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Primary, Secondary Metabolites, H(2)O(2), Malondialdehyde and Photosynthetic Responses of Orthosiphon stimaneus Benth. to Different Irradiance Levels

The resource availability hypothesis predicts an increase in the allocation to secondary metabolites when carbon gain is improved relative to nutrient availability, which normally occurs during periods of low irradiance. The present work was carried out to confirm this hypothesis by investigating th...

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Autores principales: Ibrahim, Mohd Hafiz, Jaafar, Hawa Z. E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6268385/
https://www.ncbi.nlm.nih.gov/pubmed/22286668
http://dx.doi.org/10.3390/molecules17021159
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author Ibrahim, Mohd Hafiz
Jaafar, Hawa Z. E.
author_facet Ibrahim, Mohd Hafiz
Jaafar, Hawa Z. E.
author_sort Ibrahim, Mohd Hafiz
collection PubMed
description The resource availability hypothesis predicts an increase in the allocation to secondary metabolites when carbon gain is improved relative to nutrient availability, which normally occurs during periods of low irradiance. The present work was carried out to confirm this hypothesis by investigating the effects of decreasing irradiance on the production of plant secondary metabolites (flavonoids and phenolics) in the herbal plant Orthosiphon stamineus, and to characterize this production by carbohydrate, H(2)O(2), and malondialdehyde (MDA) levels, net photosynthesis, leaf chlorophyll content and carbon to nitrogen ratio (C/N). Four levels of irradiance (225, 500, 625 and 900 µmol/m(2)/s) were imposed onto two-week old seedlings for 12 weeks in a randomized complete block design experiment. Peak production of total flavonoids, phenolics, soluble sugar, starch and total non-structural carbohydrate ocurred under low irradiance of 225 µmol/m(2)/s, and decreased with increasing irradiance. The up-regulation of secondary metabolites could be explained by the concomitant increases in H(2)O(2) and MDA activities under low irradiance. This condition also resulted in enhanced C/N ratio signifying a reduction in nitrogen levels, which had established significant negative correlations with net photosynthesis, total biomass and total chlorophyll content, indicating the possible existence of a trade-off between growth and secondary metabolism under low irradiance with reduced nitrogen content. The competition between total chlorophyll and secondary metabolites production, as exhibited by the negative correlation coefficient under low irradiance, also suggests a sign of gradual switch of investment from chlorophyll to polyphenols production.
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spelling pubmed-62683852018-12-10 Primary, Secondary Metabolites, H(2)O(2), Malondialdehyde and Photosynthetic Responses of Orthosiphon stimaneus Benth. to Different Irradiance Levels Ibrahim, Mohd Hafiz Jaafar, Hawa Z. E. Molecules Article The resource availability hypothesis predicts an increase in the allocation to secondary metabolites when carbon gain is improved relative to nutrient availability, which normally occurs during periods of low irradiance. The present work was carried out to confirm this hypothesis by investigating the effects of decreasing irradiance on the production of plant secondary metabolites (flavonoids and phenolics) in the herbal plant Orthosiphon stamineus, and to characterize this production by carbohydrate, H(2)O(2), and malondialdehyde (MDA) levels, net photosynthesis, leaf chlorophyll content and carbon to nitrogen ratio (C/N). Four levels of irradiance (225, 500, 625 and 900 µmol/m(2)/s) were imposed onto two-week old seedlings for 12 weeks in a randomized complete block design experiment. Peak production of total flavonoids, phenolics, soluble sugar, starch and total non-structural carbohydrate ocurred under low irradiance of 225 µmol/m(2)/s, and decreased with increasing irradiance. The up-regulation of secondary metabolites could be explained by the concomitant increases in H(2)O(2) and MDA activities under low irradiance. This condition also resulted in enhanced C/N ratio signifying a reduction in nitrogen levels, which had established significant negative correlations with net photosynthesis, total biomass and total chlorophyll content, indicating the possible existence of a trade-off between growth and secondary metabolism under low irradiance with reduced nitrogen content. The competition between total chlorophyll and secondary metabolites production, as exhibited by the negative correlation coefficient under low irradiance, also suggests a sign of gradual switch of investment from chlorophyll to polyphenols production. MDPI 2012-01-27 /pmc/articles/PMC6268385/ /pubmed/22286668 http://dx.doi.org/10.3390/molecules17021159 Text en © 2012 by the authors; licensee MDPI, Basel, Switzerland. http://creativecommons.org/licenses/by/3.0/ This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).
spellingShingle Article
Ibrahim, Mohd Hafiz
Jaafar, Hawa Z. E.
Primary, Secondary Metabolites, H(2)O(2), Malondialdehyde and Photosynthetic Responses of Orthosiphon stimaneus Benth. to Different Irradiance Levels
title Primary, Secondary Metabolites, H(2)O(2), Malondialdehyde and Photosynthetic Responses of Orthosiphon stimaneus Benth. to Different Irradiance Levels
title_full Primary, Secondary Metabolites, H(2)O(2), Malondialdehyde and Photosynthetic Responses of Orthosiphon stimaneus Benth. to Different Irradiance Levels
title_fullStr Primary, Secondary Metabolites, H(2)O(2), Malondialdehyde and Photosynthetic Responses of Orthosiphon stimaneus Benth. to Different Irradiance Levels
title_full_unstemmed Primary, Secondary Metabolites, H(2)O(2), Malondialdehyde and Photosynthetic Responses of Orthosiphon stimaneus Benth. to Different Irradiance Levels
title_short Primary, Secondary Metabolites, H(2)O(2), Malondialdehyde and Photosynthetic Responses of Orthosiphon stimaneus Benth. to Different Irradiance Levels
title_sort primary, secondary metabolites, h(2)o(2), malondialdehyde and photosynthetic responses of orthosiphon stimaneus benth. to different irradiance levels
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6268385/
https://www.ncbi.nlm.nih.gov/pubmed/22286668
http://dx.doi.org/10.3390/molecules17021159
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