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Quantitative description of the effect of stratification on dormancy release of grape seeds in response to various temperatures and water contents.

Wang WQ, Song SQ, Li SH, Gan YY, Wu JH, Cheng HY - J. Exp. Bot. (2009)

Bottom Line: The effect of stratification on dormancy release of grape seeds crossing from the sub- to the supraoptimal range of temperatures and water contents was analysed by modified threshold models.The thermal time approaches effectively quantified dormancy release only at suboptimal temperature, but a quantitative method to integrate the occurrence of dormancy release and induction at the same time could describe it well at either sub- or supraoptimal temperatures.Dormancy release in grape seeds can occur across a very wide range of conditions, which has important implications for their ability to adapt to a changeable environment in the wild.

View Article: PubMed Central - PubMed

Affiliation: Institute of Botany, the Chinese Academy of Sciences, Beijing, China.

ABSTRACT
The effect of stratification on dormancy release of grape seeds crossing from the sub- to the supraoptimal range of temperatures and water contents was analysed by modified threshold models. The stratification impacted on dormancy release in three different ways: (i) dormancy was consistently released with prolonged stratification time when stratified at temperatures of <15 degrees C; (ii) at 15 degrees C and 20 degrees C, the stratification effect initially increased, and then decreased with extended time; and (iii) stratification at 25 degrees C only reduced germinable seeds. These behaviours indicated that stratification could not only release primary dormancy but also induce secondary dormancy in grape seed. The rate of dormancy release changed linearly in two phases, while induction increased exponentially with increasing temperature. The thermal time approaches effectively quantified dormancy release only at suboptimal temperature, but a quantitative method to integrate the occurrence of dormancy release and induction at the same time could describe it well at either sub- or supraoptimal temperatures. The regression with the percentage of germinable seeds versus stratification temperature or water content within both the sub- and supraoptimal range revealed how the optimal temperature (T(so)) and water content (W(so)) for stratification changed. The T(so) moved from 10.6 degrees C to 5.3 degrees C with prolonged time, while W(so) declined from >0.40 g H2O g DW(-1) at 5 degrees C to approximately 0.23 g H2O g DW(-1) at 30 degrees C. Dormancy release in grape seeds can occur across a very wide range of conditions, which has important implications for their ability to adapt to a changeable environment in the wild.

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Effect of water content on dormancy release of grape seeds stratified at different temperatures. After equilibration at different relative humidities, seeds were stratified at 5 (A), 20 (B), and 30 °C (C) for 90 d, and then germinated at 30 °C/20 °C for 30 d. After subtracting the minimum germination, seed germination was finally normalized to the greatest germination and regressed to the water content. The normalized germination of seeds stratified at 5 °C related to water content with Equation 1, and at 20 °C and 30 °C with Equation 9. The changes in normalized germination at different water contents and temperatures are shown in D (solid line, 5 °C; dotted line, 20 °C; dashed line, 30 °C). All values are means ±SD. The R2 and parameters are shown in Table 2.
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fig7: Effect of water content on dormancy release of grape seeds stratified at different temperatures. After equilibration at different relative humidities, seeds were stratified at 5 (A), 20 (B), and 30 °C (C) for 90 d, and then germinated at 30 °C/20 °C for 30 d. After subtracting the minimum germination, seed germination was finally normalized to the greatest germination and regressed to the water content. The normalized germination of seeds stratified at 5 °C related to water content with Equation 1, and at 20 °C and 30 °C with Equation 9. The changes in normalized germination at different water contents and temperatures are shown in D (solid line, 5 °C; dotted line, 20 °C; dashed line, 30 °C). All values are means ±SD. The R2 and parameters are shown in Table 2.

Mentions: After equilibration at different RHs, seeds were stratified at different water contents and temperatures for 90 d. The results showed that the water content at which the seeds were stratified significantly influenced subsequent seed germination, and the effect was closely related to the stratification temperature (Fig. 7). When stratification was at 5 °C, the percentage germination of seeds increased with increasing water content of seeds, reaching a plateau level when the water content was higher than ∼0.40 g g−1 (Fig. 7A). When stratification was at 20 °C or 30 °C, the percentage germination first increased with increasing water content of seeds, and then decreased (Fig. 7B, C). The viability test of seeds stratified at different RHs for 90 d indicated that the ageing process did not occur (data not shown). Thus, lower water contents clearly promoted the effect of stratification on dormancy release, especially of warm stratification. For release of dormancy of seeds, the means of the lower (Wsl) and higher (Wsu) threshold water contents were 0.23 g g−1 and 0.30 g g−1 at 20 °C, and 0.14 g g−1 and 0.27 g g−1 at 30°C (Table 2), while the optimal water content (Wso) was 0.26 g g−1 at 20 °C and 0.23 g g−1 at 30 °C. The optimum water content for dormancy release changed with the temperature of stratification, and moved to a lower potential at higher temperature (Fig. 7D).


Quantitative description of the effect of stratification on dormancy release of grape seeds in response to various temperatures and water contents.

Wang WQ, Song SQ, Li SH, Gan YY, Wu JH, Cheng HY - J. Exp. Bot. (2009)

Effect of water content on dormancy release of grape seeds stratified at different temperatures. After equilibration at different relative humidities, seeds were stratified at 5 (A), 20 (B), and 30 °C (C) for 90 d, and then germinated at 30 °C/20 °C for 30 d. After subtracting the minimum germination, seed germination was finally normalized to the greatest germination and regressed to the water content. The normalized germination of seeds stratified at 5 °C related to water content with Equation 1, and at 20 °C and 30 °C with Equation 9. The changes in normalized germination at different water contents and temperatures are shown in D (solid line, 5 °C; dotted line, 20 °C; dashed line, 30 °C). All values are means ±SD. The R2 and parameters are shown in Table 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2724692&req=5

fig7: Effect of water content on dormancy release of grape seeds stratified at different temperatures. After equilibration at different relative humidities, seeds were stratified at 5 (A), 20 (B), and 30 °C (C) for 90 d, and then germinated at 30 °C/20 °C for 30 d. After subtracting the minimum germination, seed germination was finally normalized to the greatest germination and regressed to the water content. The normalized germination of seeds stratified at 5 °C related to water content with Equation 1, and at 20 °C and 30 °C with Equation 9. The changes in normalized germination at different water contents and temperatures are shown in D (solid line, 5 °C; dotted line, 20 °C; dashed line, 30 °C). All values are means ±SD. The R2 and parameters are shown in Table 2.
Mentions: After equilibration at different RHs, seeds were stratified at different water contents and temperatures for 90 d. The results showed that the water content at which the seeds were stratified significantly influenced subsequent seed germination, and the effect was closely related to the stratification temperature (Fig. 7). When stratification was at 5 °C, the percentage germination of seeds increased with increasing water content of seeds, reaching a plateau level when the water content was higher than ∼0.40 g g−1 (Fig. 7A). When stratification was at 20 °C or 30 °C, the percentage germination first increased with increasing water content of seeds, and then decreased (Fig. 7B, C). The viability test of seeds stratified at different RHs for 90 d indicated that the ageing process did not occur (data not shown). Thus, lower water contents clearly promoted the effect of stratification on dormancy release, especially of warm stratification. For release of dormancy of seeds, the means of the lower (Wsl) and higher (Wsu) threshold water contents were 0.23 g g−1 and 0.30 g g−1 at 20 °C, and 0.14 g g−1 and 0.27 g g−1 at 30°C (Table 2), while the optimal water content (Wso) was 0.26 g g−1 at 20 °C and 0.23 g g−1 at 30 °C. The optimum water content for dormancy release changed with the temperature of stratification, and moved to a lower potential at higher temperature (Fig. 7D).

Bottom Line: The effect of stratification on dormancy release of grape seeds crossing from the sub- to the supraoptimal range of temperatures and water contents was analysed by modified threshold models.The thermal time approaches effectively quantified dormancy release only at suboptimal temperature, but a quantitative method to integrate the occurrence of dormancy release and induction at the same time could describe it well at either sub- or supraoptimal temperatures.Dormancy release in grape seeds can occur across a very wide range of conditions, which has important implications for their ability to adapt to a changeable environment in the wild.

View Article: PubMed Central - PubMed

Affiliation: Institute of Botany, the Chinese Academy of Sciences, Beijing, China.

ABSTRACT
The effect of stratification on dormancy release of grape seeds crossing from the sub- to the supraoptimal range of temperatures and water contents was analysed by modified threshold models. The stratification impacted on dormancy release in three different ways: (i) dormancy was consistently released with prolonged stratification time when stratified at temperatures of <15 degrees C; (ii) at 15 degrees C and 20 degrees C, the stratification effect initially increased, and then decreased with extended time; and (iii) stratification at 25 degrees C only reduced germinable seeds. These behaviours indicated that stratification could not only release primary dormancy but also induce secondary dormancy in grape seed. The rate of dormancy release changed linearly in two phases, while induction increased exponentially with increasing temperature. The thermal time approaches effectively quantified dormancy release only at suboptimal temperature, but a quantitative method to integrate the occurrence of dormancy release and induction at the same time could describe it well at either sub- or supraoptimal temperatures. The regression with the percentage of germinable seeds versus stratification temperature or water content within both the sub- and supraoptimal range revealed how the optimal temperature (T(so)) and water content (W(so)) for stratification changed. The T(so) moved from 10.6 degrees C to 5.3 degrees C with prolonged time, while W(so) declined from >0.40 g H2O g DW(-1) at 5 degrees C to approximately 0.23 g H2O g DW(-1) at 30 degrees C. Dormancy release in grape seeds can occur across a very wide range of conditions, which has important implications for their ability to adapt to a changeable environment in the wild.

Show MeSH
Related in: MedlinePlus