نشریه علوم و فناوری بذر ایران
سال دهم شماره 3 (پیاپی 23، پاییز 1400)

To investigate of tolerance levels and screening of different thyme species to the temperature stresses, a factorial experiment was conducted in a completely randomized design with three replications in the vitro condition. The experiment was conducted using six Thymus species (Th. fallax, Th. fedtschenkoi, Th. pubescens,Th. vulgaris, Th. daenensis and Th. kotschyanus), at two moisture levels (dry and wet) and at 15 temperature levels (from -8 ° C to 48 ° C with an increase of 4 ° C). Measured characteristics included germination percentage and mean germination time. According to the results, the highest germination percentage belonged to Th. pubescens (70.83%) and Th.daenensis (70.44%) and the lowest germination percentage belonged to Th. vulgaris (53.04%). The average percentage of germination of seeds in dry condition (74.66%) was significantly higher than wet condition (56.12%). The highest germination percentage was observed at -4 (79.44%), zero (78.33%) and 4 (79.72%) Celsius that had significant differences with others. Interactions of species with moisture conditions showed, the highest germination percentage related to Th. kotschyanus (79.40%), Th. pubescens (78.95%), Th. daenensis (78.08%) and Th. falax (77.53%) in dry conditions and the lowest germination percentage belonged to Th. vulgaris (45.46%) in wet conditions.Using the results, different species of Thymus can be screened for temperature tolerance in dry and humid conditions and recommended for cultivation in different regions. In this experiment, native species were more resistant to temperature stresses.

Moringa peregrina) Forssk( Fiori Is one of the valuable forest species of tropical regions which has been endangered for many years due to its special vegetative characteristics as well as improper seed harvesting and regeneration. Investigation of the effect of some pre-treatments on seed germination seems to be necessary to increase germination rate and its growth and development. This study was down with factoriel by random total project and three repite in Bashagerd Hormozgan with this goal: investigating of priming affective on seed germination characteristic. Experiment threatment are giberlic acid (0,200,400,600 ppm) and kno3 (0,1,2,3%) for 24 houres. Data varianse Analysis results show that giberlicacid has affect on germination percentage index, weight index, germination daily mean, germination value in level 5% and it hasn’t affect on germination speade, hight index and aliving percentage. In addition to both giberlic acid and kNo3 has affect on germination mean max and germination time mean in 5% level. Finaly we found that giberlic acid with 200 ppm and KNo3 concentration had the most affect on seed germination Moringa prigrina and cause to increase more than twoice growth.

An experiment was done in the research laboratory of Tehran university in order to evaluate the effect of various conditions of seed storage on storability of rapeseed primed seed. The experiment factors have included the seed priming using .05% lotion of KNO3 for 12 hours (primed and non primed with a this lotion)–package (vaccum packaging, nano and aluminium bags)–seed storage condition including: moisture content (5, 9, 13 and 17 %), temperatures(15 and 30) and storage periods(1,2,3,4,5 and 6 months). Analysis of variance demonstrated that with increasing the duration of storage and also with increasing seed content humidity amount and storage temperature, the seeds vigour would be decreased and in studing indexes, this decrease occurred in the first month of storage in 17% seed water content and 30 C temperature treatment and not in other onces, which shows that storage condition in more important in storage than other factors. For all indices, germination rate and percentage in rapeseed seed, there were significant differences in main, double and triple interaction effects at 1% probability level. the nano packagings is usually suggested as a suitable packaging to preserve the seeds in these condition.

This experiment was conducted at seed technology laboratory of Agricultural Sciences and Natural Resources University of Khuzestan, in 2018 with the to evaluate the effects of seed priming on cardinal temperatures and thermal time requirements of borage seed germination. The factorial experiment was arranged based on the randomized complete block design with three replications. Treatments were gibberellic acid (0 (distilled water as control), 100, 200, 400 mg/L-1), priming durations (6 and 12 hour) and seven levels of germination temperatures (5, 10, 15, 20, 25, 30 and 35 oC). Beta model, beta modified, dent-like and segmented were used to determine cardinal temperatures. Results showed that seed germination significantly increased at both priming durations of 6 and 12 hours with increasing of temperature and gibberellic acid concentrations. The highest seed germination was observed at 200 mg/L-1gibberellic acid and 15 oC. Increase of gibberellic acid concentrations resulted higher thermal time requirements to complete 50% of germination in seed population. From the results, the beta model provided the best fit to evaluate cardinal temperatures of borage seeds. It is therefore, suggested that the base, optimum and celling temperatures of borage seeds are 0.51, 21.5 and 35.1 oC and influenced by application 200 mg/L-1GA to 0.33, 23.5 and 35.8 oC.

Experiments were carried out in a completely randomized design with 3 replication factorial arrangement. Experimental treatments were including genotype factor (including 15 sea beet samples from Khuzestan, Elam, Kermanshah, Kurdistan and Azerbaiyjan provinces and two sensitive and susceptible cultivar of sugar beet) and salinity factors (concentration of 0, 50, 100 and 400 mM) and drought factors (5 levels of 0, 3, 6, 9 and 12 bar). Results showed that the effect of salinity and drought treatments on germination percentage, radicle, plumule length, radicle, and plumule weight traits were significant and in both experiments with increasing stress intensity germination percentage, radicle and plumule length, radicle and plumule weight traits decreased. In both experiments, the germination percentage trait was less and hypocotyl weight trait more affected by stresses than other traits. Alsoو in both experiments, radicle growth was less affected by stress than the plumule. Statistical estimations showed that there was a significant difference between investigated genotypes for germination percentage, radicle length, plumule length, radicle weight and plumule weight in both experiments. In salinity and drought stress conditions, at least 5 and 7 sea beet genotypes were identified from Elam, Kermanshah, Khuzestan and Azerbaiyjan provinces, which were better in terms of germination and early growth characteristics than sugar beet cultivars. Based on this, it can be concluded that sea beet has high diversity and resistance potential against salinity and drought stresses during germination and early growth stages, and can be used to produce more resistance sugar beet against salinity and drought stresses.

This study was performed to investigate the effect of pumpkin (Cucurbita pepo L.) seed’s pre-treatment by salicylic acid and ascorbic acid on different aspects of seed germination and biochemical features. A factorial experiment was conducted based on a completely randomized design with three replications. Experimental treatments included two levels of seed maturity (normal seeds and aged seeds) and five levels of priming (control, ascorbic acid 50 and 100 mg/l, and salicylic acid 50 and 100 mg/l). The seed traits were finally measured included the germination percentage, first and second seed vigor index, seedling dry weight, peroxidase and superoxide dismutase activity, electrolyte leakage, soluble protein, and soluble carbohydrate. Based on the results, the seed pre-treatment with 100 mg/l ascorbic acid and salicylic acid could perform the highest germination indices. Moreover, the germination percentage (74%) was improved in aged seeds pre-treated by ascorbic acid and salicylic acid (especially at a concentration of 100 mg/l). Also, the antioxidant enzyme activity was increased while the cell electrolyte leakage was significantly decreased. In total, results indicate, the pre-treatment with salicylic acid and ascorbic acid, not only improved the germination quantity and vigor but also improved the germination quality mainly by the development of carbohydrate and protein content in pumpkin seeds.

Fast and precise detection of infected potato plants is an essential practice in the seed potato certification system. Spectral fingerprinting as non-destructive and rapid method is going to be developed for discriminating plants with different stress such as disease. In this research virus infections of experimental plants (that infected with both PVY and PLRV viruses) were analyzed by spectral data without any destruction. Spectral data were collected from 32 plants (16 infected plants and 16 healthy plants) that were found to be infected or healthy using the ELISA and RT-PCR test. Some pretreatment methods of spectral data such as multiplicative scatter correction were used to remove noise. Soft independent modeling of class analogy (SIMCA) based on PCA analysis predicted the disease with high detection accuracy. The results showed, none of the samples belonged to the wrong group or to two groups simultaneously. The wavelengths in three ranges of 910-863 nm (near-infrared ), 725-704 nm (red edge) and 580-530 nm (green), had the greatest contribution to the complete differentiation of infected and healthy plants and development of models respectively.

In this research, the effect of different seed priming treatments was investigated on seed germination parameters of Securigera securidaca seeds in the low temperature stress conditions. Seeds first were exposed to eight temperature levels (5, 10, 15, 20, 25, 30, 35 and 40 ° C). Experimental treatments included different priming treatments (hydropriming, osmopriming including potassium nitrate and calcium chloride and no priming). The results showed that temperature significantly reduced germination percentage and rate, seedling length and seedling dry weight, normal seedling percentage and seed vigor. 5 mM of calcium chloride treatment at 10 ° C for 20 hours had the highest germination percentage, and 1% of potassium nitrate treatment at 10 ° C for 20 hours had the maximum seedling dry weight and 0.5% of potassium nitrate at 10 ° C for 20 hours and 10 mM of calcium chloride treatments at 15 ° C for 20 hours had the highest percentage of normal seedlings. Hydropriming treatment at 15 ° C for 20 hours had the highest germination rate, seedling length and seed vigor and was also one of the best treatments in terms of normal seedling percentage. So this treatment can be introduced as a suitable treatment for this plant because it is better in most germination traits and it is easier and cheaper to do.

Centaurea balsamita is an annual plant that invades fallow and steep lands. . In this regard, in order to evaluate the effect of intermittent temperatures on germination of Centaurea balsamita, a completely randomized design with six replications in vitro was conducted in the Faculty of Agriculture, Ferdowsi University of Mashhad. Temperature treatments were alternating day / night 15-5, 5-20, 20-10, 25-10, 25-15 and C° 30-15. The results showed that intermittent night and day temperatures showed the highest germination rate at 5-15 °C. The highest percentage and rate of germination (83% and 8.9 seeds/day) were in the intermittent temperature of 5-15 °C and the lowest in the intermittent temperature of 15-30 °C. The highest values of root length (97 mm), shoot length (30 mm), root fresh weight (19 mg) and shoot fresh weight (52 mg) were obtained at 15-30, 5-15 °C, respectively. Also, the highest value of the seedling vigor index (7.75) was related to the temperature treatment of 5-15 °C, its lowest value (5.2) at an intermittent temperature of 10-25 °C. Also, the results of this experiment were in agreement with the reality of the germination of this plant (germination in November with moisture condition). Based on the results of the present study considering that November is the peak time for the emergence of this weed in Mashhad, it is suggested that in order to perform better control and reduce the use of pesticides and consequently reduce financial and environmental costs, chemical control this weed is done at this time.

To study the effect of biological treatment on germination and growth indices and pigments of flaxseed under salinity stress, a factorial experiment in a completely randomized design was conducted in three replications at the faculty of agriculture of Shahed University in 2018. Experimental treatments were salinity at four levels (zero, 2.5, 5 and 7.5 dS/m) and biological treatments at four levels (control, bacteria (Baccillus subtilis), fungi (Macrophomina phaseolina) and combination of bacteria and fungi). Effect of biological treatment was significant on germination percentage and the highest germination percentage (99 %) obtained at fungi treatment. Effect of salinity and biological treatment was significant on mean germination time and germination coefficient. The minimum mean germination time (3.79 days) obtained at combination of bacteria and fungi treatment that shows this treatment was most effective in compared with other biological treatments. With increasing of salinity, mean germination time increased. Salinity reduced radicle, plumule and seedling length. The means related to radicle length at the different levels of salinity at biological treatment of fungi was highest amount in compared with other biological treatments. Interaction effect of salinity and biological treatment was significant on chlorophyll a and total chlorophyll. With increasing of salinity, reduced pigments. Maximum amount of chlorophyll a (16.52 µm.ml1-) was obtained at the control treatment of biological treatment and zero salinity. The result of this research showed that using of microorganisms such as fungi and bacteria in salinity stress, can reduce the negative effects of salinity on germination and growth of this plant.