Effects of potassium rates and types on growth, leaf gas exchange and biochemical changes in rice (Oryza sativa) planted under cyclic water stress

Three levels of potassium rates [80 kg K2O ha−1, 120 kg K2O ha−1 and 160 kg K2O ha−1) and two types potassium (KCl and K2SO4) on rice under cyclic water stress 15 days and the absolute control (80 kg K2O ha−1 of KCl fertilizer on rice under control flooded) were exposed to rice to investigate the influence of potassium in minimizing cyclic water stress effects in rice. It was found as fertilization rates increased from 80 > 120 > 160 kg K2O ha−1 the production of proline was increased. The increase in proline production was simultaneously enhanced the production of Catalase and Maliondialdehyde. As the potassium rate increased from 80 > 120 > 160 kg K2O ha−1, the transpiration rate was observed to be increased in both potassium types. The result suggested that high potassium rates would reduce water stress effects by having high transpiration rate. High transpiration rate would increase the nutrient uptake that would repair the damage tissue under water stress thus reduce the oxidative stress of rice under water stress condition. This been showed by high significant positive correlations of transpiration rate with CAT activity (r = 0.871; p ≤ 0.05), MDA (r = 0.914; p ≤ 0.05) and Proline (r = 0.842; p ≤ 0.05). It was found that the increase of K rates by KCl increased NAR higher than the increased K rates in K2SO4. This might be due to higher absorption of K element in rice by KCl compared to K2SO4. The study has showed that application of potassium either KCl or K2SO4 would minimize the effects on rice growth and physiology under cyclic water stress. The current study also suggested that plant tolerate to cyclic water stress by increased the production of proline, MDA and decrease of Catalase activity to protect the plant from damage from water stress

The morphology, physiology and biochemical changes in Oryza sativa planted under cyclic water stress with different potassium input

Four levels of potassium rates (Control, 80 kg K2O/ha, 120 kg K2O/ha and 160 kg K2O/ha) and two types of potassium (KCl and K2SO4) were exposed to rice to investigate the influence of potassium fertilization in minimizing the impact of cyclic water stress in rice production. It was observed that panicle dry weight/hill, root dry weight, rice yield, Catalase activity, proline, maliondialdehyde and harvest index were influenced by potassium rates. The leaf numbers, total tillers and 1000-grain weight, was influenced by potassium types. Interaction effects (potassium rate x potassium type) was observed in shoot dry weight, leaf area, total spikelet/ panicle, net assimilation rate, transpiration rate and instantaneous water use efficiency. It was found as fertilization rates increased from 80120>160 kg K2O /ha the transpiration rate was observed to be increased in both MOP and K2SO4. The result suggested that high potassium rates would reduce water stress effects by having high transpiration rate. The study has showed that application of potassium fertilizer would minimize the effects on rice growth and physiology under cyclic water stress condition

Growth, leaf gas exchange and secondary metabolites of orthosiphon stamineus as affected by multiwall carbon nanotubes application

Aims: This study was conducted to study the growth, leaf gas exchange and secondary metabolites of Orthosiphon stamineus as affected by Multiwalled carbon nanotubes application (MWCNT). Study Design: Orthosiphon stamineus were exposed to four different multi-walled carbon nanotubes (MWCNTs) concentration (0, 700, 1400 and 2100 mg L-1). The experiment was organized in a randomized complete block (RCBD) design with three replications. Each experimental unit consisted of twelve plants, and there were a total of 144 plants used in the experiment. Place and Duration of Study: Department of Biology, Faculty of Science Universiti Putra Malaysia between November 2016 to March 2017. Methodology: Each plant was watered with 50 mL of MWCNTs solution in week 2 and 9. 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. The leaf gas exchange was determined using LI6400XT portable photosynthesis system. Total phenolics and flavonoid were determined using Folin-Ciocalteu reagent. Results: It was found that application of MWCNTs would reduce the growth characteristics of this plant that was shown by decreased leaf numbers, total biomass and total chlorophyll content (TCC). As MWCNTs concentration increases from 0 > 2100 mg L-1, the leaf gas exchange parameter also shows reduced patterns. Generally, as the rate of MWCNTs increased from 700 > 2100 mg L-1 NWCNTs reduce the net photosynthesis (A), stomatal conductance (gs), transpiration rate (E) and increased the plant water use efficiency. The production of the secondary metabolites was directly dependable on MWCNTs concentration. As the rate was enhanced from 0 > 700 > 1400 > 2100 mg L-1 the production of total phenolics and flavonoids was enhanced. Conclusion: The current study revealed that the high application of MWCNTs concentration reduce the growth rate of O. stamineus, leaf gas exchange and simultaneously increase the production of secondary metabolites

Impact of elevated CO2 on leaf gas exchange, carbohydrates and secondary metabolites accumulation in Labisia pumila benth

Aims: The aim of this study was to investigate different levels of CO 2 availability alters total phenolic and flavonoid, total available carbohydrate (TAC) and to determine how elevated CO 2 influences gas exchange of Labisia pumila seedlings. Study Design: The 3-months Labisia pumila seedlings of var Alata, var Pumila and var Lanceolata were put under 1 month to acclimatize in a nursery until ready for the treatment. Carbon dioxide enrichment treatments started when seedlings reached 4 months old by exposing them to three levels of CO 2 , viz., ambient CO 2 (400 µmol/mol), twice ambient (800 µmol/mol) and thrice ambient CO 2 (1200 µmol/mol). The split plot 3 x 3 factorial experiment was designed using randomized complete block design with CO 2 levels being the main plot and varieties as the sub-plot replicated Original Research Article Ibrahim et al.; ARRB, 19(6): 1-16, 2017; Article no.ARRB.36673 2 three times. Place and Duration of Study: Ladang 2, Universiti Putra Malaysia Glasshouse complex between July to November 2011. Methodology: The experiment was conducted for 15 weeks. The measurement of photosynthesis was obtained from a closed infra-red gas analyzer LICOR 6400XT Portable Photosynthesis System (IRGA, Licor Inc., USA). Total phenolics and flavonoid were determined using Follin-Ciocalteau reagent and total available carbohydrate using anthrone reagent. Results: It was found that the treatment effects were contributed by CO 2 levels in all weeks measured in leaf gas exchange properties (Net photosynthesis (A), stomatal conductance (g s), transpiration rate (E), intercellular CO 2 (C i) and Instantaneous water use efficiency, WUE). A combination of increases rates of A and E was responsible for enhancement of WUE by 50% in elevated treatment (800 and 1200 µmol/mol). Total available carbohydrate, total phenolics and flavonoid were also influenced by elevated CO 2 in all weeks of measurement. At end of 15 weeks after treatment (WAT), 44% increase in total available carbohydrate had increased total phenolic and flavonoid by 56% and 149% respectively than ambient treatment. At end of 15 WAT It was found, that the photosynthetic capacity of Labisia pumila was enhanced under elevated CO 2 by significantly have higher maximum electron transfer rate, J max and Rubisco CO 2 fixation capacity V cmax than ambient seedlings. Conclusion: In this work, it was observed that the increase in production of total phenolics and flavonoid in L. pumila might be due to increase in production of total available carbohydrate in the present study. The upregulation of photosynthesis in the present study was supported by enhancement of Maximum electron transfer rate, J max and Rubisco CO 2 fixation capacity V cmax than ambient seedlings that showed this plant has high sink strength to cope with high level of CO 2

Application effects of cadmium and humic acid on the growth, chlorophyll fluorescence, leaf gas exchange and secondary metabolites in misai kucing (Orthosiphon stamineus) benth

Aims: This experiment was conducted to investigate and distinguish the relationships in the production of total phenolics, total flavonoids, chlorophyll content, total biomass, leaf area, leaf nitrate, proline, net photosynthesis and chlorophyll fluorescence parameters under three levels of cadmium application (0, 3,6 mg/kg) and three concentration of humic acid (HA) (0, 50, 100 mg/L) for 12 weeks in Orthosiphon stamineus Benth. Study Design: Stem cuttings of O. staminues were propagated for two weeks in small pots and Original Research Article Ibrahim et al.; ARRB, 18(3): 1-14, 2017; Article no.ARRB.36401 2 then transferred to pots filled with a soilless mixture of burnt rice husk and coco peat (ratio 3:1). Orthosiphon stamineus seedlings were exposed to three levels of Cd (0, 3 and 6 mg/kg in the form of CdCl 2) during media preparation and three levels of humic acid (HA) (0, 50 and 100 mg/ L). Soluble humic acid as potassium-humate (90% humic acid, 11-13% K2O) was used. This factorial experiment was organized in a randomized complete block (RCBD) design with three replications. Place and Duration of Study: Methodology: The experiment was performed for 12 weeks using 135 plants. The measurement of photosynthesis was obtained from a closed infra-red gas analyzer LICOR 6400XT Portable Photosynthesis System (IRGA, Licor Inc., USA). Total phenolics and flavonoid was determined using Follin-Ciocalteau reagent, Nitrate using Cardy nitrate meter, Chlorophyll fluorescence was measured using a portable chlorophyll fluorescence meter (Handy PEA, Hansatech Instruments Ltd., Norwich, UK) and Proline was determined by using Glacial acetic acid and ninhydrin reagent. Results: It was found that all parameters except chlorophyll fluorescence parameters were influenced by interaction effects between cadmium and humid acid (P≤ 0.05). As the concentration of cadmium increased (0 > 6 mg/kg) the production of plant total phenolics, flavonoids and proline increased but the production of total biomass, leaf area, net photosynthesis, total chlorophyll content and nitrate uptake was reduced. The application of humid acid can reduce negative effects of cadmium. As humid acid level increases from 0 to 100 mg/L the negative effects of cadmium on total biomass, leaf area, net photosynthesis and total chlorophyll were decreased. Conclusion: This work reveals that the use of cadmium can enhance the production of secondary metabolites in O. stamineus (total phenolics and flavonoids). The study showed the negative effects of cadmium on plant growth, Gas exchange and chlorophyll fluorescence can be reduced by enhancing application of humic acid. The application of humic acid also was found to reduce the cadmium uptake of this herb. Present study showed that high levels of cadmium can lowered the nitrate concentration in this plant. This showed that application of cadmium and humic acid can serve to be a useful tool to enhance secondary metabolites properties of this plant

Morphology, leaf gas exchange and quality of pegaga (Centella asiatica) under different nitrogen fertilization rate

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

Drought tolerance and ion accumulation of rice following application of additional potassium fertilizer

Five levels of water stress cycle (control flooded, control saturated, 5, 10, and 15 days of irrigation interval) and three potassium fertilization levels [80 kg, 120 kg, and kg 160 dipotassium oxide (K2O) ha−1] were exposed to investigate the influence of potassium fertilizer for minimizing water stress effect and maximizing productivity of rice. Different phyto-physiological parameters as well as uptake of major nutrient elements [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe)] were examined. It was observed that rice yield, harvest index, and other physiological parameters reduces with increasing duration of water stress while application of additional potassium fertilizer has progressive impact on those parameters. From our observation, 10 days of watering cycle with potassium fertilization at 120 kg K2O ha−1 produces highest grain yield and harvest index. Uptake of major nutrient elements was also enhanced by potassium fertilizer. Therefore, it can be stated that additional potassium fertilizer application could be useful to mitigate water stress effect in rice

Growth, carbohydrate assimilation and leaf gas exchange characteristics of Elaeis guineensis Jacq seedlings under nitrogen fertilization

Aims: This study was conducted to characterise the growth, carbohydrate and leaf gas exchange patterns of oil palm seedlings performance (Deli Yangambi) under nitrogen fertilisation. Study Design: The palms were fertilised with three nitrogen rates: (1) Control (90 g/palm); (2) twice the control (180 g/palm), and (3) thrice the control (270 g/palm). Randomized complete block design (RCBD) with three replications was used during the experiment using Deli Yangambi seedlings Place and Duration of Study: Ladang 2, Universiti Putra Malaysia from March 2017 to June 2017. Methodology: The nitrogen treatments started when the oil palm seedlings reached four months old using Urea (46% N) as a source of nitrogen. Growth, carbohydrate and leaf gas exchange properties were measured at the end of the treatment period of two months. Results: As the level of nitrogen application increased, from 90 - 270 g/palm, the plant height, number of frond per plant, basal diameter, leaf area per seedling, root biomass, total dry matter, net assimilation rate (NAR) and relative growth rate (RGR) was statistically significantly increased between nitrogen treatments. The production of total non-structural carbohydrate (TNC) was reduced under high rates of nitrogen. The reduced in TNC under high nitrogen rates was supported by a decrease in sucrose and starch content under low nitrogen fertilisation. The net photosynthesis (A), stomatal conductance (gs), transpiration (E) and Intercellular CO2 also was found to be increased under high nitrogen rates indicated that higher rates of nitrogen would enhance the leaf gas exchange characteristics of the palms. Conclusion: In conclusion, the growth of oil palm seedlings growth was enhanced with high rates of nitrogen supplementation. As the nitrogen rates (90>270 g/palm), more production of TNC was produced and increased the sink strength of the palms. The enhanced growth and TNC accumulation also increased the leaf gas exchange properties that were showed by increased in A, gs, E, Ci and Water use efficiency in the oil palm seedlings

Fruiting-body-base flour from an oyster mushroom – a waste source of antioxidative flour for developing potential functional cookies and steamed-bun

In a commercial oyster mushroom farm, fruiting body base (FBB) was not harvested compared to the common cap and stem of the fruiting body parts, and thus remained as waste. In the present study, unused FBB was powdered and subjected to proximate analysis as floured FBB (FFBB). FFBB was found to contain 71.2% carbohydrate, 8.93% moisture, 7.18% fibre, 5.72% ash, 5.57% protein, and 1.4% fat, while raw-FBB (RFBB) contained 7.57% carbohydrate, 84.4% moisture, 5.17% fibre, 5.72% ash, 1.54% protein, and 0.85% fat. The high carbohydrate content of FFBB was subjected to hot-water extraction and yielded 7.40 g of FFBB polysaccharide (FFBBP). Total phenolic content (TPC) of FFBBP contained 1.80 mg gallic acid equivalents (GAE)/g, exhibiting the reducing activity of 1.74 mM Fe(II)/g by ferric reducing antioxidant power assay, and reduced the stable 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonate radical forms at IC50 of 25.08 mg/mL, which was comparable with other parts of oyster mushroom species. Different percentages of FFBB mixtures were utilized in the production of cookies (10% and 20%) and steamed buns (10%, 20% and 30%). Thirty-seven panellists were selected for sensory testing, which showed that 10% of FFBB in a steamed bun was more acceptable than 30% of FFBB, while the overall acceptance of cookies with 10% FBB was insignificant (p > 0.05) but 20% FFBB in cookies was significantly different from control (p < 0.05). This study indicates that potential value of FFBB as an economical antioxidative flour in the development of functional foods