Chemical Profile and Phytotoxic Action of Hibiscus trionum Essential Oil

The chemical profile and phytotoxic action of Hibiscus trionum essential oil (EO) was studied. In total 17 compounds were identified via GC/MS, representing 94.18 % of the entire oil, with phytol (40.37 %) being the dominant constituent. Bioassay revealed that the EO inhibited root elongation of Medicago sativa and Amaranthus retroflexus by 32.66 % and 61.86 % at 5 mg/mL, respectively; meanwhile, the major component phytol also exhibited significant phytotoxic activity, suppressing radical elongation of Pennisetum alopecuroides, M. sativa and A. retroflexus by 26.08 %, 27.55 % and 43.96 % at 1 mg/mL, respectively. The fact that the EO showed weaker activity than phytol implied that some constituents might trigger antagonistic action to decrease the oil's activity. Our study is the first on the chemical profile and phytotoxic effect of H. trionum EO.     

Development and characterization of microsatellite markers for Hibiscus glaber Matsum. ex Nakai, an endemic tree species of the oceanic Bonin Islands, Japan

Polymorphic microsatellite markers were developed for Hibiscus glaber, an endemic tree of the Bonin Islands. Eighty-seven of the 208 sequences from an enriched library were unique and containing microsatellites. Ten loci were proved to be highly polymorphic among 78 individuals from the Nishi-jima Island. Total exclusionary powers for the first and the second parents were 99.989% and 99.999%, respectively. Nine loci also amplified single fragment from genomic DNA of H. tiliaceus, a related and widespread congener. Our markers can be reliably used for the estimation of current gene flow within/among populations of the two woody Hibiscus species.     

响应面法优化玫瑰茄粗多糖提取工艺及其抗氧化活性的研究

利用响应面法优化玫瑰茄粗多糖的提取工艺条件,测定粗多糖的抗氧化活性。按照Box-Behnken中心组合试验设计原理,以玫瑰茄粗多糖的得率为响应值,在单因素试验的基础上,进行响应面分析试验,考察料液比、提取时间和提取温度对得率的影响。玫瑰茄粗多糖最佳提取工艺条件为：料液比1∶26 (g/mL)、提取时间3.1 h、提取温度90℃,在该最优条件下所得玫瑰茄粗多糖的得率为14.41%,与预测值接近;玫瑰茄粗多糖对DPPH、羟基、超氧阴离子自由基具有一定的清除作用。研究结果为玫瑰茄粗多糖的研究、开发和利用提供了理论基础。     

Sooty Mould on Hibiscus rosa‐sinensis Caused by Leptoxyphium kurandae is Associated with Extrafloral Nectaries

In August 2013, sooty mould was observed on Chinese hibiscus (Hibiscus rosa‐sinensis) in a propagation nursery in Seoul, Korea. The sooty mould initially developed at the junction between the leaf blade and leaf petiole and then dispersed along the vein on the abaxial surface. The fungal growth pattern on the plants was quite different from general sooty moulds growing on honeydew secreted by insects on the plants. On the basis of the morphological characteristics and phylogenetic analysis using the internal transcribed spacer rDNA, this fungus was identified as Leptoxyphium kurandae. A pathogenicity test was carried out to fulfil Koch's postulates. Through field observation and a pathogenicity test, we found an association between the sooty mould and extrafloral nectaries. To our knowledge, this is the first report of sooty mould caused by L. kurandae on the extrafloral nectaries of H. rosa‐sinensis.     

山东四种草本植物的核型研究

本文对山东４种草本植物进行了染色体研究。结果表明：阿尔泰狗哇花（Ｈｅｔｅｒｏｐａｐｐｕｓａｌ ｔａｉｃｕｓ（Ｗｉｌｄ）Ｎａｖｏｐｏｋｒ）的染色体数目为２ｎ＝３６,核型公式为Ｋ（２ｎ）＝３６＝３６ｍ,核型“１Ａ”型;求米草（Ｏｐｌｉｓｍｅｎｕｓｕｎｄｕｌａｔｉｆｏｌｉｕｓ（Ａｒｄｕｉｎｏ）ＲｏｅｍｅｔＳｃｈｕｌｔ）的染色体数目为２ｎ＝１２,核型公式为Ｋ（２ｎ）＝１２＝８ｍ＋４ｓｍ,核型“２Ａ”型;红秋葵（Ｈｉｂｉｓｃｕｓｃｏｃｉｎｅｕｓ（Ｍｅｄｉｃ）Ｗａｌｔ）的染色体数目为２ｎ＝３８,核型公式为Ｋ（２ｎ）＝３８＝１４ｍ＋２２ｓｍ＋２ｓｔ,核型“２Ｂ”型;蟋蟀草（Ｅｌｅｕｓｉｎｅｉｎｄｉｃａ（Ｌ）Ｇａｅｒｔｎ）的染色体数目为２ｎ＝１８,核型公式为ｋ（２ｎ）＝１８＝１６ｍ＋２ｓｍ,核型“２Ａ”型。     

两种消浪树种幼苗光合特性对模拟潮汐水淹的响应

滨海滩涂消浪林是沿海防护林体系的重要组成部分,在消浪护岸、促淤保滩、防御来自海洋自然灾害等方面具有不可代替的作用。本研究以中亚热带两种木本消浪植物海滨木槿（Hibiscus hamabo）和蜡杨梅（Myrica cerifera）为研究对象,模拟海水水淹,系统研究了不同海水水淹程度下两木本植物光合特性的响应规律。结果发现,随着水淹胁迫的增加,海滨木槿最大净光合速率逐渐下降、光补偿点逐渐增加,表观量子效率在7、21天时先降低后增加,后期呈现逐渐降低的趋势,说明胁迫初期通过增加光合利用率来适应水淹胁迫,暗呼吸速率在7、21天逐渐增加,而在42、70天时W8（水淹8 h,水深45 cm）处理显著小于其它处理,说明W8处理已显著影响了该树种的光合特征;蜡杨梅最大净光合速率、表观量子效率表现为逐渐降低的趋势,而光补偿点和暗呼吸速率则逐渐增加,42天后W6（水淹6 h,水深35 cm）、W8处理各项指标显著小于其它处理。经多元方差分析发现,水淹21天内海滨木槿的光合指标要显著好于蜡杨梅,而在42天后则基本相同;海滨木槿在水淹胁迫6 h内可以生长,而蜡杨梅则只能在4 h内,这可为消浪林构建提供理论依据。     

A novel block of plant virus movement genes

Hibiscus green spot virus (HGSV) is a recently discovered and so far poorly characterized bacilliform plant virus with a positive‐stranded RNA genome consisting of three RNA species. Here, we demonstrate that the proteins encoded by the ORF2 and ORF3 in HGSV RNA2 are necessary and sufficient to mediate cell‐to‐cell movement of transport‐deficient Potato virus X in Nicotiana benthamiana. These two genes represent a specialized transport module called a ‘binary movement block’ (BMB), and ORF2 and ORF3 are termed BMB1 and BMB2 genes. In agroinfiltrated epidermal cells of N. benthamiana, green fluorescent protein (GFP)‐BMB1 fusion protein was distributed diffusely in the cytoplasm and the nucleus. However, in the presence of BMB2, GFP‐BMB1 was directed to cell wall‐adjacent elongated bodies at the cell periphery, to cell wall‐embedded punctate structures co‐localizing with callose deposits at plasmodesmata, and to cells adjacent to the initially transformed cell. Thus, BMB2 can mediate the transport of BMB1 to and through plasmodesmata. In general, our observations support the idea that cell‐to‐cell trafficking of movement proteins involves an initial delivery to membrane compartments adjacent to plasmodesmata, subsequent entry of the plasmodesmata cavity and, finally, transport to adjacent cells. This process, as an alternative to tubule‐based transport, has most likely evolved independently in triple gene block (TGB), double gene block (DGB), BMB and the single gene‐coded transport system.     

Gene flow and population subdivision in a pantropical plant with sea-drifted seeds Hibiscus tiliaceus and its allied species: evidence from microsatellite analyses

The genetic differentiation and structure of Hibiscus tiliaceus , a pantropical plant with sea-drifted seeds, and four allied species were studied using six microsatellite markers. A low level of genetic differentiation was observed among H. tiliaceus populations in the Pacific and Indian Ocean regions, similar to the results of a previous chloroplast DNA (cpDNA) study. Frequent gene flow by long-distance seed dispersal is responsible for species integration of H. tiliaceus in the wide distribution range. On the other hand, highly differentiated populations of H. tiliaceus were detected in West Africa, as well as of Hibiscus pernambucensis in southern Brazil. In the former populations, the African continent may be a geographical barrier that prevents gene flow by sea-drifted seeds. In the latter populations, although there are no known land barriers, the bifurcating South Equatorial Current at the north-eastern horn of Brazil can be a potential barrier to gene flow and may promote the genetic differentiation of these populations. Our results also suggest clear species segregation between H. tiliaceus and H. pernambucensis , which confirms the introgression scenario between these two species that was suggested by a previous cpDNA study. Our results also provide good evidence for recent transatlantic long-distance seed dispersal by sea current. Despite the distinct geographical structure observed in the cpDNA haplotypes, a low level of genetic differentiation was found between Pacific and Atlantic populations of H. pernambucensis , which could be caused by transisthmian gene flow.     

木槿的发育可塑性及种下分类研究

对紫花单瓣木槿、紫花重瓣木槿和牡丹木槿在叶和花部性状上的发育可塑性研究表明,三个种下类群,特别是紫花单瓣木槿和牡丹木槿的叶片性状具有很大的发育可塑性,但花部性状的发育可塑性则相对很小,暗示着花部性状较叶片性状具有更大的分类价值。通过种下类群间表型性状的比较,发现牡丹木槿在叶缘、叶柄长度、花色、花冠直径、花梗长度、果实长宽比等性状上都与其它两个类群存在显著差异,从而建议将牡丹木槿确立为亚种(H. syriacus Linn. subsp. paeoniflorus (Gagnep.)G. R. Shi)