ECOPERSIA
Volume:1 Issue: 4, Autumn 2013

The aims of this study were to assess the effects of drought stress on peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) activities as well as free proline content and growth parameters of Pistacia khinjuk seedlings under drought stress. Therefore, the one-year seedlings of Pistacia khinjuk subjected to water stress (25%, 50%, 75%, and 100% field capacity) for 8 months in greenhouse condition. Results showed that drought stress decreased height, collar diameter, shoot dry weight and root dry weight of P. khinjuk seedlings. But it had different effects onantioxidant enzyme activities in root and shoot of P. khinjuk seedlings. Drought stress increased CAT activity in shoot and root of seedlings and its activity was higher in 25% field capacity (FC) than other treatments. Also, the POD enzyme activity increased in root and shoot of seedlings subjected to drought stress. The SOD activity was at the lowest level in 100% FC than other treatments. The results also showed that free proline accumulation was lower in well watered seedlings and increased under drought stress.

Vetiver grass is known to survive under diverse soil and water conditions. In order to test its potential of salinity and aridity tolerance ability, the effect of salinity and aridity stress on the growth of the Vetiveria zizanioides was studied by growing plants in arid soils that receiving salinity stress. The experiment was conducted in a greenhouse, arrangement in a completely randomized design using 5 replications. Salinity levels of 4 (as control), 20, 30 and 40 dS m-1; Aridity levels of field capacity irrigation (as control), -6 and -10 bars were applied. There was no significant effect on growth, yield, water content and chlorophyll concentration with 20 dS m-1 salinity level. There was significant effect on Mentioned parameters with 30 and 40 dS m-1 salinity levels. The root and length weight in -6 bar were significantly greater than those in control. The water content and chlorophyll concentration were highest in 40 dS m-1 and -10 bars salinity-aridity. Water content and chlorophyll concentration were lowest in 4 dS m-1 and FC salinity-aridity treatments. Our results suggest that in EC between 20 to 30 dS m-1 with -6 to -10 bars water content Vetiveria zizanioides could be used for soil rehabilitation.

This paper presents the analysis of the onset and withdrawal dates and the duration of summer monsoon over Nepal for last 63 years (1951-2013). The trend analysis revealed that both the onset and withdrawal of summer monsoon are delayed in recent years. The statistical analysis using cumulative deviation and Worsley likelihood tests showed a step jump in mean withdrawal date after the year 1997. The mean withdrawal date after 1997 is later than the normal withdrawal date by 10 days. Although, the trend for onset is statistically insignificant, the trend for withdrawal is significant at 5% level. Stationarity tests for the period of 1951-1996 and 1997-2013 also revealed that both the onset and withdrawal series are non-stationary. A step change in withdrawal date with delayed trend on both onset and withdrawal coupled with longer duration suggests a temporal shift in the monsoon pattern over Nepal after 1997. The temporal shift in the monsoon is consistent with published findings on the effect of global climate change on the dynamics of the South Asian summer monsoon precipitation. The shifting pattern of the summer monsoon exerts a strong stress on agriculture, water resources, ecosystems, human health and the overall economy of the country.

There are a number of ideas to generate cloud and precipitation in the southern coasts of Caspian Sea, but none of them explain the cause of precipitation particularly heavy and super heavy precipitations precisely. This study describes main thermodynamic factors when the situation and location of synoptic patterns are effective. On the basis of daily data, monthly regimes and monthly trends of the Sea Surface Temperature (SST), difference between 2m air temperature and SST over the Caspian Sea as well as the SST gradients in different distances on latitude and its anomaly were calculated. For recognition of synoptic conditions, humidity advection, geopotential and sea level pressure maps were drawn. The results showed that there are three thermodynamic factors over the Caspian Sea to produce precipitation particularly from September to December. The first factor is arrangement and well organized of the SST gradients as it decreases from the south to the north of Caspian Sea. Also, the SST over the Sea must be enough warm to produce clouds and precipitation. The last factor is the difference between 2m air temperature and SST. When the synoptic patterns in different pressure levels are suitable for instability, the air-sea interaction process is the most important factor to produce the advection humidity, clouds and precipitation particularly heavier precipitation events in the north of Iran.

Mercury levels in hepatopancreas, muscle and exoskeleton tissues of male and female green tiger prawn, P.semisulcatus, from the Persian Gulf were compared. Significantly higher levels (p<0.05) of mercury in female prawn and hepatopancreas tissue were encountered (p<0.05). Significantly higher concentration (p<0.05) of the mercury was also observed in summer than in winter season. This variation could result in internal biological cycle of the organism or variation in bioavailability of mercury in environment.

An 84-day feeding trial was carried out onfingerling (4.44 ± 0.06 g) rainbow trout (Oncorhynchusmykiss, Walbaum, 1792) to evaluate the effect of dietary supplementation with a commercial prebiotic GroBiotic®-A (G-A) on the growth, feed efficiency, haematology and immunlogical parameters. Ttreatments containing various inclusions of G-A (0 %, 0.5 %, 1.0 %, 1.5 %, 2.0 %, 2.5 %, and 3.0 %) were added to a commercial fish dietand were fed twice daily at 2-6 % of body weight. The highest weight gain (WG), specific growth rate (SGR) and average daily gain (ADG) were obtained in fish fed the diet containing 2.5 % G-A followed by 3.0 % inclusion (P<0.05). The highest feed efficiency (FE), protein efficiency ratio (PER) and net protein utilization (NPU) were also recorded in the 2.5 % G-A inclusion (P<0.05). Survival was significantly higher (P<0.05) in fish fed with 2 % and 2.5 % G-Asupplement (P<0.05). Although higher Hb, haematocrit, RBC, WBC, MCH, MCHC, MCV, lymphocytes, and neutrophils were observed at all G-A supplemented diets, the differences among themwerenot significant (P>0.05). On the other hand,significantly higher differencee (P<0.05) in lysozyme and immunoglobulin (IgM) concentrations wereobserved in 2.5% G-A inclusion. The results of this study indicated that 2.5 % G-A inclusionhad a better performance on growth and haematoimmunological parameters in rainbow trout fingerling.

Based on the morphology and corallites structures, seventeen species of scleractinian corals in seven families were described from the Chabahar Bay, fourteen species of which are being reported for the first time from this bay. The identified species include Acropora valida Dana, 1846, Acropora clathrata Brook, 1891 and Acropora nausta Dana, 1846 belonging to Acroporidae, Favia matthai Vaughan, 1918, Favites complanata Ehrenberg, 1824, Favites flexusa Dana, 1846, Leptastrea purpurea Dana, 1846, Faviafavus Forskal, 1775 and Cyphastrea microphtalma Lamarck, 1816 belonging to Favidae, Acanthastrea hillae Wells, 1955 and Scolymia australis Milne Edwards and Haime, 1849 belonging to Musidae, Pocillopora damicornis Linnaeus, 1758 belonging to Pocilloporidae, Porites solida Forskal, 1775 and Porites compressa Dana, 1846 belonging to Poritidae, Coscinaraea wellis Veron & Pichon, 1980 and Pseudosiderastrea tayami Yab and Sugiyama, 1935 belonging to Siderastreidae and Turbinaria peltata Esper, 1794 belonging to Dendrophylliidae, were identified.