Precipitation as the most affecting factor on soil–plant environment conditions affects the mycorrhizal spore numbers in three different ecological zones in Turkey

Mycorrhizal symbiosis is the one of the most important relationship between microbiota and plants to sustain plant nutrition in relatively unfavourable conditions. Somehow this relation is threatened by time, therefore, definition of the factors effecting mycorrhizal symbiosis has become essential. The aim of this study was to determine the differences in specific mycorrhizal parameters such as sporulation and soil–plant environment conditions in three different regions of Turkey. During 1996?2002, 53 soil series were selected from natural and agricultural plant communities in three different agro-ecological zones of Turkey: Central Anatolia (CA), the Southeastern Anatolian (SA) project area and the Coast of Mediterranean (CM). The arbuscular mycorrhizal fungus (AMF), spore numbers and mycorrhizal root colonization were related to the annual average precipitation, soil characteristics and host plant identity.

In the CM zone (average annual precipitation of 650?mm), soils found under natural vegetation contained a maximum value of 108?spores?g^?1, with bare soils containing a minimum number of 0.1?spores?g^?1. In the CA zone (330?mm annual average precipitation), the maximum number of spores in the soil samples was 46.5?spores?g^?1 with a minimum of 6.8?spores?g^?1 and in the SA soil samples (380?mm annual average precipitation), a maximum of 48.4?spores?g^?1 and a minimum of 14.2?spores?g^?1 were recorded. The overall mean number of mycorrhizal spores g^?1 soil was 15.5?±?14.4, 22.2?±?8.6 and 27.9?±?25.4 for the CA, SA and CM zones, respectively. Mean spore numbers differed in only two of the three zones, with the third zone being intermediate. Precipitation was the most affecting factor on the sporulation of AMF. Also host plant species and certain soil parameters, such as positive correlations with CaCO₃ and N-min and a negative correlation with organic matter, have an influence on sporulation.

The key finding is that the cropping system has a large impact on spore numbers/abundance. Seventeen standing crops as well as bare soil, fallow and natural areas were compared. There are a large number of factors which can affect mycorrhizal development; in the present work, it seems that soil and crop management, and environmental factors (such as precipitation) affect sporulation and root colonization. Covering land surface with mycorrhiza-dependent cover crop, irrigation and less soil till may increase indigenous mycorrhizal spores.     

Ethylene-inhibiting compound 1-MCP delays leaf senescence in cotton plants under abiotic stress conditions

Cotton(Gossypium hirsutum L.) plants produce more ethylene when subjected to abiotic stresses, such as high temperatures and drought, which result in premature leaf senescence, reduced photosynthetic efficiency, and thus decreased yield. This study was conducted to test the hypothesis that the ethylene-inhibiting compound 1-methylcyclopropene(1-MCP) treatment of cotton plants can delay leaf senescence under high temperature, drought, and the aging process in controlled environmental conditions. Potted cotton plants were exposed to 1-MCP treatment at the early square stage of development. The protective effect of 1-MCP against membrane damage was found on older compared to younger leaves, indicating 1-MCP could lower the stress level caused by aging. Application of 1-MCP resulted in reduction of lipid peroxidation, membrane leakage, soluble sugar content, and increased chlorophyll content, in contrast to the untreated plants under heat stress, suggesting that 1-MCP treatment of cotton plants may also have the potential to reduce the effect of heat stress in terms of delayed senescence. Application of 1-MCP caused reductions of lipid peroxidation, membrane leakage, and soluble sugar content, together with increases in water use efficiency(WUE), water potential, chlorophyll content, and fluorescence quantum efficiency, compared to the untreated plants under drought, suggesting that 1-MCP treatment of cotton plants may also have the ability to reduce the level of stress under drought conditions. In conclusion, 1-MCP treatment of cotton should have the potential to delay senescence under heat and drought stress, and the aging process. Additionally, 1-MCP is more effective under stress than under non-stress conditions.     

Chemical Composition,Antifeedant, Repellent,and Toxicity Activities of the Rhizomes of Galangal,Alpinia galanga Against Asian Subterranean Termites,Coptotermes gestroi and Coptotermes curvignathus (Isoptera: Rhinotermitidae)

Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD₅₀) of C. curvignathus was 945 mg/kg, whereas LD₅₀ value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices.     

水稻株行距配比的优化和株高密度模型的建立

为了探讨水稻高产栽培合理的株行距配比和栽插密度,在分析水稻株高与栽插密度关系的基础上,提出了确定水稻合理株行距配比的黄金分割优选法,即依赖于水稻株高（x,cm）的株行距配比为：行距（cm）=0.309 x,株距（cm）=0.191 x,建立了水稻株高密度（y,穴/m^2）的幂函数模型：y=169437x^-2（R^2=1）。应用该方法确定的目前生产上具代表性水稻品种的株行距和栽插密度,符合当前水稻高产栽培要求。     

Characteristics, composition and thermal stability of Acacia senegal (L.) Willd. seed oil

The chemical composition, main physicochemical properties and thermal stability of oil extracted from Acacia senegal seeds were evaluated. The oil, moisture and the ash contents of the seeds were 9.80%, 6.92% and 3.82%, respectively. Physicochemical properties of the oil were iodine value, 106.56 g/100 g of oil; saponification value, 190.23 mg KOH/g of oil; refractive index (25 °C), 1.471; unsaponifiable matter, 0.93%; acidity, 6.41% and peroxide value, 5.43 meq. O₂/kg of oil. The main fatty acids in the oil were oleic acid (43.62%) followed by linoleic acid (30.66%) and palmitic acid (11.04%). The triacylglycerols (TAGs) with equivalent carbon number ECN 44 (34.90%) were dominant, followed by TAGs ECN 46 (28.19%), TAGs ECN 42 (16.48%) and TAGs ECN 48 (11.23%). The thermal stability analysed in a normal oxidizing atmosphere showed that the oil decomposition began at 268.6 °C and ended at 618.5 °C, with two stages of decomposition at 401.5 °C and 576.3 °C. According to these results, A. senegal seed oil has physicochemical properties, fatty acids composition and thermal characteristics that may become interesting for specific applications in several segments of food and non-food industries.     

Crop losses due to olive moth mediated by ethylene

BACKGROUND:Studies for nine years in southern Spain on the olive moth, Prays oleae Bern., have tested the possibility of altering oviposition behaviour on newly formed olive fruits by means of a single ethylene application. RESULTS: A single spraying of ethylene on the olive trees at the beginning of fruiting significantly decreased the olive moth egg populations and consequent the olive fruit fall. At the same time, no negative effect was found in the activity of natural oophagous predators of the olive moth. CONCLUSIONS: The ethylene treatments against P. oleae yielded substantial economical benefits each year (a mean of euro526 ha(-1)), benefits that fluctuated depending on the olive crop and on the annual fruit fall caused by this major pest.     

Effect of effective microorganism and gypsum amendments on nutrient leaching,pH, electrical conductivity,and Okra growth parameters under coastal saline soil

Nutrients losses through leaching are the main problem facing coastal saline soil. Effective microorganisms (EM) and Gypsum (G) at the application rate of 5%G and 10%G by weight were used as soil amendments. The pot experiment aimed to improve the leaching of nitrate (NO₃), ammonium (NH₄) and total nitrogen (TN) on the coastal saline soil. The EM+ 5%G treatment effectively reduced the content of NO₃ and NH₄ in the leachate by 86.59% and 68.18%, respectively. EM treatment reduced the leaching of NO₃ and NH₄ by 70.86% and 62.12% and EM+ 10%G reduced NO₃ and NH₄ by 11.80% and 50.76%, respectively. Moreover, the content of TN in leachate was reduced up to 13.23%, 5.80%, and 2.67% in response to EM, EM+ 5%G, and EM+ 10%G, respectively, compared to the control. These results indicate that EM combined with G as soil amendments can reduce leaching of nutrients and further support the regulation of a coastal saline soil pH and EC.     

Carob pods (Ceratonia siliqua L.) improve growth performance,antioxidant status and caecal characteristics in growing rabbits

The objective of this study was to evaluate carob pods and their effect on growth performance, antioxidant activities, carcass and caecal characteristics and equilibrium modification of the caecal microbiota population of growing NZW rabbits. Eighty weaned rabbits (initial body weight: 625.00 ± 26.46 g) were randomly allocated into four dietary groups of 20 rabbits each until 90 days of age. Dietary groups were as follows: C (basal diet with no supplementation), CP1 (basal diet + 2.5% carob pods), CP2 (basal diet + 5% carob pods) and CP3 (basal diet + 10% carob pods). Rabbits given the CP2 diet had significantly higher daily and final body weights compared with the other experimental groups. The increase in inclusion rate of carob pods significantly decreased feed intake, whereas carob pods at 5% in the CP2 group recorded the best value of feed conversion ratio. Rabbits in the CP3 group showed the worst slaughter weight and carcass dressing percentage weight. No significant effect was found on meat protein and ash contents. Cholesterol, low‐density lipoprotein, high‐density lipoprotein and triglycerides decreased significantly (p < 0.05) in rabbits treated with carob pods compared with the control. Because of high content of the antioxidant compounds in CP2 and CP3 groups, the activities of glutathione peroxidase, glutathione S‐transferase, catalase and superoxide dismutase increased, whereas the concentration of thiobarbituric acid‐reactive substance decreased significantly. Rabbits given the CP2 diet had a significantly higher volatile fatty acid concentration and a lower pH in content of the caecum compared to the other groups. The data of microbial analysis for C group showed a significant increase in Escherichia coli and Clostridium counts. Lactobacillus and Bacillus counts increased significantly more in the CP2 and CP3 groups than in the other groups. In conclusion, 5% of carob pods in the diet stimulated the performance of growing rabbits, and thus, it has potential as an unconventional feed resource for rabbits without any adverse effects.