Synthesis of phytochelatins in Helianthus annuus is enhanced by cadmium nitrate

Phytochelatins are the principal heavy metal-detoxifying components in plants. To investigate phytochelatin (PHC) production and the importance of these compounds for heavy metal tolerance, sunflower (Helianthus annuus) was exposed to cadmium. The leaves and roots of sunflower plants cultivated in the presence of 15, 25 and 50 M Cd(NO3)2 for 3 and 9 days showed increased tolerance to cadmium and contained higher concentrations of phytochelatins. The phytochelatin level was assayed by using HPLC and the Cd level was determined by atomic spectrum analysis

Coordination between Bradyrhizobium and Pseudomonas alleviates salt stress in soybean through altering root system architecture

It is a well accepted strategy to improve plant salt tolerance through inoculation with beneficial microorganisms. However, its underlying mechanisms still remain unclear. In the present study, hydroponic experiments were conducted to evaluate the effects of Bradyrhizobium japonicum USDA 110 with salt-tolerant Pseudomonas putida TSAU1 on growth, protein content, nitrogen, and phosphorus uptake as well as root system architecture of soybean (Glycine max L.) under salt stress. The results indicated that the combined inoculation with USDA 110 and TSAU1 significantly improved plant growth, nitrogen and phosphorus contents, and contents of soluble leaf proteins under salt stress compared to the inoculation with the symbiont alone or compared to un-inoculated ones. The root architectural traits, like root length, surface area, project area, and root volume; as well as nodulation traits were also significantly increased by co-inoculation with USDA 110 and TSAU1. The plant-growth promoting rhizobacteria (PGPR) P. putida strain TSAU1 could improve the symbiotic interaction between the salt-stressed soybean and B. japonicum USDA 110. In conclusion, inoculation with B. japonicum and salt-tolerant P. putida synergistically improved soybean salt tolerance through altering root system architecture facilitating nitrogen and phosphorus acquisition, and nodule formation.Peer reviewe

One Last Puff? - Public Smoking Bans and Smoking Behavior

This paper investigates the short-term effects of public smoking bans on individual smoking behavior. In 2007 and 2008, state-level smoking bans were gradually introduced in all of Germany's sixteen federal states. We exploit this variation in the timing of state bans to identify the effect that smoke-free policies had on individuals' smoking propensity and smoking intensity. Using rich longitudinal data from the German Socio-Economic Panel Study, our difference-in-differences estimates show that the introduction of smoke-free legislation in Germany did not change average smoking behavior within the population. However, our estimates also point to important heterogeneous effects. Groups that go out more often, and hence are more exposed to the constraints of public smoking bans in everyday life, did adjust their smoking behavior. Specifically, we find that young, unmarried individuals, and those living in urban areas are groups that are both less likely to smoke and smoke less intensively following the introduction of public smoking bans. Furthermore, effects on individual smoking habits proved stronger in states that had more strict smoking bans. Public smoking bans, therefore, have important health benefits over and above the reduction in exposure of non-smokers to second-hand smoke that is their immediate and prime objective.Das vorliegende Papier untersucht anhand von Daten des Sozio-Oekonomischen Panels (SOEP) die kurzfristige Wirkung von öffentlichen Rauchverboten auf das Rauchverhalten in Deutschland. In den Jahren 2007 und 2008 wurden sukzessive Rauchverbote in allen sechzehn Bundesländern eingeführt. Diese zeitliche Variation erlaubt die Messung der Auswirkung von Rauchverboten auf die Wahrscheinlichkeit von Individuen zu rauchen sowie auf die Höhe ihres Zigarettenkonsums. Die Ergebnisse unserer Differenzen-in-Differenzen Schätzungen zeigen, dass die Verbote das durchschnittliche Rauchverhalten in der Bevölkerung insgesamt nicht beeinflussten. Doch finden wir relevante Effekte für Personengruppen, die traditionell häufiger ausgehen (jüngere Jahrgänge, unverheiratete Personen und Einwohner größerer Städte). Diese sind durch ihr häufigeres Ausgehverhalten den Beschränkungen von Rauchverboten im Alltag stärker ausgesetzt und weisen in Folge der Verbote niedrigere Wahrscheinlichkeiten auf, zu rauchen. Ferner finden sich Hinweise, dass sich striktere Rauchverbote stärker auf das Rauchverhalten auswirkten. Rauchverbote haben somit, neben ihrem eigentlichen Ziel, das Ausmaß des Passivrauchens im öffentlichen Raum zu reduzieren, eine wichtige und zusätzliche gesundheitsfördernde Wirkung

Endophytic actinomycetes from spontaneous plants of Algerian Sahara: indole-3-acetic acid production and tomato plants growth promoting activity

Twenty-seven endophytic actinomycete strains were isolated from five spontaneous plants well adapted to the poor sandy soil and arid climatic conditions of the Algerian Sahara. Morphological and chemotaxonomical analysis indicated that twenty-two isolates belonged to the Streptomyces genus and the remaining five were non- Streptomyces. All endophytic strains were screened for their ability to produce indole-3-acetic acid (IAA) in vitro on a chemically defined medium. Eighteen strains were able to produce IAA and the maximum production occurred with the Streptomyces sp. PT2 strain. The IAA produced was further extracted, partially purified and confirmed by thin layer chromatography (TLC) analysis. The 16S rDNA sequence analysis and phylogenetic studies indicated that strain PT2 was closely related to Streptomyces enissocaecilis NRRL B 16365T, Streptomyces rochei NBRC 12908T and Streptomyces plicatus NBRC 13071T, with 99.52 % similarity. The production of IAA was affected by cultural conditions such as temperature, pH, incubation period and L-tryptophan concentration. The highest level of IAA production (127 lg/ml) was obtained by cultivating the Streptomyces sp. PT2 strain in yeast extract-tryptone broth supplemented with 5 mg L-tryptophan/ ml at pH 7 and incubated on a rotary shaker (200 rpm) at 30°C for 5 days. Twenty-four-hour treatment of tomato cv. Marmande seeds with the supernatant culture of Streptomyces sp. PT2 that contained the crude IAA showed the maximum effect in promoting seed germination and root elongation

Interactions between cadmium and phytochelatin accumulation in two different sunflower cultivars

The effects of cadmium sulfate on cadmium accumulation and phytochelatin synthesis were investigated in leaf, stem and root tissues of two sunflower cultivars, cadmium tolerant Helianthus annum cv. Meriç and sensitive Tarsan 1018. The seedlings were grown for 15 days in Hoagland solution and then exposed to CdSO4 at 150 µM, 200 µM, 250 µM and 300 µM for 4 days. Most cadmium accumulations were determined in the roots of both cultivars on the 2nd and 4th day. The cadmium sensitive cultivar, Tarsan 1018, accumulated more Cd in all tissues compared to the tolerant cultivar. Phytochelatin synthesis was induced by Cd exposure in both cultivars at the 2nd and 4th day. Higher phytochelatin accumulation was observed in root tissues of Tarsan 1018 cultivar at the 4 th day. Phytochelatin levels in all tissues of both cultivars increased depending on Cd accumulation in those tissues