EFFECTS OF SOAKING TEMPERATURE,STRATIFICATION, POTASSIUM NITRATE AND GIBBERELLIC ACID ON SEED GERMINATION OF LOQUAT TREES

The present study was carried out to increase loquat seed germination with treatments consisting of two soaking temperatures (24 ± 2°C and 38 ± 2°C), chemical agents [control, 0.5% potassium nitrate (KNO₃) and 250 mgL^?1 gibberellic acid (GA₃) each for 20 h], and different moist chilling (MC) periods (1, 2, 3 and 4 weeks under 4–5°C). Compared with 24 ± 2°C, soaking at 38 ± 2°C reduced germination%, mean daily germination (MDG), and mean germination time (MGT), plumule and radicle lengths. Germination percentage, days to 50% emergence, fresh weight and lateral root numbers significantly reduced as MC period increased. KNO₃ and GA₃ had no significant effect on germination percentage, MDG, MGT and lateral root numbers. KNO₃ reduced days to 50% emergence and radicle length, but increased fresh weight compared with control and GA₃. Finally, our results suggest the soaking at 24 ± 2°C followed by 0.5% KNO₃ each for 20 h plus 1 week of MC or soaking at 24 ± 2°C followed by 250 mgL^?1 GA₃ each for 20 h plus 2 week of MC.     

Interactive Effect of Fluorescent Pseudomonads Rhizobacteria and Zn on the Growth,Chemical Composition,and Water Relations of Pistachio (Pistacia vera L.) Seedlings under NaCl Stress

The role of fluorescent pseudomonads isolates (pf₀, pf₁, pf₂, and pf₃) and zinc (Zn) (0 and 5 mg kg^?1 soil) interactions in alleviating salinity in pistachio seedlings were investigated. The experiment was conducted following completely randomized design with three replicates. The results revealed that salinity decreased the growth parameters, while application of PGPR (plant growth-promoting rhizobacteria) and Zn increased these parameters. Application of PGPR significantly enhanced phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), Zn, Ca/sodium (Na), and K/Na contents, while decreased the accumulation of Na and chloride (Cl). Application of PGPR and Zn increased the phenolic compounds, sucrose, membrane stability index (MSI), and relative water content (RWC) but reduced the malondialdehyde (MDA) amount. A positive correlation was observed between Zn concentrations with seedling dry weights, phenolic compounds, MSI, and RWC contents. These results indicated that the combined application of PGPR and Zn could be a simple treatment for growth and establishment of pistachio seedlings under Zn deficiency and soil salinity.     

Measuring and simulating pH buffer capacity of calcareous soils using empirical and mechanistic models

ABSTRACT

We studied (i) the pH buffer capacity (pHBC) of calcareous soils varied widely in calcite and texture, (ii) the contribution of soil properties to pHBC and (iii) the significance of using a model based on calcite dissolution to estimate the pHBC of calcareous soils. The pHBC of soils was measured by adding several rates of HCl to soils (100–6500 mM H⁺ kg^–1), in a 0.01 M CaCl₂ background and an equilibration time of 24 h. The pHBC (mM H⁺ kg^–1 pH^?1) varied from 55 to 3383, with the mean of 1073. The pHBC of the soils was strongly correlated with soil CaCO₃ equivalent (calcite) (r = 0.94), sand (r = ?0.72), silt (r = 0.60), EC (r = 0.63), pH (r = 0.55), and weakly (r = 0.37) but significantly with clay content. The attained pHBC values indicated that calcite was probably the main buffer system in these soils. The chemical equilibrium model successfully predicted pH titration curves based on calcite dissolution, indicating buffering of acid inputs in the calcareous soils is dominated by calcite dissolution. The model can be used to simulate acidification of calcareous soils and to provide information for making environmental management decisions.     

Influence of idebenone on ram semen quality stored at 4°C

The current study was designed to investigate the effect of idebenone (Id), an antioxidant on ram semen quality. Semen samples were collected, pooled and diluted in a Tris‐based extender supplemented with 0, 1, 2, 4 and 8 µM idebenone. Computer‐assisted sperm analysis was used to evaluate spermatozoa kinematics. Sperm viability and membrane functionality were assessed respectively, by eosin‐nigrosin staining and HOS test. Biochemical assays were carried out to measure different metabolites in spermatozoa and medium at 0, 24, 48 and 72 hr. Total and forward progressive motility were greater in 1, 2 and 4 µM idebenone treated groups compared to control at 24, 48 and 72 hr time points (p < 0.05). Semen supplementation with Id significantly increased viability and functionality of spermatozoa membrane during storage (p < 0.05). Lower amounts of lipid hydroperoxides in medium and spermatozoa were observed in Id‐treated groups compared to control one at 24 and 48 hr of storage (p < 0.05). Medium and spermatozoa amounts of malondialdehyde and nitric oxide were less in Id 4 µM group compared to the control at 72 hr (p < 0.05). Total antioxidant capacity values and superoxide dismutase activity of spermatozoa and medium were greater in 2 and 4 µM idebenone treated groups in comparison with the control at 72 hr (p < 0.05). Results of the current study indicated that ram semen supplementation with Id at 4 µM level improved quality by ameliorating nitrosative and peroxidative stress, hence could be considered as an antioxidant additive during storage at 4°C.     

Ultrasound-Assisted Extraction of Phenolic Compounds from Unripe Grape (Qora)

Optimization of the extraction and analysis of phytochemicals can improve the production and quality of foods. The aim of this study is to evaluate ultrasound-assisted extraction of phenolic compounds from unripe grape (Vitis vinifera). At first stage, conventional thermal extraction was carried out in order to optimize the temperature (50, 70, 90 °C) and duration (20, 40, and 60?min) of the process (control). Investigations showed that the optimum condition of temperature and duration is 70 °C and 30?min, respectively. Then, grape pulp was treated for 30?min by ultrasound at a fixed frequency of 20?kHz. Results showed that ultrasound application increased the total phenolic content of the samples considerably. In addition, individual phenolic composition of the samples, namely rutin, gallic acid, hydroxybenzoic acid, syringic acid, p-coumaric acid, quercetin, and resveratrol were measured by HPLC. A good relation was observed between chromatographic and total phenol results. This study showed that ultrasound-assisted extraction is a sufficient method to produce verjuice as a rich and inexpensive source of antioxidants.