نشریه علوم و تحقیقات بذر ایران
سال دهم شماره 2 (تابستان 1402)

Allelopathy is one of the biocompatible methods to reduce the germination and establishment of weeds.In order to investigate the effect of sunn hemp extract (Crotalaria juncea) extract and oats (Avena sativa L.) on the germination of wild mustard (Sinapis arvensis), an experiment was conducted in 2022 at the Faculty of Agriculture and Natural Resources of University of Mohaghegh Ardabili University. The experiment was conducted as a factorial based on completely randomized design with three replications. The experimental treatments included the type of extract and their concentrations of zero (distilled water), 1, 5, 10, 15, and 20%. The results showed that the percentage of wild mustard seed germination and its growth components of wild mustard seeds were significantly affected by the interaction of extract type and their concentrations. The lowest percentage of germination and growth components such as plumule length, radicle length, germination speed, mean germination time, and seed germination were obtained from the concentrations of 15 and 20% of the extracts. Also, the results showed that sunn hemp extract had more inhibition on germination percentage and growth components of wild mustard seeds than oat extract. It can be concluded that with the increase in the concentration of the extracts, the inhibition of germination and the establishment power of wild mustard decreased in laboratory conditions.

This research was carried out in 2022 in order to study the effect of the aqueous extract of different parts of Zygophyllum eurypterum L. on seed germination and seedling growth of wheat and Convolvulus arvensis L. in two separate experiments including the laboratory and the greenhouse conditions, respectively. The experiments were exerted based on a completely randomized design with three replications and randomized complete block design with 4 four replications, respectively. The experimental treatments included water extracts of Zygophyllum eurypterum L in concentrations of 5, 10 and 15% of roots, 5, 10 and 15% of aerial organs (stem and leaves) and control (distilled water). The results showed that with the increase in the concentration of the extracts, the germination and growth traits as well as the total chlorophyll of both plants decreased significantly. In such a way that the highest amount of inhibition was related to 15% arial parts (stem and leaf) extract. Meanwhile, the antioxidant activity of wheat and weed C. arvensis L. increased by increasing the level of Zygophyllum eurypterum extracts. The level of 15% Zygophyllum eurypterum stem and leaf extract in wheat decreased the germination percentage by 63.7% and in C. arvensis L. by 89.2% compared to the control.  Increasing of extract concentration from zero to 15% of arial parts decreased root length decreased by 72.8% in C. arvensis L., and 52.9% in wheat compared to the control. The highest level of antioxidant activity of the weed C. arvensis L. was observed at the levels of 10 and 15% of arial parts extract which were 64 and 73%, respectively. Most of the studied traits of the weed C. arvensis L., such as germination percentage and speed and root length, were more sensitive to the effects of Zygophyllum eurypterum extract than wheat. Examining the results showed that arial parts of Zygophyllum eurypterum were more capable of dealing with germination and seedling growth than the root. Therefore, 15% aqueous extract of Zygophyllum eurypterum stems and leaves can be suggested to reduce the growth and weakening of the weed C. arvensis L.

Some mites species feed on cereal seeds and cause significant economic damage by reduction their quantitative and qualitative value. In 2006, to identify grain seed mites in Golestan province, sample were taken from 8 warehouses in 5 cities, located in 5 cities including Gorgan, Mino-Dasht, Bandar Turkmen, Gonbad and Agh-Qala. In total, 192 samples and sub-samples of wheat, barley and corn seeds were collected. In this sampling, 21 species from 17 genera and 10 families were identified, of which 13 species belonged to the Astigmatina group in the Sarcoptiformes order, 7 species belonged to the Prostigmata suborder and Trombidiformes order, and one species belonged to the Mesostigmata order. Lepidoglyphus destructor (Schrank), Tyrophagus putrescentiae (Shrank) and Acarus siro L. with 42.2%, 15.4% and 12% abundance respectively, have the most relative abundance among the pest mites. Among the predatory mites, Cheyletus malaccensis Oudemans (13.4%) was the most abundant. About 66.6% of all samples were infected with mites. The frequency of mites in wheat, corn and barley seeds were respectively, 61.4%, 20.8% and 17.7%. The highest number of mites was observed in Agh-Qala Talaii warehouses (40%). The average number of mites per kilogram of sampling materials was 10.

In order to evaluate the effect of copper oxide nanoparticles synthesized from eucalyptus plant on seed germination, growth and biochemical characteristics of corn seedlings, and an experiment was carried out in a randomized complete block design with three replications at the University of Mohaghegh Ardabili in 2021. Experimental factors included synthesized copper oxide nanoparticles (0, 2.5, 5, 10, and 20 mg L-1) and the application methods of copper oxide nanoparticles (seed priming and adding to the planting medium). The results showed that in both methods of nanoparticle application (adding to the planting medium and priming), with the use of different concentrations of copper oxide nanoparticles, there was a significant increase in the percentage and speed of germination, average daily germination, germination synchronization index, strength index, length and dry weight. Corn seedlings and the reduction of the average germination time, the time for the germination of corn seeds to 50%. Among the methods of nanoparticle application, pretreating seeds with a concentration of 2.5 mg L-1 of copper oxide nanoparticles and adding a concentration of 5 mg L-1 of nanoparticles to the planting medium has the greatest effect on improving the percentage and speed of germination, seed synchronization index, length and dry weight. Seedlings and vigor index and decreased average seed germination time. The use of different concentrations of copper oxide nanoparticles in both application methods increased the activity of catalase, peroxidase, polyphenol oxidase and amino acid proline content compared to the control treatment. In general, it is recommended to use a concentration of 2.5 mg L-1 of copper oxide nanoparticles as a seed priming method and add a concentration of 5 mg L-1 of nanoparticles to the planting medium to improve seed germination, growth and biochemical characteristics of corn seedlings.

Astragalus fasciculifolius Bioss. is one of the important medicinal plants in Sistan and Baluchistan regions, and the germination of this plant in this region faces a challenge due to the sensitivity of this plant to dry conditions in the germination stage. It was carried out in the laboratory in the form of a completely randomized design in three repetitions with a factorial arrangement in 2023. Experimental treatments included four levels of osmotic potential (0, -2, -4 and -6 bar) and eight seed priming treatments including hydro-priming, non-priming, priming with gibberellin, salicylic acid, potassium nitrate, zinc sulfate, humic acid and and silicon dioxide nano-particles. The results showed that decrease in osmotic potential caused a decrease in length and weight of seedling, seed vigor, percentage and rate of germination and alpha-amylase enzyme activity. But seed priming reduced the negative effects of stress on these traits and improved these traits. Among the seed priming treatments, gibberellin and zinc sulfate had the best effectiveness in improving germination characteristics and early growth of Astragalus fasciculifolius Bioss. under conditions of no stress (osmotic potential of zero bar) and severe stress (osmotic potential of -6 bar). In mild stress conditions (osmotic potential of -2 bar), seed pre-treatment with silicon dioxide nano-particles and hydro-priming had better effectiveness in improving the studied traits. Therefore, it seems that priming treatment of Astragalus fasciculifolius Bioss. seeds with these compounds can be recommended to improve the germination and early growth characteristics of this plant.

Myrtus communis is a medicinal plant that its seeds have primary dormancy. Therefore, in current study, firstly effect of various types of scarification (treatment with H2SO4 70 or 90% or sand paper for 5 and 10 min, blade and soaking in hot water for 10, 20 min) were evaluated on seed dormancy breaking. Results showed that without scarification, seed germination was very low, whereas various types of scarification significantly increased final seed germination. Among various levels of treatments, the highest seed germinatin obtained by soaking in hot water for 20 min (33%), treatment with  H2SO4  90% for 5 min (59%), sand paper for 10 min (63%) and blade (65%). The next experiment showed that myrtle seeds were photoblastic and He-Ne laser more than white or red light increased germination of scarified seeds by above methods. He-Ne laser irradiation reached seed germination of scarified seeds by sand paper and blade to 80%. Results of the last experiment also showed that application of concentrations of 0.5% KNO3 and 100 µM sodium nitroprusside (SNP as a NO donor) also increased seed germination, seedling length and vigor of seedlings grown from all scarified seeds and seed germination of scarified seeds by sand paper and blade achieved to 80%. These results showed that myrtle seeds have combination of physical and physiological dormancy that can be attenuated with scarification by sand paper and treatment with SNP or He-Ne laser irradiation.