علی عباسی سورکی

In order to evaluate the effect of phosphate and silicate solubilizing bacteria on grain yield and biochemical compounds of Milk thistle and Fenugreek in intercropping conditions, a three replicated RCBD factorial experiment was conducted in 2019 in Kohgiluyeh and Boyar Ahmad provinces, Yasouj, Iran. Five different levels of fertilizers includes phosphate solubilizing bacteria, silicate  solubilizing bacteria, phosphate solubilizing bacteria + silicate solubilizing bacteria, and phosphate and silicate chemical fertilizers versus control (no fertilizer) as the first factor, were evaluated in different intercropping patterns (monocropping of Milk thistle, monocropping of Fenugreek, intercropping of Milk thistle and Fenugreek with arrangements (1:1) and (2:2)) as second factor. The results showed that the simultaneous application of phosphate and silicate solubilizing bacteria increased the chlorophyll a of Fenugreek (45%) and Milk thistle (21%), the total chlorophyll of Fenugreek (20%) and Milk thistle (22%), and the carotenoid of Fenugreek (60%) and intercropping pattern (2:2) caused a significant increase in chlorophyll b of Fenugreek (16%) at the probability level of one percent. The highest phenol rate of Milk thistle was obtained from the intercropping pattern (2:2) and the simultaneous application of bacteria, and the highest antioxidant property of Fenugreek was obtained from the intercropping pattern (1:1) and the simultaneous application of bacteria. The application of solubilizing bacteria increased the phenol of Milk thistle and the antioxidant property of Fenugreek extract in all cropping patterns. The highest percentage of seed oil in both plants was obtained from the intercropping pattern (2:2), and the simultaneous application of bacteria and the highest yield of Milk thistle seeds were obtained from the intercropping pattern (2:2) and chemical fertilizer. In general, it could be concluded that the application of microbial species will probably improve the yield and percentage of seed oil. In addition, better conditions for both plants in the intercropping system and more available nutrients resulting from microbial activity will increase the production of secondary metabolites and improve antioxidant property, phenol and flavonoid contents of the oil.

Predation is the common fate of most seeds produced by plants. Loss of seeds due to predation can be harmful to plants and causes such species to become rare, as rare species are vulnerable to extinction through processes that disrupt the mechanisms of plant dispersal. Therefore, the purpose of this study was to investigate the effects of pre-dispersal seed predation on rare astragalus species and their common counterparts.

In order to investigate the effects of pre-dispersal seed predation, 12 species including 6 species with herbaceous life form (including three rare species (A. Caraganae, A. Heterophyllus and A. Holopsilus) and three common species (A. Angustiflorus, A. Curvirostris and A. Effusus) and 6 species with shrub life form (including three rare species (A. Cephalanthus, A. Camphylanthus and A. Cemerinus) and three common species (A. Verus, A. Susianus and A. Rhodosemius) were compared in 2018 and 2019. From each plant type, 20 and from each plant type 10 pods (for each plant type 200 pods), randomly selected and the parameters of area size, perimeter length, length, width, length-to-width ratio, circularity, and distance between IS and CG from the seed center were measured and compared for both pods and seeds of these species. Also, pod mass and seed mass, number of pods and seeds attacked by predators, number of healthy seeds, pod shape and seed shape of species were compared.

The results of comparing the mean morphological characteristics of seeds between herbaceous and shrub astragalus species showed the highest and lowest area size, perimeter length, length, width, length-to-width ratio, circularity, and distance between IS and CG from the seed center, was related to common astragalus species. in the case of shrub species, most of the characteristics were related to common astragalus species, and the lowest characteristics were related to rare astragalus species. The results of morphological characteristics of pods between herbaceous and shrub species showed that the highest and lowest characteristics belonged to both groups of common and rare species. The results showed that the highest and lowest means of seed mass, number of damaged seeds, number of healthy seeds, and seed shape under the influence of pre-dispersal seed predation among herbaceous species showed that the highest and lowest means of seed mass, number of damaged seeds, belonged to common species. the highest and lowest numbers of healthy seeds and seed shapes belonged to rare species. Among the shrub astragalus species, the highest seed mass, the number of damaged seeds, the number of healthy seeds, and the seed shape were related to common astragalus species, and the lowest of these characteristics were related to rare astragalus species.

The overall results showed that the more species that can produce seeds of larger and smaller sizes, the better the distribution status. And the larger the seed and pod mass of the plant and the larger the shape, the more predators attack those species, but the amount of predator attacks does not lead to the rarity of the species.

The role of pre-dispersal seed predation on rare and common astragalus species was investigated.
Morphological characteristics of seeds and life forms of rare and common astragalus species were compared.

In this study, pollination of 6 herbaceous astragalus species including three rare herbaceous vegetative forms (As. Caraganae, As. Heterophyllus and As. Holopsilus) and three common herbaceous vegetative forms (As. Angustiflorus, As. Curvirostris and As. Effusus) and 6 shrub astragalus species includes three rare shrub vegetative forms (As. Cephalanthus, As. Camphylanthus and As. Cemerinus) and three common shrub vegetative forms (As. Verus, As. Susianus and As. Rhodosemius) based on comparison of phenological characteristics of the plant including maximum plant height, flowering time, total number of flowers produced, flower life and seed set produced between rare and common astragalus species were studied. For each plant studied, twenty stands were selected for sampling and the number of pollinating insect visits was recorded for 15 minutes for each. Sampling of rare and common astragalus species led to the identification of a total of 9 species of pollinating bees (Apis melifera, Megachili sp, Osmia sp, Eucera sp, Andrena sp, Anthophora sp, Xylocopa sp, Bombus zonatus and Bombus armeniacus) belonging to three family (Apidae, Megachilidae and Andrenidae). The results of herbaceous astragalus species showed the highest number of flowers and the highest number of pollinators (As. Effusus species), maximum plant height (As. Angustiflorus species), the highest seed mass (As. Angustiflorus and As. Effusus species) and the lowest plant height and the lowest number of flowers (As. Curvirostris) belonged to common astragalus species. Herbaceous astragalus species (rare and common) were not different in terms of flowering season, but flower life was longer in rare astragalus species (As. Heterophyllus).The results of shrub astragalus species showed that the highest number of flowers and the highest number of pollinators (As. Rhodosemius species), the maximum plant height (As. Susianus species) and the highest seed mass (As. Verus species) belonged to the common astragalus species. The lowest number of flowers, pollinators and plant height (As. Cemerinus) belonged to rare astragalus species. In terms of flowering season, rare (spring) and common (summer) species were different and flower life was longer in rare species (As. Camphylanthus and As. Cephalanthus).

In addition to dormancy, seeds of Allium hirtifolium have a weak emergence in the field. Among methods for improving the efficiency and emergence of seeds, nutritional priming can be considered for its performance on weak seeds. The presence of micronutrients is one of the factors that may affect the efficiency of the seeds. Therefore, the aim of this study was to investigate the effect of priming with nutrients on optimization of dormancy status, germination, and enhancement of shallot seeds for its conservational, restoration and domestication programs.

In order to study effects of nutrients on germination and emergence of Allium hirtifolium, a CRD factorial experiment was conducted with four replications at Seed Science and Technology Lab of Shahrekord University in 2015. Two dormancy breaking treatments (sulfuric acid and sulfuric acid + gibberellic acid) as the first factor and nine nutrition treatments including four levels of ZnSO4 (5, 10, 50 and 100 mM) and four levels of FeSO4 (0.5, 1, 1.5 and 2%) versus control were compared on shallot seeds.

The results showed that dormancy breaking treatments, nutrient pretreatment of seeds and their interaction had significant effects on germination percentage, germination rate, time to reach l0% and 50% germination, germination uniformity, seedling length and vigor index I at 1% probability level. Sulfuric acid and FeSO41% increased germination versus control. Application of gibberellic acid affected the behavior of iron but did not indicate significant effects for zinc. The concentration of 5 mM ZnSO4 increased the rate of germination, compared with the control but decreased with higher concentrations. The gibberellic acid did not show any sharp effects on germination rate. Time to reach 50% germination was also affected by FeSO4 0.5% and 1% and lower levels of zinc. Application of gibberellic acid did not show any significant impact on the germination time reduction, compared with control and increased T50 in higher concentrations. Although germination traits were rarely affected by gibberellic acid, seedling length and vigor index were positively influenced with GA, and the highest seedling length was achieved at 0.5 and 1% of iron and gibberellic acid.

Seed priming with nutrients can improve germination and plant vigur indices. Different concentrations of iron and zinc showed different impacts on the seeds, which showed interaction with dormancy breaking methods. Although application of gibberellic acid did not have an effective role in increasing germination rate and reducing the time to reach 10% and 50% of germination, it enhanced seedling length and vigor index I, especially for iron.

Addition of iron and zinc sulfate to shallot seeds whose dormancy was broken with sulfuric acid caused higher germination rate of  25.54%, compared with the control. Gibberellin compensated for zinc effect in germination and was able to replace it, but had a slight synergic effect with iron sulfate. Although gibberellin application did not affect germination traits, the seedling length and vigor index showed a positive response to it.

Because of small and low quality seeds, St Johns wort (Hypericum perforatum L.) have not favorable establishment in the field. In these study effects of different seed enhancement treatments were applied on the seeds and relationship of emergence with germination characteristics and amylase activity were evaluated. A factorial experiment was conducted in randomized ccompletely design with four replications. Osmopriming with Polyethylene glycol 6000 in five levels (0, -3, -6, -9 and -12 bar) were conducted as first factor and application of Gibberellic acid at four concentration (0, 500, 1000 and 1500 ppm) as second factor. Analysis of variance showed that polyethylene glycol, gibberellin and their interaction had significant effects on germination and emergence of St Johns wort seeds. Continuous application of PEG and GA had most favorable effect on germination, emergence, vigor and Amylase activity compared to the control and separate application of them. Concentration of 1000 ppm of gibberellin in -12 bar of osmotic potential caused to highest germination (91.5 %), emergence (80.5 %), seed vigor (32.08) and amylase activity (25.21 starch breakage percentage). While the control showed lowest performance in all measured traits. Correlation analysis showed a positive and significant correlation between seedling emergence of and germination percentage (r=0.89**), seed vigor (r=0.95**) and amylase activity (r=0.92**) of St Johns wort seeds. Based on the results, it is seems that application of priming techniques improve establishment of St Johns wort seeds via increasing germination, seed vigor and amylase activity.

Seeds are a good option for propagation and protection of medicinal plants. Although Seed dormancy is an adaptive strategy for wild medicinal plants, but it is considered as an undesirable trait in domestication and cultivation of them, need to be solved. Echinophora platyloba seed has dormancy despite its remarkable medicinal properties. In order to break seed dormancy, three separate experiment including stratification, hormonal treatment and combination of both were performed. For stratification 10 samples of were placed in a wet bed at 5 ° C for 2, 4, 6, 8, 10, 12, 14 and 16 Week and were compared using a completely randomized design with three replications. For hormonal treatment, the seeds were placed in GA concentrations of 0, 500 and 1000 ppm for 24 hours and then transferred to germination conditions. However, since the breaking of dormancy did not occur, this experiment was not discussed any more. For combined application of hormone and stratification, seeds were placed at mentioned concentrations of gibberellin for 24 hours at 20 ° C and then gibberellin solutions were removed and the seed transmitted to 5 ° C and compared for 2, 4, 6, 8 weeks with a CRD factorial experiment with three replications. The first factor was concentration of gibberellin in three levels and the second factor was the duration of stratification in 4 levels. Stratification had a positive effect on seed dormancy breaking and 16 week chilling lead to highest germination percentage and rate and vigor indices. The combined application of hormonal treatments accelerated dormancy release and improved seed germination characteristics, which peaked at 8 weeks. 8-week stratification treatment at 5 ° C with 1000 ppm gibberellic acid was the best treatment to overcoming of dormancy in Echinophora-platyloba seeds. It seems that seed dormancy of Echinophora seeds is physiological, which broke down by moist chilling and simultaneous application of stratification and gibberellin successfully. Although Gibberellin had no effect on dormancy break, it reduced the need for stratification. Combined application of them showed synergistic effects on dormancy release.     Highlights: Echinophora seed’s dormancy was broken under stratification conditions, but GA had no effect on it lonely. The application of gibberellin reduced the chilling demands of Echinophora seeds and the combined application of them had a synergistic effect on dormancy break

Continuous exploitation of soil results in organic matter and nutrient elements loss, and excessive chemical fertilizer application. For sugar beet, due to its higher nutritional demands, application of organic fertilizer is more important. Solitary or integrated application of green manures is a step towards reducing chemical fertilizer application. In this study, two species of green pea and Lathyrus sativus L. were planted as green manure and their dry matter accumulation and characteristics such as nitrogen and carbon content besides their effects on soil properties were evaluated compared with control. Then, effects of solitary or integrated applications of the abovementioned legumes with reduced levels of nitrogen fertilizer (80 and 160 kg ha-1 from urea source) versus 240 kg ha-1 urea as common rate and no fertilizer application as control, in total 8 treatments, were evaluated on sugar beet during 2012-14. Results showed that green manures had significant differences in terms of produced biomass, nitrogen and carbon. They changed nitrogen, carbon and carbon to nitrogen ratio of the soil in 50 days after application. Green manures showed optimum effects on weed density and biomass reduction. The highest root yield (47 t ha-1) and biomass (56.8 t ha-1) were achieved in green pea manure plus160 kg N ha-1 which was higher than chemical fertilizer (41.2 t ha-1). The highest sugar content (20.3%) was obtained under low N application in integrated green pea treatments. The highest rate of extraction coefficient of sugar was obtained in integrated green pea treatments and solitary application of green manure (about 18%), while the lowest extraction coefficient of sugar (16%) was obtained in nitrogen fertilizer treatment as well as integrated application of Lathyrus sativus + N. The highest white sugar yield (8 t ha-1) was obtained in green pea plus 160 Kg ha-1 N which showed 20% increase compared with control. In other integrated treatments, in spite of 1/3 to 2/3 reduction in N application compared with control, white sugar yield had no significant reduction. The lowest impurities rate including amino-nitrogen, K, and Na, and the lowest molasses sugar were obtained in green manure treatments or integrated application with low N levels. In conclusion, green manure application reduced chemical fertilizers usage while maintained yield, quality and product safety.

Drought stress is one of the major problems in sugar beet production in Iran, and is the most important limiting factor for germination and establishment of sugar beet in the early stages of growth. Seed priming with chemical, nutrient elements or pre-chilling techniques are the most effective methods to improve germination percentage and speed, leading to uniform and tolerant seedlings in adverse environmental conditions.
Material and

In order to assess the effect of cold stratification and HCl treatments on the germination of sugar beet seed, cv. Ekbatan, under drought stress conditions, a RCBD factorial experiment with three replications was conducted in Seed Science and Technology Lab of Shahrekord University. The first factor was stratification in two levels; the second factor was seven levels of pretreatments including 2, 4 and 6 hours’ soaking in water and 0.03 HCL accompanied with control, and the third factor was four drought levels (control, -2, -4, -6 bar).

Compared with the control, seed germination percentage and germination rate increased by at least 5-fold, relative germination by 50% and root and shoot length by 10%, due to stratification and duration of exposure to HCl treatments. With no stratification, germination traits increased with increases in exposure time in acid, and the highest values were obtained for the seeds exposed to HCl 0.03 normal for 6 hours. Although under optimal conditions, the effect of HCl was compensated for by stratification, in drought conditions, the highest values ​​were observed in stratified seeds and those placed in acid.

Since successful establishment of sugar beet seedlings at drought stress conditions is critical to achieving optimum density and yield, application of stratification treatments for one week and seed exposure to HCl increased the seed performance under stress conditions. This trend continued to increase with drought stress intensity, and placement of seeds in acid doubled seed germination in -2 bar drought conditions, which continued by 4 times in -6 bar, compared with stratified control seeds. Compared to separate application of the treatments, application of stratification and HCl treatments had synergistic effects on sugar beet seed performance, especially under drought stress conditions.


Highlights: Cold stratification and hydrochloric acid treatments increase the efficiency of sugar beet seeds under drought stress conditions.
Cold stratification and Hydrochloric acid treatment have a synergistic effect on sugar beet seeds