide metabolism and incorporation dep...

The ability to stay-green (SG) in later stages of the crop cycle is a valuable trait for plants cultivated in standard or stressful environments. Few QTLs studies for SG have been conducted in temperate maize, apart from some experiments carried out with Chinese lines. The aim of our study was to identify QTLs related to SG in temperate maize using PHG39, an important SG line in private breeding. We developed two large F 2 mapping populations by crossing PHG39 to the no stay-green (NSG) lines B73 (Corn Belt Dent) and EA1070 (European Flint). Samples of individuals of the extreme tails (high and low) of the populations for visual score were genotyped. We found an association between markers and SG in three regions at bins 1.

The volatile monoterpene analogs, 1,4-cineole and 1,8-cineole, have been identified as components of many plant essential oils, but relatively little is known about their biological activities. We compared the effects of 1,4-and 1,8-cineole on two weedy plant species by monitoring germination, mitosis, root and shoot growth, chlorophyll content, and photosynthetic efficiency. 1,4-Cineole severely inhibited growth of roots and shoots, causing corkscrew shaped morphological distortion, whereas 1,8-cineole caused a decrease in root growth and germination rates. Chlorophyll fluorescence data (yield and F v/ F m) indicated that 1,4-cineole caused significantly higher stress (P ≤ 0.001) to photosynthesis when compared to controls. Mitotic index data showed that 1,8-cineole severely decreased (P ≤ 0.001) all stages of mitosis when compared with controls, while 1,4-cineole only caused a decrease in the prophase stage (P ≤ 0.05). Although superficially similar in structure, these two cineoles appear to have different modes of action.

A series of thiazolo[3,2-a]pyridin-8-yl-phosphonate derivatives have been obtained by the reaction of diethyl (E)-((4-oxothiazolidin-2-ylidene)methyl)phospohonate, malononitrile and two equivalent of various aromatic aldehydes in a multicomponent reaction with good yields. The structures of the new compounds are confirmed by spectroscopic methods (IR, 1 H, 13 C, 31 P NMR and HRMS). Compound diethyl-(Z)-(5-amino-6-cyano-2-(4-nitrobenzylidene)-7-(4-nitrophenyl)-3-oxo-3,7-dihydro-2H-thiazolo[3,2-a]pyridin-8-yl)phosphonate (4k) at 1 mM concentration enhanced biomass plant height, number of branches and leaf area of tomato plants of at least twofold compared to the control plants. In common bean plants, this compound enhanced the chlorophyl content and delayed senescence in comparison to the control plants. Therefore, in future studies, the compound(s) would be further tested to evaluate deeply their mode of action at physiological, biochemical and molecular level to finally enhance crop productivity of various plants.

Two separate experiments were conducted to determine the response of 'Solo' and 'Sinta' papaya fruits harvested at color break stage to 1methylcyclopropene (1-MCP). In the first experiment, 'Solo' papaya fruits were exposed to 0.1 or 0.5 µl L-1 1-MCP for 24 h at 25°C prior to storage at 13°C for 18 days. This was followed by ethephon treatment upon transfer at 25°C for ripening. The second experiment consisted of treating 'Sinta' papayas with the same concentration of 1-MCP but fruits were kept at ambient condition (25-28°C). Regardless of cultivar and storage condition, 1-MCP significantly retarded the ripening of papaya fruits. At 13°C, 1-MCP-treated 'Solo' papayas remained at color break stage for 18 d. In the case of 'Sinta' papayas, ripening was delayed for about 6 days at 25-28°C. Respiration rate and ethylene production of 1-MCP-treated fruits were greatly suppressed and no distinct climacteric peak was observed. Upon treatment with ethephon, only non-MCP-treated fruits softened to table ripe stage. 1-MCP-treated fruit on the other hand, remained hard although the flesh attained the full orange ripe color. Rubbery pulp texture was noted in some fruit treated with 0.5 µl L-1 1-MCP. The onset of stem end rot and anthracnose resulted in reduced shelf life. 1-MCP only reduced the severity of infection but did not delay its onset as well as incidence.

Two arbuscular mycorrhizal fungi, Glomus mosseae and Acaulospora laevis either alone or in combination with Trichoderma viride showed the dependence of Rauwolfia serpentina on endomycorrhizal fungi. After 60 days, G. mosseae singly or in combination with Trichoderma viride showed enhanced height increment compared to control plants. Maximum phosphorus content was shown by plants treated with G. mosseae plus T. viride (0.444 ± 2.62) in roots and (0.437 ± 4.71) in shoots. Phosphorus content in roots was more than that in shoots. Chlorophyll content and stomatal conductivity also showed similar trend.

The genetic relationships among different inbred stocks of corn with respect to different indices of photosynthetic efficiency and plant productivity was assessed by means of dialM graphs. The salient feature of the current study was "apparent overdominance" for some important indices of photosynthetic efficiency, viz. photosynthetic rate/unit leaf area (at the silking stage), total chlorophyll content and chlorophyll a content, as well as for total dry matter production and economic yield. The results could be explained in terms of complementary gene action and the multiplicative effects of the sub-components that comprise these traits. However, complete dominance was recorded for photosynthetic rate (at the grain filling period), leaf area/plant, number of leaves/plant, number of leaves above the ear, ratio of chlorophyll a/b and harvest index. In the majority of cases graphic analysis was possible only when a number of epistatic parents were omitted from the analysis. Although the position of the array points for different indices of photosynthetic efficiency was consistent across the years, the ontogenetic and seasonal differences in the genetic behaviour of parents, meaning thereby, different loci being active at different stages and seasons, was apparent. The same was true for the epistatic parents. Non-allelic interaction of the genes rather than the nonrandom distribution of the genes among the parents seemed to be the most common cause of disturbance in the Wr/V r relationship. Inbred stock MG 115 was identified to be the most promising because it embodied an efficient photosynthetic machinery by virtue of increasing the number of alleles for a majority of the indices of photosynthetic efficiency,

Three sugarcane clones viz., NIA-98, NIA-0819 and BL4 were used for induction of genetic variability through In-vitro mutagenesis. Apical meristametic region was used for callus induction on 4mg/l 2,4-D. Actively growing callus was treated with four different doses of gamma rays (10Gy, 20Gy, 30Gy and 40Gy). Maximum callus, proliferation and plantlets regeneration growth was observed in control and minimum at 40Gy. Maximum chlorophyll mutation frequency was recorded in 30 and 40 Gy. Maximum number of roots was observed in control followed by 10Gy. The maximum root length (10.3cm) was obtained in control at 2 mg/l IBA. The maximum number of tiller in the irradiated population was observed in 10Gy. The treatments 30Gy and 40Gy exhibited negative impact on the tillering potential of the plant.

RESUMO A necessidade premente de aumento no número de mudas plantadas anualmente, bem como a menor disponibilidade de matérias-primas tradicionais para composição de substratos têm levado à necessidade de desenvolvimento de estudos que visem à avaliação e disponibilização de novos materiais para composição de substratos, técnica e economicamente eficientes. Com base nisso, o presente estudo objetivou avaliar a viabilidade técnica da utilização de componentes renováveis a base de fibra de coco (FC), casca de arroz carbonizada (CAC) em diferentes granulometrias, biossólido (BIO) e casca de pinus semidecomposta na composição de substratos para a produção de mudas de Eucalyptus benthamii, bem como, avaliar a correlação entre as propriedades físicas e químicas dos substratos formulados com a qualidade das mudas produzidas. Para tanto, foram formulados 41 tratamentos, os quais tiveram suas propriedades físicas e químicas avaliadas, sendo a semeadura realizada em tubetes de 55 cm³. Foram a...

The physiological responses of sugarcane (Saccharum officinarum L.) to oxidative stress induced by methyl viologen (paraquat) were examined with respect to photochemical activity, chlorophyll content, lipid peroxidation and superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities. Thirty-day-old sugarcane plants were sprayed with 0, 2, 4, 6 and 8 mM methyl viologen (MV). Chlorophyll fluorescence was measured after 18 h and biochemical analyses were performed after 24 and 48 h. Concentrations of MV above 2 mM caused significant damage to photosystem II (PSII) activity. Potential and effective quantum efficiency of PSII and apparent electron transport rate were greatly reduced or practically abolished. Both chlorophyll and soluble protein contents steadily decreased with MV concentrations above 2 mM after 24 h of exposure, which became more pronounced after 48 h, achieving a 3-fold decrease. Insoluble protein contents were little affected by MV. Oxidative stress induced by MV was evidenced by increases in lipid peroxidation. Specific activity of SOD increased, even after 48 h of exposure to the highest concentrations of MV, but total activity on a fresh weight basis did not change significantly. Nondenaturing PAGE assayed with H 2 O 2 and KCN showed that treatment with MV did not change Cu/Zn-SOD and Mn-SOD isoform activities. In contrast, APX specific activity increased at 2 mM MV but then dropped at higher doses. Oxidative damage induced by MV was inversely related to APX activity. It is suggested that the major MV-induced oxidative damages in sugarcane leaves were related to excess H 2 O 2 , probably in chloroplasts, caused by an imbalance between SOD and APX activities, in which APX was a limiting step. Reduced photochemical activity allowed the early detection of the ensuing oxidative stress.