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1
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The effect of achene heteromorphism on germination in the shaggy soldier [Galinsoga ciliata (Rafin) S.F. Blake]

100%
Kucewicz M., Wardzynska A., Zrobek-Sokolnik A.
Acta Agrobotanica
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2011
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tom 64
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nr 1
Heteromorphic achenes are formed within each capitulum of Galinsoga ciliata (Rafin) S.F. Blake. We examined (1) the effects of the duration of dry storage on germination and (2) the effect of burial in soil on viability and germination of heteromorphic diaspores. Fresh harvested peripheral achenes remained dormant, while central achenes germinated at 60%. Both achene types became non-dormant after one month of dry storage. In successive months of dry storage, peripheral achenes demonstrated a higher germination percentage than central achenes. The peripheral and central achenes showed similar temperature requirements during dry storage. A similar germination pattern was observed in both achene types, with a germination peak in March (96% of peripheral achenes at 12, 26 and 34oC; 90% of central achenes at 26 and 34oC). The germination capacity deteriorated over time. After 19 months of dry storage, both achene morphs failed to germinate at 12oC. At a 26o and 34oC, the same group of achenes continued to germinate at a relatively high level. After six and seven months of soil storage, 90-95% of both achene types remained alive. Dimorphic achenes were characterized by similar germination percentage (89-99%) at all temperature intervals, whereas peripheral achenes exhumed in May were the fastest to germinate. After 18 months of storage in soil (successive growing season), most of the harvested achenes were dead. The studied achenes did not form a permanent seed bank.
2
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The effect of achene heteromorphism on progeny traits in the shaggy soldier [Galinsoga ciliata (Rafin) S. F. Blake]

100%
Kucewicz M., Gojlo E., Kowalska A.
Acta Agrobotanica
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2010
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tom 63
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nr 2
The shaggy soldier [Galinsoga ciliata (Rafin) S. F. Blake], family Asteraceae] is an invasive species that poses a growing threat to crop production. This annual plant produces heteromorphic achenes in a capitulum type inflorescence. The objective of this study was to compare selected morphological and phenological parameters and the success of generative reproduction in plants developed from peripheral and central achenes of the capitulum. The somatic variability of G. ciliata diaspores contributed to differences in the growth rates, development and fertility of the resulting populations. The progeny of central diaspores developed at a slower rate than the individuals derived from peripheral achenes, but at the end of their life cycle, the offspring of dimorphic achenes formed homogenous groups as regards height values. On average, the initial phenophases of G. ciliata plants derived from central achenes began one day later, and they entered the flowering stage eight days later than the individuals developed from peripheral seeds. At the initial growth stage (experimental day 65 to 83), the progeny of central achenes produced fewer capitula. On day 133, the individual fertility of the plants derived from central diaspores was 10% higher on average in comparison with the offspring of peripheral achenes.
3

The ecological importance of seed dimorphism in corn spurry (Spergula arvensis L.). 2. The effects of nitrate concentrations and temperature on seed germination

84%
Kucewicz M., Gojlo E.
Polish Journal of Ecology
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2013
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tom 61
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nr 4
Spergula arvenis produces two types of seeds that differ in the absence (non papillate, NP) or presence (papillate, P) of papilla on the seed coat. Corn spurry inhabits cultivated soils and ruderal fields and usually encounters substantial variations in soil nutrients. The objective of this study was to determine the effects of nitrate concentrations and temperature (10–30°C) on the germination of heteromorphic seeds. NP and P seeds were characterized by different nitrate optima, dormancy-breaking temperature and initial germination times. NP seeds germinated better and faster than P seeds. NP seeds germinated at all nitrate solutions and all temperatures. NP seeds responded to 5 mM nitrate concentration at 15, 20 and 30°C. In 25 and 50 mM KNO₃ solution, the germination was relatively high and leveled out at a wider temperature range (15–30°C). The highest germination of NP seeds was at 25°C (25, 50 mM KNO₃). NP seeds began to germinate on the second day of the germination test at 15–30°C (in 25 mM KNO₃ solution) and at 20–30°C (in 50 mM KNO₃ solution). The germination percentage of P seeds was lower than NP seeds under identical conditions. P seeds in water failed to sprout at any of the applied incubation temperatures. Seeds incubated in low and medium nitrate concentrations did not germinate or germinated weakly at all temperatures. Seed dormancy was released in solutions with high nitrate levels incubated at 10–25°C. The highest germination of P seeds was at 50 mM solution and at 15°C. Under these conditions, the P seeds germinated the most (reaching 43%), with the initial germination being observed on experimental day 3,7. P seeds had more requirements for germination than NP seeds. However, in 50 mM KNO₃ solution the range of temperatures over which these seeds were able to germinate was the same regardless of seed type. Nevertheless, the percentage of NP germinants was still much higher. The different requirements for germination of NP and P seeds may result in the production of two offspring cohorts that differ in response to nitrate levels in the soil, population density and temperature conditions. Most likely, this germination strategy is an important mechanism of ecological adaptation that enables the survival of S. arvensis plants in an unpredictable environment.
4

Pollen heteromorphism in wild and ornamental pansies (Sect. Melanium, Violaceae)

67%
Slomka A., Kuta E., Pilarska M., Kellner K., Kawalec P., Bohdanowicz J.
Acta Biologica Cracoviensia. Series Botanica. Supplement
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2008
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tom 50
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nr 1
5

Cytogenetic studies of the genus Tettigonia [Orthoptera, Tettigonioidea, Tettigoniinae]. II. Heteromorphism of C-bands

67%
Warchalowska-Sliwa E., Maryanska-Nadachowska A.
Folia Biologica
|
1995
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tom 43
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nr 3-4
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