ชีววิทยาการสืบพันธุ์และองค์ประกอบทางเคมีบางประการของสายพันธุ์สาหร่ายผมนางสกุล Gracilaria จากบ่อเลี้ยง จังหวัดปัตตานี และจังหวัดสงขลา

Abstract

The agarophytic seaweed, Gracilaria is used as a raw material for agar extraction and consumption. A study on reproductive biology and some chemical compositions of Phom Nang strain genus Gracilaria from cultivation pond in Pattani and Songkhla province were conducted for the information to support the culture and the propagation. Thirty-four samples were collected from harvested production from earthen ponds in 2018 for study on external internal structures. Reproductive organs were observed with naked eyes and under a microscope on the cross-section of thalli and genetic characteristics using DNA were confirmed. The nutritional values were recorded for all. Water parameters from some ponds were determined. The most popular culture species, Gracilaria fisheri S1, then selected to study the stimulation of sexual reproduction by using 30 seedlings of 2 cm high from tetraspore to grow in a 1-liter flask with an armed tube to allow air inlet. The conditions to stimulate the reproductions by separating were salinity levels of 10, 20, and 30 ppt, the light intensity of 20, 40, and 60 umol photons m? s, the concentration of carbon dioxide 0 and 1%, and the concentration of plant hormones, namely cytokinin 6-benzyl adenine and auxin of 0.00, 0.05, 0.10 and 0.50 mg L. The examination of the initial cystocarp of reproduction was observed by the naked eye during the cultured period and cross-section to investigate under the microscope on the characteristics of the reproductive cell was done in the final time. An efficiency of quantum yield of photosynthesis system II (Fv / Fm) was measured. The taxonomic structures revealed that there are 2 species, 3 strains of Gracilaria from cultured ponds, namely Agarophyton tenuistipitata (Gracilaria tenuistipitata), Gracilaria fisheri S1, and Gracilaria fisheri S2. The DNA information was declared in the same of Agarophyton tenuistipitata for pior species but decleared as different species, Gracilaria changii for both strains of G. fisheri. Examining nutritional values was found to have different nutrient contents. The G. fisheri S2, had the highest protein and ash content with of 16.51 ‡ 0.14 and 21.11 + 0.41 %, respectively. In G. fisheri S1 and G. fisheri S2 had the same fat content of 0.54 + 0.30%. The fiber in G. fisheri S1 contained a most maximum of 22.01 ÷ 0.13 % while the most carbohydrate and moisture in G. teunistipitata was a most maximum of 58.01 + 1.33 and 6.31 1.07%. The effect of stimulating by the physical and chemical factors on the sexual reproduction in G. fisheri S1, the cystoscopy was observed in all conditions of salinity and light intensity. At 20 ppt salinity and light intensity 60 umol photons m'', cystocarp showed that fastest in week 2 of culturing as a convex surface from the thallus surface. The male completed male structure and cystocarp were observed when there was a cross-section. Under the condition of filling carbon dioxide and both plant hormones were unavailable to observed sexual reproduction of in this alga. From culturing under various factors: light intensity, carbon dioxide and plant hormones provided Fv/Fm in the range of 0.54 # 0.09-0.63 0.14, 0.46 0.11-0.56 + 0.18, 0.49 ÷ 0.09-0.65 # 0.07 and 0.50 # 0.15-0.60 $ 0.09 respectively. This study suggests that the stimulated sexual reproduction of G. fisheri S1 which was popular strain should be used salinity and light intensity factors while chemicals such as carbon dioxide and plant hormones may inhibit the sexual reproduction of the alga.