Reproductive Biology and Prospects for Conservation of Caldesia parnassifolia (Alismataceae)——A Threatened Monocot in China

Caldesia parnassifolia (Bassi ex Linn.) Parl. in China has declined in number in recent years and is increasingly faced with the risk of extirpation arising from anthropogenic changes associated with rapid urbanization and expansion of both agriculture and infrastructure. To aid in provision of the data needed for effective conservation of the species, studies on the habitat, pollination ecology, and breeding system of C.parnassifolia were carried out on natural populations occurring in Southeastern China. Flowering in the study populations extended for more than eighty days beginning in early summer. Floral anthesis occurred in the morning hours and proceeded rapidly, lasting about 45 min. Flowers lasted ca.8h. Caldesia parnassifolia is self-compatible; however autogamy resulted in lower seed set than geitonogamy and xenogamy as well as free pollination. The data on pollen/ovule (P:O) ratio is consistent with a partially selfing and outcrossing mating system. Interpopulational crosses yielded similar seed set to within-population crosses. Agamospermy did not occur in the study populations. Propagation is achieved through seeds as well as through turions which commonly occur in the inflorescences. Flies (Insecta; Diptera) were the most frequent visitors to the flowers of C.parnassifolia; however bees (Insecta;Hymenoptera )composed a larger proportion of effective pollinators. The Syrphidae species Sphaerophoria indiana (Bigot) presents evidence of oligolectic foraging behavior. Recommendations are made on the immediate steps necessary for conservation of Caldesia species in China.     

Tobacco floral homeotic gene homologues: partial sequence and expression pattern

Using PCR approach, three cDNA sequences, NTSQUA4, NTSQUA12 and NTSQUA15, were amplified from first_strand cDNAs of wild tobacco flower buds and identified as homologues for floral homeotic genes. All the three clones contained domains that a floral homeotic gene generally had, i.e. I domain, K domain and C_terminal domain except MADS_ box since the PCR primers were designed beyond this region. In addition, the amino acid sequences of them showed 50%-60% identity (70%-80% similarity) with the known floral organ identity class A gene AP1 and SQUA, possibly indicating that they are class A_like genes. NTSQUA4 and NTSQUA412 shared 95% identity in their amino acid sequence, while NTSQUA415 exhibited only 47% identity as compared with NTSQUA4 and NTSQUA12. Within tobacco flower, NTSQUA4 was expressed in sepals, petals and carpels, but not in stamens, while NTSQUA15 was expressed in every whorl of the flower. The possible functions of these genes are discussed.     

三色堇(Viola tricolor L.var.hortensis DC.)花蜜腺的亚显微结构

本文用透射和扫描电镜对三色堇花不同发育时期蜜腺进行了研究,了解到该植物花蜜中糖份主要来源于蜜腺分泌组织自身的光合产物;内质网参与了前蜜的加工和运输;质膜的啜入和反啜入作用是分泌组织细胞间前蜜传递的主要方式;蜜最后通过表皮细胞质膜的分子渗透作用而排放出体外;表皮细胞向外的指状突起是蜜汁分泌的主要部位。     

辽宁白石砬子苔藓植物群落及其区系成份的研究

本文报道了辽宁省白石砬子国家级自然保护区苔藓植物251种,9变种,2亚种,3变型,其中中国新记录种2种,东北地区新记录属3个,新记录种10种.并就其苔藓植物群落其及区系成份和地理分布特征等作一初步分析探讨。     

多效唑对东魁杨梅花芽孕育的生理效应

对6年牛东魁杨梅叶片喷施多效唑溶液,研究其花芽孕育期间的生理生化特征.结果表明,低浓度多效唑能降低丙二醛含量和电解质渗漏率,提高SOD,POD和CAT活性,减缓膜脂过氧化程度,提高叶绿素和类胡萝卜素含量,提高叶片的蒸腾速率和气孔导度,促进净光合速率,从而有利于叶片中Hr溶性糖和蛋白质含量的累积,促进东魁杨梅的成花诱导.高浓度的多效唑会产生负效应.     

Episodic evolution of prolactin gene in primates

In the present study, we obtained exon 2--5 of prolactin (PRL) gene from four primate species by PCR and sequencing. Adding other genes available in GenBank, we calculate amino acid substitution rates for prolactin gene in primate. Comparison of nonsynonymous substitution rate to synonymous substitution rate ratios shows no evidence of positive selection for any lineage of primate prolactin gene.According to this and the facts that (i) no sites under positive selection are inferred by using maximum-likelihood method;(ii) among 32 amino acid replacement that occurred along the rapid evolutionary phase, only two are included in the 40 functionally important residues, indicating that amino acid replacement tends to occur in those functionally unimportant residues; (iii) partial of prolactin function is replaced by placental lactogen in primate at the rapid evolutionary phase of prolactin gene, we thus deem that it is relaxation of purifying selection to some extent rather than positive selection that enforces the rapid evolution of primate prolactin gene.     

基于风格进化模型的产品生成设计方法

针对产品风格进化现象与创新设计问题,提出了产品风格历时性与共时性进化模型.在该模型基础上,结合生物遗传学理论定义产品风格基因.以典型汽车产品风格为例,在引入造型参数化表征前提下,运用主成分分析进行参数规约,并利用形状文法实现风格基因表达.然后,建立基于遗传算法的生成设计机制,该机制采用正交分析的策略来精简初始种群规模,通过适应度函数实现方案收敛.最后,开发出面向汽车产品的风格生成设计系统,并验证其有效性和实用性.风格进化规律、风格基因建模方法及创新设计技术对于动漫设计、平面设计、服装设计等领域研究也具有指导或借鉴作用.     

Self-organized evolution of mechanism kinetic scheme based on axiomatic design

The self-organized evolution technology of the mechanism kinetic scheme based on axiomatic design is presented.This technology tries to express the constraints between kinetic mechanisms briefly in a semantic form which is more familiar to the designers.Though the mapping process between the kinetic chain unit and the unit instance,the evolution from abstract unit to concrete engineering instance is achieved.The subdivision of unit coupling semantics is studied.and the evolution of semantics is finished.Also.the semantic constraints evolution of unit coupling semantics is described.The product structure models with function and assembly meanings are constructed based on the kinematic chain unit and unit coupling.It provides a basis to realize the inheritance and transfer of constraint information from conceptual design to design for assembly(DFA).As the engineering practice result shows,the method Can help the engineers express their design intension more clearly and naturally in a high semantic level.And the automation,recursion and visualization of the mechanism kinetic scheme design are realized.     

Molecular evolution of scorpion a-toxins----Accelerated substitutions and functional divergence

Scorpion a-toxins are a family of toxic proteins with similar scaffold, but possess divergent pharmacological properties. Analysis of cDNA sequences reveals that the numbers of nucleotide substitutions per site ( K ) for 5' and 3' UTRs are smaller than those per synonymous site ( Ks) for the mature peptide-coding sequences, whereas the numbers of nucleotide substitutions per nonsynonymous site (-Ka) are close to or larger than Ks values for relevant pairs of cDNAs. These results, together with phylogenetic analysis, indicate that scorpion a-toxins have evolved by accelerated substitutions in the mature toxin regions. In addition, the 15 amino acids, absolutely conserved in all the scorpion a-toxins described so far. are mostly located in molecular interior, which may be involved in structural constraints for stabilizing the CSa(3 fold in evolution of these molecules. Four hot spot mutation sites in the molecular surface are found to distribute in the putative functional regions of a-toxins. suggesting that positive Darwinian selection drives the accelerated evolution of scorpion a-toxins. These findings reasonably explain the relationship between three-dimensional structure conservation and functional divergence of scorpion a-toxins and are of important value in guiding us in our engineering experiments to obtain higher affinity ligands to Na+ channels.     

Origin and evolution of new genes

Organisms have variable gcnome sizes and contain different numbers of genes. This difference demonstrates that new gene origination is a fundamental process in evolutionary biology. Though the study of the origination of new genes dated back more than half a century ago, it is not until the 1990s when the first young genejingwei was found that empirical investigation of the molecular mechanisms of origination of new genes became possible. In the recent years, several young genes were identified and the studies on these genes have greatly enriched the knowledge of this field. Yet more details in a general picture of new genes origination are to be clarified. We have developed a systematic approach to searching for young genes at the genomic level, in the hope to summarize a general pattern of the origination and evolution of new genes, such as the rate of new gene appearance, impact of new genes on their host genomes, etc.