Iris revoluta Colas., natural hybrid origin species: characterization and preservation problems

Abstract

In order to preserve ex situ rare or vulnerable species, it is necessary to characterise their reproductive mechanisms, and to locate the origin of the interference with their development in their natural habitat. Iris revoluta Colas. is a very rare endemic species of the Salento peninsula (Italy), showing scarce sexual reproduction, but good vegetative propagation through rhizomes, as many other Iris species of natural hybrid origin. For many years this Iris has been cultivated in the Botanical Garden of the Di.S.Te.B.A., University of Lecce, where a detailed study has been initiated to investigate the phenomena that may limit its sexual reproduction.     

德国鸢尾对Cd胁迫的生理生态响应及积累特性

通过盆栽研究了Cd胁迫下德国鸢尾的生长状况、生态效应、生理特性及吸收和富集Cd的能力.结果表明:德国鸢尾对小于5 mg/kg的Cd有较强的耐性,适用于城区土壤修复;Cd浓度大于5 mg/kg时抑制德国鸢尾生长,降低了其生态效应.随着Cd浓度的增大,德国鸢尾根系活力、叶绿素含量和含水量逐渐降低,游离脯氨酸和可溶性糖含量先升高后降低,细胞膜透性逐渐升高.Cd在德国鸢尾体内分布为根系＞地上部分,随着Cd浓度的增大,德国鸢尾根系和地上部分Cd积累浓度逐渐升高、富集系数和转运系数逐渐降低;Cd浓度为20 mg/kg时德国鸢尾对Cd的积累量最大,为2.122 mg/plant.     

亚热带常绿阔叶林不同土壤和林冠环境下蝴蝶花的克隆可塑性

对黄壤和喀斯特土壤两种土壤类型的森林内部和林窗中蝴蝶花的生长指标进行调查,研究异质生境下蝴蝶花的克隆可塑性.结果表明:蝴蝶花在黄壤生境中的分株高度、分株基径和根茎直径均高于喀斯特土壤生境,而分株密度低于喀斯特土壤生境.光照显著影响分株密度,在同一光照条件下土壤质地对分株密度没有显著影响.喀斯特森林内部蝴蝶花的花蕾数及开花数为0,这可能解释为光照和土壤质地双重压力下蝴蝶花对资源摄取和能量分配的权衡与生长维持.在一定程度上,蝴蝶花在黄壤生境中通过增强单个分株的竞争力、减少个体数量来适应环境,趋向K对策,在喀斯特生境中则通过增加个体数量、维持分株竞争力来适应环境,趋向r对策.     

Flavans from Iris tenuifolia and their effects on β-amyloid aggregation and neural stem cells proliferation in vitro

Two new flavans (1, 2) and a new flavanone (3), together with three known compounds (4-6), were isolated from the roots of Iris tenuifolia. Their structures were elucidated by means of spectroscopic methods including 1D and 2D NMR techniques and mass spectrometry. Compounds 1, 4, and 6 were further confirmed by single-crystal X-ray diffraction analysis. Biological evaluation showed that compounds 1 and 4 were positive in inhibiting β-amyloid (Aβ) aggregation and promoting neural stem cells (NSCs) proliferation, respectively.     

Global analysis of population structure,spatial and temporal dynamics of genetic diversity,and evolutionary lineages of Iris yellow spot virus (Tospovirus: Bunyaviridae)

Thrips-transmitted Iris yellow spot virus is an economically important viral pathogen of Allium crops worldwide. A global analysis of known IYSV nucleocapsid gene (N gene) sequences was carried out to determine the comparative population structure, spatial and temporal dynamics with reference to its genetic diversity and evolution. A total of 98 complete N gene sequences (including 8 sequences reported in this study) available in GenBank and reported from 23 countries were characterized by in-silico RFLP analysis. Based on RFLP, 94% of the isolates could be grouped into NL or BR types while the rest belonged to neither group. The relative proportion of NL and BR types was 46% and 48%, respectively. A temporal shift in the IYSV genotypes with a greater incremental incidence of IYSV_BR was found over IYSV_NL before 2005 compared to after 2005. The virus population had at least one evolutionarily significant recombination event, involving IYSV_BR and IYSV_NL. Codon substitution studies did not identify any significant differences among the genotypes of IYSV. However, N gene codons were minimally positively selected, moderately negatively selected denoting the action of purifying selection, thus rejecting the theory of neutral mutation in IYSV population. However, one codon position (139) was found to be positively selected in all the genotypes. Population selection statistics in the IYSV_BR, IYSV_NL genotypes and in the population as a whole also revealed the action of purifying selection or population expansion, whereas IYSV_other displayed a decrease in population size. Genetic differentiation studies showed inherent differentiation and infrequent gene flow between IYSV_BR and IYSV_NL genotypes corroborating the geographical confinement of these genotypes. Taken together the study suggests that the observed diversity in IYSV population and temporal shift in IYSV_BR genotype is attributable to genetic recombination, abundance of purifying selection, insignificant positive selection and population expansion. Restricted gene flow between the two major IYSV genotypes further emphasizes the role of genetic drift in modeling the population architecture, evolutionary lineage and epidemiology of IYSV.     

红籽鸢尾高频离体再生条件的初步筛选

红籽鸢尾(Iris foetidissima Linn.)为鸢尾科(Iridaceae)鸢尾属(Iris Linn.)多年生草本植物,原产于西欧和非洲北部。该种的叶鞘呈深绿色剑形,蒴果饱满且蒴果成熟开裂后露出红、橙黄和白等不同色泽的种子并一直垂挂到翌年春天,集观花、观叶和观果为一体,观赏价值较高。另外,该种还具有耐寒性好、在长江中下游地区四季常绿、适应性强及耐粗放管理等优     

Reference Gene Selection for qRT-PCR Normalization in <i>Iris germanica</i> L.

Quantitative real-time PCR (qPCR) is an effective and widely used method to analyze expression patterns of target genes. Selection of stable reference genes is a prerequisite for accurate normalization of target gene expression by qRT-PCR. In Iris germanica L., no studies have yet been published regarding the evaluation of potential reference genes. In this study, nine candidate reference genes were assessed at different flower developmental stages and in different tissues by four different algorithms (GeNorm, NormFinder, BestKeeper, and RefFinder). The results revealed that ACT11 (Actin 11) and EF1α (Elongation factor 1 alpha) were the most stable reference genes in different tissues, whereas TUA (Tubulin alpha) and UBC9 (Ubiquitin-protein ligase 9) were the most stable ones in different flower developmental stages. UBC9 and ACT11 were the most stable reference genes in all of the tested samples, while the SAMDC (S-Adenosylmethionine decarboxylase) showed the least stability. Finally, to validate the suitability of the selected reference genes, the relative expression level of IgTPS (beta-caryophyllene synthase) was assessed and highlighted the importance of suitable reference gene selection. This work constitutes the first systematic evaluation of potential reference genes in I. germanica and provides guidelines for future research on gene function and molecular mechanisms on I. germanica and related species.     

Effects of myoinhibitory peptides on food intake in the German cockroach

Abstract.  Insect myoinhibitory peptides were discovered through their inhibitory activity on visceral muscle contraction. The present study tests the antimyotropic gut properties of three galanin-related myoinhibitory peptides (Mas-MIP II: GWQDLNSAW-NH2; Grb-AST-B1: GWQDLNGGW-NH₂; and Grb-AST-B3: AWRDLSGGW-NH2) in adult females of the cockroach Blattella germanica (L.) (Dictyoptera, Blattellidae). The three peptides elicit a strong inhibitory effect on both foregut and hindgut contractions, with ID₅₀ values in all the cases within the nanomolar range. In addition, the modulatory effects of these three peptides on food intake are studied on previously starved female cockroaches. The results show that Grb-AST-B3 is the most active peptide, inhibiting food intake by 60–80% at doses between 15 and 50 µg, followed by Grb-AST-B1 (45% inhibition of food intake at the 50 µg dose), whereas Mas-MIP II is inactive even at the 50 µg dose. The differences between the three peptides may be due to a differential effect of their structure on activity or to a differential degradation. These results show that myomodulatory gut activity in vitro and antifeeding effects do not always correlate.     

A new coumaronochromone and phenolic constituents from the leaves of Iris bungei Maxim.

A novel compound, irisbungin, which was isolated from the leaves of Iris bungei Maxim., was elucidated as 5,7,5′-trihydroxy-coumaronochromone by spectroscopic methods and literature data. Along with the new coumaronochromone, nine known compounds, ayamenin B, mangiferin, hispidulin, apigenin, 3-phenyllactic acid, syringic acid, vanillic acid, p-coumaric acid and 3′,5′-dimethoxy-4′-O-β-d-glucopyranosyl-cinnamic acid were also isolated. All of the compounds were first isolated from this species. The presence of irisbungin and mangiferin in I. bungei Maxim. has important systematic significance for this species and the Iris genus.