Growth and agar quality of Gracilaria heteroclada (Zhang et Xia) grown in a filter tank
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Gracilaria heteroclada Zhang et Xia was grown in filter tanks to determine the growth, agar quality and uptake pattern of nitrogen and to observe the water quality in recirculating water system with seaweed. Rapid uptake of nitrogen in G. heteroclada was observed within the first 24th of culture. Filling up of the nitrogen pools in the cell may have continued until the fifth day, the plants started to increase in weight, proportionate to the uptake rate of nitrogen duing the experiment. G. heteroclada stocked at 1 kg m-2achieved a specific growth rate (SGR) of approximately 10.4% d-1 during 15d of culture, at total ammonia-nitrogen and nitrite-nitrogen levels of 0.03-0.27 mg L-1 and 0.04-0.19mg L-1, respectively, in the filter tank. Approximately 11% of nitrogen in the water was removed by the seaweed.
CitationLuhan, M. R. J., Harder, F., & Hurtado, A. Q. (2006). Growth and agar quality of Gracilaria heteroclada (Zhang et Xia) grown in a filter tank.
PublisherCollege of Agriculture, University of the Philippines Los Baños
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Impact of AMPEP on the growth and occurrence of epiphytic Neosiphonia infestation on two varieties of commercially cultivated Kappaphycus alvarezii grown at different depths in the Philippines IAG Borlongan, KR Tibubos, DAT Yunque, AQ Hurtado & AT Critchley -
Journal of Applied Phycology, 2011 - SpringerTwo varieties of the carrageenophyte Kappaphycus alvarezii (Tungawan, TUNG; and Giant tambalang, GTAM) from Zamboanga Sibugay, Philippines were used to test the efficacy of Acadian Marine Plant Extract Powder (AMPEP) as source of nutrients for growth, and to determine if applications had any effect on the percent occurrence of an epiphytic infestation of the red alga Neosiphonia sp. at four different depths in the sea. Results showed that the use of AMPEP significantly (P < 0.05) increased the growth rate of both Kappaphycus varieties tested but decreased the percent occurrence of Neosiphonia sp. The percent occurrence of Neosiphonia sp. infection (6–50% at all depths) of both Kappaphycus varieties with AMPEP treatment was significantly lower than the controls (i.e., 10–75% at all depths). Both the growth rate of the cultivated seaweed and the percent occurrence of the epiphytes decreased as the cultivation depth increased. Plants dipped in AMPEP and suspended at the surface had the highest growth rates (i.e., 4.1%, TUNG; 3.1%, GTAM) after 45 days; those without AMPEP dipping had the highest percent occurrence of Neosiphonia infection (viz. 70–75%). The occurrence of Neosiphonia infestation was found to be correlated with changes in irradiance and salinity at the depths observed. The results suggested that both varieties of K. alvarezii used in this study have the fastest growth rate when grown immediately at the water surface. However, in order to minimize damage caused by the occurrence of epiphytic Neosiphonia, K. alvarezii should be grown within a depth range of 50–100 cm. These observations are important for the improved management of Kappaphycus for commercial farming. Furthermore, the use of AMPEP treatments for enhancement of growth and reduction deleterious Neosiphonia sp. infections is encouraging.
Optimization of culture conditions for tissue culture production of young plantlets of carrageenophyte Kappaphycus DAT Yunque, KR Tibubos, AQ Hurtado & AT Critchley -
Journal of Applied Phycology, 2011 - Springer VerlagTo improve the production of Kappaphycus plantlets in tissue culture, optimum media concentrations of an Ascophyllum nodosum extract (Acadian Marine Plant Extract Powder, AMPEP), plant growth regulators (PGR), pH–temperature combinations, and explant density were determined. Kappaphycus alvarezii var. tambalang purple (PUR), kapilaran brown (KAP), vanguard brown (VAN), adik-adik (AA), tungawan green (TGR), and K. striatum var. sacol green (GS) were used as explants. Based on the shortest period for shoot emergence and the economical use of AMPEP, the optimum enriched media was 3.0 mg L−1 AMPEP and 0.1 mg L−1 AMPEP + PGR 1 mg L−1 each phenylacetic acid (PAA) and zeatin for PUR, 1.0 mg L−1 AMPEP + PGR for KAP and GS, 0.1 mg L−1 AMPEP + PGR for VAN, and 3.0 mg L−1 AMPEP and 0.001 mg L−1 AMPEP + PGR for AA and TGR. Results showed that the addition of PGR to low concentrations of AMPEP hastened shoot formation. pH–temperature combinations for the most rapid shoot formation were determined for the brown (KAP) and purple (PUR) color morphotypes of K. alvarezii var. tambalang and the green morphotype of K. striatum var. sacol (GS) cultured in 1.0 mg L−1 AMPEP + PGR. The brown morphotype produced the most number of shoots at pH 7.7 at 20°C after as little as 20 days. Purple K. alvarezii showed an increased shoot formation at pH 6.7 at 25°C and the green K. striatum morphotype at pH 8.7 at 25°C. The optimum number of explants added to the culture media was also determined for tungawan green (TGR), brown (KAP), and tambalang purple (PUR) varieties of K. alvarezii in 1.0 mg L−1 AMPEP + PGR. The number of explants and the volume of the culture media combination were also tested. The highest average number of shoots formed occurred in two explants:1 mL culture media (2:1) for KAP and PUR (35.00% and 16.67%, respectively) and 1 explant: 2 mL culture media for the TGR (100.00%) with a range of 0.5–3.0 mm shoot length after 40 days in culture. The earliest shoot formation was observed after 21 days for the brown and 9 days for both the green and purple color morphotypes of Kappaphycus, in all densities investigated. This indicated that within the range tested, the density of explants did not have a significant effect on the rate of shoot formation but did influence the average number generated from the culture. The rate of production of new and improved Kappaphycus explants for a commercial nursery stock was improved through the use of AMPEP with optimized culture media pH, temperature, and density conditions.
Conference paperSA Rifai - In Proceedings of the International Workshop on Pen Cage Culture of Fish, 11-22 February 1979, Tigbauan, Iloilo, Philippines, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center; International Development Research CentreThree kinds of aquatic plants, namely, Hydrilla verticillata, Lemna minor , and Chara sp. were used as feed for the T. nilotica reared in floating cages at three levels of stocking densities: 5, 15, and 45 fishes per cage. Results of the study showed that Lemna minor gave the best effect on growth rate of the fish in every level of stocking density. Feed conversion rate ranged from 19 to 33; Lemna minor was the lowest (33:1), while Chara sp. was the highest (19:1).