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ABSTRACT: An experiment was conducted to investigate the effects of different shading regimes [i.e., 60% (heavy), 30% (moderate), and 0% (control)] on 25 traits associated with the morphological features, photosynthetic gas exchange and agronomic characteristics of winged bean (Psophocarpus tetragonolobus), an underutilized protein-rich legume from the tropics. Collectively, 80% of the studied variables displayed significant differences (P<0.05) between at least two shade treatments. Shading generally showed most pronounced effect on the physiological traits of the legume, whereby the stomatal conductance, photosynthetic and transpiration rate differed significantly among plants for all treatments. The non-shaded plants were observed to have superior growth and physiological responses than the shaded plants. Interestingly, the moderately shaded plants exhibited the highest yield per plant, which significantly differed from the non-shaded and heavily shaded plants. This indicated that winged bean can adapt to partial canopy cover, making it a potential nitrogen-fixing cash crop which can be planted together with fruit or oil trees in commercial plantations.
RESUMO: Foi conduzido um experimento para investigar os efeitos de diferentes regimes de sombreamento [60% (pesado), 30% (moderado) e 0% (controle)] em 25 características associadas às características morfológicas, trocas gasosas fotossintéticas e características agronômicas de feijão alado (Psophocarpus tetragonolobus), leguminosa subutilizada rica em proteínas dos trópicos. Coletivamente, 80% das variáveis estudadas apresentaram diferenças significativas (P<0,05) entre pelo menos dois tratamentos à sombra. O sombreamento mostrou efeito mais pronunciado nas características fisiológicas da leguminosa, pelo que a condutância estomática, a taxa fotossintética e a transpiração diferiram significativamente entre as plantas em todos os tratamentos. Observou-se que as plantas não sombreadas apresentaram crescimento e respostas fisiológicas superiores às plantas sombreadas. Curiosamente, as plantas moderadamente sombreadas exibiram o maior rendimento por planta, que diferiu significativamente das plantas não sombreadas e fortemente das sombreadas. Isso indica que o feijão alado pode se adaptar a cobertura parcial do dossel, tornando-o uma cultura potencial de fixação de nitrogênio que pode ser plantada em conjunto com árvores frutíferas ou oleaginosas em plantações comerciais.
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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.
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Aims: This study was conducted to characterize the growth patterns of tenera oil palm seedlings performance (Deli AVROS) under elevated CO2, that is expected to increase in the future due to climate change. Study Design: The palms were exposed to three carbon enrichment treatments: (1) ambient CO2 (400 ppm); (2) twice ambient CO2 (800 ppm), and (3) thrice ambient CO2 (1200 ppm). Randomized complete block design (RCBD) with three replications was used during the experiment using Deli AVROS seedlings. Place and Duration of Study: Department of Biology, Faculty of Science Universiti Putra Malaysia from March 2017 to December 2017. Methodology: Carbon dioxide enrichment treatments started when seedlings reached three months old by exposing them to three levels of CO2, i.e., ambient CO2 (400 ppm), twice ambient CO2 (800 ppm) and thrice ambient CO2 (1,200 ppm). Growth, carbohydrate and macronutrients properties were measured at the end of the treatment period of 3 months. Results: It was found that CO2 had the greatest influence on the growth over the three months’ period of experiment. As the level of CO2 increased, from 400>800>1200 ppm, 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 significant increased between the CO2 levels. The enhanced plant growth under elevated CO2 might be contributed by increased in production of total non-structural carbohydrate (TNC) of the palm under elevated CO2. The increased in TNC exposed to elevated CO2 was supported by increase in sucrose and starch content under these conditions. More sucrose was available than starch indicate that no feedback inhibition was occurred and the palm have enough sink strength to cope with elevated CO2. The macronutrients contents (N, P, K, Ca, Mg) also was found to be reduced under elevated CO2 treatments, indicated that growth enhancement under elevated have dilute the nutrient content in the palms. Conclusion: In conclusion, the growth of oil palm seedlings was enhanced with elevated CO2 at double and triple concentration than the ambient. It was found that the increase might be due to increase in production of total non-structural carbohydrate. The enhanced growth also increased the macronutrient demands under the elevated levels of CO2. This show in future the palm needs more fertilizers with enhanced levels of elevated CO2.
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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.
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Aims: The study was conducted to investigate the impact of nitrogen fertilization on growth, leaf gas exchange and bio-metabolite accumulation in Ipomea aquatica. Treatment and Experimental Design: Ipomea aquatica plants were exposed to four different rates of nitrogen (0, 30, 60 and 90 N kg/ha) using Urea (46% N) as a nitrogen source. The experiment was laid out in Complete Randomize Design (CRD). Place and Duration of Study: Department of Biology, Faculty of Science, Universiti Putra Malaysia between September to November 2016. Methodology: Four nitrogen rates were applied (0, 30, 60 and 90 N Kg/ha) using Urea as a nitrogen source. The growth data collections were conducted once a week after the application of the treatments for the plant growth parameters. The total chlorophyll content in the leaves was measured using a Soil Plant Analytical Device (SPAD-502) chlorophyll meter. The leaf gas exchange was determined using a LI-6400XT portable photosynthesis system. Total phenolics and flavonoid were determined using Folin-Ciocalteu reagent. Results: It was found that the highest measurements of growth parameters namely plant height, leaf numbers, branches numbers, total biomass and chlorophyll content were observed at 90 kg N/ha and the lowest at 0 kg N/ha. As for the leaf gas exchange, the positive effect of nitrogen fertilization on kangkung was shown by the increased in photosynthesis rate (A) and stomatal conductance (gs) where the highest measurement recorded at 90 kg N/ha, and the lowest at 0 kg N/ha. However, the water use efficiency (WUE) decreased as the nitrogen rates increased. At lower rates of nitrogen fertilization (30 kg N/ha) produced the highest production of secondary metabolites, where the total phenolics and flavonoids production were enhanced compared to other nitrogen treatments. Conclusion: In conclusion, as the nitrogen rates increased, the growth and leaf gas exchange properties was enhanced however the production of secondary metabolites was decreased in I. aquatica.
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Aims: To study the effect of different nitrogen fertilizer rates on growth, carbon assimilation and biochemical changes of Polygonum minus. Study Design: Polygonum minus were treated with different nitrogen fertilizer (0 kg N ha-1, 50 kg N ha-1, 100 kg N ha-1 and 150 kg N ha-1) using Urea (46%N) as a source of nitrogen. This experiment was arranged in Randomized Complete Block Design (RCBD) with three replications. Place and Duration of Study: The experiment was conducted at Taman Pertanian Universiti (TPU), Universiti Putra Malaysia between April 2017 to July 2017. Methodology: The growth parameters measured includes the leaf number, plant height, diameter of the stem, and the leaf area. The carbon assimilation parameters were measured using LICOR 6400XT Portable Photosynthesis System. Total phenolic and flavonoids contents from the leaves extracts of Polygonum minus were measured using Folin-Ciocalteu reagents. Results: The best rates of nitrogen in enhancing the best growth and quality of Polygonum minus was observed at 150 kg N ha-1 in most parameters of growth and carbon assimilation. At the final harvest, the parameters such as number of leaves, plant height, stem diameters, total chlorophyll contents, leaves area, total dry weight, net assimilation rate (NAR), water use efficiency (WUE), net photosynthesis rate (A) stomatal conductance (gs), and maximal efficiency of photosystem II (fv/fm) were highest at 150 kg N ha-1treatments. In the terms of biochemical changes, the parameter such as total phenolics contents and total flavonoids gain the highest production of total phenolics and flavonoids at 50 kg N ha-1. Conclusion: This study indicated growth and carbon assimilation parameters were upregulated under higher nitrogen fertilization and production of secondary metabolites was decreased with high rates of nitrogen. The recommended nitrogen fertilization for P. minus was at 50 kg N Ha-1, where it obtained the highest harvest index.
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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 LI-6400XT 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 MWCNTs 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.
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A series of water stress cycles [5, 10, 15, 20, 25 and 30 days of irrigation intervel including control flooded (CF), control saturated (CS)] were exposed to investigate the impact of cyclic water stress on growth, physiological responses and yield of a famous Malaysian rice variety, MR220. The study also aimed to determine optimum irrigation schedule for better production of rice. It was observed that grain yield, total biomass, filled spikelet, 1000 grain weight, total panicle, tillers mortality, plant height and number of tillers per plant reduces with increased duration of water stress cycles. Grain yield was higher both in CF and CS condition and those are statistically identical to 5 days of stress cycle or irrigation intervel. The present experiment shows that growth performance and physiological activities of rice differ marginally for 5 days of irrigation difference, exceding that time would reduce yield significantly. The study also showed that proline accumulation and malondialdehyde (MDA) contents in levels increased with increasing duration of water stress cycle. Depending on the findings of the present, it can be stated that rice variety MR220 do not require flooding irrigation and irrigation cycle of 5 days interval is more apprapriate to increase water use and higher yield of rice.
Deficiência hídrica com ciclos de 5, 10, 15, 20, 25 e 30 dias de intervalo e irrigação incluindo controle irrigado (CF), controle de saturação (CS)] foram usadas para investigar o impacto do estresse hídrico sobre o crescimento cíclico, fito-respostas fisiológicas e rendimento de variedade de arroz MR220. O estudo também teve como objetivo determinar o cronograma de irrigação ideal para melhorar a produção de arroz. Observou-se que a produção de grãos, biomassa total, spiguetas, 1000-peso de grãos, panículas totais, a mortalidade de perfilhos, altura de planta e número de perfilhos por planta foi reduzida com o aumento da duração do ciclo de estresse hídrico. O rendimento de grãos foi maior tanto na CF e CS condição e foi estatisticamente igual a cinco dias do ciclo de estresse. O experimento mostra que o desempenho do crescimento e atividades fisiológicas de arroz diferem ligeiramente para cinco dias de diferença de irrigação, aumentado esse tempo, reduziria o rendimento significativamente. O estudo também mostrou que o acúmulo de prolina e conteúdo de malondialdeído (MDA) em níveis aumentaram com o increremento da duração do ciclo de estresse hídrico. Pode-se afirmar que a variedade de arroz MR220 não necessita de irrigação e ciclos de irrigação de cinco dias de intervalo é mais apropriado, além de aumentar a utilização de água e assim ter uma maior produção de arroz.