نشریه علوم و فناوری بذر ایران
سال دوازدهم شماره 4 (پیاپی 32، زمستان 1402)

The Henbane (Hyoscyamus SPP.) belongs to the potato genus and due to the presence of alkaloids such as atropine, hyoscyamine and scopolamine, it affects the human nervous system. Among the annual and perennial species of this genus, five of them are endemic in Iran. The aim of this study was to determine the cardinal temperatures and evaluate the germination response of five seed ecotypes (Hyoscyamus SPP.) to water temperature and potential. For this purpose, a factorial experiment was conducted in a completely randomized design with four replications. Experimental treatments were run according to eight temperature levels (5, 10, 15, 20, 25, 30, 35, and 40°c) and six water potential levels (0, -0.2, -0.3, -0.4, -0.6 and -0.9 MPa). The results showed that with decreasing water potential, the percentage and germination rate of Ecotypes decreased. Estimation of cardinal temperatures showed that the base temperature and ceiling temperature of the five studied Ecotypes were the same and were equal to 8 and about 40 ° C, respectively. Furthermore, the optimum temperature of these Ecotypes was recorded in the range of 25-35 ° C. The Dashty Ecotype had a wider optimum temperature range. According to R2 and RMSE statistics, the Dent-like model well describes the germination rate response of the studied ecotypes to temperature and water potential.

In order to study the effect of different levels of drought stress and temperature on seed germination of buckwheat, a factorial experiment was conducted as completely randomized design with three replications. Experimental treatments were included different levels of drought stress (0, -0.2, -0.4, -0.6 and -0.8 MPa) and different temperatures (8, 12, 16, 20, 25, 30, 35 and 40 oC). Results indicated that all models of thermal time, hydro time, and hydrothermal time could predict the germination of buckwheat in temperature and osmotic potential. Basic temperature (Tb) was estimated from -0.98 to 11 oC, optimum temperature (To) from 21.7 to 24.7 oC, and maximum temperature (Tc) from 30 to 41.5 oC, which osmotic potential increased Tb and decrease To and Tc in Buckwheat. Also, increasing temperature enhanced germination rate (decrease θHT from 18 MPa day at 8 oC to 3 MPa day at 35 oC), and decreased stress tolerance due to increasing basic potential (increase ψ50 from -0.927 MPa to 0.043 MPa). According to the hydrothermal time model output, Tb in this plant was about 1.93 oC and at 92 MPa oC day, highest germination rate was recorded and ψTb in this plant in Tb was about -1.31 MPa. Also it was defined that, each of these three models predicted buckwheat seed germination under different temperature and water potential, but hydrothermal time was a general model and we can suggested it.

In order to determine the cardinal temperature of decayed sugarcane seeds, this study was carried out factorially in a completely randomized design with three replications in Khuzestan University of Agriculture and Natural Resources. The first factor was aging at 5 levels (0, 24, 48, 72 and 96 hours of decline) and germination temperatures at 7 levels (5, 10, 15, 20, 25, 30, 35 and 40 ° C). The results showed that the percentage and speed of germination were affected by the interaction of temperature in the decay so that their highest value was in the temperature range of 20 to 25 ° C and the decay in addition to reducing their amount increased the range of changes of this plant at different temperatures. The highest germination percentage was observed at 20 ° C in undeveloped seeds and 15 to 20 ° C at 24 and 48 h. Estimation of different non-linear models on germination rate also showed that among the evaluated models, the better toothed model was the model for germination of sugarcane seeds at different levels of decay. The germination basal temperature of sugarcane was estimated to be 1 ° C in non-degradable conditions, which increased to 1.8 ° C in 24 hours of decline and decreased again in higher degradations. The optimum germination temperature of this plant was between 20 to 32 at no aging conditions.

Parsley, which today is classified as a vegetable, has many properties and is used in food and pharmaceutical industries. The seeds of the native populations of this plant do not have a good germination percentage and many efforts are being made to improve the growth and germination of the seeds. In order to investigate the seed germination rate of native stands and the effect of hydropriming treatment in increasing the germination power of the seeds of these stands, an experiment was conducted in the form of a completely randomized design at four time levels (12, 24, 48 and 72 hours) against the control and with four replications among 24 native stands collected from different parts of the country and two populations with foreign origin imported were carried out. The results showed that the average seed germination percentage of the stands before treatment was 56.7% (the lowest rate was 20% in curled leaf Parsley stand and the highest was 78% in Jiroft 1 stand). Also, the hydropriming treatment had a significant effect at the level of 1% on the emergence of parsley seeds, and its greatest effect was in 24 hours. Also, the highest effect of treatment on Arak, Garmsar and Pich of Tehran was 21.8, 20.9 and 20%, respectively. The least effect of hydropriming was on the population of curled leaf parsley (7.4%). Totally, it was concluded that hydropriming can increase the germination percentage and quality of parsley seeds.

This research was conducted as a factorial in a completely randomized design with four replications. The studied treatments include salinity stress in the form of irrigation with normal water (0.4) and with salinity of 4 and 8 dS/m of NaCl salt and seed priming with hydrogen peroxide, including no priming and seed priming in 25 and 50 mM solutions. In this experiment, the traits of germination percentage, germination rate, root length, stem length, root dry matter, stem dry matter and seed vigor index were investigated. In this research, the effect of salinity stress and hydrogen peroxide was significant on all investigated traits. The interaction effect of salinity stress and hydrogen peroxide on the studied traits was significant except germination rate. The maximum percentage of germination, length and dry matter of root and stem and seed vigor index was obtained under absence of stress (normal water) and application of 50 mM hydrogen peroxide and the minimum was under salinity of 8 dS/m and no application hydrogen peroxide. The maximum germination rate was obtained in the 50 mM hydrogen peroxide and no salt stress. In general, the results showed that the use of hydrogen peroxide in the presence of salinity stress was effective through the improvement of indices, and this can be considered as a strategy for better and proper seedling establishment.

This experiment was conducted to investigate the germination and seedling growth of two papaya (Carica papaya L.) varieties in response to the inoculation of mycorrhizal fungi and culture substrates in a factorial in the form of a completely randomized design. The experiment factors include varieties at 2 levels (Red Lady (V1) and Bangladeshi (V2)), culture substrate at 5 levels (compost + perlite + vermicompost (1:1:1) (S1), compost + perlite + cocopeat (1:1:1) (S2), compost + vermicompost + cocopeat (1:1:1) (S3), perlite + vermicompost + cocopeat (1:1:1) (S4) and compost + perlite + vermicompost + cocopeat (1:1:1:1) (S5)), and mycorrhizal at 2 levels (no inoculation as control (M0) and inoculation (M1)). The results indicated a significant effect of culture substrate and mycorrhizal on germination and growth characteristics of papaya varieties. In the mycorrhizal inoculation treatment, the highest germination percentage (77.33%) and germination speed index (0.63) were observed in the Bangladeshi variety and the lowest average germination time for both varieties . The highest seedling height and root length were recorded for V1S4M1 and V2S5M1 treatments, and the highest shoot dry weight (0.276 g) was recorded for V2S5M1 treatment. According to the obtained results, inoculation of seeds in both Red Lady and Bangladeshi papaya varieties with mycorrhizal fungi and substrates containing organic matter, especially vermicompost, improved the germination and growth characteristics of the seedlings. Therefore, according to the advantages and compatibility of mycorrhizal fungi, it can be used as a suitable treatment to improve the germination and growth of papaya seedlings.