International Letters of Natural Sciences Vol. 67

Abstract: The occurrence of forest fires is frequent phenomenon in Greece, especially during the warmest period of the year, the summer. Timely and reliable estimation of the meteorological risk for their onset is of crucial importance for their prevention. Thus, the purpose of our current work was firstly the estimation of the values of a suitable relevant index for Greece, meteorological forest fire risk index (MK_s,t), derived from actual air temperature (T) and relative humidity data (RH) as well as from regressed T and RH, in a mountainous region (MR) for the most dangerous period of the year (July-August) and day (11:00 h-16:00 h), for five successive years (2006-2010) and secondly the comparison of the two ways of MK_s,t values estimation (from actual and regressed T and RH), based on MK_s,t classes. Regressed T and RH data were estimated with the aid of simple linear regression models from remote T and RH data, respectively, of an urban region, 175 Km away from MR, taking into account firstly the warmest (2007) and the coldest (2006) year of the examined year period. It was confirmed that MK_s,t values (based on regressed T and RH data) coincided in their classification to the respective ones resulted from actual T and RH data, that is, there was absolute success (100%). Using common regression lines and applying them to estimate separately T and RH at MR, for the most dangerous period of year and day concerning the whole examined year period, it was found that almost all the estimated MK_s,t values coincided, regarding their classification, with those estimated from actual T and RH data (97% success), which was considered very satisfactory. Therefore, our research methodology contributes a new perspective to a reliable estimation of MK_s,t from remote T and RH data using simple statistical models.

Abstract: Lactic acid has known as a one of compounds to cause cellular harm in waterlogged tissue through the process of cytoplasmic acidosis. The effects of lactic acid on α-amylase activity and phytic acid content using an assay for high phosphate in germination stage of rice were evaluated. It is showed that lactic acid inhibited rice germination at every treated dose. The reduction of α-amylase content attributed to lactic acid at 24 h after germination of rice seeds was observed. The analysis of phosphate concentration at 48 h after treatment noted that although the content of phytic acid was reduced in Japonica varieties, but in contrast its amount was enhanced in Indica cultivars. The findings highlighted the positive effects of lactic acid on α-amylase activity and phytic acid content and suggested that this compound may play a potent role as a germinated regulator in rice.

Abstract: The effect of irradiated chitosan coating on post-harvest preservation of tomato was observed in this study. Irradiated chitosan (40 kGy) solution of various concentrations (500, 750, 1000, 1500 and 2000 ppm) were applied on post-harvest preservation of tomato. Both chitosan treated and untreated (control) tomato were stored at room temperature in open and zip bag conditions. The effect of coating of various chitosan solutions on tomato were observed during storage period. The percentage of weight loss and spoilage rate of the preserved and control tomato samples were investigated. Several parameters (such as total bacteria count, total mold count, moisture, ash, acidity, vitamin C, sugar, protein and fat) were analyzed for irradiated chitosan coated tomato in open condition after 3-weeks storage period. In addition, the same parameters were also analyzed for control tomato. Considering all parameters, the results revealed that 1500 ppm chitosan solution performed better in extending the shelf- life of tomato as compared to the control and other treated samples. Thus, this observation recommend that irradiated chitosan coating have the potential to be used as natural preservative to maintain quality and extending shelf-life of tomato.

Abstract: Analysis of genetic diversity of 90 Vietnamese local-colored rice accessions was evaluated by using 40 SSR markers. The numbers of polymorphic alleles ranged from 3 to 12 alleles per locus and average of 7.1 alleles per locus. The similarity coefficients of the rice landraces fluctuated from 0.76 to 0.93; at a genetic correlation level of 0.78. Ninety accessions of rice landraces were divided into five groups based on analysis of genetic relationships. The results have indicated that 11 markers included: M250, RM302, RM10926, RM208, RM227, RM17231, RM23251, RM5647, RM1376, RM339 and RM228 which gave the unique allele. These markers can be used effectively for genetic diversity of colored rice and provided a specific database and useful materials for landraces identification, local germplasm conservation for further colored rice improvement on rice quality via rice breeding programs in Vietnam.

Abstract: The experiments were conducted at the Teaching and Research Farm, Ladoke Akintola University of Technology, Ogbomoso, Nigeria in 2010 and 2011 to determine the effect of propagule size and nitrogen levels on the growth and rhizome yield of ginger. The nitrogen source was from Tithonia compost (TC). Three propagule sizes were tested (20, 30 and 40 g) and seven nitrogen levels (0, 40, 60, 80, 100, 120 and 140g kg N/ha). The experimental pots were laid out in a randomized complete block design with three replicates. Data were collected on growth parameters (plant height, number of leaves, leaf length and leaf width); rhizome yield components (number of tillers and rhizomes, and rhizome weight and length); and proximate composition (crude protein (CP), crude fibre (CF), total lipid (TL); Total Ash (TA), Starch and water soluble extract). Data collected were subjected to analysis of variance and significant means were compared using Duncan Multiple Range Test (DMRT) (P ≤ 0.05). Propagule size, N levels and their interactions significantly (P≤ 0.05) influenced most of the parameters assessed. In most cases, the use of 30 and 40 g planting material gave similar results. Plants nourished with 140 kg N/ha significantly and consistently outperformed others fertilized with other nitrogen levels. Crude protein obtained from 40 g propagule size was significantly ( P ≤ 0.05) higher than other tested propagule sizes. The rhizome yields of fertilized plants were significantly higher than the non fertilized plants. Rhizome yields ranged from 1.57 t/ha in none fertilized plants to 3.71 t/ha in 140 kg N/ha. In conclusion, establishment of ginger with 40 g planting materials and its nourishment with 140 kg N/ha enhanced its growth, rhizome yield and proximate compositions of the plant.