Drastic post‐LGM expansion and lack of historical genetic structure of a subtropical fig‐pollinating wasp (Ceratosolen sp. 1) of Ficus septica in Taiwan

The climatic oscillations of the last glacial period have had profound influences on the demography and levels of genetic diversity of extant species. Molecular evidence of glacial effects on temperate species has been well documented, whereas little is known regarding that on subtropical species. Here we present analyses based on partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene (1052 bp) and genotypes at 15 microsatellite loci to investigate the historical demography, population structure and ongoing gene flow of an undescribed fig‐pollinating wasp (Ceratosolen sp. 1) of Ficus septica in subtropical Taiwan. Reconstructed historical demography based on the coalescent tree of COI sequences suggests that C. sp. 1 has undergone a drastic population expansion which was tightly coupled with climatic changes since the last glacial maximum (LGM). The magnitude of the population size change was approximately 500‐fold, indicating that the population of this wasp and its host was likely highly compressed during the last glacial period. The lack of significant population differentiation (F_ST < 0.02, for all pairwise F_ST values) may be due to rapid postglacial expansion facilitated by long‐distance dispersal, although a low frequency of first‐generation migrants was detected. Our results clearly demonstrate how recent climatic changes since the LGM and dispersal ability have jointly shaped the genetic composition of a subtropical fig‐pollinating wasp.     

模拟增温对川西亚高山人工林土壤有机碳含量和土壤呼吸的影响

采用原位OTCs模拟增温方法,研究了川西亚高山人工云杉林下土壤有机碳含量、土壤呼吸速率及土壤酶活性对温度升高的响应.结果表明：在2005年11月—2007年7月的模拟增温试验期间,林下空气平均温度和土壤平均温度分别比对照提高了042 ℃和025 ℃.增温1年和2年后的0～10 cm和10～20 cm层土壤有机碳、C/N均比对照有所降低：增温1年后,在0～10 cm层分别降低了869%和852%;增温2年后的降低幅度比增温1年后有所缓解.与对照相比,增温1年后土壤呼吸速率显著提高;2年后,土壤呼吸没有明显差异,表现出对温度升高的适应性.增温1年后,蔗糖酶、过氧化氢酶、蛋白酶、脲酶和多酚氧化酶活性均增强,其中0～10 cm土层的蔗糖酶和多酚氧化酶活性与对照的差异达到显著水平;增温2年后,蔗糖酶、蛋白酶和脲酶活性仍有所增强,但过氧化氢酶和多酚氧化酶活性与对照相比则呈下降趋势.     

水曲柳幼苗根系吸收不同形态氮的动力学特征

采用常规耗竭法研究水曲柳幼苗根系吸收不同形态氮素特征的结果表明:二年生水曲柳幼苗根系对NO3-和NH4 离子的亲和力比一年生幼苗要小许多,二年生幼苗对氮素的吸收优势比较明显;苗木根系吸收NH4 离子的最大吸收速率(Imax)均大于对N03一的吸收,而米氏常数(Km)则相反;在低浓度范围内随着NO3-浓度的增加,根系吸收NO3-的速率增大并趋稳定:NH4 的存在明显抑制根系对NO3-吸收,其对一年生幼苗的影响大于二年生幼苗.     

基于叶绿体trnL-F序列以及matK序列探讨虎杖属与西伯利亚蓼的系统学位置

以蓼科Polygonaceae酸模亚科Rumicoideae酸模族Rumiceae大黄属Rheum L.作外类群,对蓼亚科Polygonideae蓼族Polygoneae 4属19种1变种的trnL-F序列以及16种1变种的matK序列进行了测定(部分序列取自GenBank)和聚类分析,探讨了虎杖属Reynoutria Houtt.和两伯利亚蓼Polygonum sibiricum Laxm.的系统学位置,结果表明:(1)虎杖属在两个严格一致树中都聚到了何首乌属Fallopia Adans.的内部,trnL-F序列的支持率为99%,marK序列的支持率为100%,说明虎杖属应归入何首乌属中,所以虎杖属的R.japonica Hour.与R.sachalinense(F Schmidt ex Maxim.)Nakai应分别命名为Fallopia japonica(Houtt.)Ronse Decraene和F sachalinense(F Schmidt ex Maxim.)Ronse Decraene;(2)两个严格一致树都表明,西伯利亚蓼远离蓼属Polygonum L.,聚到了何首乌属的附近,两个序列支持率都为99%,应将该种从蓼属中移出来,提升为属级,即西伯利亚蓼属Knorringia Tzvel.,西伯利亚蓼应命名为Knorringiasibirica(Laxm.)Tzvel..另外,本文对何首乌属与西伯利亚蓼属作了界定.     

福建泉州两栖动物调查及区系分析

根据1997～2001年的调查证实,泉州市有两栖动物32种,属于古北界的3种,东洋界的29种,其中华南区与华中区共有者10种,华中区的种类18种,华南区的种类只有1种,说明泉州市两栖类的区系组成是以华中区的种类占优势。     

闽西北稻区"晚改中"避蚊减害技术研究与应用

针对闽西北海拔300-500m的单、双季水稻混栽区稻瘿蚊危害重、单季稻三代稻瘿蚊危害突出的情况,通过研究提出“晚改中”的依据和技术,在正常年份下,把以往5月份播种的单季稻的播种期提早到4月5日前,就可以有效地避开三代稻瘿蚊的危害,而不必提早到3月20日前,与农民农时操作习惯更吻合,农民更易接受采用。     

微生物饲料添加剂的研究进展

综述了微生物饲料添加剂的分类、作用机理、国内应用现状、发展前景及其存在的问题。     

The Smad pathway in transforming growth factor-β signaling

The transforming growth factor b (TGF-b) superfamily comprises a great number of structurally related polypeptide growth factors, such as TGF-bs, activins, inhibins, bone morphogenic proteins (BMPs), growth differentiation factors (GDFs), M黮lerian inhibitory substance, and glial cell-derived neurotrophic factor (GDNF), etc[1]. The TGF-b superfamily members are multifunctional agonists involved in a broad spectrum of biological processes such as cell proliferation and differentiation, e…     

Genetic analysis and mapping of gene fzp(t) controlling spikelet differentiation in rice

Monocots and dicots have diverged for 120 million years. The floral morpha of cereals isunique and much different from that of dicot plants. Nevertheless, it has been found that most genes controlling flower development share a conserved sequence called MADS-box[1]. Therefore,it is likely that monocots and dicots could have similar basic characteristics of flower developmentbut the mechanisms of genetic regulation for flowering induction and floral differentiation might be different[2,3]. Du…