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Shading during the grain filling period increases 2-acetyl-1-pyrroline content in fragrant rice.

Mo Z, Li W, Pan S, Fitzgerald TL, Xiao F, Tang Y, Wang Y, Duan M, Tian H, Tang X - Rice (N Y) (2015)

Bottom Line: In this study the effect of shading (i.e. the reduction of SI) on yield, quality, and 2-AP concentration in two elite Chinese fragrant rice varieties, 'Yuxiangyouzhan' and 'Nongxiang 18', has been investigated.In this study, we have demonstrated that shading during grain filling has significant effects on yield and quality traits in rice, and leads to the accumulation of GABA and 2-AP.Finally we discuss possible effects of variation in solar intensity resulting from anthropogenic emissions on fragrant rice production.

View Article: PubMed Central - PubMed

Affiliation: College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, 510642 China ; Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture. P. R. China, Guangzhou, Guangdong 510642 China.

ABSTRACT

Background: Fragrant rice, including Thai jasmine and Indian basmati varieties, is highly valued by consumers globally. 2-acetyl-1-proline (2-AP) is the major compound responsible for the aromatic character of fragrant rice. Previously, environmental factors such as water management and salinity have been proven to influence 2-AP levels in fragrant rice; assessing the effect of additional environmental factors on 2-AP concentration is therefore eminent. The level of solar radiation (solar intensity; SI) to which a crop is exposed can affect growth, yield and grain quality, and other photosynthetic and physiological characteristics. In this study the effect of shading (i.e. the reduction of SI) on yield, quality, and 2-AP concentration in two elite Chinese fragrant rice varieties, 'Yuxiangyouzhan' and 'Nongxiang 18', has been investigated. Furthermore, accumulation of the plant stress response molecules proline and gamma-aminobutyric acid, which have also been implicated in pathways leading to 2-AP production, was assessed to study shading effects on these compounds in fragrant rice, and to further possibly determine fluxes in biochemical pathways leading to 2-AP accumulation.

Results: This study has revealed significant changes in the yield and quality characters under shading treatment. Additionally, 2-AP and GABA content in grains was significantly increased for all shading treatments in both varieties. In addition to 2-AP, ten other volatile compounds were studied; results indicated that shading treatments could have a selective effect on the metabolism of these volatile compounds.

Conclusions: In this study, we have demonstrated that shading during grain filling has significant effects on yield and quality traits in rice, and leads to the accumulation of GABA and 2-AP. We discuss the implications of these findings in terms of pathways leading to 2-AP and GABA production in fragrant rice, which have not been fully elucidated. The shading effect on ten additional volatile compounds is also discussed. Finally we discuss possible effects of variation in solar intensity resulting from anthropogenic emissions on fragrant rice production.

No MeSH data available.


Effect of shading treatment on grain 2-AP content in grains. Vertical bars with different lower case letters above are significantly different at P = 0.05 by LSD tests. Capped bars represent SD.
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Fig1: Effect of shading treatment on grain 2-AP content in grains. Vertical bars with different lower case letters above are significantly different at P = 0.05 by LSD tests. Capped bars represent SD.

Mentions: The 2-AP content in grains was significantly increased for all shading treatments in both varieties, with increases of 59.07 – 106.65%, and 11.89 – 42.37% detected for Yuxiangyouzhan and Nongxiang 18, respectively. In both varieties, the highest mean 2-AP content in grains was identified for plants exposed to S2 treatment, with 2-AP contents of 175.86 μg∙kg−1 in Yuxiangyouzhan and 135.02 μg∙kg−1 in Nongxiang 18, compared to respective means of 85.10 and 94.84 μg∙kg−1 in the absence of shading (S0) (Figure 1). All shading treatments also significantly increased GABA in the grains of Yuxiangyouzhan (23.59 - 31.01% ) and Nongxiang 18 (56.99 - 94.18%) (Figure 2). In Yuxiangyouzhan, a significant increase in proline content was identified for S1 and S2, but not for S3 (Figure 3). For Nongxiang 18, proline content was not significantly affected by any shading treatment (Figure 3). No significant difference in total nitrogen content in grains between shading treatments was observed (Figure 4).Figure 1


Shading during the grain filling period increases 2-acetyl-1-pyrroline content in fragrant rice.

Mo Z, Li W, Pan S, Fitzgerald TL, Xiao F, Tang Y, Wang Y, Duan M, Tian H, Tang X - Rice (N Y) (2015)

Effect of shading treatment on grain 2-AP content in grains. Vertical bars with different lower case letters above are significantly different at P = 0.05 by LSD tests. Capped bars represent SD.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384914&req=5

Fig1: Effect of shading treatment on grain 2-AP content in grains. Vertical bars with different lower case letters above are significantly different at P = 0.05 by LSD tests. Capped bars represent SD.
Mentions: The 2-AP content in grains was significantly increased for all shading treatments in both varieties, with increases of 59.07 – 106.65%, and 11.89 – 42.37% detected for Yuxiangyouzhan and Nongxiang 18, respectively. In both varieties, the highest mean 2-AP content in grains was identified for plants exposed to S2 treatment, with 2-AP contents of 175.86 μg∙kg−1 in Yuxiangyouzhan and 135.02 μg∙kg−1 in Nongxiang 18, compared to respective means of 85.10 and 94.84 μg∙kg−1 in the absence of shading (S0) (Figure 1). All shading treatments also significantly increased GABA in the grains of Yuxiangyouzhan (23.59 - 31.01% ) and Nongxiang 18 (56.99 - 94.18%) (Figure 2). In Yuxiangyouzhan, a significant increase in proline content was identified for S1 and S2, but not for S3 (Figure 3). For Nongxiang 18, proline content was not significantly affected by any shading treatment (Figure 3). No significant difference in total nitrogen content in grains between shading treatments was observed (Figure 4).Figure 1

Bottom Line: In this study the effect of shading (i.e. the reduction of SI) on yield, quality, and 2-AP concentration in two elite Chinese fragrant rice varieties, 'Yuxiangyouzhan' and 'Nongxiang 18', has been investigated.In this study, we have demonstrated that shading during grain filling has significant effects on yield and quality traits in rice, and leads to the accumulation of GABA and 2-AP.Finally we discuss possible effects of variation in solar intensity resulting from anthropogenic emissions on fragrant rice production.

View Article: PubMed Central - PubMed

Affiliation: College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, 510642 China ; Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture. P. R. China, Guangzhou, Guangdong 510642 China.

ABSTRACT

Background: Fragrant rice, including Thai jasmine and Indian basmati varieties, is highly valued by consumers globally. 2-acetyl-1-proline (2-AP) is the major compound responsible for the aromatic character of fragrant rice. Previously, environmental factors such as water management and salinity have been proven to influence 2-AP levels in fragrant rice; assessing the effect of additional environmental factors on 2-AP concentration is therefore eminent. The level of solar radiation (solar intensity; SI) to which a crop is exposed can affect growth, yield and grain quality, and other photosynthetic and physiological characteristics. In this study the effect of shading (i.e. the reduction of SI) on yield, quality, and 2-AP concentration in two elite Chinese fragrant rice varieties, 'Yuxiangyouzhan' and 'Nongxiang 18', has been investigated. Furthermore, accumulation of the plant stress response molecules proline and gamma-aminobutyric acid, which have also been implicated in pathways leading to 2-AP production, was assessed to study shading effects on these compounds in fragrant rice, and to further possibly determine fluxes in biochemical pathways leading to 2-AP accumulation.

Results: This study has revealed significant changes in the yield and quality characters under shading treatment. Additionally, 2-AP and GABA content in grains was significantly increased for all shading treatments in both varieties. In addition to 2-AP, ten other volatile compounds were studied; results indicated that shading treatments could have a selective effect on the metabolism of these volatile compounds.

Conclusions: In this study, we have demonstrated that shading during grain filling has significant effects on yield and quality traits in rice, and leads to the accumulation of GABA and 2-AP. We discuss the implications of these findings in terms of pathways leading to 2-AP and GABA production in fragrant rice, which have not been fully elucidated. The shading effect on ten additional volatile compounds is also discussed. Finally we discuss possible effects of variation in solar intensity resulting from anthropogenic emissions on fragrant rice production.

No MeSH data available.