Genetic diversity and conservation of two threatened dipterocarps(Dipterocarpaceae) in southeast Vietnam     

Dinh-Duy Vu  Thi Tuyet-Xuan Bui  Minh-Duc Nguyen  Syed Noor Muhammad Shah  Dinh-Giap Vu  Yi Zhang  Minh-Tam Nguyen  Xiao-Hua Huang 《林业研究》2019,(5):1823-1831

Two threatened dipterocarp species,Dipterocarpus costatus and Dipterocarpus alatus are well-known endangered species in lowland forests of southeastern Vietnam,primarily from habitat loss and over-exploitation of their wood.To develop conservation strategies for these species,we analyzed 242 samples using nine microsatellite markers to determine the genetic variability within and among five populations of D.alatus and three of D.costatus,representing the natural range of dipterocarps in Southeast Vietnam.Results indicated low levels of genetic variability within populations with an average gene diversity of 0.223 for D.alatus and 0.152 for D.costatus.Results of bottleneck tests indicated a reduction in population size of both species(P>0.05).Genetic differentiation among populations was high(FST=0.347 for D.costatus and 0.274 for D.alatus),indicating limited gene flow(Nm=0.662 for D.costatus and 0.47 for D.alatus)and isolated populations related to geographical distances.Analysis of molecular variance showed high genetic variation within populations(72.92%for D.alatus and 60.81%for D.costatus)compared to among populations.Bayesian analysis and UPGMA tree also indicated the two optimal genetic clusters related to geographical distances.These results will provide a platform for the conservation,management and restoration of these species.  相似文献   

Comparison of three processing methods for laminated bamboo timber production     

Edi Suhaimi Bakar  Muhammad Nadzim Mohd Nazip  Rogerson Anokye  Lee Seng Hua 《林业研究》2019,(1):363-369

Three processing techniques, split-squaring(SS),V-grooving(VG), and split-edging(SE), were evaluated and compared in terms of their processing time and recovery. Semantan bamboo(Gigantochloa scortechinii Gamble) was used as a raw material and the results showed that the VG-method required the longest processing time(32.1 min), followed by the SS-method(18.2 min), and the SE-method(17.9 min). However, the VG-method showed the highest recovery(82.0%) compared to the SS-method and SE-method, 31.0 and 49.4%, respectively. When both processing time and recovery factors were combined with the same weighing factor, the highest value was recorded with the VG-method(49.1), while the SE-method had values of 31.1 and the SS-method 12.8. The results suggest that the VG-method is the best option. However, the V-grooving machine is still a prototype and therefore the SE-method could be an alternative option until the improved V-grooving machine is available.  相似文献   

Alleviation of arsenic toxicity by phosphate is associated with its regulation of detoxification,defense, and transport gene expression in barley     

Gerald Zvobgo  Jonas Lwalaba Wa Lwalaba  Tichaona Sagonda  James Mutemachani Mapodzeke  Noor Muhammad  Imran Haider Shamsi  Guo-ping ZHANG 《农业科学学报》2019,18(2):381-394

Arsenic(As) contamination in soils has posed a severe threat to safe crop production. The previous studies showed the antagonism between phosphorus(P) and As in plant growth and As uptake, while the mechanisms of alleviating As toxicity by P is not completely clear. Due to the limiting P condition, it is imperative to understand how low P addition can be used to suppress arsenate As(V) uptake and the subsequent mechanisms involved. Thus in this study we investigated the effect of P addition on As uptake, anti-oxidative enzyme activity, and anti-oxidant content, and the relative expression of transport, defense, and detoxification genes using two barley genotypes differing in As toxicity tolerance. P addition significantly reduced As concentration in plant tissues, and caused the great changes in activities of catalase and superoxide dismutase, glutathione content, and the relative expression of examined genes when the plants of the two barley genotypes were exposed to 100 μmol L~(–1) As, with ZDB160(As-tolerant) being much more affected than ZDB475(As-sensitive). The current results show that P addition can alleviate As toxicity by regulating the expression of As transport, defense, and detoxification genes to a greater extent in As tolerance of barley, suggesting the possibility of controlling As uptake and toxicity by applying low amount of P fertilizers in the As-contaminated soils.  相似文献   

Comparative studies on some yield contributing traits of wheat sown in binary mixtures     

Sabina Asghar  Muhammad Kashif  Abdus Salam Khan  Ihsan Khaliq  Jehanzeb Farooq 《Frontiers of Agriculture in China》2011,5(2):141-145

Cultivar mixtures have been suggested as ways to increase crop productivity. This field study was conducted to investigate the competition among five cultivated varieties of wheat (Triticum aestivum L.) for the traits like plant height, flag leaf area, fertile tillers per plant, spike length, spikelets per spike, spike density, grain weight per spike, and seed index in relation to competition with yield per plant. It was observed that cultivar mixtures ought to be more productive than corresponding pure stands. Four binary combinations of Seher2006-Kohistan97, Farid2006-SH2002, SH2002-Shahkar95, and SH2002-Kohistan97 were superior in performance, showing land equivalent ratio (LER) values greater than one for plant height, fertile tillers per plant, spike density, grain weight per spike, and grain yield per plant. It was observed that the performance of binary mixtures was mainly due to the increased average performance in spike density, grain weight per spike, and grain yield per plant. The competitive ability of wheat varieties in mixtures was independent of each other for the respective traits, which lead to cumulative effects for the increased performance within the associates in mixtures.  相似文献   

Impact of Methylenetetrahydrofolate Reductase C677T Polymorphism on the Risk of Gastric Cancer and Its Interaction with Helicobacter pylori Infection     

Samaneh Saberi  Kazem Zendehdel  Sahar Jahangiri  Yeganeh Talebkhan  Afshin Abdirad  Nazanin Mohajerani  Maryam Bababeik  Najmeh Karami  Maryam Esmaili  Akbar Oghalaie  Parisa Hassanpour  Neda Amini  Mohammad Ali Mohagheghi  Mahmoud Eshagh Hossieni  Marjan Mohammadi 《Iranian Biomedical Journal》2012,16(4):179-184

Background

Attempts for early detection of gastric cancer have recently focused on host''s genetic susceptibility factors and gene-environment interactions. We have, herein, studied the association of MTHFR C677T single nucleotide polymorphism (SNP) and its interaction with Helicobacter pylori infection, smoking, age and gender on the risk of gastric cancer among an Iranian population.

Methods

Gastric cancer patients (n = 450) and cancer-free controls (n = 780) were studied for serum H. pylori-specific IgG antibodies by ELISA and MTHFR C677T polymorphism (SNP) by PCR-RFLP. Demographic and life style data were collected through patient interviews. Unconditional logistic regression model estimated odds ratio (OR) and the corresponding 95% confidence intervals (CI).

Results

The interactions of MTHFR genotype with H. pylori infection (P = 0.03), age (P = 0.049) and gender (P = 0.007) were statistically significant. Accordingly, MTHFR C677T carriers who were also positive for H. pylori infection exhibited 80% (OR = 1.8, 95% CI = 1.0-2.9) significant excess risk of non-cardia gastric cancer. Furthermore, subjects over the age of 50 or female subjects carrying MTHFR C677T SNP showed 40 (OR = 1.4, 95% CI = 1.0-2.0) and 100 (OR = 2.0, 95% CI = 1.2-3.2) percent increased risk of gastric cancer, respectively.

Conclusion

MTHFR C677T SNP seems to increase the risk of gastric cancer and the effect is significantly inflated by interactions with H. pylori infection, age and gender. Key Words: Helicobacter pylori, Smoking, Gender identity, Age group, Methylenetetrahydrofolate reductase  相似文献   

Boron Application Improves Growth,Yield and Net Economic Return of Rice   总被引：1，自引：1，他引：0  

Mubshar HUSSAIN  M.Ayaz KHAN  M.Bismillah KHAN  Muhammad FAROOQ  Shahid FAROOQ 《水稻科学》2012,19(3):259-262

A field trial was conducted to evaluate the role of boron (B) application at different growth stages in improving the growth,yield and net economic return of rice at farmer’s fields during summer season,2009.Boron was soil applied (1.5 kg/hm2) at the transplanting,tillering,flowering and grain formation stages of rice;foliar applied (1.5% B solution) at the tillering,flowering and grain formation stages of rice,and dipped seedling roots in 1.5% B solution before transplanting;while control plots did not apply any B.Boron application (except dipping of seedling roots in B solution,which caused toxicity and reduced the number of tillers and straw yield than control) substantially improved the rice growth and yield.However,soil application was better in improving the number of grains per panicle,1000-grain weight,grain yield,harvest index,net economic income and ratio of benefit to cost compared with the rest of treatments.Overall,for improving rice performance and maximizing the net economic returns,B might be applied as soil application at flowering.  相似文献   

Biotic changes in relation to local decrease in soil conduciveness to disease caused by <Emphasis Type="Italic">Rhizoctonia solani</Emphasis>     

Muhammad Anees  Arne Tronsmo  Véronique Edel-Hermann  Nadine Gautheron  Vincent Faloya  Christian Steinberg 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(1):29-41

The relationships between biotic changes and local decrease in soil conduciveness in disease patches towards the disease incited by Rhizoctonia solani AG 2-2 in a sugar beet field in France were investigated. Soil samples from healthy and diseased areas were analysed for bacterial and fungal densities, molecular and physiological microbial community structures, and antagonistic abilities of Trichoderma isolates collected from diseased and healthy areas. Although the inoculum density was higher inside the disease patches, the respective soil was less conducive towards disease incited by R. solani AG 2-2. It was concluded that the pathogen was present in healthy areas but did not incite disease in field conditions. Conversely, the response of the microflora to previous development of R. solani in diseased areas prevented further pathogenic activity. Indeed, genetic and physiological structures of the fungal communities and physiological structures of the bacterial communities were modified in disease patches compared to healthy areas. The terminal restriction fragment length polymorphism (T-RFLP) analysis revealed that the peaks corresponding to R. solani and Trichoderma spp. were higher inside the patches than in the healthy areas. Trichoderma isolates from the disease patches were more antagonistic than those from the healthy areas. These results suggest that disease caused by R. solani AG 2-2 induced changes in genetic and physiological structure of microbial populations and development of antagonists. The decreased conduciveness inside the patches may help explain patch mobility in the following season.  相似文献   

行距对棉花生长发育、产量及早熟性指数的影响的研究(英文)   总被引：3，自引：1，他引：2  

王龙昌  薛兰兰  ALI Shafaqat 《棉花学报》2010,22(6):611-616

棉花窄行密植生产是缩短棉花生长季节实现棉花早熟的主要举措,并且窄行密植对棉花的产量无显著影响。田间试验于2006年6月到2007年1月在巴基斯坦费萨拉巴德农业大学试验田进行,以确定行距对不同品系棉花的生长、生产和早熟性指数的影响。试验选取NIAB-111,CIM-496和FH-901 3个棉花品种,设置了60、75和90 cm 3种行距进行试验研究。结果表明:行距对棉花生长发育、产量和早熟性指数具有极显著影响;行距75 cm的处理产量最高达到2603 kg·hm-2,其次是行距60 cm的处理,产量为2541 kg·hm-2,但二者间差异不显著;行距60 cm的处理早熟性指数达到50.92%,显著大于其它处理;行距75 cm的处理次之。子棉产量最高的品种是FH-901,同时其早熟性指数也最高,达到54.34%。  相似文献   

Study of heritable variation and genetics of earliness in mungbean (<Emphasis Type="Italic">Vigna radiata</Emphasis> L. Wilczek)     

Aziz ur Rehman  Muhammad Amjad Ali  Muhammad Saleem  W. Tadesse 《Euphytica》2010,176(3):331-339

Fifty-five mungbean lines were evaluated for days to maturity and grain yield per plant. This material showed considerable range of variability for the target traits. Eight genetically diverse parents were selected and used for a full diallel set of crosses to study the mode of inheritance for earliness related parameters (days to flowering, days to maturity and length of reproductive phase) during summer 2005. The F₁ generation of these crosses was sown during the spring of 2006 and the selfed seeds were used to raise the F₂ generation during kharif season. The data recorded from two generations were subjected to genetic analysis. The formal ANOVA showed the significance of both additive and dominance effects for all the traits in both generations. Significance of D, H₁ and H₂ components also confirmed the contribution of both additive and dominance effects in controlling the inheritance of these traits. The estimates of narrow sense heritability were low to moderate except higher estimates for days to maturity in F₂ generation, while the broad sense heritability estimates were relatively higher. Seasonal and environmental effects were also found to be significant. In view of the complex nature of gene action for earliness, it is suggested that breeders should look for transgressive recombinants of earliness and other desirable attributes in later segregating generations to gain higher genetic advance. The variety NM92 was found to be the best source of earliness in mungbean breeding.  相似文献   

Megasporogenesis and Megagametogenesis in Autotetraploid Indica/Japonica Rice Hybrid     

Muhammad Qasim SHAHID 《水稻科学》2010,17(4):296-302

Autotetraploid indica/japonica rice hybrid combines both the advantages of polyploidy and the heterosis between indica and japonica rice.Embryo sac abortion is an important factor influencing spikelet fertility in autotetraploid rice hybrid.To clarify the cytological mechanism of embryo sac abortion,the megasporogenesis and megagametogenesis in an autotetraploid japonica/indica hybrid were examined by the whole-mount eosin B-staining confocal laser scanning microscopy(WE-CLSM)technique.Abnormalities were ob...  相似文献