Evaluation of dormancy and germination responses to temperature in<i>Carduus acanthoides and Anagallis arvensis</i>using a screening system, and relationship with field-observed emergence patterns

Kruk, Betina Claudia; Benech‐Arnold, Roberto L.

doi:10.1017/s096025850000009x

Cited by 24 publications

(10 citation statements)

References 22 publications

(31 reference statements)

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“…As expected, fluctuating temperatures promoted total seed germination in relation to that observed at constant temperature. This is in agreement with previous results of Soriano et al (1963) for B. campestris, Kruk and Benech-Arnold (2000) for C. acanthoides, and Forcella and Wood (1986) for C. vulgare. In contrast, our C. vulgare results under fluctuating temperatures were inconsistent with those published by Groves and Kaye (1989); the higher incubation temperatures used in their studies (20/ 308C) or a higher dormancy level in their seeds might account for these differences.…”

Section: Discussionsupporting

confidence: 94%

Incubation under fluctuating temperatures reduces mean base water potential for seed germination in several non-cultivated species

Huarte

Benech‐Arnold

2005

Seed Sci. Res.

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Seeds of Carduus acanthoides, Cynara cardunculus, Cirsium vulgare, Brassica campestris, and Sisymbrium altissimum were incubated at a range of decreasing osmotic potentials (C o ) under fluctuating temperatures or the median temperature of the fluctuation cycle. Fluctuating temperatures promoted total seed germination in water and at reduced osmotic potential. Total germination was reduced as the C o decreased. However, this trend was smallest under fluctuating temperatures, signalling a higher tolerance of seeds to reduced osmotic potential. Effects of osmoticum and temperature were modelled with the hydrotime model. The parameters estimated from the model, the hydrotime constant (u H ), the mean base water potential C b (50) and its standard deviation (s Cb ) gave good descriptions of germination time courses. For all species, incubation under fluctuating temperatures shifted C b (50) values downwards without modifying their distribution substantially. This accounted for the greater tolerance of germination to reduced C o under fluctuating temperatures. To confirm that these effects were mediated by temperature fluctuations per se, the behaviour of C. acanthoides and C. cardunculus incubated at the minimum, the mean and the maximum temperature of the fluctuation cycle was also analysed. Constant maximum and minimum temperatures of the cycle did not stimulate germination, nor did they shift C b (50) towards more negative values. The hydrotime model provides a physiologically based quantitative description for germination promotion due to fluctuating temperature.

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Section: Discussionsupporting

confidence: 94%

Incubation under fluctuating temperatures reduces mean base water potential for seed germination in several non-cultivated species

Huarte

Benech‐Arnold

2005

Seed Sci. Res.

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“…The germination test system (Washitani, ) consisted in exposing one batch of seeds to gradually increasing temperatures from 4°C to 36°C in steps of 4°C ( IT‐regime ) and a second batch to gradually decreasing temperatures from 36°C to 4°C ( DT‐regime ). As the germination rate is generally higher at higher temperatures in the physiological range, the duration of exposure differed depending on the prevailing temperature: 7 days at 4°C and 8°C, 5 days at 12°C and 16°C, 4 days at 20°C and 24°C, 3 days at 28°C and 2 days at 32°C and 36°C (modified from Kruk & Benech‐Arnold, , ). The number of germinated seeds was recorded immediately before a temperature change and at the end of the test.…”

Section: Methodsmentioning

confidence: 99%

“…For example, seeds of Portulaca oleracea L. have low seed dormancy at the end of winter, but incubating seeds at low temperatures under controlled conditions does not reduce the level of seed dormancy during the same period, showing that other factors interact in weed dormancy breaking (Kruk & Benech‐Arnold, ). It has also been observed that high temperatures do not induce secondary dormancy in P. oleracea , but rather cause the opposite effect and that the effect of temperature on the level of seed dormancy can be modulated by soil moisture (Kruk & Benech‐Arnold, , ). Moreover, once they have reached a low dormancy level, most weed seed populations require the termination of dormancy through exposure to light (Kruk et al ., ) and/or fluctuating temperatures (Thompson et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Dormancy, germination and emergence ofUrochloa panicoidesregulated by temperature

Ustarroz¹,

Kruk

Satorre

et al. 2015

Weed Research

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Summary Urochloa panicoides is an annual weed of summer crops. In Argentina, in subhumid areas with monsoon rainfall, it germinates and establishes in a single flush. To (i) identify the environmental factors that modify its seed dormancy level and germination and (ii) quantify the parameters describing the thermal behaviour of the germination and emergence dynamics of this weed under non‐limiting water conditions, we established a set of germination experiments performed (i) under controlled conditions using seeds after ripened for 3 or 6 months in different thermal and hydric conditions and (ii) under field conditions, where the soil temperature was modified by applying different shading levels. Seed dormancy level remained high with 3 months after ripening in all treatments. After 6 months, seeds stored at 4°C in dry conditions did not germinate at any temperature, while seeds stored at 25°C in dry conditions and in situ germinated c. 20% and 60% respectively. Germination percentage was higher in seeds harvested before their natural dispersal. The base, optimum and maximum temperatures for seed germination were 6, 35 and 45°C respectively. Shading reduced the number of emerged seedlings, possibly by reducing the soil thermal amplitude. The results explained the dormancy‐breaking mechanism of U. panicoides that allows a high germination rate in the field when rainfall occurs.

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“…In weed species requiring environmental signals to terminate dormancy, the strength of the regulation of the emergence by the presence of a crop canopy will depend on the overlap between the ‘emergence window’ of the weed (i.e. the period at which the seed population displays minimum dormancy; Kruk & Benech‐Arnold 2000; Vleeshouwers & Kropff 2000) and the density of the crop canopy modifying these signals. The capacity to detect these changes in the thermal and light environments will also depend on the position of the seeds within the soil (Bliss & Smith 1985; Ghersa, Benech‐Arnold & Martinez‐Ghersa 1992), which will determine the probability of a seed germinating, emerging successfully and its relative time of emergence (Grundy, Mead & Burston 2003).…”

Section: Discussionmentioning

confidence: 99%

Light and thermal environments as modified by a wheat crop: effects on weed seed germination

Kruk¹,

Insausti

Razul³

et al. 2006

Journal of Applied Ecology

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Summary 1.Knowledge of the regulatory effects of the crop canopy on weed seed germination is necessary to understand fully the behaviour of weed seed banks during a crop cycle. It is well known that canopy presence interferes with seed germination through modifications to the light and thermal environment, but the changing effect of a growing canopy has not been assessed, thus precluding the identification of shading-intensity thresholds for triggering the different types of canopy-detection mechanisms in different seed populations. 2.Field experiments were performed with artificially modified thermal and light environments, using two types of seed banks (seeds buried or located at the soil surface). Conditions below a wheat canopy were modified to match light and thermal conditions prevailing on bare soil (i.e. soil without vegetation). 3. Most weed emergence patterns during the early stages of crop establishment were not modified by the thermal regime produced by the incipient canopy compared with a bare soil control. However, the reduction of the red : far-red ratio from the bare soil value of 1·2-0·9 below the wheat canopy reduced germination of some weed species located at the soil surface, and the effect could by reversed by far-red filters. 4. The weed Galinsoga parviflora developed two generations during the crop cycle. The modified light and thermal environments beneath an establishing wheat canopy was not sufficient to inhibit the germination of Galinsoga parviflora , even if seeds were located at the soil surface. Only for seeds of the second generation, dispersed from seeds of the first plant generation, was there sufficient modification of the photothermal environment below the wheat canopy to interfere with dormancy termination. 5. Synthesis and applications . Understanding seed responses to modifications in the photothermal environment below a crop canopy (e.g. wheat crop) should allow us to improve weed management strategies by manipulating crop canopy attributes. This could be achieved by modification of sowing date, crop density, spatial arrangement and genotype. For example, increasing the crop plant density would diminish the number of weeds emerging during the first phase of crop establishment. This strategy would be appropriate where weed seeds are predominantly located at the soil surface, typically found in a no-till cropping system.

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Evaluation of dormancy and germination responses to temperature inCarduus acanthoides and Anagallis arvensisusing a screening system, and relationship with field-observed emergence patterns

Cited by 24 publications

References 22 publications

Incubation under fluctuating temperatures reduces mean base water potential for seed germination in several non-cultivated species

Incubation under fluctuating temperatures reduces mean base water potential for seed germination in several non-cultivated species

Dormancy, germination and emergence ofUrochloa panicoidesregulated by temperature

Light and thermal environments as modified by a wheat crop: effects on weed seed germination

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