ABSTRACT
Aims: To characterize the growth, carbon assimilation and quality of Ipomoea aquatica as influenced by magnetic nanoparticles (MNP) application as well as to determine the best rates of iron oxide nanoparticles that give high growth, carbon assimilation and quality of Ipomoea aquatica. Study Design: Ipomoea aquatica plants were exposed to four different treatments of magnetic iron oxide nanoparticles (Fe3O4) (0, 50, 100 and 150 mg L-1). The experiment was conducted in a randomized complete block design (RCBD) with 3 replications. One unit of experiment consisted of 8 plants and there were 96 plants used in the experiment. Place and Duration of Study: Department of Biology, Faculty of Science, Universiti Putra Malaysia, between March 2018 and July 2018. Methodology: The growth parameters measured included: plant height, basal diameter, total leaf number, leaf temperature, total chlorophyll content and plant biomass. The carbon assimilation parameters were measured using IRGA (Infrared Gas Analyzer, LICOR 6400 XT Portable Photosynthesis System). i.e. transpiration rate (E), stomatal conductance and water use efficiency (WUE). The chlorophyll fluorescence were measured by using Pocket PEA that measured maximum efficiency of photosystem ii, (fv/fm), maximum quantum yield of phytochemical and non-photochemical process in photosystem II (fv/fo), minimal fluorescence (fo), performance index (PI) and Density of Reaction Centers Per PSII Antenna Chlorophyll (RC/ABS). Total phenolics and flavonoids contents in leaves were measured using Folin-Ciocalteu method. Results: It was observed that plant height, shoot length, plant temperature, total biomass, and total chlorophyll content were significantly influenced (p≤0.05) by the different concentrations of magnetic nanoparticles. The net photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), maximum efficiency of photosystem II (Fv/fm), maximum quantum yield of phytochemical and non-photochemical process in photosystem II (Fv/fo), performance index and the density of reaction centers per PSII antenna chlorophyll of Ipomoea aquatica were significantly reduced at higher concentration of magnetic nanoparticles. However, water use efficiency and minimal fluorescence value (Fo) of Ipomoea aquatica increased with increase of MNP concentration. In addition, the application of magnetic nanoparticles significantly influenced (P≤0.05) the total flavonoids and total phenolics content in water spinach. Both of these parameters were increased when higher concentration of magnetic nanoparticles was applied to Ipomoea aquatica. This study showed that MNP affected the growth, carbon assimilation and secondary metabolites production of Ipomoea aquatica. Conclusion: In conclusion, the higher concentration of magnetic nanoparticles reduced the growth rate and carbon assimilation of water spinach and enhanced the production of secondary metabolites.
ABSTRACT
Aims: To investigate the physiological, leaf gas exchange and quality of Centella asiatica (pegaga) under different nitrogen fertilization rates. Study Design: Centella asiatica were exposed to four different nitrogen fertilization rates (0, 50, 100, 150 kg/ha) using urea (46% N) as nitrogen sources. The experiment was conducted in a randomized complete block (RCBD) design with three replications. Each treatment consisted of eight plants making the total of plants used in this study is 96 plants. Place and Duration of Study: Department of Biology, Faculty of Science, Universiti Putra Malaysia From May 2016-June 2016. Methodology: The growth parameters measured include total leaves numbers, leaf area, total chlorophyll content and total plant biomass. The carbon assimilation parameters were measured using LICOR 6400 XT Portable Photosynthesis System i.e net photosynthesis (A), Transpiration rate (E) and water use efficiency (WUE). Total phenolic and flavonoids contents from the leaves extracts were measured using Folin-Ciocalteu reagents. Results: The growth parameters such as leaves number, chlorophyll content, leaf area and total biomass were significantly influenced by nitrogen fertilization (P≤ 0.05), However, there were no significant difference observed between 50, 100 and 150 kg N/ha suggesting that 50 kg N/ha was the efficient rates to apply to enhance the growth of this plant. Meanwhile, the net photosynthesis (A) and water use efficiency (WUE) were enhanced with the increasing rate of nitrogen from 0>150 kgN/ha. The production of total phenolics and flavonoids was found to be highest under 100 kg/ha. The harvest index of total phenolics also showed the applications of 100 kg/ha gave the highest harvest index compared to the other nitrogen treatments. Conclusion: This study indicated growth and carbon assimilation parameters were enhanced under higher nitrogen fertilization and production of secondary metabolites was decreased with high rates of nitrogen. The recommended nitrogen fertilization for C. asiatica was at 100 kg N /ha, where it obtained the highest harvest index.
ABSTRACT
Aims: This study was conducted to investigate the effect of salinity by using a different concentration of sodium chloride (NaCl), on growth, chlorophyll fluorescence and secondary metabolites production of Centella asiatica. Study Design: Centella asiatica plants were exposed to four different concentration of sodium chloride (0, 50, 100 and 150 mM). This research was conducted using a randomized complete block design 4 x 3 with three replications for each treatment and each treatment consists of 12 plants regarding four times harvesting. Place and Duration of Study: Glasshouse of SLAM field, University Agriculture Park, Universiti Putra Malaysia from February to April 2015. Methodology: Salinity stress was induced by irrigating the plants using four salinity levels (0, 50, 100 and 150 mM) of salt concentrations for 12 weeks. The leaves number were counted manually and the total plant biomass was taken by calculating the dry weight of root, stem, and leaf per seedling. The total chlorophyll content in the leaves was measured using a SPAD chlorophyll meter. Chlorophyll fluorescence was measured using Hansatech Pocket PEA, The leaf gas exchange were determined using a LI-6400XT portable photosynthesis system. Total phenolics and flavonoid was determined using Folin-Ciocalteu reagent. Phytochemical screening was conducted to determine the presence of tannin, terpenoids, phenolics, flavonoids, saponin, and alkaloids of plant samples under salinity stress. Results: Increased in salinity levels from 0 > 150 mM, the number of leaves, total biomass and total chlorophyll content were gradually decreased. Centella asiatica exhibit a significant decrease in net photosynthesis (A), transpiration rate (E), maximum efficiency of photosystem II (fv/fm) and Performance index (PI) when the salinity level increased. However, it was noticed that salinity stress significantly enhanced the total phenolic and flavanoid content of C. asiatica. It was also observed, that under salinity there were more presence of phytochemicals (tannin, terpenoids, phenolics, flavonoids, saponin and alkaloids) compared to the control. Conclusion: This study revealed that the increase in salinity level have greatly reduced the growth of C. asiatica but high salinity level also can enhance the production of secondary metabolites (total phenolic and flavonoid content) in C. asiatica.