| چکیده انگلیسی مقاله |
Introduction
Asian spider flower weed (Cleome viscose L.) has recently entered the flora of weeds in Golestan province and causes significant damage to farmers in Golestan province every year. The seed production potential of this weed is high (> 38000 seeds per plant). Also, the seeds of this weed are very small (weight of 1000 seeds is equal to 1.05 grams) and thay have dormancy. Thus the annual shedding of the seeds of this weed and their accumulation in the soil form a stable seed bank that can be the source of weed contamination in fields for many years. Therefore, understanding the stability of the seed bank of this plant is very important and is very important in the successful management of this weed.
Materials and Methods
Ripe seeds of Asian spider flower were collected from a soybean field in Minoodasht city-Golestan province at the end of October and were transferred to the seed technology laboratory of Gorgan University of Agricultural Sciences and Natural Resources to perform various tests. Immediately after harvest, the germination ability of fresh seeds was examined at 30 °C. The germination percentage of freshly harvested seeds was 7%. In order to investigate the effect of After- ripening on the germination ability of Asian spider flower seeds, a part of the seeds was stored in the laboratory. In order to investigate the stability of the seed bank of this weed, 65 grams of sieved soil along with 13 grams of Asian spider flower seeds were placed in 26 mesh bags and buried at two depths of 10 and 20 cm on November 4, 1401. Sampling was done at 15, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330 and 360 days after burial. At each sampling stage, the number of germinated seeds in the soil, null, dead and healthy seeds were counted carefully. Healthy seeds were used to perform tests to determine seed moisture, electrical conductivity, and germination at different temperatures of 15, 20, 25, 30, and 35 degrees Celsius and in two conditions of light and darkness, as well as the use of gibberellic acid and its non-use.
Results and Discussion
The freshly harvested seeds of Asian spider flower had very little germination. After- ripening (in laboratory conditions or buried in soil) and gibberellic acid were effective in eliminating the commune, so that it increased the germination of Asian spider flower seeds in both dark and light conditions. With the removal of the seed dormancy, the germination of the seeds of this plant has occurred in a wider range of temperatures. The germination response of Asian spider flower seed during the after- ripening and burial period was different to light and darkness and the ambient temperature also had an effect on it. Examining changes in the percentage of live and dead seeds at two depths of 10 and 20 cm showed that in both burial depths, the percentage of live seeds decreased over time and the number of dead seeds increased. So that in the last sampling, corresponding to 360 days after burial, the number of live seeds in two depths of 10 and 20 cm was 12 and 23%, respectively.
Conclusion
Considering that the germination percentage of Asian spider flower seeds increased during the after- ripening period and the use of gibberellic acid also improved the germination during the after-ripening period, it seems that the seeds dormancy of this plant are of physiological type. The occurrence of low temperatures in winter caused the removal dormancy of the buried seeds, and vice versa, the occurrence of high temperatures in the summer caused the induction of secondary dormancy in the remaining seeds. According to the increasing trend of the number of dead seeds in two depths of 10 and 20 cm, it can be said that the emptying of the seed bank of this weed occurred faster in the depth of 10 cm. Asian spider flower seed bank is a permanent type. Therefore, the frequent dropping of this weed's seed in the soil can turn this plant into a permanent and serious challenge for farmers. |