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A comparative study of germination ecology of four Papaver taxa.

Karlsson LM, Milberg P - Ann. Bot. (2007)

Bottom Line: Germination preferences varied between taxa, resulting in different temperature optima and intervals for germination, and dormancy strength was to some extent taxon-specific, but highly variable.Hence, there is no need to interpret the within-taxon temporal differences in seedling emergence as local adaptations.Instead, emergence will be distributed over several seasons, regardless of local climate, weather and soil cultivation methods.

View Article: PubMed Central - PubMed

Affiliation: IFM Division of Ecology, Linköping University, SE-581 83 Linköping, Sweden.

ABSTRACT

Background and aims: Comparative studies of closely related taxa can increase understanding of adaptations and changes in seed dormancy and germination preferences in an evolutionary perspective. For such studies, a method to describe and compare the performance of taxa in a general way is needed. The germination ecology of four Papaver taxa was studied with the aim of describing and comparing their responses to different seasonal temperature regimes.

Methods: Germination of Papaver argemone, P. rhoeas, P. dubium ssp. dubium and P. dubium ssp. lecoqii was investigated in three different artificial climates over 2.5 years. Seeds were collected in southern Sweden, and samples from different populations were used as replicates of taxa.

Key results: Despite substantial intra-taxa variation, there were clear taxon-specific responses. Most germination occurred in the warmest climate. In general, the warmer the climate the more germination occurred in autumn instead of spring. Papaver argemone, phylogenetically most distant from the other taxa, was, in contrast to the others, restricted to germinating only at lower temperatures.

Conclusions: Seed dormancy and germination may be described by dormancy pattern, germination preferences and dormancy strength. The general dormancy pattern was a common feature for these taxa and therefore probably an evolutionary conservative character. Germination preferences varied between taxa, resulting in different temperature optima and intervals for germination, and dormancy strength was to some extent taxon-specific, but highly variable. The dormancy pattern explained how the taxa can perform as winter annuals in warmer climates, but mainly as summer annuals in colder climates. Hence, there is no need to interpret the within-taxon temporal differences in seedling emergence as local adaptations. In the field, an entire seed cohort will not germinate during a single season. Instead, emergence will be distributed over several seasons, regardless of local climate, weather and soil cultivation methods.

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Germination of four Papaver taxa when subjected to three different artificial climates and provided with light during daytime. Four seed batches were collected from each taxon. Seed batches were collected either during summer or autumn [each symbol shape (triangles, squares or circles) shows one collection site], and all were subjected to two starting points in the annual cycles: summer and autumn.
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MCM045F3: Germination of four Papaver taxa when subjected to three different artificial climates and provided with light during daytime. Four seed batches were collected from each taxon. Seed batches were collected either during summer or autumn [each symbol shape (triangles, squares or circles) shows one collection site], and all were subjected to two starting points in the annual cycles: summer and autumn.

Mentions: Light condition, time, climate, taxon, starting point and time of collection were all important explanatory factors (Table 4). Light condition was the single most important factor (Table 4), with much more germination in light (Fig. 3) than in darkness (Fig. 4). Overall, the warmer the climate the more germination occurred, both in light (Fig. 3) and in darkness (Fig. 4). In general, the taxa differed (Table 4), with P. rhoeas germinating most, and P. argemone and P. dubium ssp. dubium least and about the same. Seed batches collected during the autumn germinated more than those collected in the summer (Fig. 3).


A comparative study of germination ecology of four Papaver taxa.

Karlsson LM, Milberg P - Ann. Bot. (2007)

Germination of four Papaver taxa when subjected to three different artificial climates and provided with light during daytime. Four seed batches were collected from each taxon. Seed batches were collected either during summer or autumn [each symbol shape (triangles, squares or circles) shows one collection site], and all were subjected to two starting points in the annual cycles: summer and autumn.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2802914&req=5

MCM045F3: Germination of four Papaver taxa when subjected to three different artificial climates and provided with light during daytime. Four seed batches were collected from each taxon. Seed batches were collected either during summer or autumn [each symbol shape (triangles, squares or circles) shows one collection site], and all were subjected to two starting points in the annual cycles: summer and autumn.
Mentions: Light condition, time, climate, taxon, starting point and time of collection were all important explanatory factors (Table 4). Light condition was the single most important factor (Table 4), with much more germination in light (Fig. 3) than in darkness (Fig. 4). Overall, the warmer the climate the more germination occurred, both in light (Fig. 3) and in darkness (Fig. 4). In general, the taxa differed (Table 4), with P. rhoeas germinating most, and P. argemone and P. dubium ssp. dubium least and about the same. Seed batches collected during the autumn germinated more than those collected in the summer (Fig. 3).

Bottom Line: Germination preferences varied between taxa, resulting in different temperature optima and intervals for germination, and dormancy strength was to some extent taxon-specific, but highly variable.Hence, there is no need to interpret the within-taxon temporal differences in seedling emergence as local adaptations.Instead, emergence will be distributed over several seasons, regardless of local climate, weather and soil cultivation methods.

View Article: PubMed Central - PubMed

Affiliation: IFM Division of Ecology, Linköping University, SE-581 83 Linköping, Sweden.

ABSTRACT

Background and aims: Comparative studies of closely related taxa can increase understanding of adaptations and changes in seed dormancy and germination preferences in an evolutionary perspective. For such studies, a method to describe and compare the performance of taxa in a general way is needed. The germination ecology of four Papaver taxa was studied with the aim of describing and comparing their responses to different seasonal temperature regimes.

Methods: Germination of Papaver argemone, P. rhoeas, P. dubium ssp. dubium and P. dubium ssp. lecoqii was investigated in three different artificial climates over 2.5 years. Seeds were collected in southern Sweden, and samples from different populations were used as replicates of taxa.

Key results: Despite substantial intra-taxa variation, there were clear taxon-specific responses. Most germination occurred in the warmest climate. In general, the warmer the climate the more germination occurred in autumn instead of spring. Papaver argemone, phylogenetically most distant from the other taxa, was, in contrast to the others, restricted to germinating only at lower temperatures.

Conclusions: Seed dormancy and germination may be described by dormancy pattern, germination preferences and dormancy strength. The general dormancy pattern was a common feature for these taxa and therefore probably an evolutionary conservative character. Germination preferences varied between taxa, resulting in different temperature optima and intervals for germination, and dormancy strength was to some extent taxon-specific, but highly variable. The dormancy pattern explained how the taxa can perform as winter annuals in warmer climates, but mainly as summer annuals in colder climates. Hence, there is no need to interpret the within-taxon temporal differences in seedling emergence as local adaptations. In the field, an entire seed cohort will not germinate during a single season. Instead, emergence will be distributed over several seasons, regardless of local climate, weather and soil cultivation methods.

Show MeSH