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1
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Mutagenic effect on seed germination, seedling growth and seedling survival of pigeon pea (Cajanus cajan (L.) Millsp)

100%
Ariraman M., Gnanamurthy S., Dhanavel D., Bharathi T., Murugan S.
International Letters of Natural Sciences
|
2014
|
tom 16
In the present investigation the seeds of Pigeon pea (Cajanus cajan (L.) Millsp) were treated with different doses of gamma radiation (05KR, 10KR, 15KR, 20KR, 25KR, 30KR, 35KR, 40KR, 45KR, and 50KR) and concentration of Ethyl Methane Sulphonate (05mM, 10mM, 15mM, 20mM, 25mM, 30mM, 35mM, 40mM, 45mM, and 50mM) for studying seed germination, seedling height, (shoot and root), seedling injury, seedling vigour index, and seedling survival of plants at 30th day. The seed germination percentage was decreased with increased in the concentration/doses when compared to control. The LD50 (Lethal dose) value was determined based upon the seed germination percentage. The 50 percentage of seed germination and reduction was observed in 20KR of gamma rays and 25mM of EMS and it is considered as LD50 value for both the treatments. The decrease in seed germination was more prominent with gamma rays than that of EMS treatments. The seedling parameters of gamma rays and EMS treated seedlings were progressively decreased with increase dose/concentration in all mutagenic treatments when compared to control. The maximum seedling parameters were observed in 05KR of gamma rays and 05mM of EMS. Minimum seedling parameters were observed in 50mM of EMS and 50KR of gamma rays respectively.
2

Elodeid species as nursery beds for the successful seed restoration of Vallisneria spiralis L.

100%
Cao J., Ruan H.
Polish Journal of Ecology
|
2015
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tom 63
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nr 1
Submerged aquatic vegetation (SAV) is often difficult to restore due to their low seedling survival rates. Therefore, we hypothesized that the elodeid macrophytes serve as effective “nursery” areas to promote success for seedlings of other SAV. However, the high density of the elodeid community may inhibit the establishment of other SAV. An experiment was conducted to explore this “nursery effect” as a restoration approach to increase the success of seed restoration. Two elodeid species were pre-planted into mesocosms to create three levels of “nursery beds” i.e., bare, sparse (approx. 100 g m⁻²) and dense (approx. 200 g m⁻²). Seeds of Vallisneria spiralis were then placed into these beds to test the seed germination and growth of V. spiralis seedlings. After three months, seed germination was lower in the bare treatment than in the sparse and dense treatments. The growth of V. spiralis seedlings was greater in the sparse treatment than in the bare and dense treatments. These results revealed that the established elodeid bed had a positive effect on the seed restoration of V. spiralis but that the restoration efficiency was significantly reduced by the high-density cover of the elodeid community.
3

Seedling survival and dynamics of upper timberline in Central Apennines

84%
Catorci A., Scapin W., Tardella F. M., Vitanzi A.
Polish Journal of Ecology
|
2012
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tom 60
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nr 1
Despite several studies on the timberline dynamics in Europe were carried out in the last decades, very few papers refer to mountain areas where the timberline is composed of broadleaved trees, and no research was conducted on the dynamics of Apennine beech timberline in relation to seedling survival. The research aim was to analyse the beech wood timberline dynamics in the central Apennines, with reference to seedling survival. Furthermore, factors affecting seedling survival were identified. To assess the forest ecotone dynamics, vegetation layer cover, rock fragment cover and information about forest management and krummholz occurrence were collected in sampling plots placed over 1,600 m a.s.l., on north-facing slopes. The beech seedlings occurring in Brachypodium genuense-dominated stands above the timberline were counted and monitored along two growing seasons. Soil temperature, soil moisture, and photosynthetically active radiation available for seedlings (PHAR) in grasslands above timberline were measured. The research outputs indicate that timberline is not a natural boundary and that there is no evidence of its extension upwards. The greatest number of beech seedlings was recorded in late spring. The one-year mortality rate ranged from 71 to 100%. None of the seedlings still alive in the early autumn of the first year were recorded in the following spring. The competitive exclusion by Brachypodium genuense individuals, which limit the incident PHAR, and the low soil moisture during summer, were identified as the main factors that account for the high mortality of seedlings and affect beech regeneration above timberline. The effect of competition is probably intensified by the lack of pioneer shrubs which could otherwise serve as nurse plants for beech seedlings and protect them from browsing by wild ungulates. Thus, both the current and the past land use may be considered as driving forces in timberline dynamics. Probably, also the trend of global warming, that in the Mediterranean and sub-Mediterranean climatic context would determine the increase of summer drought stress, could worsen the effect of competitive exclusion of beech seedlings, so that it can be hypothesized that the expansion upwards of the upper timberline in the Apennines could be totally blocked.
4

Effect of indolebutyric acid on root regeneration and seedling survival after transplanting of three Pistacia species

67%
Mobli M., Baninasab B.
Journal of Fruit and Ornamental Plant Research
|
2009
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tom 17
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nr 1
5-13
The species of Pistacia vera, P. mutica and P. khinjuk can be used as rootstocks for pistachio cultivars due to their adaptability to severe environmental conditions and resistance to some pests and diseases. However, low percentage of seedling survival following transplanting has been a major problem. This study was conducted to test the effects of different concentrations of indolebutyric acid (IBA) on root regeneration of transplanted bare-rooted seedlings of these three species. The seedlings treated with IBA at all concentrations tested (1000, 1500, 2000, 2500 and 3000 mg l-1) developed more roots, which were longer and had higher fresh and dry weight, and increased the survival rate of treated seedlings compared to their respective controls. The most effective concentrations in this respect were 2000 and 2500 mg l-1. There was a significant interaction between the species and IBA concentration. Shoot height, root and shoot diameter, leaf number, shoot fresh and dry weight were not affected by IBA. Results also showed that survival rate of the seedlings was significantly correlated with root number, length and fresh and dry weight.
5
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Sensitivity of 24 sugar beet cultivars to water deficit during emergence

51%
Skonieczek P., Nowakowski M., Piszczek J., Matyka L., Zurek M., Rychcik B., Kazmierczak M.
Acta Agrophysica
|
2018
|
tom 25
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nr 4
The aim of this study was to evaluate, in 3 experiments, seedling emergence and sensitivity to temporary soil water deficit in 24 sugar beet cultivars. Seeds were sown in 2012 and 2013 in containers (60x40x15 cm) filled with a soil classified as Luvisol (with 65% field water capacity) and placed in an phytotron. For 2 weeks, until the first counting of seedlings, the temperature was maintained at 10°C, and then it was raised to 15°C to simulate the temperature increase occurring in the spring period in the field. At the first stage of the study, the number of emerged seedlings was counted 14 and 21 days after sowing. After the following 2 weeks, in the second pair of leaves unfolded stage, the plants were not watered for 6 days to evaluate on day 7 their sensitivity to soil moisture deficit. The above cycle was repeated, and the plants were not supplied with water over a period of 6 successive days. At the end of that period, the seedlings were counted, and the ratio of surviving seedlings to the number of seedlings before the first water deficit was calculated again. Under controlled conditions, high emergence capacity (14 days after sowing) was noted in cv. Janosik, Julietta, and Silvetta, whereas very high final emergence capacity (21 days after sowing) was observed in cv. Agent and Julietta. Sugar beet cv. Huzar, Lukas, and Expert were the least sensitive to soil moisture deficit and they can, therefore, be recommended for cultivation in areas prone to water deficit at the beginning of the growth season. Among the conventional cultivars of sugar beet, there are also cultivars with a low susceptibility to drought that increasingly more often causes problems in regions of intensive production of root crops.
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