نشریه تحقیقات بذر
پیاپی 41 (زمستان 1400)

One of the effective methods against stress in seed germination is to use the seed priming technique. For this purpose, a factorial experiment in a randomized complete design was carried out on the effect of salicylic acid pretreatment (500, 1000, and 1500 mM) on germination and some seed characteristics of borage (Borago officinalis. L.) under salinity levels (50, 100 and 150 mM). The traits included length, weight, ratio of root and shoot, seed protein concentration, and seed germination percentage. Based on the results in response to salinity stress conditions, seed morphological growth changed drastically, reducing the length of the radicle and shoot as well as their weight decreased. However, salicylic acid treatment by changing the ratio caused maintenance and stability of the morphological activity in borage seeds. In general, salicylic acid treatment under salinity stress can be used to enhance the germination and growth activity of borage.

To break the seed dormancy in Alyssum homalocarpum weed, an experiment was done in a completely randomized design with three replications. The treatments included chilling (control, 7-day, 14-day, and 28-day at 4 °C temperature), ultrasound (0, 5, 10, 15, and 20 minutes), and priming with salicylic acid (0, 50, 100, and 200 ppm). The results showed that the highest germination percentage was in the chilling treatment of 14 days (62.5%). As the treatment increased the germination of Alyssum homalocarpum to 40% compared to the control. A significant effect was observed in all ultrasound treatments compared to the control. The highest germination percentage was obtained at 15 minutes and then at 20 and 10 minutes. The best germination percentage and germination rate in 15-minute ultrasound treatment were 61.5% and 38.2%, respectively. The use of salicylic acid had a more significant effect than the control treatment. The highest germination percentage was obtained in the 200 ppm (84.6%) treatment. The lowest germination percentage was obtained in the control treatment. In 200 ppm salicylic acid treatment the germination percentage increased compared to the control by 90.11%. Among the methods used in this study, salicylic acid was better than other methods, and the germination percentage of Alyssum homalocarpum weed increased.

This study was carried out to investigate the effects of salinity stress on the germination properties of O. basilicum seed. Seeds were placed in 9-cm Petri dishes. The seeds were germinated in distilled water and different concentrations of NaCl (50, 100, 150, and 200 mM). The number of germinated seeds was measured for twenty days. Germination percentage, germination rate, stem length, seedling length, root/stem length ratio, root fresh weight, stem fresh weight, root dry weight, stem dry weight, and biomass were measured. Germination percentage (p<0.05) and germination rate (p<0.05) were influenced by the treatments. Germination percentage was significantly lower in seeds treated with 200 mM compared with other treatments. Application of salinity showed significant effects on root length (p<0.01), stem length (p<0.01), seedling length (p<0.01), root/stem length ratio (p<0.01), root fresh weight (p<0.05), stem fresh weight (p<0.01), stem dry weight (p<0.01) and biomass (p<0.01). Root length, stem length, seedling length, root/stem length ratio, and stem dry weight were significantly lower in the 200 mM treatment compared with other treatments. In summary, basil seeds could tolerate salinity stress up to 150 mM. The obtained results help farmers with the appropriate production.

To evaluate the effect of hydropriming and Agrotin organic fertilizer on seed germination, growth indices, and grain yield of three dryland wheat cultivars, a factorial experiment in a randomized complete block design with three replications was done in Delfan, Lorestan province during 2016-2017. Experimental factors included organic fertilizer in two levels (consumption and non-consumption), seed hydro-priming at two levels (prime and non-prime), and three dryland wheat cultivars (Baran, Ouhadi, and Azar 2). The results of the experiment showed that the characteristics of average duration and germination speed coefficient, number of tiller per plant, crop growth rate, a hundred seed weight, leaf area index, chlorophyll index, and seed yield were influenced by all treatments. However, the germination percentage and germination speed were significant in the Agrotin and priming treatments. The interaction effect between Agrotin and priming treatments on germination speed and the number of tillers per plant was significant. Agrotin consumption also increased the efficiency of wheat seeds primed. The highest grain yield was obtained by applying Agrotin and priming (2504 kg/ha) and the lowest (1755 kg/ha) in non-application of the treatments. Ouhadi cultivar with a yield of 1944 kg/ha had a higher grain yield than the other cultivars. It seems that the use of organic fertilizers and hydropriming is a suitable solution for greater availability of nutrients and increasing wheat growth and yield.

In order to study the effect of priming on germination characteristics and activity of antioxidant enzymes of rice aged seeds, a factorial experiment was conducted in a completely randomized design with 4 replications and 12 treatments including 3 levels of aging (control with germination of 97% 87 and 77% germination) and 4 priming levels (control without priming, hydropriming, priming with gibberellin and salicylic acid). After RNA extraction and cDNA synthesis, gene expression of antioxidant enzymes was studied using qRT-PCR, activity of antioxidant enzymes and some of germination characteristics were measured. The results showed that the highest germination rate was obtained from priming treatment with gibberellin without aging, and the highest activity of catalase, peroxidase and superoxide dismutase enzymes observed in gibberellin pre-treatment and 77% aging and the least activity of these enzymes was related to non-priming treatment without aging. Also, analysis of qRT-PCR data showed that expression of the enzyme peroxidase gene in gibberellin pre-treatment and without aging level was higher than expression of other enzymes.

Salinity is one of the most limiting factors in crop growth and hence many attempts have been undertaken to reduce this stress. Therefore, this study investigated the effect of the interaction of salicylic acid and ascorbic acid on salt stress in St. John's wort (Hypericum perforatum L.) using a completely randomized factorial design. Different concentration of salicylic acid (0.0, 0.3, 0.6, 0.9 mm), ascorbic acid (0.0, 0.1, 0.2 and 0.3) and salt stress (0, 30, 60, 90 and 120 mM) were used. The results showed that pre-treatment of seed priming of salineexposed plants with ascorbic and salicylic acids significantly improved germination percent, germination rate, and germination average time, but had negative effects on these traits. According to the results of this study, It can be concluded that seed priming of St. John's wort either with salicylic or ascorbic acid improves germination traits and plant resistance to salinity.