نشریه تحقیقات بذر
پیاپی 39 (تابستان 1400)

An appropriate planting date of the mother plant can improve the germination and growth of the seeds resultant from these plants. This experiment was conducted as a split-plot design with three replicates during 2016-2017 and 2017-2018. The main factors included three planting dates (October 11, November 10, and December 10 as the early, usual, and delayed). The secondary factors were wheat cultivars (Zare and Heidari with winter growth habit, Pishgam and Alvand with the mid-growth habit, and Pishtaz and Sirvan with spring growth habit). The results of the standard germination test related to the seeds resulting from this research indicated that the highest thousand kernel weight and alpha-amylase activity with winter growth habit were obtained on October 11 planting date. On the other hand, the delay in sowing due to the increase in electrical conductivity reduced the germination rate and percentage, especially in the cultivars with winter growth type. It seems that the activity of enzymes involved in seed germination, including the activity of the alpha-amylase enzyme, could be affected by delays in planting in winter cultivars through increasing the electrical conductivity. Winter cold on the planting date of October 11 in the cultivars with spring growth type caused the production of weaker seedlings. However, the dry weight of seedlings in cultivars with spring and intermediate growth type was greater than the winter cultivars on December 10. In general, the delayed planting significantly reduced germination rate and percentage, especially in cultivars with winter growth habits. Therefore, it is recommended to use intermediate and spring cultivars in delayed cultivation.

In order to investigate the effect of various priming methods on physiological and biochemical traits of French bean seedling under cadmium chloride stress, a factorial experiment was conducted in a completely randomized design with three replications in the laboratory of the Faculty of Agriculture, Mohaghegh Ardabili University, Iran. Factors included three levels of cadmium chloride (0 (control), 100 and 200 mg/L) and four levels of priming (content control (no priming), distilled water, mannitol and salicylic acid each with a concentration of 100 mg/L) were for 12 hours. The results showed that priming with salicylic acid increased the percentage and germination rate by 3 to 61% under stress of 100 mg/L cadmium chloride compared to the control treatment. Also, the interaction of salicylic acid and cadmium chloride increased the longitudinal strength and weight of French bean seed by 42 to 160%, shoot and root dry weight by 30 to 400% compared to the control treatment. Therefore, priming with salicylic acid is the best way to increase and improve the growth of red beans under non-stress and cadmium chloride stress.

The first negative effect of waterlogging stress for the plant is the lack of oxygen in the soil. Reduction of available oxygen reduces the development of roots and aerial parts of the plant. In order to evaluate wheat cultivars in Golestan province under experimental oxygen restriction in December 2016 in the greenhouse of Gonbad Kavous University Faculty of Agriculture in a pot and to investigate the effect of waterlogging periods on root traits and physiological characteristics of seedlings of wheat cultivars as a factorial experiment in a completely factorial design. 3 flood levels (zero, 10 and 20 days) and 10 wheat cultivars (Aftab, Azar, Karim, Kuhdasht, Line 17, Sardari, Qaboos, Morvarid and Zagros domes) were performed in 4 replications. Results of germination test shosed that the highest germination percentaged was occurred in kohdasht and the most amount of germination rate was showed in sardari cultivar. The experimental results showed that the effect of waterlogging period, cultivar and cultivar interaction effect on waterlogging on all root traits was significant at 1% level and the effect of flooding stress on chlorophyll a and total chlorophyll at 5% probability level and proline at 1% probability level was significant. Were not significant on carotenoids. Also, the effect of cultivar was significant only on chlorophyll b trait at the level of 1% probability and did not show a significant effect on other traits. The interaction of cultivars in waterlogging on chlorophyll b, carotenoids and proline was significant at the level of 1% probability. Koohdasht cultivar had the highest root length, fresh root weight, root dry weight and root surface density compared to other cultivars and had less fluctuations in stress conditions than other cultivars. The rest was the highest. It is better not to use Azar and Line 17 cultivars in flooded conditions in the early stages of the plant and also Aftab cultivars in weak stress and Zagros in more severe stress. Sardari and Kuhdasht cultivars had the highest content of chlorophyll b and carotenoids at non- stress and 10-day levels, respectively, which produced the highest proline in severe stress.

In order to investigate the effect of water stress and application potassium nanofertilizer on mother plant on germination components of quinoa seed (Chenopodium quinoa Willd), an experiment with two water stress factors at four levels (distilled water (control), -0.3, -0.6. And - 0.9 MPa) using polyethylene glycol and two types of seeds obtained from field experiments (pre-treated) in a completely randomized design with four replications in a petri dish. For this purpose, seed samples were collected from two field experimental treatments (1- received nano- potassium fertilizer for field seeds and 2- field seeds without receiving nano-potassium fertilizer). The results showed that with increasing stress intensity, the germination percentage was significantly reduced and from 91.0% in the control treatment to 77.1% in severe stress conditions. With increasing stress intensity, the germination value was significantly reduced and from 1184 in the control treatment to 784 under severe stress. The longitudinal index of seedling vigor increased from 1411 in the control treatment to 1032 in severe stress conditions. Longitudinal index of seedling vigor in seeds treated with (1204) was significantly superior to untreated seeds with (1175). There was a significant difference between the average daily germination of treated seeds (11.6 days per seed) and untreated seeds (10.5 days per seed). Thus, application of potassium nanofertilizer on mother plant improved the germination components of quinoa seeds and their initial seedling growth.

Due to the presence of phenolic and antioxidant compounds in the Albizia julibrissin, it has been studied extensively in traditional medicine. Due to the impermeable cover of the seed of this plant and the problems related to germination, this study was carried out in vitro to compare the effects of mechanical (hot water) and chemical (bleach and sulfuric acid) dormancy failure on seed germination of A. julibrissin. Treatments included hot water with temperature (55, 65, 75 and 85 ° C) for 10 minutes, bleach for (30 minutes, 1, 12, and 24 hours), different levels of sulfuric acid (0, 2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20 and 22.5%) and control treatment (distilled water) with 4 replications. During different days, the number of germinated seeds was counted until it reached a constant level. Finally, the average germination rate, seed germination percentage, seed vigor index, and allometric coefficient were calculated for different treatments. The results showed that the best germination performance was in the treatment of hot water and sulfuric acid, but the treatment of bleach did not have a significant effect. As a result, it can be said that hot water and sulfuric acid treatment by softening the husk can greatly improve the performance of seed germination indices and in species that do not germinate under normal conditions, their use is recommended, however, the optimal temperature and dose for improving germination performance varies according to plant type and environmental factors which require further research in the future.

The germination is one of the most important processes in the plant life cycle and it has been determined that, if the germination stage is successful, later in the growing stages, plants with proper establishment and better vigor will be created. In this study, the interaction of Ascophyllum nodosum and temperature changes on germination and growth parameters of lentil (Gachsaran cultivar) were investigated. A factorial experiment was carried out based on completely randomized design with 3 replications.The studied treatments included: seaweed extract at levels of 0, 1.5, 2.5, 3.5 and 4.5% and temperature at 3 levels of 20, 25 and 30 °C. Temperature treatments similar to the natural conditions of autumn in Khuzestan province were selected. The results of this study showed that temperatures of 20 and 30°C compared to 25°C significantly reduced all the studied traits (germination percent, germination rate, germination vigor, seed vigor index, endosperm consumption, plumule length, radicle length, seedling length, plumule dry weight and radicle dry weight. Seaweed extract in level of 2.5% in all temperature treatments (20, 25 and 30 °C) compared to the control caused a significant increase in germination vigor, seed vigor index, endosperm consumption, plumule length, seedling length, plumule dry weight and radicle dry weight. High level of seaweed extract (4.5%) compared to the control level had significant negative effects on germination percentage and germination rate, seed vigor index, seedling length, plumule dry weight, plumule length and radicle length. Due to autumn lentil cultivation and temperature changes in this season (temperature range 20 to 30 °C) the use of Ascophyllum nodosum seaweed extract as an affordable and inexpensive biofertilizer to improve the germination and growth parameters of lentil seeds and establishment suitable for seedlings in the above temperature range is recommended.