Effect of Nitrogen and Intercropping Ratios on Grain Yield and Some Morphological Traits of Corn and Sunflower in North Khouzestan

Abstract\ud In order to study the effect various nitrogen and intercropping ratios on grain yield and some morphological traits of corn (Zea mays L.) and sunflower (Helianthus annus L.), a field experiment was conducted at the research farm of Agricultural Faculty of Islamic Azad University of Shoushtar (Khouzestan), in 2006. The split-plot set of treatments was arranged within a randomized complete block with three replicates. Treatments were various nitrogen rates (50, 100 and 150 kg N ha-1) as main-plots and different ratios of intercropping corn and sunflower (pure stand of corn, intercrop 75% corn plus 25% sunflower, 50% corn plus 50% sunflower, 25% corn plus 75% sunflower and pure stand of sunflower) in sub-plots. The results showed that the lowest and the highest grain yield were specified for corn (980 and 1225 g m-2), and for sunflower (346 and 387 g m-2) at 50 and 150 kg N ha-1, respectively. While in intercropping the highest and the lowest grain yield of corn were obtained in pure stand (1265 g m-2), and in 25% corn plus 75% sunflower ratio (957 g m-2). This was also valid for sunflower and resulted in decrease of grain yield of sunflower in 75% corn:25% sunflower intercrop. The oil percent of sunflower increased with decreasing sunflower proportion in intercropping. In addition increasing nitrogen levels resulted to increased land equivalent ratio (LER). So the highest (1.7) and the lowest (1.4) LER based on grain yield was achieved in 25% corn:75% sunflower and 50% corn:50% sunflower intercrops, respectively where 150 kg N ha-1 was applied

Effects of different light regimes on prolactin concentration in rat

Prolactin is a peptide hormone which is secreted from hypophysis. Prolactinconcentration differs in male and female. Even though prolactin has  lactotpope effect, it has disturbances effects on pulsatory secretion of gonadotropins as well as on ovulation. In spite of different plasma level of prolactin in different seasons, the effects of light regime on prolactin secretion still is unclear. Eighty Wistar rats were selected and dividedinto four groups. Each treatment was exposed in different photoperiod; natural light (control NL), 24 hours light (permanent light LL), 24 hours darkness (permanent darkness DD), and 12 hours light-12 hours darkness (light-dark LD). Blood samples from the heart were taken every 3 month during year. Prolactin concentration was determined using RIA. Data were analyzed using ANOVA and means were compared using Duncan multiple range test. Prolactin concentration in control (NL), dark (DD), light-dark (LD) and permanent light (LL) were 1.10, 1.00, 0.80 and 0.60 ng/ml, respectively. Light regime had a significant effect on prolactin concentration (p<0.05). Prolactin was significantly lower in permanent light than other treatments. Means of prolactin in permanent dark and light-dark weren’t differ with control (p>0.05). Permanent light will reduce the prolactin level. It seems to be one of the causes of short estrous cycles in permanent light is prolactin levels. These finding can be used as a model in humansocieties.Keywords: Photoperiods, Prolactin concentration, Lactogen, Mammotropin, Lactotropic hormone, Hypothalamus, Hypophysis, Metabolic performance, Rat

Polycomb contraction differentially regulates terminal human hematopoietic differentiation programs

Background Lifelong production of the many types of mature blood cells from less differentiated progenitors is a hierarchically ordered process that spans multiple cell divisions. The nature and timing of the molecular events required to integrate the environmental signals, transcription factor activity, epigenetic modifications, and changes in gene expression involved are thus complex and still poorly understood. To address this gap, we generated comprehensive reference epigenomes of 8 phenotypically defined subsets of normal human cord blood. Results We describe a striking contraction of H3K27me3 density in differentiated myelo-erythroid cells that resembles a punctate pattern previously ascribed to pluripotent embryonic stem cells. Phenotypically distinct progenitor cell types display a nearly identical repressive H3K27me3 signature characterized by large organized chromatin K27-modification domains that are retained by mature lymphoid cells but lost in terminally differentiated monocytes and erythroblasts. We demonstrate that inhibition of polycomb group members predicted to control large organized chromatin K27-modification domains influences lymphoid and myeloid fate decisions of primary neonatal hematopoietic progenitors in vitro. We further show that a majority of active enhancers appear in early progenitors, a subset of which are DNA hypermethylated and become hypomethylated and induced during terminal differentiation. Conclusion Primitive human hematopoietic cells display a unique repressive H3K27me3 signature that is retained by mature lymphoid cells but is lost in monocytes and erythroblasts. Intervention data implicate that control of this chromatin state change is a requisite part of the process whereby normal human hematopoietic progenitor cells make lymphoid and myeloid fate decisions.Medicine, Faculty ofScience, Faculty ofOther UBCMedical Genetics, Department ofMicrobiology and Immunology, Department ofReviewedFacultyResearche