Effects of Salinity,Commercial Salts,and Water Type on Cultivation of the Cryptophyte Microalgae Rhodomonas salina and the Calanoid Copepod Acartia tonsa

Marine aquaculture facilities positioned far from the sea need access to seawater (SW); hence, commercial salts are often the chosen solution. In marine hatcheries, most fish larvae require live feed (zooplankton) that are in turn fed with microalgae. The objective of this research was to investigate the applicability of commercial salts and clarify the potential effects on the cultivation of the microalga Rhodomonas salina and the copepod Acartia tonsa. Three commercial salts were tested, Red Sea Salt (RS), Red Sea – Coral Pro Salt (CP), and Blue Treasure Salt. R. salina was cultured at salinities of 10, 20, and 30 psu resulting in equal growth rates at salinities 20 and 30 in SW and RS mixed with deionized (DI) water. The optimum salinity for R. salina was 29 psu. For A. tonsa eggs, we observed highest hatching success in 30 psu with CP or RS mixed with DI water. The egg hatching success was not affected by salinities 15–40 and optimal hatching was obtained at 27 psu. Results confirm it was possible to use commercial salts for rearing of both R. salina and A. tonsa, widening the application of these species for aquaculture facilities without access to SW.     

Reattachment of tooth fragment: an in vitro study

Canine tooth fracture is common in dogs. Application of an esthetic and durable restoration may be challenging in veterinary dental practice. This study used traditional human dental laboratory methods to evaluate fracture strength of intact dog canine teeth and fractured teeth that had been restored by reattachment of the tooth fragment. The results showed that the teeth restored by reattachment of the tooth fragment supported a test load equal to 45.4 % of the load necessary to fracture intact canine teeth.     

Mineral imbalance in hevea brasiliensis micro‐cuttings: Relation with in vitro multiplication and acclimatization

The mineral composition of Hevea brasiliensis shoots was analyzed at different stages of the microcutting procedure from mother plants grown in greenhouses to rooted microcuttings at the acclimatization stage. Compared to the mineral status of the mother plants, a mineral imbalance was noticed in shoots right from the in vitro establishment phase. Phosphorus (P), potassium (K), sodium (Na), chloride (Cl), and zinc (Zn) contents increased, while calcium (Ca), magnesium (Mg), iron (Fe), and copper (Cu) diminished, resulting in a substantial modification to the mineral balance. The N: P, N: K, Mg: P and K: Na ratios were very low, whereas the K: Mg, K: P, and K: Ca ratios were very high. During the multiplication phase, the N: P ratio returned virtually to its initial value but the other ratios remained modified. A mineral analysis of shoots after three years multiplication in vitro revealed a very low N: P ratio, a very high K: Ca ratio and a normal K: Na ratio. The same results were obtained right from the initial culture cycles on shoots developed in vitro from mother plants with a high multiplication potential. These results are discussed and lead us to consider the N: P, K: Ca, and K: Na ratios as potential markers of Hevea brasiliensis multiplication ability in vitro. During the rooting phase, the Mg: P and K: Ca ratios returned to their normal values, whereas the other ratios returned to normal values on formation of the second leaf flush ex‐vitro.     

微繁橡胶种植材料在大田试验中的生长及产量表现

一直以来,因无法得到自根无性系或砧木无性系使得橡胶树的选育种受到极大的限制和阻碍。法国国际农业研究与发展中心(CIRAD)自1980年代开始橡胶树离体培养研究,现已成功建立若干老态无性系的离体微繁体系,并培育出2类新型的种植材料,即自根无性系和芽接复壮无性系。自1989年以来,CIRAD相继在3个亚非国家建立了65hm2大田试验区以期对这些新型种植材料在生长势及产量等方面的表现作出客观、科学的评价鉴定。鉴定分析结果显示,来自"初始愈伤体细胞胚胎发生"的自根无性系以及来自微型扦插的芽接复壮无性系其生长势及产量表现均优于常规芽接无性系,而来自"保存愈伤体细胞胚胎发生"的自根无性系其生长势及产量则显著差于常规芽接无性系。本文还就这些新型种植材料的应用前景作了进一步的讨论。     

Semimicro Chemical and X-ray Fluorescence Analysis of Lunar Samples

Major and selected minor elements were determined in seven whole rock fragments, five portions of pulverized lunar rock, and the lunar soil. Three different rock types were represented: vesicular, fine-grained basaltic rocks; medium to coarse-grained, vuggy gabbroic rocks; and breccia. The ranges (in percent) for the major constituents of the lunar samples are: SiO(2), 38 to 42; Al(2)O(3), 8 to 14; total iron as FeO, 15 to 20; MgO, 6 to 8; CaO, 10 to 12; Na(2)O, 0.5 to 1; K(2)0, 0.05 to 0.4; TiO(2), 8 to 13; MnO, 0.2 to 0.3; and Cr(2)O(3), 0.2 to 0.4. The high reducing capacity of the samples strongly suggests the presence of Ti(III).     

Relation between nitrogen uptake,amino acid contents,and embryogenic intensity of rubber tree calli

Ammonium and nitrate uptake as well as free and protein amino acid contents were compared in calli grown on three culture media favouring rubber tree (Hevea brasiliensis Mull. Arg.) somatic embryogenesis to varying degrees. The percentage of embryogenic calli increased during embryogenesis induction in line with nitrate uptake, whereas ammonium uptake dropped during the same period in the following phases as this ratio tended to balance out. Free amino acids cumulated temporarily at the end of embryogenesis expression, then their content diminished. A decreasing gradient was revealed for free glutamic acid and glutamine between calli, proembryos, and developed somatic embryos. On the other hand, the protein content increased over time in the highly embryogenic culture reflecting the increasing protein content of embryos as they developed.