云南烟草赤星病菌及近似种rDNA ITS序列分析

 为了进一步研究云南省烟草赤星病病原的系统发育关系,提取28份供试菌株的菌丝基因组DNA,进行rDNA ITS序列及两侧ITS序列扩增。28个供试菌株与GenBank中登录的链格孢属7个种（包括5个小孢子种Alternaria citri,A．alternata,A．longipes,A．mali,A．gaisen和2个大孢子种A．porri,A．solani）14个菌株的序列进行聚类分析：42个菌株明显地分成两支,供试菌株与5个小孢子种聚为一个分支,序列同源性高达99％～100％,没有明显的地域性差异;但另2个大孢子种聚为单独的一支,明显地与供试菌株和其他5个小孢子种区分开。rDNA ITSl 58S ITS2序列在相对保守的基础上又存在一定变异,在一些菌物属的研究中可作为分类鉴定、分子标记、系统发育的重要依据,但通过对世界各地Alternaria菌株序列的分析发现,rDNA ITS1 58S ITS2仅能将大孢子种和小孢子种分开,还不能作为区分不同地域不同来源菌株的标准。     

四会沙糖桔地球化学模型及适宜种植区划研究

沙糖桔生长所需的营养元素主要来源于土壤,地质背景的不同明显影响沙糖桔的产量和品质。通过对四会沙糖桔品质、营养元素含量与土壤地球化学元素之间相关性等研究,获取影响沙糖桔生长及果实品质的根系土壤营养元素(包括MgO、CaO、S、V),从而建立沙糖桔优生地球化学模型及适宜性评价体系,并编制沙糖桔种植区划图,圈定四会沙糖桔最适宜种植范围。     

Trichoderma atroviride promotes growth and enhances systemic resistance to Diplodia pinea in radiata pine (Pinus radiata) seedlings

Root drench application of Trichoderma atroviride isolates R32, R33, R40 and R84 promoted the growth of potted radiata pine seedlings. After 6 weeks, seedlings treated with R33 and R84 had thicker stems and greater stem and root biomass (p < 0.05) than untreated controls. Treatment with R32 increased seedling root biomass whilst R40 increased stem diameter. None of the isolates affected seedling height. One isolate, R33, induced systemic resistance to stem inoculation with Diplodia pinea and reduced dieback incidence by 20% compared with untreated controls. To our knowledge, this is the first report of systemic induced resistance by Trichoderma in a pine species. Furthermore, seedlings that were treated with R33 (root drench) plus foliar application of methyl jasmonate (MeJA) expressed elevated peroxidase activity in their stems 2 weeks later, compared with seedlings treated only with MeJA. Because R33 itself did not affect peroxidase activity, this may be indicative of treatment synergy or defence potentiation by R33. Curiously, R33 + MeJA induced terpenoids but suppressed phenylalanine ammonia‐lyase activity suggesting possible trade‐offs between phenolic and terpenoid defence pathways in the treated seedlings.     

圆叶决明草粉替代不同比例精料喂兔效果研究

利用豆科牧草圆叶决明Chamaecrista routundifolia CPI34721草粉分别以10%,15%,20%不同比例替代精料进行肉兔喂养试验.试验结果表明:与对照相比较,在兔只平均日增重、饲料利用率方面,各处理与对照差异不显著.替代10%和15%精料处理可显著提高兔肉品质,替代20%精料的处理在经济效益方面最佳,可提高经济效益5.15%.     

Survival of hypoxic human mesenchymal stem cells is enhanced by a positive feedback loop involving miR-210 and hypoxia-inducible factor 1

The use of mesenchymal stem cells (MSCs) has emerged as a potential new treatment for myocardial infarction. However, the poor viability of MSCs after transplantation critically limits the efficacy of this new strategy. The expression of microRNA-210 (miR-210) is induced by hypoxia and is important for cell survival under hypoxic conditions. Hypoxia increases the levels of hypoxia inducible factor-1 (HIF-1) protein and miR-210 in human MSCs (hMSCs). miR-210 positively regulates HIF-1α activity. Furthermore, miR-210 expression is also induced by hypoxia through the regulation of HIF-1α. To investigate the effect of miR-210 on hMSC survival under hypoxic conditions, survival rates along with signaling related to cell survival were evaluated in hMSCs over-expressing miR-210 or ones that lacked HIF-1α expression. Elevated miR-210 expression increased survival rates along with Akt and ERK activity in hMSCs with hypoxia. These data demonstrated that a positive feedback loop involving miR-210 and HIF-1α was important for MSC survival under hypoxic conditions.     

沼渣对铅锌冶炼废渣生物化学性质及植物生长的影响

为研究沼渣作为改良剂对铅锌冶炼废渣环境条件的改善及修复植物生长的影响,采用盆栽试验研究不同比例(0,1%,3%,5%,7%,9%)沼渣添加和黑麦草(Lolium perenne L.)生长对废渣养分含量、微生物学特性、重金属赋存形态及黑麦草的生物学特征的综合影响。结果表明:与对照废渣相比,添加沼渣后废渣养分(N、P、K)、有机质、酶活性(碱性磷酸酶、蔗糖酶、脲酶、过氧化氢酶)、微生物数量(细菌、真菌和放线菌)以及微生物活性(呼吸强度)均显著(p0.05)增加;不同比例沼渣添加均显著增加黑麦草鲜重、根长、株高并显著降低植物组织(地上和地下部)中重金属含量(p0.05)。沼渣添加和黑麦草生长通过促进废渣中酸溶态重金属(Cu、Cd、Zn、Pb)向残渣态转化进而降低废渣中重金属的生物有效性。典范对应分析表明,沼渣施用量在5%,7%,9%时对废渣微环境条件改善作用较大,其中,较低的沼渣添加量(5%)就能显著改善废渣的微环境条件及促进修复植物健康生长。因此,综合考虑沼渣作为有机改良剂的最佳费用和效应间的关系,在设置试验条件下,可将5%的沼渣添加量作为铅锌冶炼废渣有机改良及植物修复的最佳施用比例。     

植稻年限对土壤铁锰氧化物的影响

以浙江不同耕作年限水田和旱地为研究对象,探讨了植稻年限对土壤铁锰氧化物的影响,并揭示了水稻土发育过程中铁锰氧化物的剖面运移规律和诊断意义。结果表明:①土壤剖面中,全Fe、游离Fe及全Mn的变异随着种稻时间的延长而增大。种植达到一定年限时,全Fe、全Mn以及游离Fe在土壤剖面下层出现淀积。在各种铁锰氧化物中,对水稻土最具诊断意义的是游离Fe和全Fe。②无定形Fe以及络合态Fe、Mn与有机质呈显著正相关。植稻年限对它们的影响是通过对有机质的影响达到的。     

稻田免耕年限与复耕次数对土壤容重和水稻生长的影响

试验以免耕1~10年稻田和免耕3~6年后复耕1次、复耕2次、复耕3次稻田为对象,探索不同免耕年限与复耕次数对稻田土壤容重和水稻生长的影响,以期为因地制宜推广免耕技术提供科学依据。结果表明：无论土壤表层还是下层,免耕土壤容重总是大于翻耕土壤,且随着免耕时间的延长,其土壤容重逐渐加重,免耕3年及以后处理土壤容重显著大于翻耕处理(P<0.05),随着复耕次数的增加,土壤容重逐渐降低。连续免耕1~5年的田块,免耕栽培处理水稻最高苗和有效穗以及产量均表现为比翻耕栽培处理高,免耕6年处理表现相对平缓稳定,免耕7年及以后分蘖能力和产量明显下降。免耕3~5年后进行复耕处理水稻分蘖能力和产量总是低于对应的免耕4~6年处理,且随着复耕次数的增加差距逐渐扩大,免耕7年处理水稻分蘖能力和产量与免耕6年后进行复耕1次处理基本持平。结论为稻田免耕应以6年内为宜,当稻田连续免耕超过最适年限后,需要进行复耕作业,复耕1次即可。