فهرست مطالب مهندس سیما جورابی

In order to the investigation of  Zn nano-chelate foliar application effects on photosynthetic parameters, glutamine synthetase, protein, grain yield and yield components of soybean under water deficit, a split-plot experiment was conducted as a randomized complete block design with three replications at Research Farm, Faculty of Agriculture, University of Lorestan, in 2016. The treatments consisted of irrigation regime (100, 80, 60 and 40% of plant water requirement) in the main plots and zinc nano-chelate foliar application (Control or distilled water and zinc as zinc nano-chelate containing 20% zinc absorbable ion) in the subplots. The results showed that by decreasing of water requirement some traits such as photosynthesis, transpiration, stomatal conductance, glutamine synthetase, the number of pods per plant, the number of grain per pod, 100-grain weight, grain yield, protein percentage of grain and protein yield were reduced. In contrast, internal CO2 concentration (Ci) and SPAD value increased in stress condition. In normal condition, zinc nano-chelate treatment was not any effect on SPAD value, the number of seed per pod, 100-seed weight, seed and protein yield. In water deficit conditions, zinc nano-chelate foliar application increased the mentioned traits by 4.2, 13.8, 17.3, 45.7 and 39.3 percent, respectively. In addition, in water deficient, zinc nano-chelate decreased Ci and stomatal conductance of leaves. In general, zinc nano-chelate application mitigated effects of water deficit and it was positive for improving soybean yield. Therefore, its application may improve tolerance of soybean.

Platelet activating factor (PAF) is a novel signaling phospholipids that in addition to platelet activation has many biological properties. The acrosome reaction, as an essential step in mammalian fertilization, can occur in response to several agents such as PAF. Therefore, the present study aimed to assess the effect of PAF on the motility and acrosome reaction of ram spermatozoa. Semen was collected from 18 fertile rams and incubated with four levels of PAF (10-7, 10-8, 10-9 and 10-10 mol) at 37°C for 15, 30, 60 or 120 min. Sperm motility and acrosome reaction were analyzed at varying levels of PAF with different incubation periods. With increasing PAF concentration, acrosome reaction was enhanced, while sperm motility was reduced (P<0.001). As the period of incubation increased, there was a gradual decrease in sperm motility and increase in acrosome reaction percentages. There were high correlation between PAF concentrations and incubation times on induction of acrosome reaction (R2 = 0.86) and reduction in sperm motility (R2 = 0.82). In addition, it was found that a PAF level of 10-9 and incubation time for 30 min is the best optimum for inducing acrosome reaction in ram spermatozoa without drastically decreases in sperm motility. The present study optimized for the first time the concentration and incubation time of PAF for induction of acrosome reaction in fresh ram spermatozoa.

To study the hardseed breakdown trend in annual medic (Medicago scutellata var Robinson) in spring cultivation in Khoramabad، two medic seed lots both produced in dry farming and irrigated systems were kept under three different environmental conditions viz: 1. pods kept at soil surface among plant residues with no cultivation practices 2. pods kept at 2 cm soil depth (loam texture) and 3. pods kept at 10 cm soil depth (loam texture). Germination percent of different storage conditions were tested on monthly intervals on the first day of August، September، October and November and the data were statistically analyzed using a factorial split plots in time design with four replications. The results indicated that there is a significant difference (P<0. 05) in percentage of hard seed and the speed of hardseed breakdown trend between seeds produced in irrigated and dry farming systems. With time from physiological maturity، the percentage of hardseed significantly (P<0. 05) decreased in both seeds produced in irrigated and dry farming systems. As the depth of seed storage increased، the hard seed breakdown followed a slower trend in time for both production systems.