荞麦根的转录组学分析及黄酮合成基因的鉴定

荞麦基因资源相对匮乏。以甜荞根和金荞根为材料,利用Illumina Hi SeqTM2000对其进行转录组测序,经过de novo从头组装得到64 618条Unigene,其中37 546条基因得到了有效注释。对甜荞根和金荞根中的差异基因进行筛选,共获得了4 709个差异基因,其中2 460个上调表达,2 249个下调表达。这些差异基因的GO注释集中在10个细胞组分(cellular component)、12个分子功能(molecular function)和22个生物学过程(biological process)中。对差异基因参与的代谢途径进行富集,上调基因中共有40个代谢途径显著富集,下调基因中共有18个代谢途径显著富集,这些显著富集的代谢途径参与甜荞根和金荞根的生物学调控。最后对转录组中注释到黄酮合成途径中的关键基因进行了分析,共有21个基因注释到黄酮合成途径中的关键酶。不仅丰富了荞麦的基因资源,为荞麦分子生物学研究提供数据基础,也为筛选甜荞根和金荞根中相关基因的表达趋势提供参考依据。     

复合发酵液对致病疫霉的抑制机理

[目的]研究复合发酵液对致病疫霉[Phytophthora infestans （Mont.） de Bary）]的抑制机理。[方法]研究了白菜黑斑病菌和梨黑斑病菌的复合发酵液对致病疫霉的抑制作用机理。[结果]白菜黑斑病菌和梨黑斑病菌复合发酵液使致病疫霉菌丝形态发生畸变;对致病疫霉游动孢子释放和休止孢萌发的抑制率分别为95.93%和78.25%;经复合发酵液处理的致病疫霉病菌菌丝体中可溶性蛋白含量与对照相比有一定的下降,但与单一发酵液处理相比均无显著差异。[结论]该研究可为开发有效控制马铃薯晚疫病的高效、低成本复合型生物农药提供理论依据。     

豹纹鳃棘鲈仔、稚、幼鱼的形态观察

参照鮨科鱼类胚后发育时期划分的一般方法,结合豹纹鳃棘鲈的形态特征将其胚后发育时期划分为仔鱼期（分卵黄囊期仔鱼和后期仔鱼）、稚鱼期和幼鱼期,并对各时期的形态特征进行了描述。记录了各时期的形态特征,豹纹鳃棘鲈体型修长,幼鱼通体红色,在鱼体上有数列排列整齐的蓝色或黑色斑点;在早期发育阶段第二背鳍棘和腹鳍棘的绝对平均长度可达13．12mm和10．19mm,而臀鳍发育较慢,当腹鳍棘和第二背鳍棘开始回收时其臀鳍棘才开始长出。     

致病疫霉拮抗菌梨黑斑病菌发酵条件的优化

为提高梨黑斑病菌(Alternaria kikuchiana)102菌株发酵产物对致病疫霉(Phytophthora infestans)Z182菌株生长的抑制效率,本研究利用涂布法和滤纸片法、采用单因素试验设计方法,在静置培养条件下,对梨黑斑病菌的最佳发酵条件进行了优化。结果显示,该菌株在28℃、自然pH、80 mL/250 mL装液量、6%接种量、黑暗培养8 d,所得发酵液对致病疫霉有较强的抑制作用,抑菌率可达85.7%。该菌株的抑制率优化后比优化前高出约15%,表明利用该菌株在抑制致病疫霉生长方面有进一步研究和利用的潜力。     

法国三大现代公园对勒·诺特尔式园林的传承

勒·诺特尔式的园林融合了法国传统园林和意大利园林的造园精髓,一直影响着法国现代公园的设计。巴黎的拉·维莱特、雪铁龙和贝西三大公园的设计,深受勒·诺特尔式园林的影响,以新的元素营造出了具有勒·诺特尔风格的布局和空间,并形成各自的特色,对当代城市公园的营造有着重要的借鉴意义。     

铁线莲里昂城的组织培养研究

以铁线莲里昂城的茎段、茎节和花为外植体,在MS基本培养基中添加2.0、3.0 mg/L6-BA,0.05、0.1 mg/LNAA和1.5、2.0 mg/L KT,对其进行初代诱导和继代增殖培养。结果表明:粗嫩茎的成活率远高于细嫩茎,可达到96.7%;MS+2.0 mg/L6-BA+0.05 mg/LNAA+1.0 mg/L KT对里昂城花的诱导优于茎段和茎节,高达100%;MS+3.0 mg/L 6-BA+0.1 mg/L NAA+1.5 mg/L KT适合愈伤组织的增殖,茎段、茎节和花的愈伤增殖率均在90%以上。     

Mycorrhiza and soil fertility effects with growth,nodulation and nitrogen fixation of leucaena grown on a typic eutrustox

Abstract

The rapidly growing, woody perennial legume, Leucaena (Leucaena leucocephala (Lam.) de Wit), is adaptable to a wide range of neotropical soil conditions. Effective Rhizobium inoculation and endophyte mycorrhizal colonization are essential for high levels of production and symbiotic N₂ fixation. The objective of this study was to determine growth, nodulation, nitrogenase activity and nodule composition of inoculated Leucaena as affected by mycorrhizal colonization and factorial soil fertility treatments of a Typic Eutrustox. Highly significant increases in top growth, nodule fresh wt. and nitrogenase activity resulted with Glomus fasciculatum colonization, soil K and linear increases with low‐soluble P fertilization to 300 mg P kg^‐1 soil. Highly significant interactions for increased nodulation and nitrogenase activity resulted with K × mycorrhiza. Interactions of all three factors P, K and mycorrhiza were highly significant for nodule fresh wt. However, responses comparing inoculation with G. fasciculatum and with combined G. fasciculatum, G. microcarpus and G. clavium were not significant. Highly significant increases with applied K levels to 300 mg K kg^‐1 soil resulted with top and root growth, nodulation and nitrogenase when applied with soluble P at 100 mg kg^‐1 soil and 500 mg Ca kg^‐1 soil. Significant and highly significant interactions of P, Ca and K level resulted for all parameters. Plant nutrient element composition of nodules increased with the fertilization treatments for P, Ca and increased K levels. A highly significant inverse relation was apparent with decreased Na resulting with increased K levels. Half or more of total nodule K, P and Mg but less than 20% of Ca and Na were within the nodule cytosol. Sodium, Mg, P, and Ca decreased in the cytosol fraction with increased K content.     

Late blight resistance in the British Neo-Tuberosum potato population

Summary Development of the British Neo-Tuberosum population included selection for resistance to late blight. High levels of foliage resistance are most often found in later-maturing clones but some early-maturing clones have good resistance. Resistance of foliage to Race 4 and to a complex race is associated. Some clones give variable results in tests for resistance in tubers. While those consistently displaying resistance are most frequent among those with resistant foliage, some have rather susceptible foliage. Tuber resistance appears most common among early maturing clones but this could be misleading, perhaps being due to tubers of later-maturing clones tending to be immature when tested (resistance often increasing as tubers mature). However some ‘lates’ are resistant, suggesting that genes for resistance in immature tubers occur. Selections are being used experimentally as parents in breeding for blight-resistant cultivars, and controlled breeding within Neo-Tuberosum to produce superior parents has commenced.     

Acid soil tolerance of leucaena species in greenhouse trials

Abstract

Lines of Leucaena leucocephala (Lam.) de Wit were grown in greenhouse pots of an acid, Al‐toxic Tatum subsoil (clayey, mixed, thermic typic Hapludult) treated with 0 or 3000 ppm CaCO₃ to give final soil pH values of 4.1 and 5.3, respectively. Lines of L. leucocephala, plus those of other Leucaena species, were also tested on an acid, Monmouth soil (clayey, mixed, mesic, typic Hapludult) treated with 0 or 1500 ppm CaCO₃ to give final soil pH values of 4.8 and 6.6, respectively. The major index of acid soil tolerance used was relative root yield (unlimed/limed %).

Relative root yields of 117 L. leucocephala lines on Tatum soil ranged from 34 to 246%. Hence, liming the soil from pH 4.1 to 5.3 was highly beneficial to some lines and highly detrimental to others. Because Tatum subsoil is 89% Al saturated at pH 4.1, line tolerance to unlimed soil indicates tolerance to Al. Causes of yield depression at pH 5.3 were not determined.

On Monmouth soil, in a test involving 148 lines of 6 Leucaena species, relative root yields (unlimed/limed %) ranged from 23 to 386%. The line showing highest tolerance to the acid soil (P.I. 279578) and that showing lowest tolerance (P.I? 281636) are both L,. leucocephala. The majority of lines used on Monmouth soil (124 of a total of 148) were from this species. Average performances of the 6 species indicated that L. diversifolia Benth. (5 lines) was most tolerant to the acid Monmouth soil and liming the soil from pH 4.8 to 6.6 actually decreased root yields. The species L.. leucocephala (124 entries) and L. pulverulenta Benth. (4 lines) were intermediate, and L. lanceolata S. Wats. (3 lines) and I., retusa Benth. (1 line) appeared more sensitive to acid Monmouth soil. The Al saturation of Monmouth soil at pH 4.8 was only 23% (compared with 89% for Tatum at pH 4.1). The major growth limiting factor in acid Monmouth soil is believed to be Al toxicity, but this soil has not been as throughly characterized as has Tatum, and other factors may well be involved in explaining differential tolerances of Leucaena lines on the unlimed versus limed soil.

Results of these studies indicate that Leucaena species and lines within species differ significantly in tolerance to acid soils having high levels of exchangeable Al. Acid soil tolerant lines of Leucaena may be useful in expanding the acreage of this crop on oxisols and ultisols of the tropics and subtropics.