An investigation of the relationship between reproductive growth and yield loss in hazelnut

This study was carried out in Samsun during a 2-year period to examine the relationship between reproductive and yield loses in the ‘Tombul’ and ‘Palaz’ hazelnut cultivars. In hazelnuts, male and female flowering occur in winter after the breaking of inflorescence dormancy. In the present study, growth of the ovary of the hazelnut started in April and continued until mid-June. At the time of flowering the ovary did not form. The ovule growth showed a rapid increase at the end of June. Change in the diameter of the ovary and ovule with time showed a simple sigmoid growth curve. Fertilization occurred during the period between mid-May and the beginning of June, namely, 3.5–5 months after pollination. At this time, the diameter of the nut was 9.54 mm. Twin kernel was not observed. The ratio of double kernels was close to zero. The time period from fertilization to harvest was 89 days in 1997 and 96 days in 1998 for Tombul cultivar. For the Palaz, this period was 84 days in 1997 and 86 days in 1998. The rate of pistillate flower clusters which dropped in April–May was more than those dropped in June–August.     

Effects of diazinon at different doses on rat liver and pancreas tissues

Diazinon is one of the most widely used organophosphates in agriculture. Toxic effects of diazinon are due to the inhibition of acetylcholinesterase, an enzyme needed for proper nervous system function. This study was designed to investigate the effects of diazinon at different doses on pancreas and liver tissues and in which dose level diazinon shows its effects. Sixty male Wistar albino rats were included in this study. Animals were initially divided into control and diazinon given groups. There were 10 animals in the control group and 50 animals in diazinon administered group. The latter was divided into five equal subgroups: 25, 50, 100, 200 and 300 mg/kg of diazinon administered groups. Control group was given only saline. All animals in 300 mg/kg diazinon group died. After 24 h, rats were sacrificed under ether anesthesia. Tissue and blood samples were taken for biochemical and histopathological analysis. Sample tissues were examined under light microscope. In biochemical analysis, AST, ALT, LDH, amylase and lipase enzyme activities were measured. One-way ANOVA test was used to compare the groups. In 200 mg/kg diazinon given group, it has been observed some histopathological changes in pancreas and liver tissues. Cholinesterase activities were significantly decreased and alkaline phosphatase levels were increased in all diazinon given groups, when compared with the controls. There was statistically significant difference between the control and diazinon given groups by means of serum amylase, lipase, ALT and AST activities (p < 0.05). LDH activities were significantly increased in 100 and 200 mg diazinon given groups, when compared with the controls (p < 0.05). Histopathological changes were observed only in 200 mg diazinon given group. This evidence suggest that diazinon effect is dose dependent and this is possibly 10-15% of the LD₅₀ dose (200 mg/kg), which cause acute pancreatitis and histopathological changes in liver.     

迪那河-阳霞河绿洲土壤盐渍化现状特征分析

迪那河-阳霞河绿洲土壤盐渍化日益严重,直接影响当地农业发展和生态环境建设。在野外考察、GPS定点和土壤采样分析的基础上,运用统计特征值和趋势分析等方法,探讨了研究区土壤含盐量、盐分化学组成、空间分布以及电导率与各离子含量间的关系、各盐离子间的相关性等现状特征。分析结果表明:(1)研究区土壤pH值的平均值为7.46,属于中性土壤。0~50 cm土层盐分含量呈T型分布,0~10 cm土层的含盐量最大,平均值为2.10%。土体中各阳离子含量为Na++K+Ca2+Mg2+,阴离子含量为SO42-Cl-HCO3-,而CO32-未检出。(2)不同土地类型的盐渍化空间变异显著,果园地的盐渍化最轻,含盐量为1.04%,盐生草地的最高,为5.28%。耕地和果园地的离子含量以Na++K+和SO42-为主,其它土地类型的以Cl-、SO42-和Na++K+为主。(3)土壤含盐量与电导率有较好的相关性。总溶解固体和各离子含量之间也存在很密切的关系。     

A new ZTL-type F-box functions as a positive regulator in disease resistance: VIGS analysis in barley against powdery mildew

In our previous studies, we found a new Zeitlupe (ZTL) type F-box protein which is expressed at a higher level upon avirulent pathogen infection (Bozkurt et al., 2007). F-box proteins mark the proteins to be degraded through 26S proteasome system by ubiquitination. Since the information on the role of ubiquitin mediated proteolysis in disease responses is advancing rapidly, we sought to understand the way which F-box functions in resistance response as part of ubiquitin–proteasome pathway. Interestingly, in response to silencing of this F-box gene via BSMV mediated virus induced gene silencing (VIGS) method, barley plants lost resistance towards avirulent pathogen race. The Pallas-01 line having Mla1 R-gene showed hyphae formations when inoculated with avirulent powdery mildew race, Bgh103, after 4-fold silencing. This observation suggests that F-box protein functions as a positive regulator in powdery mildew disease mechanism and broadens the function of ZTL-type F-box proteins, previously known to have roles only in circadian clocks, flowering time control, and phytochrome pathway.     

Determination of genotoxicity of Fenaminosulf by Allium and Comet tests

Genotoxic effects of Fenaminosulf, fungicide and micro-biocide, were examined by using mitotic index (MI), mitotic phase, and Comet assay on the root meristem cells of Allium cepa. In the Allium root growth inhibition test, EC₅₀ value was firstly determined as 25 ppm and, 12.5 (0.5 × EC₅₀), 25 (EC₅₀) and 50 (2 × EC₅₀) ppm concentrations of Fenaminosulf were introduced to onion tuber roots. Distilled water was used as a negative control. All obtained data were subjected to statistical analyses by using SPSS 15.0 for Windows software. For comparison purposes, Duncan multiple range tests by using one-way analysis of variance (ANOVA) were employed and p < 0.05 was accepted as significant value. While MI (except in 24 h at 12.5 and 50 ppm) and prophase index increased, metaphase, anaphase and telophase indexes decreased in all concentrations compared to control at each exposure time. A significant increase in DNA damage was also observed at the concentration of 25 ppm in 24 h, 25 and 50 ppm in 96 h by Comet assay.     

Effect of Weed Removal on Productivity of Chickpea (Cicer arietinum L.) and Lentil (Lens culinaris Med.) in a Mediterranean Environment

Three field experiments were conducted on chickpea ( Cicer arietinum L.) and four on lentil ( Lens culinaris Med.) at different winter-sown rainfed locations in Jordan from 1988/89 to 1990/91 to study the effect of the duration of weed-free and weed-infested conditions on yields and yield components of the crops. Chickpea seed yields were reduced on average by 81 % and straw yields by 63 % when fields remained weed infested until harvest compared with weed-free conditions throughout the growing season. The corresponding lentil seed and straw yield decreases were 63 % and 55 %. As the duration of weed-free period increased and the duration of weed-infested period decreased, yields increased. However, the critical period of weed interference was between 35 and 49 days after emergence in chickpea and between 49 and 56 days after emergence in lentil, when these crops were at an advanced stage of vegetative growth. There were significant negative correlations between the weed dry weight and the seed or straw yields. The reduction in seed yields in both crops because of weed interference occurred mainly through the reduced number of pods /plant, which in turn was partly the result of reduced number of secondary branches. In chickpea, some reduction also occurred through reduced 100-seed weight.