柑橘褐斑病的病原分离和药物筛选

从云南马关近2 a来发生的一种柑橘褐斑病的病理组织中分离得到1株病原菌,依其培养性状和形态特征,初步鉴定为径点霉属,并比较了其对11种市售农药的敏感性。结果表明:氟硅唑、中生菌素、多抗霉素、丙森锌、氟菌唑、异菌脲6种药物对病菌菌丝生长的抑制活性较高,其中氟硅唑最灵敏,其EC50为0.03μg/mL;丙森锌和中生菌素次之,EC50分别为1.8μg/mL和3.14μg/mL;氟硅唑和百菌清对孢子的抑制效果较好,1μg/mL抑制率均在80%以上;丙森锌、佳爽和多抗霉素也有一定的保护作用。     

中韩食用菌生产态势及贸易竞争力分析

针对中韩两国食用菌生产和贸易竞争关系,利用联合国商品与贸易统计数据,从两国食用菌贸易总量、食用菌种类、运输方式和进出口贸易国家等角度进行比较分析,提出了开拓国际贸易市场的一些方法,为提升我国食用菌国际贸易竞争力提供参考。     

荔枝根毛与菌根水平年动态规律研究

本研究以12年生妃子笑/怀枝结果树和2年生怀枝实生苗为材料,观测根毛在须根上的着生方式与丛枝菌根真菌的侵染方式,并测定结果树与实生苗根系活力、菌根侵染率、根毛长度与密度的周年变化,以此明确荔枝植菌复合根吸收功能的年动态变化规律。实验结果显示,距离荔枝须根根冠约2.5 mm的位置就有根毛发生,而根毛成熟区则位于根冠后(0.5~2 cm)区域。此区域根毛着生方式多样,呈不规则块状着生或对生且此区域菌根真菌的侵染也较为频繁。怀枝实生苗与荔枝结果树根系活力、菌根侵染率的年动态曲线相似,但其出现极值的时间点不同。实生苗根系活力水平、总侵染率、丛枝侵染率的变化规律基本一致,先下降后上升;实生苗泡囊侵染率则与上述指标相反,先上升后下降。结果树总侵染率和丛枝侵染率的变化规律为先上升后下降再略有上升;泡囊侵染率的变化规律为先下降后上升。实生苗根毛长度、密度均显著低于结果树,且2个指标随时间的变化不显著。     

接种丛枝菌根真菌对柑橘不同钙剂吸收及苗木生长效应的影响

以柑橘苗为试材，分别对未接种植株、接种摩西球囊霉和幼套球囊霉的植株外施5nmol/L硝酸钙和醋酸钙，比较了三种处理下植株茎粗、株高、侵染率、根系活力和植株根系、叶片中钙和氮含量。结果表明，接种丛植菌根真菌促进植株的生长，其根系和叶片中钙元素和氮元素含量均比未接种的植株的高；施用硝酸钙的植株根系和叶片中钙、氮元素含量比施用醋酸钙的植株高。     

牛至精油及其主要成分香芹酚和百里酚对16种植物病原真菌的抑制活性

为评价牛至精油及其2种主要成分香芹酚和百里酚在植物真菌病害防治方面的应用前景，采用菌丝生长速率法和孢子萌发法测定3种物质对16种植物病原真菌菌丝生长和孢子萌发的抑制活性，并采用黄瓜子叶法测定其对黄瓜灰霉病的防治效果。结果表明，牛至精油在500 mg/L浓度处理下可完全抑制番茄早疫病菌Alternaria solani、黄瓜灰霉病菌Botrytis cinerea和小麦根腐病菌Bipolaris sorokiniana等12种植物病原真菌的菌丝生长，对棉花黄萎病菌Verticillium dahliae的菌丝生长抑制率也达到97.66%。牛至精油对这13种病原真菌的EC₅₀在83.09~236.58 mg/L之间，香芹酚和百里酚对这13种病原真菌的毒力均高于牛至精油，其中香芹酚对黄瓜灰霉病菌、油菜菌核病菌Sclerotinia sclerotiorum、小麦全蚀病菌Gaeumannomyces graminis、棉花黄萎病菌和小麦茎基腐病菌Fusarium pseudograminearum菌丝生长的毒力较强，EC₅₀分别为9.09、22.45、24.28、28.40和28.80 mg/L；百里酚对黄瓜灰霉病菌和小麦全蚀病菌菌丝生长的毒力较强，EC50分别为21.32 mg/L和27.08 mg/L。香芹酚和百里酚对棉花黄萎病菌、玉米大斑病菌Setosphaeria turcica、苦瓜枯萎病菌Fusarium oxysporum f.sp.momordicae、黄瓜灰霉病菌和黄瓜炭疽病菌Colletotrichum orbiculare的孢子萌发亦有较强毒力，其EC₅₀为3.78~289.07 mg/L。1 000 mg/L牛至精油对黄瓜灰霉病的预防效果与400 mg/L嘧霉胺悬浮剂的预防效果无显著差异；500 mg/L百里酚对黄瓜灰霉病的预防效果和治疗效果均与400 mg/L嘧霉胺悬浮剂的效果相当，而香芹酚的治疗效果显著优于400 mg/L嘧霉胺悬浮剂。表明牛至精油及其主要成分香芹酚和百里酚的抑菌谱广且活性强，具有作为植物源杀菌剂的开发应用潜力。     

Phylogenetic structure of arbuscular mycorrhizal community shifts in response to increasing soil fertility

Understanding the underlying mechanisms driving responses of belowground communities to increasing soil fertility will facilitate predictions of ecosystem responses to anthropogenic eutrophication of terrestrial systems. We studied the impact of fertilization of an alpine meadow on arbuscular mycorrhizal (AM) fungi, a group of root-associated microorganisms that are important in maintaining sustainable ecosystems. Species and phylogenetic composition of AM fungal communities in soils were compared across a soil fertility gradient generated by 8 years of combined nitrogen and phosphorus fertilization. Phylogenetic patterns were used to infer the ecological processes structuring the fungal communities. We identified 37 AM fungal virtual taxa, mostly in the genus Glomus. High fertilizer treatments caused a dramatic loss of Glomus species, but a significant increase in genus richness and a shift towards dominance of the lineage of Diversispora. AM fungal communities were phylogenetically clustered in unfertilized soil, random in the low fertilizer treatment and over-dispersed in the high fertilizer treatments, suggesting that the primary ecological process structuring communities shifted from environmental filtering (selection by host plants and fungal niches) to a stochastic process and finally to competitive exclusion across the fertilization gradient. Our findings elucidate the community shifts associated with increased soil fertility, and suggest that high fertilizer inputs may change the dominant ecological processes responsible for the assembly of AM fungal communities towards increased competition as photosynthate from host plants becomes an increasingly limited resource.     

Antitumor Profile of Carbon-Bridged Steroids (CBS) and Triterpenoids

This review focuses on the rare group of carbon-bridged steroids (CBS) and triterpenoids found in various natural sources such as green, yellow-green, and red algae, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. In addition, this group of rare lipids is found in amoebas, fungi, fungal endophytes, and plants. For convenience, the presented CBS and triterpenoids are divided into four groups, which include: (a) CBS and triterpenoids containing a cyclopropane group; (b) CBS and triterpenoids with cyclopropane ring in the side chain; (c) CBS and triterpenoids containing a cyclobutane group; (d) CBS and triterpenoids containing cyclopentane, cyclohexane or cycloheptane moieties. For the comparative characterization of the antitumor profile, we have added several semi- and synthetic CBS and triterpenoids, with various additional rings, to identify possible promising sources for pharmacologists and the pharmaceutical industry. About 300 CBS and triterpenoids are presented in this review, which demonstrate a wide range of biological activities, but the most pronounced antitumor profile. The review summarizes biological activities both determined experimentally and estimated using the well-known PASS software. According to the data obtained, two-thirds of CBS and triterpenoids show moderate activity levels with a confidence level of 70 to 90%; however, one third of these lipids demonstrate strong antitumor activity with a confidence level exceeding 90%. Several CBS and triterpenoids, from different lipid groups, demonstrate selective action on different types of tumor cells such as renal cancer, sarcoma, pancreatic cancer, prostate cancer, lymphocytic leukemia, myeloid leukemia, liver cancer, and genitourinary cancer with varying degrees of confidence. In addition, the review presents graphical images of the antitumor profile of both individual CBS and triterpenoids groups and individual compounds.     

北美蓝云杉菌根化育苗技术研究

为提高北美蓝云杉引种成活率并促进其幼苗生长，于2007年进行了适宜菌种的筛选和菌根化育苗技术的研究。结果表明:1）普通裂褶菌和Pt菌剂为较适宜的菌种。2）接种Pt菌剂后，不同种源间的平均苗高差异不显著，不同接种时间的平均苗高差异极显著。3）不同种源的适宜Pt菌剂接种量不同。1号和3号种源施用1 g/株的菌剂，2号和4号种源施用0.5 g/株的菌剂促进生长的效果最好，2个月后1～4号种源幼苗的平均苗高分别为3.31、3.90、3.84和3.54 cm。4）在幼苗移植时接种Pt菌剂不仅可以提高移植成活率，还有助于保持观赏性状。接种Pt菌剂后移植成活率均达85%以上，其中4号种源移植成活率最高，为92.86%；与对照相比，接种Pt菌剂后1级苗增多，其中3号种源的1级苗率最高，为56.67%。      

禾草内生真菌与丛枝菌根互作对多年生黑麦草生长及叶斑病的影响

为明确禾草内生真菌和丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)互作对多年生黑麦草Lolium perenne生长发育及叶斑病的影响,设置禾草内生真菌处理(由带有和不带禾草内生真菌种子建立)、AMF(幼套球囊霉Claroideoglomus etunicatum和根内球囊霉Rhizophagus intraradices)单独接种和混合接种处理及不接菌处理(对照),并在植物生长6周后接种或不接种多年生黑麦草叶斑病病原菌根腐离蠕孢Bipolaris sorokiniana,测定各处理多年生黑麦草的发病率、叶绿素含量、净光合速率、水分利用效率、AMF侵染率、P含量和生物量。结果表明:接种病原菌2周后,多年生黑麦草叶斑病的发病率为25.00%～38.75%,禾草内生真菌和幼套球囊霉均在一定程度上降低了多年生黑麦草的发病率,二者共同作用时发病率显著降低了35.48%。禾草内生真菌与AMF互作能在一定程度上提高植物叶绿素含量,促进光合作用,并促进P吸收和植物生长,二者的互作效应因禾草内生真菌与AMF组合而异,但均优于二者单独使用时的效应,其中禾草内生真菌与幼套球囊霉互作对多年生黑麦草生长及叶斑病防治的效果最好。     

玫烟色棒束孢几丁质酶基因上游调控序列克隆与结构预测分析

为探明玫烟色棒束孢几丁质酶基因Ifuchi1的表达调控机理，根据Ifuchi1基因组全长核苷酸序列，采用基因组步移方法，获得Ifuchi1的5′-上游区序列(总长为2 402 bp)。与cDNA 序列进行比对，其中含有2个内含子。TFSEARCH 1.3 软件分析转录因子结合位点的结果显示，该序列中没有明显的TATA和CAAT框，含有4个可能的碳调控因子的结合位点5＇>(g/c)YggRg<3＇和3个氮调控因子的结合位点-相隔很近的GATA。其中含有可能的葡萄糖抑制调控序列和压力反应元件。本研究结果为深入研究玫烟色棒束孢几丁质酶基因的表达调控机制及其分子机理奠定了一定基础。