Total Amount Of Chlorophyll Research Articles

Detection and Response of Sugarcane against the Infection of Sugarcane Mosaic Virus (SCMV) in Indonesia

Sugarcane mosaic virus (SCMV) is one among many viruses that infect sugarcane, cause yield loss, and become serious disease agents on sugarcane plantations. Since the morphological symptoms of SCMV are similar to other symptoms caused by Sugarcane streak mosaic virus (SCSMV) or nitrogen deficiency, the detection of SCMV is important through accurate diagnostic-like ELISA or RT-PCR. This research aimed to study the causative mosaic pathogen of SCMV in East Java, Indonesia, including mosaic development. The results showed that the mosaic symptom is present in all sugarcane plantations with 78% and 65% disease incidence and severity, respectively. Moreover, the detection procedure based on an amplification of cDNA of the coat protein gene sequence confirmed that SCMV was the causative agent of mosaic disease on sugarcane. Re-inoculation of healthy sugarcane plants with plant sap from a symptomatic leaf from the field showed similar mosaic or yellowish chlorotic areas on the leaf blade, and appeared on the fourth leaves upward from the inoculation leaf, in addition to showing different levels of peroxidase but not total phenol. Mosaic also correlated with the amount of total chlorophyll. Although Sucrose phosphate synthase (SPS) protein accumulation and activity were at a lower level in infected leaves, sucrose accumulation was at a higher level in the same leaves.

Effect of Salinity on the Growth and Cadmium Accumulation of Vetiveria nemoralis

One of the major targets for phytoremediation is the removal of toxic heavy metals from the contaminated sites. This study investigated the effect of the salt stress (EC 3.5 dS/m) on the growth and removal of cadmium (Cd) (333 mg/kg) from spike contaminated soils by growing vetiver grass ( Vetiveria nemoralis ) in a pot experiment for forty five days. There were four treatments, including uncontaminated soil, uncontaminated saline soil, contaminated soil, and contaminated saline soil. V. nemoralis survived and grew well in the saline soil with or without contaminants. The presence of salt did not affect the total amount of chlorophyll in the plant tissues. No toxicity symptoms were evident from plant morphology after forty five days of exposure. Cd had accumulated mainly in the roots of V. nemoralis , while plants grown in saline soil showed the highest Cd accumulation in the roots (191.5 mg/kg) and uptake (2.8 g/plant) . The results suggested that Cd accumulation in plants was not affected by either salinity or contaminant, while slight reduction in shoot height was caused by contaminants.

Physiological effects of hot water dipping, chitosan coating and gibberellic acid on shelf-life and quality assurance of sugar snap peas (Pisum sativum L. var. macrocarpon)

Abstract The effects of chitosan coating (CC), gibberellic acid (GA3), and hot water dipping (HWD) to improve quality and extend shelf-life of chilled pea by reducing chilling injury and postharvest decay were evaluated. Pea pods were subjected to treatments consisting of CC (at 1 and 3%), GA3 (at 1 and 2 mmol L −1 ), and HWD (at 45 °C for 20 min and 55 °C for 1 min) followed by storage at 4 °C in a refrigerator set at 85–90% relative humidity for 35 d. No decay occurred in pods treated with GA3 at 1 mmol L −1 while CC at 1% resulted in 7% decay compared to 22–55% decay by CC at 3% and HWD treatments. Chitosan coating (1%) and GA3 (1 mmol L −1 ) reduced titratable acidity by 11.5 and 13.4%, respectively and chilling injury by 0.18 and 0.20%, respectively compared to 7% chilling injury by HWD treatments and the untreated control at the end of the storage period. The HWD treatment enhanced active oxygen-scavenging systems, such as peroxidase and catalase compared to CC and GA3 treatments. The content of reducing sugars was stable in all storage periods. Pods treated with CC and GA3 had the highest amount of total chlorophyll (8.4 and 8.9 mg g −1 FW), vitamin C (1.2 and 1.8% mg 100 g −1 FW), phenolics (1.9 and 1.6 mg g −1 FW), and protein (11.5 and 13.2 mg g −1 FW) at the end of the storage period.

The effect of lanthanides on photosynthesis, growth, and chlorophyll profile of the green alga Desmodesmus quadricauda.

Lanthanides (La, Gd, Nd, Ce) accumulated in the green alga Desmodesmus quadricauda but their intracellular localizations were distinctly different: lanthanum and gadolinium were localized in cytoplasm, while neodymium and cerium were in the chloroplast. The effect of lanthanum and neodymium, as representatives of these two groups, on growth, chlorophyll content and photosynthetic rate at different light intensities was studied. At the lowest light intensity used (50µmol photons m-2s-1), in the presence of lanthanides (Nd), growth was enhanced by as much as 36% over lanthanide free control, and the photosynthetic rate increased by up to 300%. At high light intensities (238, 460, and 750µmol photons m-2 s-1), photosynthetic rate increased markedly, but there was no significant difference between rates in the presence or absence of lanthanides. However, growth, measured as a percentage of dry weight, if compared with lanthanide free control, increased at all light intensities (31, 39, and 20%, respectively). The total amount of chlorophyll after lanthanide treatment increased by up to 21% relative to the control culture, mainly due to an increase in the level of chlorophyll b. Addition of lanthanides caused a change in the chlorophyll a/b ratio from 4.583 in control cultivation, to 1.05. Possible mechanisms of lanthanide-induced photosynthetic change, alterations in photosynthetic structures, and increases in growth are discussed and compared with findings in higher plants. The hypothesis that the lanthanide effect could be due to formation of lanthanide-pheophytins was not confirmed as lanthanide pheophytins were not found in D. quadricauda. Furthermore, we have shown that the preferential incorporation of heavy isotopes of magnesium, namely 25Mg and 26Mg, into chlorophyll during photosynthesis that occurred in controls was diminished in the presence of lanthanides.

PRODUCCIÓN DE BIOMASA DE LA MICROALGA MARINA CHROOMONAS SP. , EN FUNCIÓN DEL PH, INTENSIDAD LUMINOSA Y SALINIDAD

We report the characterization of a marine microalga of the genus Chroomonas, isolated from a salt lagoon located to the north of Maracaibo, Zulia State, Venezuela. We evaluated the growth and the pigment production in discontinuous culture at different salinites (5, 10, 35, 50, 70 Y 100 ppm),Iight intensites (39,78,117 and 156 µmol quanta.m-2.s-1) and pH (5.0,5.5,6.0,7.0, 8.0 and 9.0). The highest cellular density, 117.99±2.62x106 cel.ml-1, was reached at 35ppm, 156 µmol quanta.m-2.s-1 of light intensity and a pH between 6.0 and 8.0. The cellular content of total chlorophyll and carotenoids increased with the salinity up to 100 ppm, with amounts of 246.55±61.8 and 69.79±18.19 fg.cel-1 respectively. The cellular productivity 4.31x109 cel.l-1d-1 was obteined when the microalga, was grown in semi-continuous culture, at a 2.0 I volume and at a daily renewal rate of 30 % (v/v). The total amount of chlorophyll and carotenoids 1.4 mg.l-1.d-1 and 0.48 mg.l-1.d-1 respectively. This results indicate that this planktonic microalga could be used as daily live food for larvae in aquaculture and for the production of microalgaI biomass and/or pigments.

Relationship between incidence of Leucinodes orbonalis (Guenee) and Chlorophyll content in leaves of Brinjal (Solanum melongena L.)

The present study on biochemical basis of resistance against Leucinodes orbonalis infestation was conducted during the year 2011-2012. The results revealed that highest chlorophyll-‘a’- content of 0.497 mg/gfw was recorded in the susceptible genotype SHB-1.The lowest amount of 0.319 and 0.381 mg/gfw was observed in the resistant genotypes Brinjal-85 and Local long respectively, which were significantly different from other evaluated genotypes. The chlorophyll ‘a’content was positively correlated with the brinjal shoot and fruit borer infestation. Thehighest chlorophyll -‘b’- content of 0.442 mg/gfw was recorded at 70 DAT (days after transplanting). The amount of chlorophyll -‘b’- varied significantly among the genotypes at different ages and decreased with the age of crop. The average highest amount of chlorophyll -‘b’- was estimated in the genotype SBH-1 which was significantly at par with hybrid SBH-2. The lowest chlorophyll -‘b’- content was recorded at 40 DAT in the genotype Brinjal-85 followed by Local Long. The lowest amount of total chlorophyll was estimated in the resistant variety as compared to susceptible therefore exhibiting lowest level of infestation.

The Synthesis Potential of Some Sweet Cherry Cultivars under the Influence of Different Rootstocks

Abstract In relation cultivar / rootstock at sweet cherry, delayed incompatibility phenomena can be highlighted by distorted evolution of metabolic processes. For researches undertaken, in order to evaluate the potential for synthesis of different cultivars of cherry grafted on some rootstocks, it were chosen two moments, namely stage fruit ripening (late May) and the second growth stage of the vegetation season (mid-July) when the trees are fruitless. Measurements were performed using portable device LCpro + and assimilating pigments were determined by Arnon spectrophotometric method using the CECIL CE 1011 device. Determinations of photosynthesis, transpiration, stomatal conductance and respiration were made on shoots leaves, rosettes leaves with and without fruits. Leaf area and the amount of total chlorophyll were lower in trees with symptoms of incompatibility in Royal Mill plantation. Compatibility and harmonious evolution in time of the trees is dependent by the physiological processes synchronization between the two partners, the intensity of substances translocation by joint zone, in a simple way by the new individual metabolism seen from the perspective of both partners.

A RELATIONSHIP BETWEEN CHLOROPHYLL PHOTOSYNTHETIC POTENTIAL AND YIELD IN WINTER WHEAT (Triticum aestivum L.) AT ELEVATED TEMPERATURES

Development of the indices for selection of high-yielding crops and the models, forecasting crop yields, necessitate the analysis of the relationship between photosynthetic traits and productivity. Chlorophyll photosynthetic potential, characterizing the total amount of chlorophyll in the aboveground parts of plants (or in leaves) per unit of ground surface area during the growing season or a certain period, under optimal weather conditions correlated most closely with yield (T.M. Shadchina et al., 2007; E. Kutasy et al., 2005). Modern global climate change may primarily affect the heatsensitive crops in particular winter wheat causing disruption in the relationship between photosynthetic traits and productivity. In field experiment, we examined the effects of increased air temperatures during the spring—summer growing season on indices of photosynthetic apparatus in the highyielding varieties of common winter wheat Smuhlyanka and Pereyaslavka on the different levels of mineral nutrition (without fertilizers and fertilizing in the fall and at different phases of the spring— summer vegetation in doses N90P60K60S10 and N120P90K90S20). Investigations were carried out in 2009 and 2011 with elevated air temperatures during the growing season at the experimental agricultural station of the Institute of Plant Physiology and Genetics, National Academy of Sciences of Ukraine (Kiev region). It was shown that such weather conditions led to a decrease in the chlorophyll content in the leaves, the size of crop surface and the duration of its operation, as well as grain yield. In all cases (both at high level of mineral nutrition and without fertilizers) leaf surface area in 2009 was higher than under the corresponding treatments in 2011 at all studied vegetation phases. Mineral fertilizers increased the leaf area index in both years by average 1.5-2.0 times (in Pereyaslavka at milk-wax ripeness phase it increased almost 5 times if compared to the control). Chlorophyll content in leaves of both varieties depended on year: it was 5.5-6.0 and 3.5-4.5 mg/dm2, respectively, in 2009 and 2011 if fertilizers were used, and 3.2-4.3 and 2.8 mg/dm2, respectively, in the control. In most cases, the maximum values of the pigments content in the averaged sample of all green leaves from plant were observed in the phase of milk ripeness, probably, due to the complete withering away of leaves of lower layers. Mineral fertilizers increased the amount of chlorophyll in the leaves of both varieties. According to the results of dispersion analysis (F-Fisher test), the greatest influence on changes in the indices of the photosynthetic capacity in our experiments have the conditions of the year, the second most important factor was the level of mineral nutrition. The value of chlorophyll photosynthetic potential was more dependent on a combination of factors «variety ½ year conditions» and less on the interaction of the factors «year conditions ½ mineral nutrition level» and «variety ½ mineral nutrition level». High and similar correlation coefficient values (0.93 to 0.99) between grain yield and chlorophyll photosynthetic potential were observed for data sets within single year, variety or mineral nutrition treatment, a strong positive dependence revealed for the combined data sets for both years. The data have shown that the close correlation between the leaf chlorophyll photosynthetic potential and yield of winter wheat is retained in the conditions of air high temperature and this dependence can be described by the same regression equation for any varying factors.

СВЯЗЬ МЕЖДУ ВЕЛИЧИНОЙ ХЛОРОФИЛЛЬНОГО ФОТОСИНТЕТИЧЕСКОГО ПОТЕНЦИАЛА И УРОЖАЙНОСТЬЮ ОЗИМОЙ ПШЕНИЦЫ (Triticum aestivum L.) ПРИ ПОВЫШЕННЫХ ТЕМПЕРАТУРАХ

Development of the indices for selection of high-yielding crops and the models, forecasting agrocenosis yields, necessitate the analysis of the relationship between photosynthetic traits and productivity. Chlorophyll photosynthetic potential, characterizing the total amount of chlorophyll in the above-ground parts of plants (or in leaves) per unit of ground surface area during the growing season or a certain period, under optimal weather conditions correlated most closely with the magnitude of yield (T.M. Shadchina et al., 2007; E. Kutasy et al., 2005). Modern global climate change may primarily affect the heat-sensitive crops in particular winter wheat causing disruption in the relationship between photosynthetic traits and productivity. In field experiment, we examined the effects of increased air temperatures during the spring-summer growing season on performance of photosynthetic apparatus in the high-yielding varieties of common winter wheat Smuhlyanka and Pereyaslavka on the different levels of mineral nutrition (without fertilizers and fertilizing in the fall and at different phases of the spring-summer vegetation in doses N 90P 60K 60S 10 and N 120P 90K 90S 20). Investigations were carried out in 2009 and 2011 with elevated air temperatures during the growing season at the experimental agricultural station of the Institute of Plant Physiology and Genetics, National Academy of Sciences of Ukraine (Kyiv region.). It was shown that such weather conditions led to a decrease in chlorophyll content in the leaves, the size of crop surface and the duration of its operation, as well as grain yield. In all cases (both at high level of mineral nutrition and without fertilizers) leaf surface area in 2009 was higher than under the corresponding treatments in 2011 at all studied vegetation phases. Mineral fertilizers increased the leaf area index in both years by average 1.5-2.0 times (in Pereyaslavka at milk-wax ripeness phase it increased almost 5 times if compared to the control). Chlorophyll content in leaves of both varieties depended on year: it was 5.5-6.0 and 3.5-4.5 mg/dm 2, respectively, in 2009 and 2011 if fertilizers were used, and 3.2-4.3 and 2.8 mg/dm 2, respectively, in the control. In most cases, the maximum values of the pigments in the averaged sample of all green leaves from plant were observed in the phase of milk ripeness, probably, due to the complete withering away of leaves of lower layers. Mineral fertilizers increased the amount of chlorophyll in the leaves of both varieties. According to the results of dispersion analysis (F-Fisher test), the greatest influence on changes in the indices of the photosynthetic capacity in our experiments have the conditions of the year, the second most important factor was the level of mineral nutrition. The value of chlorophyll photosynthetic potential was more dependent on a combination of factors variety ½ year conditions and less on the interaction of the factors year conditions ½ mineral nutrition level and variety ½ mineral nutrition level. High and similar correlation coefficient values (0.93 to 0.99) between grain yield and chlorophyll photosynthetic potential were observed for data sets within single year, variety or mineral nutrition treatment, a strong positive dependence revealed for the combined data sets for both years. The data have shown that the close correlation between the leaf chlorophyll photosynthetic potential and yield of winter wheat is retained in the conditions of air high temperature and this dependence can be described by the same regression equation for any varying factors.

Evaluation of significant pigmets in green teas of different origin

This work monitors flavonoid pigments (theaflavins and thearubigins), and chlorophyll in green teas from different growing regions (India, China, Russia, Vietnam). These pigments affect the quality of the finished tea infusion and their quantity is affected by the way of tea processing (fermentation). 15 samples of green loose teas were selected for the analysis. The content of these pigments was determined using UV-Vis spectrophotometry, the concentration of flavonoid pigments was measured at a wavelength of 665 nm (theaflavins) and 825 nm (thearubigins). Concentration of flavonoid pigments was determined using the standard conversion coefficients, which are 38.7 for TRs and 1.4 for TFs. Chlorophyll concentration was measured at 642.5 and 660 nm. Chlorophyll concentration was determined by the conversion using international standard conversion coefficients and calculation of linear regressions. The results were statistically processed and evaluated in the program of UNISTAT version 5.6. The total amount of chlorophyll ranged from 0.20 to 1.33 mg/L of tea. Concentrations of theaflavin ranged from 0.15 to 0.66 g/100 g of tea and TRs from 2.00 to 11.15 g/100 g of tea. The results showed that the amount of theaflavins, thearubigins and chlorophyll in green teas varied (P <0,05), especially in teas from lowlands in Vietnam and Krasnodar (Russia). Statistically demonstrable difference (P <0,05) in the content of pigments was also recorded in a group of Indian teas (from lowlands) and, from a group of Chinese teas, a statistical difference (P <0,05) was demonstrated in the content of pigments in the mountain teas. On the basis of the results it can be concluded that the quality of green tea is mainly influenced by the processing method depending on the processing area (the factory), than by their country of origin.

Studies on the interaction of growth regulators with potassium ions in some physiological processes in bean (Phaseolus vulgaris L.). III The effect of growth regulators on growth, chlorophyll level and transpiration depending on potassium concentration

Leaf growth and chlorophyll level in GA<sub>3</sub>-treated bean, and leaf growth and transpiration intensity in ABA-treated bean plants were studied at two potassium concentrations in the medium (1 and 3 mM KNO<sub>3</sub>). The plants were grown on Hoagland's solution and growth regulators were applied to the shoot growth apexes. Both GA<sub>3</sub> and K<sup>+</sup> ions were found to stimulate growth of primary leaves and increase their potassium amount. GA<sub>3</sub> contrary to K<sup>+</sup> slightly decreased the potassium content in leaves Both factors reduced the chlorophyll content but did not affect the total chlorophyll amount in these organs Interaction between GA<sub>3</sub> and K<sup>+</sup> ions was of additive nature. The effect of ABA and K<sup>+</sup> ions on growth of both kinds of leaves and on the amount and content of potassium in them were antagonistic. The inhibitory effect of the hormone was stronger at higher potassium concentration in the medium. Either factor reduced transpiration intensity in leaves, however, the inhibitory effect of the growth regulator was stronger at lower potassium concentration. The potassium level modified both the physiological effect of the regulators and the sensitivity of bean particularly to ABA.

English

The foliar spray of seaweed liquid extracts (SLE) (Fucus spiralis and Ulva rigida) was applied at three different concentrations (12.5, 25 and 50) to the plants of Salvia plants (Salvia officinalis L.) submitted or not to water stress (moderate and severe stress). The application of seaweed extract significantly enhanced growth parameters. The highest plant height was obtained with application of 50% concentration of U. rigida,followed by 25% concentration of F. spiralis that resulted in 40 and 15% increases, respectively, compared to the control plants. The maximum dry weight was also achieved with the same concentration of seaweed extract. Improved photosynthetic pigment content such as chlorophyll a and chlorophyll b was also observed with seaweed extracts application. Total chlorophyll amount was enhanced to 2.15 and 1.62 times when the plants were sprayed with U. rigida (50%) and F. spiralis (25%) extracts, respectively. Water deficit effect on S. officinalis L was notably reduced by the application of seaweed extracts. Thus, under moderate stress, the plant showed an important reduction of total chlorophyll (55.34%) compared to plant treated with U. rigida extract (32%) and F. spiralis (33%). The lipid peroxidation was low pronounced in plants stressed and treated by seaweed extract. Hence, low content ofmalondialdehyde (MDA) (7.30 µM g-1 FW. and 5.7 µM g-1 FW.) was exhibited in plant stressed and treated with 50% of U. rigida extract and 25% of F. spiralis extract, respectively, compared to plant controls (13.99 µM g-1 FW). In conclusion, these data suggests that seaweed extract can be applied as natural fertilizer in agricultural sector. Key words: Fucus spiralis, growth parameters, Morocco, peroxidation, proline, Salvia officinalis, seaweed extract, Ulva rigida, chlorophyll.

Zinc-induced oxidative damage, antioxidant enzyme response and proline metabolism in roots and leaves of wheat plants

The purpose of this study was to evaluate antioxidative responses and proline metabolism in roots and leaves of wheat seedlings after treatment with different zinc (Zn) concentrations (0, 0.5, 1 and 3mM) for 6 days. A notable reduction in Zn content was observed in 0.5mM Zn-treated leaves, but a significant elevation in response to 1 and 3mM Zn treatment. Significant increases in Zn levels were observed in roots exposed to all applied Zn concentration. The highest Zn concentration resulted in significant reduction in the amount of total chlorophyll (chl) and chl a, while chl b content decreased under all applied Zn concentrations. In wheat leaves, Zn excess caused an insignificant enhancement of hydrogen peroxide (H2O2) content as well as unaltered malondialdehyde (MDA) level. Unchanged superoxide dismutase (SOD) activity, increased peroxidase (POD), catalase (CAT), glutathione reductase (GR) and ascorbate peroxidase (APX) activities were also observed in the leaves of Zn-treated seedlings. By contrast, higher H2O2 and MDA contents in Zn-treated roots were correlated with the stimulation of SOD and the inhibition of POD and GR. There were significant enhancements of soluble sugar and proline in both leaves and roots of wheat seedlings under Zn stress, but the increased rate of proline was higher in the roots than in the leaves. Differently, soluble protein content due to Zn treatment was lower in the leaves but higher in the roots, as compared with untreated seedlings. Additionally, ornithine δ-aminotransferase in both leaves and roots was stimulated by Zn stress, but different Zn concentrations exhibited inhibitory effect on glutamate kinase activity in wheat seedlings. In contrast, all applied Zn concentration resulted in an elevation of proline dehydrogenase activity in the leaves while the highest Zn concentration inhibited this parameter in the roots.

Physiological and Genetic Responses to Pesticide Mixture Treatment of Veronica beccabunga

The effects of a five-pesticide mixture on pesticide accumulation, phytohormone levels (indole-3-acetic acid, gibberellic acid, jasmonic acid, and salicylic acid), pigment contents (total chlorophyll and carotenoid), antioxidant enzyme (catalase and guaiacol peroxidase) activities, lipid peroxidation product (malondialdehyde), and DNA profiles were investigated in the leaves of Veronica beccabunga. Laboratory-acclimatized plants were treated with a mix of five pesticides (atrazine, disulfoton, chlorpyrifos, metalaxyl, and ethion) in doses of 50 ppt, 1 ppb, 100 ppb, and 1 ppm for 1, 3, and 6 days. The accumulation of each pesticide, from highest to lowest, was as follows: chlorpyrifos, atrazine, metalaxyl, disulfoton, and ethion. The amounts of total chlorophyll and protein decreased with increased pesticide concentration. Antioxidant enzyme activities and malondialdehyde amount increased linearly with increasing pesticide exposure. However, the highest pesticide concentration caused decreases in guaiacol peroxidase (POD) activity and malondialdehyde (MDA) content at all treatment times. Both jasmonic and salicylic acid levels increased with pesticide exposure and decreased gradually after. It was also determined that application of the pesticide mixture affected the DNA profiles of V. beccabunga. The most band changes were detected on the sixth day of treatment.

Tillage effects on physical qualities of a vertisol in the central highlands of Ethiopia

Chlorofluorocarbons are mainly responsible for the depletion of stratospheric ozone layer which results in increase of UV-B radiation on earth’s environment and causing adverse effects on flora. In the present study we have investigated the effect of ultraviolet-B (UV-B) radiation on two cryptogamic plants (Xanthoria elegans and Bryum argenteum) growing at high altitude of central Himalayan region of India. These plants were naturally receiving UV-B radiation and were analyzed for photosynthetic pigments, UV-B absorbing compounds and phenolics. In the field experiments, both of these plants contain higher amounts of UV-B absorbing compounds and phenolics and no major changes in total chlorophyll and carotenoid under UV-B exposed conditions were recorded. B. argenteum contains higher amounts of total chlorophyll, carotenoids, UV-B absorbing compounds and phenolics than the X. elegans at the duration of 120 h. The maximum average UV-B irradiance was 4.38 Minimal Erythemal Dose per hour (MED/ h) at the experimental site while minimum average UV-B irradiance was 1.72 MED/ h. The UV-B absorbing compounds and phenolics provide protection to these plants against UV-B radiation. Key words : Total chlorophyll, high altitude, pigments, UV-B absorbing compounds, UV-B radiation.

Physiological responses of Egeriadensa to high ammonium concentration and nitrogen deficiency

High ammonia (i.e. the total of NH 3 and NH 4 + ) concentration or nitrogen deficiency in water can exert stress on growth and health of many aquatic plants. To investigate the physiological impacts of high ammonia-N (NH 4Cl) concentration and nitrogen deficiency on plant physiology, apical shoots of submerged macrophyte Egeria densa were first treated with five levels of nitrogen: 0, 1, 10, 30, 60 mg L −1 ammonia-N (NH 4Cl) for 5 d. After having explored the stress range of ammonia-N, its effect on E. densa was further examined at three levels of ammonium (0, 1, 30 mg L −1 ammonia-N) and at six exposure times (0, 1, 2, 3, 5 and 7 d). In testing the concentration-dependent stress, the increase of ammonia-N reduced the amounts of total chlorophyll (chl a and b), soluble proteins and soluble carbohydrates, but increased the activity levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase and peroxidase in E. densa. In the N-free medium, total chlorophyll, soluble proteins, soluble carbohydrates and the activities of SOD and peroxidase in E. densa decreased significantly compared with the control (1 mg L −1 ammonia-N). When comparing the ammonia-N impacts over time, the plants showed a declining trend in total chlorophyll, soluble proteins and soluble carbohydrates, but an rising trend in MDA, SOD, peroxidase and catalase in 30 mg L −1 ammonia-N over 7 d. Compared with the control, the N-free medium significantly decreased the amounts of total chlorophyll, soluble proteins, soluble carbohydrates, SOD and peroxidase in E. densa over time. Our study indicates that high ammonium (ammonia-N ⩾ 10 mg L −1) affects the growth of E. densa through inducing oxidative stress and inhibiting photosynthesis, and nitrogen deficiency can also induce an abiotic stress condition for the E. densa growth by reducing photosynthetic pigments, soluble proteins, soluble carbohydrates, and the activity of antioxidant enzymes.

English

The effect of salt stress (NaCl) on shoot height (cm), root length (cm), dry and fresh weight (g), chlorophyll a and b, total chlorophyll (mg-1) and carotenoid amount was investigated in this study. In addition, the positive effects of Ca+2 (20 mM) were also investigated. Triticum durum Desf. Mirzabey, Kunduru-1149, and DH-6 and DH-8, derived from Kunduru-1149 using wide hybridization, were used as plant materials in this study. Arnon-Hoagland solution was used as food source for the plants and various NaCl concentrations (0, 50, 150 and 200 mM) and Ca+2 (as CaCl2) were added to Arnon-Hoagland solution. The research was completed at the end of the fifth week and the effect of NaCl on the root length of genotypes was found to be significant (P<0.05). Ca+2 caused an increase in root length in all NaCl applications, except for the 200 mM NaCl, whereas shoot height decreased with increasing salt concentration, except for the 50 mM NaCl. This character also increased with Ca+2application significantly. Dry and fresh weight of the plant decreased with increasing salt concentration. Ca+2 ameliorated dry and fresh weight of the plant at 50 mM NaCl in all the genoypes and NaCl doses, except for the Kunduru-1149 and DH-6.The highest increase in total chlorophyll amount was found in 50 mM NaCl + CaCl2in DH-8 (from 17.29 to 20.14 mg g-1). However, the rate of increase in the amount of carotenoid by the addition of Ca+2 was also determined for each genotype.   Key words: Triticum durum Desf., salinity, calcium, chlorophyll, carotenoid.

A critical role of STAYGREEN/Mendel's I locus in controlling disease symptom development during Pseudomonas syringae pv tomato infection of Arabidopsis.

Production of disease symptoms represents the final phase of infectious diseases and is a main cause of crop loss and/or marketability. However, little is known about the molecular basis of disease symptom development. In this study, a genetic screening was conducted to identify Arabidopsis (Arabidopsis thaliana) mutants that are impaired specifically in the development of disease symptoms (leaf chlorosis and/or necrosis) after infection with the bacterial pathogen Pseudomonas syringae pv tomato (Pst) DC3000. An ethyl methanesulfonate-induced Arabidopsis mutant (no chlorosis1 [noc1]) was identified. In wild-type plants, the abundance of chlorophylls decreased markedly after Pst DC3000 infection, whereas the total amount of chlorophylls remained relatively unchanged in the noc1 mutant. Interestingly, noc1 mutant plants also exhibited reduced disease symptoms in response to the fungal pathogen Alternaria brassicicola. Genetic and molecular analyses showed that the nuclear gene STAYGREEN (SGR; or Mendel's I locus) is mutated (resulting in the aspartic acid to tyrosine substitution at amino acid position 88) in noc1 plants. Transforming wild-type SGR cDNA into the noc1 mutant rescued the chlorosis phenotype in response to Pst DC3000 infection. The SGR transcript was highly induced by Pst DC3000, A. brassicicola, or coronatine (COR), a bacterial phytotoxin that promotes chlorosis. The induction of SGR expression by COR is dependent on COI1, a principal component of the jasmonate receptor complex. These results suggest that pathogen/COR-induced expression of SGR is a critical step underlying the development of plant disease chlorosis.

Effect of water stress on leaf relative water content, chlorophyll, proline and soluble carbohydrates in Matricaria chamomilla L.

The effect of water stress, excess water and water deficit, on the leaf relative water, amounts of proline, water soluble sugars and total chlorophyll and chlorophyll a, b were examined, to characterize the involvement of these components in the adaptive processes. An experiment was carried out with four irrigation levels (W1, W2, W3 and W4 consisting 100, 85, 70 and 55% of field capacity, respectively) arranged in randomized complete block design with five replications. Potted seedlings of Matricaria chamomilla were used as a test medicinal plant. Leaf relative water content, percentage of proline and total soluble sugar were not affected by irrigation regimes. But, irrigation had significant effect on amount of total chlorophyll and chlorophyll a, b. The maximum amount of chlorophyll a (19 mg/g), chlorophyll b (16 mg/g) and total chlorophyll (35 mg/g) obtained from W2 and W3. The minimum amount of chlorophyll a (15 mg/g), chlorophyll b (11 mg/g) and total chlorophyll (26 mg/g) obtained from W1, W4, W4, respectively. The values of total chlorophyll and chlorophyll a, b were the same in irrigation, at 100 and 55% of field capacity. Key words: Drought stress, irrigation, Matricaria chamomilla, osmolytes, proline, soluble sugar.

Detoxification of malachite green and textile industrial effluent by Penicillium ochrochloron

Malachite green was detoxified into p-benzyl-N,N-dimethylaniline and N,N-dimethyl-aniline hydrochloride by Penicillium ochrochloron. Degradation metabolites were analyzed by TLC, HPLC, and FTIR and identified by GCMS analysis. Phytotoxicity testing revealed the nontoxic nature of these metabolites. The percentage decolorization of malachite green (50 mg/L) was 93% in czapek dox broth after 14 h with an optimum pH of 7 at 30°C. The induction in the activity of lignin peroxidase after degradation suggested that the degradation of malachite green was peroxidase-mediated. Fungal culture was also found to have detoxified the textile effluent. The values of TDS, TSS, COD, and BOD were reduced in the treated samples compared to the control effluent. The treated effluent was non-toxic to the plants of Triticum aestivum and Ervum lens Linn, and the amount of total chlorophyll was higher in plants with treated effluent when compared to control effluent.