ABSTRACT
Leaf water potential of peanut subjected to drought stress is positively related to the oil content of peanut kernels. The aim of this study was to directly screen the high oil mutants of peanut and create the new peanut varieties using hydroxyproline as water potential regulator. In vitro mutagenesis was carried out with the embryonic leaflets of peanut variety Huayu 20 as explants and pingyangmycin as a mutagen added into the somatic embryo formation medium. The formed somatic embryos were successively transferred to somatic embryo germination and selection medium containing 6 mmol/L hydroxyproline (at -2.079 MPa water potential ) to induce regeneration and directionally screen high oil content mutants. After that, these plantlets were grafted and transplanted to the experimental field and 132 high oil mutants with oil content over 55% were obtained from the offspring of regenerated plants. Finally, among them, the oil contents of 27 lines were higher than 58% and of 2 lines were higher than 60%. A new peanut variety Yuhua 9 with high yield and oil content was bred from the regenerated plant progenies combining the pedigree breeding method. The yield was 14.0% higher than that of the control cultivar in the testing new peanut varieties of Liaoning province, and also it has passed the national registration of non-major crop varieties. Yuhua 9 with an oil content of 61.05%, which was 11.55 percentage points higher than that of the parent Huayu 20, was the peanut cultivar with the highest oil content in the world. The result showed that it was an effective way for directional breeding of high oil peanut varieties by means of the three-step technique including in vitro mutagenesis, directional screening by reducing water potential in medium and pedigree selection of regenerated plant progenies.
Subject(s)
Arachis , Droughts , Germination , Mutagenesis , Plant BreedingABSTRACT
BACKGROUND:In view of the unavoidable problems of autogenous and al ogenous bone grafts, it is an urgent need to develop biodegradable bone substitute materials, among which is calcium phosphate material that has become a hot spot in the domestic and foreign research. OBJECTIVE:To develop a biodegradable calcium phosphate material for bone repair based on tetracalcium phosphate (TTCP). METHODS:The biodegradable calcium phosphate cement made from TTCP, dicalcium phosphate anhydrous and different constituents of curing liquids was prepared under room temperature (about 25 ℃). The effects of solid components, liquid components as well as calcinations and drying temperature on the physical and biological performances were detected through X-ray diffraction test, hardness test, decay in a simulated body fluid, hemolysis and cytotoxicity tests, respectively, to select the bone repair material with excel ent performances. RESULTS AND CONCLUSION:When the calcination temperature was lower than 1300 ℃, TTCP was rarely available;only close to 1400 ℃, the relatively pure TTCP was gained. A large number of pure TTCP were gained by rapid cooling because of avoidance of the moisture impact, but slow cooling made the main products to be hydroxyapatite, suggesting that rapid cooling is essential to obtain pure TTCP. With the increase of the proportion of citric acid solution in the liquid phase, the pH values and the hemolysis rate in the bone cement soak solution were increased gradually, illustrating that citric acid solution is easy to induce hemolysis. In vitro cel experiments showed that the hemolysis rate of bone cement with a solution of 2:1 NH4/Na ratio was the lowest, and the biocompatibility was the best, which was the most favorable to cel growth. Cements was made of calcined powders sieved at 1400 ℃ and showed the shortest initial setting time, least effect on pH values, lowest disintegration rate and hemolysis rate, and slightest inhibition effect on the cel proliferation, indicating that the bone cements made of sieved powder after 1400 ℃ calcination is more suitable for clinical application.
ABSTRACT
Objective To compare the clinical effects of dynamic hip screw(DHS),Gamma interlocking intramedullary nail and proximal femoral nail antirotation (PFNA) in the treatment of intertrochanteric femoral fractures in elderly patients.Methods From January 2008 to June 2015,103 elderly patients with intertrochanteric femoral fracture were treated with DHS (DHS group,33 cases),Gamma nails (Gamma group,30 cases),or PFNA (PFNA group,40 cases).By the AO classification,there were 44 cases of type 31-Al,30 cases of type 31-A2 and 29 cases of type 31-A3.The 3 groups were compared in terms of incision length,operation time,intraoperative blood loss,fracture healing time,postoperative weight-bearing time,Harris scoring,and incidence of postoperative complications.Results PFNA group incurred significantly shorter incision length (5.4 ±0.5 cm) and operation time (70.8 ± 16.2 min) than DHS group (12.6 ±2.7 cm and 102.6±17.4min) and Gamma group (7.5±0.8 cmand93.0±35.9 min) (P ＜0.05).The intraoperative blood loss in PFNA group (163.2 ± 60.6 mL) was significantly less than in DHS group (280.5 ±89.8 mL) and in Gamma group (204.9 ±62.2 mL),and that in Gamma group was also significantly less than in DHS group (P ＜ O.05).PFNA group had significantly shorter weight-beating time (11.0 ± 0.8 weeks),fracture healing time(13.6 ± 1.5 weeks) and significantly higher Harris good to excellent rate (92.5％) than DHSgroup (13.3±1.0weeks,15.8 ± 1.2 weeks and 84.8％) and Gamma group (12.5±1.3 weeks,14.2 ± 1.0 weeks and 86.7％) (P ＜ 0.05).The incidence of postoperative complications in DHS group (21.2％)was significantly higher than in Gamma group(10.0％) and in PFNA group (7.5％) (P ＜ 0.05).Conclusions DHS,Gamma nail and PFNA are effective means for the treatment of intertrochanteric femoral fractures in the elderly.Intramedullary fixation,especially by PFNA,shows superiority in the clinical outcomes.