Iranian Journal of Seed Research

Application of zinc can improve the tolerance and resistance of plants especially sunflower to environmental stresses and be effective on kernel set and yield. To investigate the effects of zinc oxide nanoparticles on the length, effective period, the rate of kernel filling and kernel weight in sunflower cultivars, a factorial experiment based on randomized complete block design with three replications was conducted at the University of Mohaghegh Ardabili, Ardabil, Iran. Treatments were three sunflower cultivars as Aline 191, Aline 122 and Farrokh and three concentrations of nano zinc oxide including 0, 0.5 and 1 g lit^-1 which sprayed at three stages. Results showed that interaction of cultivar and nano zinc oxide was significant on kernel filling rate, the effective period of kernel filling, maximum kernel weight and duration of kernel filling. The rate of filling and maximum kernel weight increased with 0.5 g lit^-1 spraying of Nano zinc oxide in Aline 191 and 122, but in Farrokh cultivar was significantly reduced in comparison to the control. Also, no significant difference was found between 0, 0.5 and 1 g lit^-1 of nano zinc oxide on kernel filling rate, effective kernel-filling period and duration in Farrokh cultivar. In conclusion, foliar application of zinc oxide nanoparticles led to the improvement of kernel weight and their filling parameters and the more appropriate response was observed in foreign cultivars for this treatment, while final kernel weight decreased in Farrokh cultivar. Therefore, it can be used 0.5 g lit^-1 of nano zinc oxide for increasing grain yield in foreign cultivars of Aline.

Extended Abstract
Introduction: It is obvious that all plants adopt mechanisms to control NaCl accumulation because sodium chloride is the most soluble and most abundant salt. Binweed (Convolvulus arvensis L.) is among the ten widespread noxious weeds in the world that it is reproduced by seed, horizontal lateral root, and rhizome. Because of the extensive underground root system of the bindweed with abundant buds and established root reserves, binweed competes more tolerant than crops under salinity and drought stress. More information on morphophysiological traits of binweed under salinity conditions and comparison of salinity tolerance index between germination and seedling can also be contributed to the most effective management. In order to investigate the germination and seedling growth characteristics of binweed two experiments were conducted separately under salinity stress.
Materials and Methods: Germination experiment was done in a completely randomized design with 9 levels of salinity stresses include 0 (control), 5, 10, 15, 20, 25, 30, 35, and 40 dS.m^-1, with four replications in the lab. The seedling experiment was performed in a random complete block design consisted of five levels of salinity (tap water, 10, 20, 30, and 40 dS.m^-1) with three replications as the pot in a non-shade greenhouse of Agricultural College of Shahid Chamran University of Ahvaz.
Results: The results showed that with raising salinity, percentage germination and vigure index of seed declined, but Radicle/ Plumule ratio rose. After two weeks, in response to salinity a decrease in root and shoot characteristics of the seedling was observed. Salinity stress data were fitted to a three-parameter logistic for seedling stage showed that the salinity levels higher than 7.86 dS.m^-1 led to 50 percent reduction in tolerance index. It was found that 19.84 dS.m^-1 caused 50% decrease in the tolerance index at germination stage. Sufficient tolerance index –growth stage variation in response to salinity was found which suggests that bindweed tolerance to salinity at germination stage is about 3 times more than that of seedling stage.
Conclusions: Radicle/ plumule ratio at germination stage and root lateral branches at seedling stage increased in concentrations of up to 25  and 20 dS.m^-1, respectively. It seems the maintenance of root area and branches in response to increased salinity provide an acceptable mechanism of salinity tolerance for binweed. According to the three-parameter logistic model, the salinity tolerance of bindweed at germination and seedling stages was estimated at 20 and 8 dS.m^-1, respectively.
Keywords: Logistic model, Root lateral branches, Relative water content, Salinity tolerance index
Highlights:
1 Salinity tolerance of bindweed was investigated in germination and seedling growth.
2- Salinity tolerance index was compared between germination and seedling of bindweed and was introduced a proper trait which is more effective to pointing salinity tolerance.
3- The best sigmoidal model based on salinity criterion was introduced for salt tolerance index of bindweed.

Introduction: Today, population growth has placed a significant burden on global agricultural resources. As a result, meeting global food demand and increasing farmers' incomes has become a challenging task. Salinity is one of the most harmful factors in the arid and semi-arid regions of the world that influences crop production. Seed priming is a technology by which seeds are physiologically and biochemically prepared for germination before being placed in their bed and exposed to the ecological conditions of the environment. The aim of this study was to evaluate the efficiency of the effect of chitosan on bean germination indices under salt stress.
Materials and Methods: The experiment was conducted as factorial based on a completely randomized design with four replications in a row (tube or sandwich culture) between filter paper at the University of Mohaghegh Ardabili in 2021. Treatments included four salinity levels (0, 50, 100, and 150 Mm) and four chitosan levels (0, 25, 50, and 75% by weight volume), all of which had been dissolved in 1% acetic acid. The studied traits included germination coefficient, allometric coefficient, daily germination rate, mean daily germination, seedling length and weight index, radicle length, plumule length, seedling length, radicle fresh and dry weight, plumule fresh and dry weight and residual dry weight. Data analysis was performed using the SAS 9.2 software and Duncan's test at p<0.05 probability level was used for mean comparison.
Results: The results showed that salinity stress decreased allometric coefficient (AC), seedling length vigor index (SLVI), radicle and seedling length (RL and SL), and radicle fresh and dry weight (RFW and RDW) and increased daily germination rate (DGS) and residual dry weight (RDW). Seed pretreatment with chitosan increased AC, SLVI, RL, SL, RFW, and RDW. The comparison of the means showed that there was a significant difference between the levels of chitosan so that the highest number of traits was obtained from the use of 75% chitosan and the lowest was obtained from the chitosan-free treatment. SLVI, SL, and RDW in 75% chitosan pre-treatment were higher at about 31, 26, and 27% compared to the control (priming with distilled water), respectively. The highest AC was observed in priming with 50% chitosan. Comparison of the mean for salinity stress also showed that the highest and lowest values of the measured traits respectively were obtained from the application of 0 and 150 Mm salinity levels. Also, with increasing salinity, chitosan increased germination coefficient (GC), seedling weight vigor index (SWVI), plumule length (PL), and plumule fresh and dry weight (PFW and PDW).
Conclusions: The results of this study show that among the different treatments, pre-treatment of seeds with 75 % Chitosan may be considered an effective way to improve seed germination of bean. It also can reduce the harmful effects of salinity stress on some traits in bean seedlings and improve seedling growth. Also, pretreatment with distilled water is an easy, low-cost and effective way to increase bean seedling germination and growth indices. Farmers can use this method for fast germination and better seedling growth under salt stress conditions.

Highlights:

Extended Abstract
Introduction: The use of seed priming technology to accelerate the germination and seedling emergence of multi-purpose plants such as halophytes (Alhagi) with the ability to produce medicine and forage under environmental stress conditions or use of saline water (such as seawater of Persian Gulf) has received much attention today. Therefore, the present study was conducted to investigate seed priming methods and different salinity levels on germination, seedling emergence, and some growth responses of Alhagi plant.
Material and Methods: Two separate split-factorial experiments were conducted based on a randomized complete block design with four replications as a petri dish culture (first experiment) and a pot experiment in the field was performed in the Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University (Ahwaz, Iran) during 2020-21. In both experiments, different levels of salinity (municipal water source with EC=0.96 dS.m-1, 8 and 16 dS.m-1 using seawater of Persian Gulf) were assigned as the main plot, and different methods of seed priming (non-priming, hydro priming, hormonal priming with 50 ppm gibberellin and hydro priming+hormonal priming with 50 ppm gibberellin) and species (A. maurorum and A. graecorum) were assigned as sub-factors.
Results: The results showed the significance of salinity × species × priming interaction on all studied traits. According to the mean comparison results, the highest values of germination percentage, seed vigor index, seedling emergence, plant height, number of branches, total dry matter and stomatal conductance were obtained from a municipal water source with EC=0.96 dS.m-1 and hydro priming+hormonal priming with 50 ppm gibberellin for A. graecorum (29.1, 90.2, 24.0, 32.3, 52.5, 52.1 and 32.4% increase compared to non-priming and control salinity stress on this species, respectively). The output of the fitted logistic model to seedling emergence percentage showed that this model well explained the relationship between seedling emergence of two Alhagi species in responses to salinity and seed priming (R² adj≥0.98 and RMSE≤3.38). Therefore, in both studied species, the decline in seedling emergence started from the 8 dS/m salinity level. However, at the 16 dS/m salinity level, the slope of increase in seedling emergence percentage was slower per time unit.
Conclusion: To cultivate and exploit the saline coastal lands and also to restore the pastures in the country, A. graecorum species under the combined treatment of hydro priming + hormonal priming with 50 ppm gibberellin are recommended in comparison with other treatment levels.

Highlights:
1- Germination and growth responses of two Iranian Alhagi species and the possibility of production by irrigation of seawater of Persian Gulf were investigated.
2- Seed priming technique was used to accelerate seedling emergence and improve some traits in two Alhagi species.

Extended Abstract
Introduction: At present, the increase in population has created an additional burden on the world's agricultural resources. As a result, meeting global food demand and increasing farmers' incomes has become a challenging task. Salinity is one of the abiotic stresses that strongly affects the germination, growth, and yield of crops. Seed priming is a simple technology that hydrates seeds to the point where the metabolic activity for germination is initiated, but no radicle emerges. In fact, the seeds are physiologically and biochemically ready to germinate before being placed in their bed and exposed to environmental conditions. This research was conducted with the aim of investigating the effect of seed priming with chitosan on germination indices and biochemical traits of beans under salt stress.
Materials and Methods: This experiment was conducted at the University of Mohaghegh Ardabili in 2021 as a factorial in the form of a completely randomized design with four repetitions. The treatments included four levels of salinity (0, 50, 100, and 150 mM) and four levels of chitosan (0, 0.25, 0.50, and 0.75% w/v), all of which were dissolved in 1% acetic acid.
Results: The results showed that salinity stress decreased germination percentage (GP), Peak value (PV), and germination value (GV). However, seed priming with different levels of chitosan, especially 0.75% chitosan, improved GP, PV, and GV by 7, 21, and 17%, respectively, compared to the control. With increasing salinity, the amount of proline and polyphenol oxidase enzyme activity increased, but the application of chitosan 0.75% increased these traits by 34% and 43%, respectively, compared to the control (priming with distilled water). Electrolyte leakage in priming with 0.75% chitosan decreased by 31% compared to the control, which indicates maintaining the stability of the cell membrane. The amount of soluble sugars in the treatment with 0.75% chitosan and 150 mM salinity showed an increase of about 78% compared to the control. The highest correlation among traits was observed between peak value and germination coefficient (0.995*) and between proline and polyphenol oxidase enzyme (0.917*).
Conclusions: The results of this study show that among the different treatments, pre-treatment of seeds with 75 % Chitosan may be considered as an effective way to improve germination indices and biochemical characteristics of bean and it can be used as a treatment to deal with salinity conditions in bean seedlings and improve the growth of seedlings.

Highlights: