نشریه علوم و تحقیقات بذر ایران
سال دهم شماره 1 (بهار 1402)

Drought stress reduces the germination and growth of plants, and it is very important to provide solutions such as seed priming to increase the uniformity of germination and growth of plants and to deal with drought stress. Thus, a factorial study was conducted in the form of a complete randomized design on cumin seeds in three replications in the Seed Technology Laboratory of Islamic Azad University, Karaj Branch. The treatments of this experiment included: five levels of priming (chitosan, humic acid, vermicompost, distilled water and control (without primer)) and four levels of drought stress (0, -0.3, -0.6, -0.9 MPa). The results showed that drought stress reduced germination percentage, growth and quality of cumin seedlings in no prime conditions and with increasing intensity of drought stress, seedling growth decreased. Priming of chitosan, humic acid and vermicompost were more effective than hydropriming in increasing germination properties as well as drought stress and reducing the negative effects of drought stress, as well as cumin seed priming. The above treatments decreased the proline content and increased ascorbate peroxidase, alpha-amylase and catalase activity. Priming of chitosan (44.02%), humic acid (42.08%), and vermicompost (44.04%) increased the germination of cumin seeds compared to the control (without primer and without drought stress).

Halogenation, seed moisture content (MC) reduction and suitable packaging are the practical methods that could have positive effect on retaining the seed viability during storage. This study was carried out by the factorial experiment based on Randomized Complete Block Design. Factors included type of the packaging at two levels (single layer and double layer packaging), seed halogenations at four levels (0, 3, 6, and 9 gram per kilogram seed), paddy moisture content (wet basis) at three levels (17-17.7%, 11-12% and 9-10%) and storage durations at three levels (without storage, six months and one year storage). The results showed that after one year storage, the lowest germination percentage with 47.92% was belonging to seed with MC of 17-17.7% and the germination of seeds with MC of 11-12% and 9-10% was above 97%. Vigor index of seed in double layer packaging after 6 and 12 months decreased by 13.82 and 21.63 percent, and in single layer packaging, it decreased by 17.97 and 39.81 percent, respectively. Treatment with MC of 9-10%, halogenated with 9 gram per kilogram seed had the highest germination percentage, pedicle length and seed vigor. In addition, Sitotroga cerealella was observed as an important paddy insect in non-halogenated seeds, packed in the single layer packaging after one year storage. Generally, MC reduction of rice seed to 9-10% along with halogenation and the use of double layer packaging were able to maintain seed quality better than the other treatments during storage.

Eryngium caucasicum is one of the important endemic plants in the northern provinces of Iran. Few studies have been done in relation to its germination. Studying its domestication and propagation can play an important role in preserving and commercializing. To evaluate seed germination and plantlet vigor of Eryngium caucasicum, a laboratory experiment was conducted as factorial based on a completely randomized design in 3 replications with two factors, temperature (5, 10, 15, 20, 25 and 30 °C) and stratification (0, 1, 2, 3 and 4 weeks). According to morphological studies, the thousand seed weight of Eryngium small seeds was estimated 1.45 g and a moisture content of 24%. The average of flowers per plant is 11.3 and the average of seeds per fruit is 56. The highest germination percentage (74.6), germination rate (1.25), germination uniformity (0.21), and seed vigor (2.2) are shown at 15°C without stratification. The highest germination energy and the shortest germination time (15.26) were observed in 20°C without stratification (64), which is not significantly different from the treatment of 15°C (63.3). In general, the results of the experiment showed that Eryngium seeds germinate at temperatures between 15 and 25 °C, and no germination was observed at temperatures of 5, 10, and 30 °C, and the best temperature for Eryngium germination is 15 °C without stratification.

Caper, Capparis spinosa, has medicinal, edible, and industrial uses and has been used since ancient times to treat kidney, spleen, liver, paralysis, gout, and rheumatism diseases. Dormancy caused by hard seed shell is one of the problems of seed germination in this plant, In order to study on improving seed germination methods and biochemical characteristics, a factorial experiment on the basis of completely randomized design was conducted with three replications. To improve seed germination, four caper populations (Tehran, Torbat-e-Jam, Firuzabad, and Barazjan) were treated with six seed treatments (control, ultrasonic, potassium nitrate, gibberellic acid, chilling, and scarification). Phytochemical characteristics of the populations were also compared. The results of phytochemical traits showed that the Torbat-e-Jam population had the highest antioxidant activity with an IC50 equal to 26.4. The highest amount of total phenol equal to 227.03 mg of gallic acid per gram of dry extract, and total flavonoid equal to 71.54 mg of quercetin per gram of dry extract was obtained from Tehran population. The results showed that the highest percentage of germination with 62% and the highest germination rate with 3.5% per day was identified in the treatment of Firozabad population under scratching conditions. Also, the results of this study showed that in Tehran, Torbat-e-Jam, Firozabad, and Barazjan, the percentage of germination increased by 6.55, 7.25, 3.44, and 11.25 times, respectively compared to the controls. According to the results of the current study, seed scarification is recommended to increase the germination rate of a caper valuable medicinal plant.

Drought stress is a major restrain in the growth and yield of lentil plants especially under rain feed areas. One of the problems of semi-arid regions in the world and Iran is poor seedling establishment due to lack of sufficient water. To study the effects of seed size of local genotypes (accessions) of lentil on the germination and seedlings growth characteristics and some related biochemical reactions under drought stress, a factorial based on completely randomized design experiment with 4 replications was conducted in vitro. The treatments were 4 drought (0, -0.4, -0.8, -1.2 Bar) levels and seed size (small- medium, and large). The results showed that the interactions of all measured traits except root length, root dry weight, shoot dry weight, seedling dry weight and superoxide dismutase activity were significant at the level of 1% probability. So that, the small seeds were superior in germination percentage, germination rate, and shoot length compared to the other seed sizes. With the drought intensity of -0.8 bar, the total antioxidant activity, total soluble protein, hydrogen peroxide content and guaiacol peroxide activity were increased. However, for ascorbate peroxide, the increasing pattern was up to -1.2 bar. Seemingly, the small seeds are more tolerable to the drought stressful conditions the germination and the seeds would be more suitable to be employed under the water scarcity conditions.

In order to investigate the effect of priming and aging on germination indices and activity of hydrolytic enzymes and cycle glyoxylate in corn seed, a factorial experiment was conducted based on completely randomized design at the University of Mohaghegh Ardabili in 2022 with 3 replications. Treatments were accelerated aging (control without aging, 11 and 13 days) and priming (control, hydro-priming, priming by gibberellin (20 mg lit-1) and salicylic acid (100 mg lit-1)).The results showed that aging of germination indicators including germination percentage (GR), Germination Rate (GR), Mean Daily Germination (MDG), Germination Coefficient (GC), Germination Value (GV) decreased, but priming with salicylic acid, hydro especially gibberellin improved these traits. The lowest Daily Germination Speed (DGS) and Mean Germination Time (MGT) were obtained in hydropriming, priming with salicylic acid, especially priming with gibberellin and the control (without priming). The amylase and malate synthase enzymes activity in gibberellin treatment and non-aged compared to the control showed an increase respectively about 71% and 26%. The most lipase enzyme activity (73.41 unit mg-1 protein) was observed in treatment with gibberellin. Aging decreased lipase enzyme activity. In general, using gibberellin pretreatment strengthened weak corn seeds the germination indices and activity of hydrolytic enzymes glyoxylate cycle and increased seedling growth.