Effects of water and nitrogen stresses on growth, phytochemicals and antioxidant of orthosiphon stamineus plant
Abiotic stresses particularly water stress and nutrient deficiency may elicit the biosynthesis pathway of herbal metabolites, where they are also useful to enhance the yield of herbal metabolites. Thus, this study was carried out to investigate the effects of soil water and nitrogen stresses on the...
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| Format: | Thesis |
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| Language: | English |
| Subjects: | |
| Online Access: | http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/78265/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/78265/2/Full%20text.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/78265/3/Noorhaslina.pdf |
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| Summary: | Abiotic stresses particularly water stress and nutrient deficiency may elicit the biosynthesis pathway of herbal metabolites, where they are also useful to enhance the yield of herbal metabolites. Thus, this study was carried out to investigate the effects
of soil water and nitrogen stresses on the accumulation of herbal bioactive compounds. The primary experiment was to refine the methanol extraction conditions (methanol concentrations and times) in order to improve extract quality of O. stamineus. The leaf
and stem were extracted in 0, 25, 50 and 100% methanol for 2, 4 and 8 hours at 400C. The results of total phenolic content and antioxidant capacity were increased when the leaf and stem extracted with 50% methanol but the time extraction did not influence
the phenolics concentration and the antioxidant capacity. For the bioactive compunds concentration, the rosmarinic acid is the highest bioactive compounds as compared to 3’-hydroxy-5,6,7,4’-tetramethoxyflavone, sinensetin and eupatorin when extracted
with 100% methanol for 4 hours. Another experiment was to investigate the effects of water stress at different levels and duration on bioactive concentration of O. stamineus
leaf, stem and root. The water stress were set; high (25-35% of field capacity),
moderate (45-65% of field capacity) and low (75-90% of field capacity). The water
stress levels and stress duration main effects have significantly influenced the
phenolics and flavonoids content in the leaf, stem and root of O. stamineus plant. For
the bioactive concentration, the leaf, stem and root was significantly increased when
treated for 4 week of water stress. The enzyme activity reveals that the cinnamic acid
4-hydroxylase activity increased when the plant stressed for four weeks. Next
experiment aimed to identify the effects of nitrogen stress at different levels on
bioactive concentration of O. stamineus leaf, stem and root. They were consisted of 0
N kg/ha (high N stress), 110 N kg/ha (low N stress), 170 N kg/ha (medium N stress)
and 250 N kg/ha (control). The phenolics and flavonoids content for the plant was
significantly affected when the plant imposed with medium N stress but the N stress
had not influenced the antioxidant capacity of the plant. The N stress also not
significantly affects the bioactive concentration in leaf, stem and root of O. stamineus
plant. The last experiment was to determine the effects of water and nitrogen stresses
at different levels on bioactive concentration of O. stamineus plant. |
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