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Effect of diurnal fluctuating versus constant temperatures on germination of 445 species from the eastern Tibet Plateau.

Liu K, Baskin JM, Baskin CC, Bu H, Du G, Ma M - PLoS ONE (2013)

Bottom Line: Overall, species growing in disturbed ground showed a significant germination response to temperature fluctuation, but those living in Alpine/subalpine meadow, forest margin /scrub, marshland and dry sunny slope habitats did not.Species distributed only at high elevations (>2000m) did not show a significant germination response to temperature fluctuation, whereas those occurring at both high and low elevations had a significant positive response.Germination of forbs had a positive response to temperature fluctuation, but germination of graminoids did not.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Glassland and Agroecosystems, School of Life Sciences, Lanzhou University, Lanzhou, PR China.

ABSTRACT
Germination response to fluctuating temperatures is a mechanism by which seeds detect gaps in vegetation canopies and depth of burial in soil, and it is very important for plants. Thus, studies on the effect of fluctuating temperature on germination at the community level are valuable for understanding community structure and biodiversity maintenance. We determined the effects of two alternating temperatures (5/25°C and 10/20°C) and one constant temperature (15°C) on seed germination of 445 species in a grassland community on the eastern Tibet Plateau. Seed mass was determined for each species, and data on habitat, type of life cycle, altitudinal distribution and functional group (graminoids or forbs) were obtained from the literature. Taking all species into account, alternating temperatures increased germination percentages regardless of amplitude. Overall, species growing in disturbed ground showed a significant germination response to temperature fluctuation, but those living in Alpine/subalpine meadow, forest margin /scrub, marshland and dry sunny slope habitats did not. Species distributed only at high elevations (>2000m) did not show a significant germination response to temperature fluctuation, whereas those occurring at both high and low elevations had a significant positive response. Germination of annuals/biennials was significantly promoted by 5/25°C, but not by 10/20°C, whereas germination of perennials was significantly promoted by both 5/25°C and 10/20°C. Small-seeded species were more likely than large-seeded species to respond positively to fluctuating temperatures. Germination of forbs had a positive response to temperature fluctuation, but germination of graminoids did not. Regeneration ability by seeds for about 36% of the species studied in the grassland can be increased by temperature fluctuation. The differential response among species to alternating vs. constant temperatures helps maintain community structure and biodiversity. A positive germination response to temperature fluctuation can partly explain why there are more forbs in degraded meadows.

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Relative importance of response groups I, II, III and IV when habitat (a), seed mass (b), life cycle type (c), altitudinal distribution (d) and functional group (e) are considered.I, species with a negative germination response to temperature fluctuation; II, species with a positive germination response to temperature fluctuation; III, species that cannot germinate well regardless of the temperature fluctuation; IV, species that can attain a high germination percentage regardless of the temperature fluctuation. AM: alpine/ subalpine meadow; DG: disturbed ground; FS: forest margin/scrub; ML: marshland; DS: dry sunny slope.
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pone-0069364-g002: Relative importance of response groups I, II, III and IV when habitat (a), seed mass (b), life cycle type (c), altitudinal distribution (d) and functional group (e) are considered.I, species with a negative germination response to temperature fluctuation; II, species with a positive germination response to temperature fluctuation; III, species that cannot germinate well regardless of the temperature fluctuation; IV, species that can attain a high germination percentage regardless of the temperature fluctuation. AM: alpine/ subalpine meadow; DG: disturbed ground; FS: forest margin/scrub; ML: marshland; DS: dry sunny slope.

Mentions: Based on habitat, the order of proportion of species that responded positively to temperature fluctuation was disturbed ground > forest margin/scrub > marshland > alpine/subalpine meadow >dry sunny slope (Figure 2a). Our results (Table 1Figure 3) indicated that, overall, species growing in disturbed ground showed a significant germination response to alternating temperature with a large amplitude (5/25°C), but not to alternating temperature with a small amplitude (10/20°C). Species living in alpine/subalpine meadow, forest margin /scrub, marshland and dry sunny slope habitats did not have a significant germination response to alternating temperature, regardless of the amplitude.


Effect of diurnal fluctuating versus constant temperatures on germination of 445 species from the eastern Tibet Plateau.

Liu K, Baskin JM, Baskin CC, Bu H, Du G, Ma M - PLoS ONE (2013)

Relative importance of response groups I, II, III and IV when habitat (a), seed mass (b), life cycle type (c), altitudinal distribution (d) and functional group (e) are considered.I, species with a negative germination response to temperature fluctuation; II, species with a positive germination response to temperature fluctuation; III, species that cannot germinate well regardless of the temperature fluctuation; IV, species that can attain a high germination percentage regardless of the temperature fluctuation. AM: alpine/ subalpine meadow; DG: disturbed ground; FS: forest margin/scrub; ML: marshland; DS: dry sunny slope.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3722265&req=5

pone-0069364-g002: Relative importance of response groups I, II, III and IV when habitat (a), seed mass (b), life cycle type (c), altitudinal distribution (d) and functional group (e) are considered.I, species with a negative germination response to temperature fluctuation; II, species with a positive germination response to temperature fluctuation; III, species that cannot germinate well regardless of the temperature fluctuation; IV, species that can attain a high germination percentage regardless of the temperature fluctuation. AM: alpine/ subalpine meadow; DG: disturbed ground; FS: forest margin/scrub; ML: marshland; DS: dry sunny slope.
Mentions: Based on habitat, the order of proportion of species that responded positively to temperature fluctuation was disturbed ground > forest margin/scrub > marshland > alpine/subalpine meadow >dry sunny slope (Figure 2a). Our results (Table 1Figure 3) indicated that, overall, species growing in disturbed ground showed a significant germination response to alternating temperature with a large amplitude (5/25°C), but not to alternating temperature with a small amplitude (10/20°C). Species living in alpine/subalpine meadow, forest margin /scrub, marshland and dry sunny slope habitats did not have a significant germination response to alternating temperature, regardless of the amplitude.

Bottom Line: Overall, species growing in disturbed ground showed a significant germination response to temperature fluctuation, but those living in Alpine/subalpine meadow, forest margin /scrub, marshland and dry sunny slope habitats did not.Species distributed only at high elevations (>2000m) did not show a significant germination response to temperature fluctuation, whereas those occurring at both high and low elevations had a significant positive response.Germination of forbs had a positive response to temperature fluctuation, but germination of graminoids did not.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Glassland and Agroecosystems, School of Life Sciences, Lanzhou University, Lanzhou, PR China.

ABSTRACT
Germination response to fluctuating temperatures is a mechanism by which seeds detect gaps in vegetation canopies and depth of burial in soil, and it is very important for plants. Thus, studies on the effect of fluctuating temperature on germination at the community level are valuable for understanding community structure and biodiversity maintenance. We determined the effects of two alternating temperatures (5/25°C and 10/20°C) and one constant temperature (15°C) on seed germination of 445 species in a grassland community on the eastern Tibet Plateau. Seed mass was determined for each species, and data on habitat, type of life cycle, altitudinal distribution and functional group (graminoids or forbs) were obtained from the literature. Taking all species into account, alternating temperatures increased germination percentages regardless of amplitude. Overall, species growing in disturbed ground showed a significant germination response to temperature fluctuation, but those living in Alpine/subalpine meadow, forest margin /scrub, marshland and dry sunny slope habitats did not. Species distributed only at high elevations (>2000m) did not show a significant germination response to temperature fluctuation, whereas those occurring at both high and low elevations had a significant positive response. Germination of annuals/biennials was significantly promoted by 5/25°C, but not by 10/20°C, whereas germination of perennials was significantly promoted by both 5/25°C and 10/20°C. Small-seeded species were more likely than large-seeded species to respond positively to fluctuating temperatures. Germination of forbs had a positive response to temperature fluctuation, but germination of graminoids did not. Regeneration ability by seeds for about 36% of the species studied in the grassland can be increased by temperature fluctuation. The differential response among species to alternating vs. constant temperatures helps maintain community structure and biodiversity. A positive germination response to temperature fluctuation can partly explain why there are more forbs in degraded meadows.

Show MeSH
Related in: MedlinePlus