ABSTRACT
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.
ABSTRACT
Even though Arthrospira is a well-known superfood, it is not extensively commercialized in developing countries like Malaysia due to the high production cost with low biomass yield. Based on literature, the algal production cost can be discounted by reducing the cost of medium utilizing cheaper and readily available chemicals. Therefore, the present study was conducted to experiment the prospect of Arthrospira platensis cultivation in newly designed medium with commercial or industrial grade fertilizers under real environment. Consequently, growth and yield of A. platensis was investigated under outdoor condition using modified Kosaric medium (MKM) which was designed by substituting the major laboratory chemicals in standard Kosaric medium (SKM) with commercial grade baking soda, sea salt, urea, phosphoric acid, potassium hydroxide and Epsom salt. Urea as an alternative nitrogen resource to sodium nitrate was pulse-fed throughout the cultivation period. The algal growth was measured through optical density, biomass dry weight and chlorophyll a content. The algal yield was determined by calculating its productivity and specific growth rate. The growth and yield of A. platensis was significantly higher (p < 0.05) in MKM in terms of optical density with 2.541 ABS, biomass dry weight with 1.30 g L-1, chlorophyll a content with 12.96 mg L-1, productivity with 0.141 g L-1 d-1 and specific growth rate with 0.253 µ d-1 compared to SKM in eight days of cultivation period. The present finding showed the potential of MKM in lowering the medium cost up to 97% compared to SKM without compromising the algal yield under natural condition with proper cultivation techniques such as preadaptation and fed-batch addition of urea in the late evening.