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The use of high quality sowing material is the fundamental condition for good yielding of crop plants. One of new, unconventional methods of seed quality improvement is low-frequency variable magnetic field. It has been found that this physical factor has a favourable effect on seed germination, emergence and growth of many crop plants. The objective of the study was to determine the effect of low-frequency magnetic field (LFMF) on the germination of radish seeds, with particular emphasis on old seeds. The experimental material were seeds of 7 lots of radish cv. ‘Mila’, with germination capacity of 66.5–92.5%. The age of the seeds was from 1 to 8 years. Seeds from all the lots were treated with variable magnetic field with frequency of 50 Hz, at 3 doses of magnetic induction as follows: 0 (control), 30 and 60 mT for 30 seconds. Then, the seed germination energy and capacity were determined, as well as the length of the hypocotyl and of the radicle of the seedling, dry weight of seedling, and emergence and mean time of emergence. The low frequency magnetic field exposure (30 and 60 mT) improved radish seed germination energy and capacity of every old seed lot. The increase of germination energy of old seeds amounted to 12.3–19.2%, and the increase of germination capacity was 5.8–10%. Magnetic field stimulation caused the increase of germination energy for 3 out of 4 seed lots of high quality but did not affect the improvement of germination capacity of those lots. No significant effect of magnetic field of seeds on the hypocotyl and radicle elongation was observed with the exception of 1 out of the 7 seed lots. For the 2 old seed lots out of the 3 total, magnetic field treatment caused the increase of emergence by 4.4–13.0%.
The problem in the cultivation of scorzonera is often poor, slow and non-uniform field emergence despite the use of seeds with high germination capacity for the sowing. The goal of the study was to determine the effect of pre-sowing laser stimulation of seeds on the germination, emergence and root yield of scorzonera. Seeds were irradiated with a He-Ne laser with wavelength of 632.4 nm. Two doses of laser beam irradiation were applied in terms of surface power density – 6 and 8 mW·cmˉ². Seeds were irradiated 1, 3 and 5 times, and the duration of each irradiation treatment was ca. 0.1 s. Seed treatment with laser light caused an increase of germination capacity, radicle length and dry weight of seedling, and an improvement of field emergence and only a partial increase of the total yield of roots. Depending on the irradiation dose applied, the germination capacity of the seeds increased by 1.5-13.2% in relation to the control. The most beneficial effect on the germination capacity and field emergence was that of the 5-time laser irradiation. Increase of total root yield as a result of pre-sowing seed irradiation was related with increased emergence.
Potential costs to badgers Meles meles (Linnaeus, 1758) of living in groups may be offset by the ability of a group to either improve predator detection, or reduce the time each individual must be vigilant to attain a certain likelihood of predator detection. Using an infra-red video-surveillance system, we show that badgers emerge later from their dens in a population that has been repeatedly subjected to lethal control by humans as compared to badgers from a nearby, undisturbed population. We further illustrate that, despite the apparent lack of a visual or vocal alarm signal to alert group members to a threat, corporate vigilance increases and individual vigilance levels decrease as badgers aggregate in groups (up to 4). These results highlight the pos­sibility that the role of (human) predation in badger social evolution has not been sufficiently considered.
Eragrostis tenuifolia is a weed species that is gaining ground in Brazil. This weed occurs in pastures, grasslands, crop fields, and roadsides. The objective of this study was to examine the effects of different environmental factors on E. tenuifolia seed germination and seedling emergence. The optimum constant temperature for germination was around 35–30°C. It was also found that 85% of seeds germinated under a 30/20°C alternate temperature regime. Light appears to have a positive effect on seed germination. No seedlings emerged when seeds were buried 3 cm or deeper. The results suggested that E. tenuifolia has the potential to spread into pastures and in no-tillage crop systems in Brazil. Measures such as the use of cover crops and/or soil cultivation can be used to limit germination and seedling emergence, respectively.
Although chemical priming agents have been successfully used to improve seed germination, emergence and seedling quality in different plant species, still they are not yet useful for organic cultivation. Marigold is a multipurpose plant and rich source of lutein and gallic acid, to be explored as an organic priming agent. The purpose of this study was to identify an organic priming agent for organic growing and to develop appropriate methods by using two different species of marigold (Tagetes patula L. and T. erecta L.). Herbal tea obtained from the dried flower of marigold was used as a priming agent for eggplant (Solanum melongena L) cv. Pala seeds. Hydropriming and control seeds were compared with organic priming (T. patula and T. erecta) for germination percentage, mean germination time, germination rate, two different emergence tests, seedling height, seedling fresh and seedling dry weights. Data obtained from the application of organic priming (T. patula and T. erecta) showed a difference in both the germination (82 and 80%), and the emergence (73 and 76%) from Controls and Hydropriming. Seeds emerged in, which unprimed in 52 and 39% respectively, when primed with T. patula, emerged in 73 and 56% respectively. The mean germination time and the mean emergence time were shortened compared with Controls and Hydropriming. MET decreased in 1 cm and 2.5 cm depth sowing from 14.0 and 16.1 days than 10.3 and 11.9 days in Emergence-1 and 10.4 and 10.2 days in Emergence 2, respectively. Seedling quality characteristics were examined in the seedling height, the seedling fresh and dry weights of T. patula and T. erecta applications were also statistically significant. This is the first report which results showed that marigold species can be used as a potential organic priming agent.
The cercaria of Haplorchis pumilio exhibited diurnal pattern in the emergence from the snail host, with peak between 10 am and 12 noon and limited emergence during night. Continuous light permitted emergence to continue rhythmically while continuous dark has suppressed the emergence. Inversion of photoperiod has resulted in immediate reversal of the emergence pattern. Variation is found in the numbers of cercariae released by different individuals of snails and by the single snail on different days, but consistency is maintained in the emergence pattern. Temperature of 30-35°C is found to be favourable for the cercarial emergence. The results of the study demonstrate that emergence pattern is influenced by both exogenous and endogenous factors.
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