Do cover crops change the lability of phosphorus in a clayey subtropical soil under different phosphate fertilizers?

Plants have developed different mechanisms to absorb and solubilize phosphorus (P) in the soil, especially in environments with low P availability. This study evaluated the effects of different winter cover crops on soil P availability in a clayey subtropical (Hapludox) soil receiving soluble P fertilizer and a rock phosphate applied to the summer crop, under no‐tillage. The experiment was carried out over 3 yrs (2009–2011) with five different cover crop species: common vetch, fodder radish, ryegrass, black oat, white clover and fallow as control. The soil was sampled after the third year of cover crop cultivation and analysed for inorganic and organic P forms according to the well‐established Hedley fractionation procedure. Phosphate fertilizers promoted accumulation of both labile and nonlabile P pools in soil in the near surface layer, especially under rock phosphate. Fertilizer applications were not able to change P fractions in deeper layers, emphasizing that the Brazilian clayey soils are a sink of P from fertilizer and its mobility is almost nil. Although the cover crops recycled a great amount of P in tissue, in a short‐term evaluation (3 yrs) they only changed the content of moderately labile P in soil, indicating that long‐term studies are needed for more conclusive results.     

Association of TNF-α, IL-10 and IL-6 promoter polymorphisms in pulmonary tuberculosis patients and their household contacts of younger age group

Single nucleotide polymorphisms (SNPs) of cytokine genes have been found to be involved in the clinical outcome of Tuberculosis. The present study was aimed to identify the high risk genotypes in Tuberculosis patients and their household contacts. A total of 490 subjects were studied which includes 150 active pulmonary tuberculosis patients (APTB), 190 household contacts (HHC) and 150 healthy controls (HC). The SNPs of TNF-α (-308A/G), IL-10(-1082G/A) and IL-6(-174G/C) were performed by ARMs PCR. The IL-10 GA genotype showed significant association in APTB and HHC and was 2.3 times higher risk in APTB and 3.7 times in HHC compared to HCs. The A allele was found to be significantly associated with the risk of disease. The CC genotype of IL-6 was found to be significantly associated in APTB and an insignificant positive association in HHCs. The multifactor dimensionality reduction (MDR) analysis indicated that the genotypes of IL-6 were showing high risk with GA genotype of IL-10. In conclusion the gene interaction may be useful for identification of genotypes as biomarkers to distinguish high risk individuals.     

牛Myostatin基因单核苷酸多态性分析

Myostatin基因即肌肉生长抑制素,是一种肌肉生长的负调控因子。应运PCR-SSCP和测序的方法对中国秦川牛、南阳牛以及国外引入品种皮埃蒙特牛双肌基因的第三外显子进行了多态性分析。结果表明:第三外显子938处G→A的单核苷酸的突变造成了南阳牛、皮埃蒙特牛第三外显子扩增片段多态性,秦川牛则不然。     

Development of Chinese Near-isogenic Line of Rice and Their Differentiating Ability of Pathogenic Races of Blast Fungus

The rice( Oryza L. ) variety, Lijiangxintuanheigu(LTH), is a universally susceptible variety. A set of near-isogenic lines (NILs) of rice which has single resistance gene for each line was developed by use of LTH as recurrent parent and Kusabue,Tsuyuake, K1, PiNo. 4, K60 and BL1, which are from Kiyosawa‘s differential varieties(KDV), as donor parents. Differentiating ability of these NILs to Philippine isolates was compared with that of their donor parents, KDV and IRRI‘ s NILs. The results of comparative studies were as follows: (1) Differentiating ability of Chinese NILs to Philippine isolates was much stronger than that of their donor parents and that of KDV. (2) Chinese NILs had similar ability to differentiate races to IRRI‘s NILs or higher differentiating ability than them. But IRRI‘s NILs almost had no differentiating ability to isolates from japonica rice-growing regions. They can not be used to differentiate races of isolates from japonica ricegrowing regions. Whereas, Chinese NILs can be used to differentiate races of isolates from both japonica ricegrowing regions and indica rice-growing regions. It was concluded that the set of Chinese NILs can be used as international differentials.     

In vitro Plant Regeneration from the Mature Tissue of Navel Orange (Citrus sinensis L. Osbeck) by Direct Organogenesis

An efficient in vitro regeneration system by direct organogenesis from mature nodal and internodal stem segments of Newhall navel orange (Citrus sinensis L. Osbeck) was developed. Illuminating conditions together with plant growth regulators affected the adventitious bud regeneration frequency and efficiency. The initial 15 d darkness inoculation is beneficial for the adventitious bud regeneration. The highest regeneration frequency (85.2%) and bud formation efficiency (3.7 per responsive internodal stem segment) were obtained in the media supplemented with 1.0 mg L-1 BAP and 0.5 mg L-1 NAA. ABA at 0.2 mg L-1 positively affected the bud formation efficiency, which amounted to 8.5 buds per internodal segment in the presence of BAP at 1.0 mg L-1. The adventitious shoots successfully rooted and were transferred to the soil.     

Utilization of Aromatic Rice in Improving Grain Quality of Hybrid Rice

ThesuccessfuldevelopmentandcommercialuseofhybridricehasgreatlyraisedriceyieldlevelinChina .However ,ithasbeenagreatchallengeforbreederstoim provethegrainqualityofhybridricewithoutsacrificeofitsyield ,i.e .,todevelophybridricecombinationswithgoodgrainqualityaswellashighyield .AromaticricelikeBasmatiinIndiaandPakistanandJasmineinThailand ,isfamousforitshighqualityandu niquepleasantflavorofaroma ,soitishighlyfavoredbyriceconsumersaroundtheworld .Itmightbeaneffectiveapproachtoimprovethegrainqual…     

作物活体多探头测量仪的研制

采用TP—801单板机制作作物活体多探头测量仪。该机可在田间对生长状态下的农作物进行多点体内养分积累、运输、分配等测定,且结果可靠。     

西瓜核型雄性不育两用系POD同工酶研究

用PAGE(聚丙烯酰胺凝胶)电泳技术,研究了西瓜核型雄性不育两用系不同器官的POD(过氧化物酶)同工酶酶谱差异。试验结果表明,不育株与可育株主要差异在雄花蕾,表现为不育株较可育株多2条活性强的酶带;其他器官差异小,仅表现为酶谱带强弱不同。并对POD同工酶与雄性不育性的相关性进行了研究。     

Inhibitory effects of LDL-ACM complex on subcutaneous implanted tumors in nude mice()

AIM: In order to evaluate the applicable value of LDL as a targeted vehicle for chemotherapeutic agents, we investigated and compared the inhibitory effects of LDL-ACM complex and free ACM on nude mice's subcutaneous implanted tumors derived from gastric cancer cell lines, SGC-7901 and NKM-45. METHODS: LDL-ACM complex was prepared and the tumor model of nude mice was established by subcutaneous implantation of SGC-7901 and NKM-45. Then, the groups of nude mice developed subcutaneous implanted tumors were received either LDL-ACM complex or free ACM. Subsequently, the tumor size, weight and leukemia cell counts were measured and the rates of tumor-inhibition and the survival were compared among the groups. RESULTS: The inhibitory effects of LDL-ACM complex on the tumors, especially on SGC-7901 implanted tumors were much more obvious than that of free ACM. It was also indicated that the action of LDL-ACM complex was mediated by LDL receptor. CONCLUSION: These results showed that LDL-ACM complex had significant inhibitory effects on the implanted tumors and the effect might be mediated by LDL receptor.     

Identification of a major gene (Mex-1) from Coffea canephora conferring resistance to Meloidogyne exigua in Coffea arabica

Among the most damaging root-knot nematode species, Meloidogyne exigua is especially common in Latin America and constitutes a major agronomic constraint in all major coffee-growing ( Coffea arabica ) areas. Growing nematode-resistant coffee represents the most promising option for control of the pest. The present study aimed to determine the mode of inheritance of the M. exigua resistance transferred into C. arabica from a related species, Coffea canephora , and to identify associated molecular markers. Segregation data analysis of F ₂ progeny derived from a cross between the resistant introgression line T5296 and the susceptible accession Et6 showed that the resistance to M. exigua is controlled by a simply inherited major gene (designated the Mex -1 locus). The gall index distribution exhibited by the F ₂ individuals suggested incomplete dominant expression. Fourteen AFLP markers were found associated with the resistance to M. exigua and a localized genetic map of the chromosome segment carrying Mex -1 was constructed. Furthermore, the association of the identified AFLP markers with Mex -1 was confirmed by analysis of a set of genotypes involving 28 introgression Arabica lines either resistant or susceptible to M. exigua in field conditions. These results represent an important starting point to enhance backcross breeding programmes and to perform an early selection of resistant seedlings.