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951.
952.
953.
为了探讨添加冷冻干燥保护剂对Lactobacillus.plantarum(L.plantarum)LIP-1微胶囊性能的影响,该试验以植物乳杆菌(L.plantarum) LIP-1微胶囊的包埋率和冻干存活率为指标,通过单因素及正交试验,筛选出最佳冷冻干燥保护剂,在此基础上将其添加到微胶囊中,观察对L.plantarum LIP-1微胶囊形态、释放性等性能的影响。试验结果表明冷冻干燥保护剂的最佳配方为质量分数分别为甘油2%、麦芽糖1%、L-半胱氨酸2%、乳糖2%,此时微胶囊的包埋率为67.60%,冻干存活率为83.80%;与未添加保护剂的空白对照组相比,添加适宜保护剂的微胶囊在表观形态、肠液释放性、耐胃酸性及在不同温度(4、20、37℃)下的耐贮藏性能均显著提高(P<0.05)。添加适宜保护剂的微胶囊表面更加光滑致密,粒径更小,约100 μm(空白对照组约为150~200 μm);在模拟肠液中,添加适宜保护剂的微胶囊完全释放仅需60 min,而空白对照组需要90 min才能释放完全;在耐胃酸性上,添加适宜保护剂的LIP-1微胶囊在120min后,活菌数才开始显著下降(P<0.05),150 min后,活菌数下降约30%;空白对照组在90 min后活菌数开始显著下降(P<0.05),150 min后,活菌数下降约44%;在4、20、37℃贮藏28 d后,加保护剂组的活菌数分别下降0.76、1.33、1.88 lg(cfu/g),而空白对照组的活菌数分别下降0.96、 1.50、2.40 lg(cfu/g)。试验结果表明添加适宜的冷冻干燥保护剂可以提高L.plantarum LIP-1微胶囊的性能,为工业化生产中提高益生菌微胶囊的性能提供一定的理论和技术指导。 相似文献
954.
955.
Oryza granulata, an upland wild rice species, represents an unique germplasm for possessing abilities of tolerance to shade and drought,
immune to bacterial blight and resistance to brown planthopper. Although low degree of genetic variability has been revealed
within its populations, little genetic information at the species level is available in determining rational conservation
strategies. Here we used dominant DNA marker random amplified polymorphism DNA (RAPD) to assess the genetic variability among
23 accessions of O. granulata that collected from main distribution areas worldwide. Twenty decamer primers generated a total of 243 bands, with 83.5%
of them (203 bands) being polymorphic. Calculation of Shannon index of diversity revealed an average value of 0.42 ± 0.25,
indicating that O. granulata maintains a relatively high degree of genetic diversity on the species level. Analysis of genetic dissimilarity (GD) showed
that genetic differentiation occurred among studied accessions, which supports the feasibility of current ex situ conservation strategies. We also suggested that information based on population studies, which could be achieved by international
co-operation, is needed to conserve this widespread germplasm more effectively. 相似文献
956.
Ji-Hoon Kim Won Sik Shin Dong-Ik Song Sang June Choi 《Water, air, and soil pollution》2005,166(1-4):367-380
Single- and bi-solute sorption and desorption of 2,4-dichlorophenol (2,4-DCP) and 2,4,5-trichlorophenol (2,4,5-TCP) in montmorillonite modified with hexadecyltrimethylammonium (HDTMA) were investigated using multi-step sorption and desorption procedure. Effect of pH on the multi-step sorption and desorption was investigated. As expected by the magnitude of octanol-water partition coefficient, K ow , both sorption and desorption affinity of 2,4,5-TCP was higher than that of 2,4-DCP at pH 4.85 and 9.15. For both chlorophenols, the protonated speciation (at pH 4.85) exhibited a higher affinity in both sorption and desorption than the predominant deprotonated speciation (about 95% and 99% of 2,4-dichlorophenolate and 2,4,5-trichlophenolate anions at pH 9.15, respectively). Desorption of chlorinated phenols was strongly dependent on the current pH regardless of their speciation in the previous sorption stage. Freundlich model was used to analyze the single-solute sorption and desorption data. No appreciable desorption-resistant (or non-desorbing) fraction was observed in organoclays after several multi-step desorptions. This indicates that sorption of phenols in organoclay mainly occurs via partitioning into the core of the pseudo-organic medium, thereby causing desorption nearly reversible. In bisolute competitive systems, sorption (or desorption) affinity of both chlorophenols was reduced compared to that in its single-solute system due to the competition between the solutes. The ideal adsorbed solution theory (IAST) coupled to the single-solute Freundlich model successfully predicted bisolute multi-step competitive sorption and desorption equilibria. 相似文献
957.
958.
Y. N. Song P. Marschner L. Li X. G. Bao J. H. Sun F. S. Zhang 《Biology and Fertility of Soils》2007,44(2):307-314
Cereal/cereal and cereal/legume intercropping systems are popular in the north, northwest, and southwest of China and often
result in yield increases compared to monocropping. Rhizosphere interactions may play a significant role in the yield increases,
particularly with respect to nutrient availability. The aim of this study was to investigate the effects of intercropping
on N availability and community composition of ammonia-oxidizing bacteria in the rhizosphere of wheat, maize, and faba bean
at different growth stages. Denaturing gradient gel electrophoresis (DGGE) based on 16S rRNA genes was used to analyze the
community composition of bacterial ammonia oxidizers belonging to β-proteobacteria. The results showed that intercropping
with faba bean significantly increased nitrate concentrations in the rhizosphere of wheat and maize at the second sampling
time (20 June) compared to monocropping or intercropping between maize and wheat. Intercropping significantly affected the
community composition of ammonia-oxidizing bacteria in the rhizosphere compared to monocropping, and the effects were most
pronounced in the maize/faba bean and wheat/maize intercropping systems when faba bean and wheat were at anthesis and maize
was in seedling stage. In wheat/faba bean intercropping, the effects of intercropping on community composition of ammonia-oxidizing
bacteria were less pronounced at the seedling stage of the two species but were significant at anthesis. 相似文献
959.
Xiao-Ping Jia Yun-Su Shi Yan-Cun Song Guo-Ying Wang Tian-Yu Wang Yu Li 《Genetic Resources and Crop Evolution》2007,54(2):233-236
The development of EST-SSR in foxtail millet (Setaria italica) for polymorphism and transferability study was reported here. From 1213 EST sequences, 30 SSRs were obtained and primers
were designed for 26 SSRs. Among them, four pairs of SSR primers amplified polymorphic products in 12 foxtail millet cultivars
and one accession of Setaria viridis, a wild relative of foxtail millet, with 10 alleles detected for the four loci and 2.5 alleles per locus. In addition, ten
SSR markers could be transferred to other nine Gramineae species. The putative functions of 11 ESTs containing polymorphic
and transferable SSRs were also identified. 相似文献
960.
G. F. Koopmans P. F. A. M. Römkens J. Song E. J. M. Temminghoff J. Japenga 《Water, air, and soil pollution》2007,181(1-4):355-371
The applicability of phytoextraction to remediate soils contaminated with heavy metals (HMs) depends on, amongst others, the duration before remediation is completed. The impact of changes in the HM content in soil occurring during remediation on plant uptake has to be considered in order to obtain a reliable estimate of the phytoextraction duration. To simulate the decrease in the HM content in soil and to assess the resulting decrease in the uptake of HMs by plants, contaminated soil was mixed with uncontaminated, but otherwise similar soil. Uptake of Cd, Pb, and Zn by the indicator plant Lupinus hartwegii and the Zn hyperaccumulator Thlaspi caerulescens (La Calamine ecotype) was a log-linear function of the in-situ measured HM soil solution concentrations. Over a wide range in dissolved Cd and Zn concentrations, uptake of these HMs by T. caerulescens was (much) greater than by L. hartwegii. Experimentally derived regression models describing the relationships between soil, soil solution, and plant were implemented in a HM mass balance model used to obtain estimates of the phytoextraction duration. For our target soils, estimates of the Cd phytoextraction duration using L. hartwegii or T. caerulescens increased significantly by more than 100 or 50 years when experimental soil—soil solution—plant relationships were used instead of the assumption of constant plant uptake of Cd. The two approaches gave similar results for phytoextraction of Zn by T. caerulescens. 相似文献