Biogeography and phylogenetic relationships of Hyrcanian wild apple using cpDNA and ITS noncoding sequences

The Hyrcanian forest of northern Iran is considered one of the potential centres for the evolution and domestication of the genus Malus (Rosaceae). However, the biogeography, phylogenetic position, and taxonomic status of the Hyrcanian wild apples have never been evaluated. In our study, the nucleotide sequences of the internal transcribed spacer (ITS) and the trnH-psbA intergenic spacer region from 14 natural populations were analysed. Phylogenetic analysis based on the ITS and the Maximum-likelihood (ML) tree showed that all Hyrcanian samples were closely related to M. orientalis and M. asiatica and can be placed within section Malus and series Malus. Furthermore, based on a comparison of ITS2 secondary structures, the Hyrcanian samples were identical to M. orientalis and M. sieversii. Biogeographic scenarios constructed using Statistical Dispersal-Vicariance Analysis (S-DIVA) and the Bayesian Binary Method (BBM) indicated that the ancestor of Malus originated during the Eocene, ～53 million years ago (Ma), and that China played a vital role in the expansion of the range of the genus. The members of Malus colonized the Hyrcanian region from China during the Miocene, ～22-10?Ma.     

半干旱黄土丘陵区人工林叶面积特征

 该文通过对黄土丘陵区4个密度的刺槐（Robinia pseudoacacia）人工林、3个密度的侧柏（Platycladus orientalis）人工林生长季叶面积变化的研究,揭示了不同密度林分叶面积生长与林分密度的关系;通过对灌木生长季叶面积变化的研究,建立了灌木柠条(Caragana korshinskii)、沙棘（Hippophae rhamnoides）和紫穗槐（Amorpha fruticosa）叶面积与叶鲜重、枝条基径的经验公式,为半干旱区灌木生长调查提供了一种方便、快捷的方法。结果表明：1）刺槐和侧柏各密度林分的单株林木叶面积和叶面积指数均在9月达到最大值,其中刺槐林叶面积指数峰值可达到10.5,侧柏峰值可达到3.2;灌木柠条、沙棘和紫穗槐叶面积和叶面积指数都在8月份达到各自的最大值,柠条、沙棘和紫穗槐的叶面积指数峰值分别为1.1 95、1.123和1.882;2）刺槐叶面积与叶鲜重具有极显著相关的幂函数关系,侧柏、柠条、沙棘、紫穗槐叶面积与叶鲜重具有极显著相关的线性函数关系,其中柠条枝条基径与叶面积还具有极显著相关的幂函数关系,沙棘、紫穗槐枝条基径与叶面积还具有极显著相关的线性函数关系;3）黄土丘陵区,由于林地土壤水分条件的限制,承载力有限。人工林进入生长盛期后, 不同密度刺槐和侧柏林分叶面积指数趋于一致,与最初的造林密度和现存密度没有关系。在不同密度的刺槐和侧柏林分间,单株叶面积与其林分密度成反比。在对上述结果分析的基础上得出：黄土丘陵区,由于林地土壤水分条件的限制,承载力有限。该文所研究的刺槐和侧柏各林分均已达到了当地土地承载力的上限,基于提高单株林木质量的考虑,建议刺槐林郁闭后的密度不超过833株&;#8226;hm^-2,侧柏则不超过1 111株&;#8226;hm^－2。如以全林分生物量为目标,林分密度也可适当减小。     

侧柏乙醇提取物对21种植物病原真菌的抑菌活性

采用菌丝生长速率法测定了侧柏(Platycladus orientalis)叶、小枝、球果和种子4个不同部位乙醇提取物对21种植物病原真菌的抑菌活性。结果显示:(1)在供试浓度为50g/L(相当于干样)时,侧柏各部位乙醇提取物对4种供试植物病原真菌均具有较好抑制作用,其中侧柏叶提取物的抑菌效果最好,对供试葡萄白腐病菌(Conio-thyrium diplodiella)、葡萄黑痘病菌(Elsinoe ampelina)、番茄绵腐病菌(Phytophthora melongenae)和青霉病菌(Penicilliu mexpansum)的EC50分别为:5.424、3.186、8.913和19.000g/L。(2)侧柏叶乙醇提取物的石油醚萃取物和乙酸乙酯萃取物抑菌活性均较好,在供试浓度为0.5g/L时,石油醚萃取物对苹果腐烂病菌(Valsa mali)和葡萄黑痘病菌(E.ampelina)的抑菌率分别为80.35%和60.23%;乙酸乙酯萃取物对以上2种植物病原菌的抑菌率分别为81.88%和64.06%。结果表明:侧柏叶、小枝、球果和种子乙醇提取物均具有一定抑菌活性,叶乙醇提取物的活性最好,活性成分主要集中在石油醚萃取物和乙酸乙酯萃取物中。     

Purification and characterization of poly(L-lactic acid)-degrading enzymes from Amycolatopsis orientalis ssp. orientalis

Polylactide or poly(l-lactic acid) (PLA) is a commercially promising material for use as a renewable and biodegradable plastic. Three novel PLA-degrading enzymes, named PLAase I, II and III, were purified to homogeneity from the culture supernatant of an effective PLA-degrading bacterium, Amycolatopsis orientalis ssp. orientalis. The molecular masses of these three PLAases as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were 24.0, 19.5 and 18.0 kDa, with the pH optima being 9.5, 10.5 and 9.5, respectively. The optimal temperature for the enzyme activities was 50-60 degrees C. All the purified enzymes could degrade high-molecular-weight PLA film as well as casein, and the PLA-degrading activities were strongly inhibited by serine protease inhibitors such as phenylmethylsulfonyl fluoride and aprotinin, but were not susceptive to chymostatin and pepstatin. Taken together, these data demonstrated that A. orientalis ssp. orientalis produces multiple serine-like proteases to utilize extracellular polylactide as a sole carbon source.     

杉木远交亲本群体遗传多样性研究

借助ISSR分子标记技术,对杉木和侧柏远交亲本群体的遗传多样性进行了研究,采用国际上流行的软件（PopGENE）进行数据处理,获得如下结果：(1)群体多态性位点百分率为88.2%;(2)Nei’s基因多样性指数平均值为0.399 7;(3)Shannon信息指数多样性数为0.582 4;(4)群体内亲本间的平均遗传距离为0.669 8,变幅为(0.069 0,1.609 4),其变异系数为69.19%。经与国内外同类研究结果比较分析后认定:杉木远交亲本群体具有较高的遗传多样性,具有较大的改良潜力,由其衍生的生产群体亦具有较宽的生态适应性。     

黄土丘陵区刺槐和侧柏人工林树干液流特征及其对降水的响应

水分供应不足及水热不同步常导致黄土丘陵地区在春末和夏初出现季节性干旱。为阐明该地区主要造林树种的蒸腾耗水特征及其对降水的响应, 使用热扩散式树干茎流计(TDP)于2009年4-10月对黄土丘陵区安塞国家生态试验站刺槐(Robinia pseudoacacia)和侧柏(Platycladus orientalis)的树干液流密度(F_d)进行连续观测, 并同步测定了气象、土壤水分等环境因子。结果表明: 刺槐和侧柏在生长季内不同生长时期的F_d均表现为单峰型日变化特征, 刺槐最高液流峰值为0.12068 m³·m^-2·h^-1, 是侧柏最高液流值(0.03737 m³·m^-2·h^-1)的3.23倍。除生长旺盛季(7-8月)外, 刺槐和侧柏降水后的F_d明显高于降水前。同时反映水汽压差(VPD)和太阳辐射(R_s)的蒸腾变量(VT)能够很好地模拟F_d, 且两者呈显著的指数正相关关系, 随VT的增加F_d逐渐增大, VT增加到50 kPa (W·m^-2)^1/2左右时, F_d的变化趋于稳定; 通过对降水前后两个树种水力导度(拟合参数b值)分析, 相对于侧柏, 刺槐更易受降水的影响(p < 0.001)。因此, 可认为刺槐是降水敏感型植物, 而侧柏是降水不敏感型植物。该研究通过分析黄土丘陵区人工林树种对降水的差异性响应, 从树木水分利用方面能够为当地生态恢复过程中人工林的管理提供科学依据。     

泽泻中二个三萜新成分的研究Ⅱ

继前文鉴定的七个泽泻醇类成分后 ,又从泽泻中分离、鉴定出六个三萜成分 ,其中 11 乙酰 2 5 脱水泽泻醇A(2 5 anhydroalisolA 11 acetate,Ⅳ )、2 4 乙酰 2 5 脱水泽泻醇A (2 5 anhydroalisolA 2 4 ac etate ,Ⅴ )为新化合物 ,新泽泻醇 (neoalisol,Ⅵ )为新天然产物 ,其它已知成分是泽泻醇A(alisolA ,Ⅰ )、2 4 乙酰泽泻醇A(alisolA 2 4 acetate ,Ⅱ )、2 5 脱水泽泻醇A(2 5 anhydroalisolA ,Ⅲ )。     

鸟类对山黄麻种子的传播及其生态作用

在云南西双版纳的勐宋和勐仑地区观察和研究了传统山黄麻种子的鸟类。在野外持网捕获摄食山黄麻果实的鸟类,称量后分别放在布袋内,让其自然排泄,然后标志释放,观察和网捕共记录到摄食山黄麻果实的鸟类36种,其中26种挂网捕获并从排泄物得到种子。用鸟类排泄物中的山黄麻种子、山黄麻树上采摘的成熟果实及人工分离山黄麻种子播种,进行萌发对比实验,实验结果表明,直接播种成熟果实,在阳光充足的空旷地、林冠下或用树叶覆盖遮光等条件下都未萌发,种子容易霉烂或被虫蚀;从山黄麻果肉中分离出来的种子具有萌发能力;而经鸟类摄食、消化后从果肉中分离的种子,具有较好的萌发活力。在不同条件下山黄麻种子萌发情况差异明显,林冠下条件对种子有抑制作用,阳光作用下种子显示出很好的萌发及成活率。鸟类排泄物种子放在林上或用树叶覆盖遮光,经过较长时间便可萌发,而人工分离种子不能萌发。鸟类摄食及消化过程对山黄麻种子的处理表现出很好的生态互惠关系,观察萌发后的山黄麻幼苗的生长情况还表明,幼苗生长也需要光照和较开阔的生境条件,鸟类取食山黄麻果实及其将种子远距离传播适宜生境,正好具有这样的生态作用。     

东方对虾蜕皮周期中外表皮对钙、磷、镁和钾的矿化作用

采用原子吸收分光光度法研究了东方对虾在蜕皮过程中,壳、肌肉、肝胰脏和蜕下壳中Ca,P,Mg和K含量的变化。蜕皮间期壳中的各元素含量显著高于蜕皮后矿化期,蜕皮后矿期肝胰脏中的P和K的含量显著高于蜕皮前期。     

Chemical Constituents of Siegesbeckia orientalis L.

The aerial parts of Siegesbeckia have been used as the traditional Chinese medicine in the treatment of rheumatic arthritis, hypertension, malaria, neurasthenia, and snakebite. In order to find new and bioactive compounds, the chemical constituents of the aerial parts of S. orientalis L. were investigated and two new compounds, namely β-D-glucopyranosyl-ent-2-oxo-15,16-dihydroxy-pimar-8（14）-en-19-oic-late （compound 1 ） and [1 （10） E,4Z]-8β-angeloyloxy-9α-methoxy-6α, 15-dihydroxy-14-oxogermacra-1 （10）,4,11 （13）-trien-12-oic acid 12,6-1actone （compound 2）, as well as five known ent-pimarane diterpenes （compounds 3-7） were isolated. The structures of the two new compounds were identified by their physicochemical properties and spectral analysis, particularly oneand two-dimensional nuclear magnetic resonance spectral methods.