生长调节物质对组培暗紫贝母小鳞茎生长的影响

应用正交实验研究了生长调节物质病毒唑（ｒｉｂａｖｉｒｉｎ）、茉莉酸甲酯（ｊａｓｍｏｎｉｃａｃｉｄｍｅｔｈｙｌｅｓｔｅｒ）、油菜素内酯（ｂｒａｓｉｎｏｌｉｄｅ）、腐殖酸钠（ｓｏｄｉｕｍｈｕｍａｔｅ）对组织培养暗紫贝母（ＦｒｉｔｉｌａｒｉａｕｎｉｂｒａｃｔｅａｔａＨｉｓａｏｅｔＫ．Ｃ．Ｈｓｉａ）小鳞茎生长的影响,发现病毒唑有显著活性。进一步对不同浓度病毒唑的效果进行优化试验,结果表明：病毒唑１０ｍｇ／Ｌ是提高小鳞茎生长率的最适浓度。     

伊贝母根系分泌物自毒作用研究

采用生物测定的方法,研究了伊贝母(Fritillaria pallidifloraSchvek)根系分泌物及其主要成分1,3,5-三烯丙基-1,3,5-三嗪-2,4,6(1H,3H,5H)三酮、苯酚和二者的混合液对伊贝母生长的影响。结果表明,伊贝母根系分泌物对其种子萌发及胚根胚轴的生长有明显抑制作用,各浓度处理液对种子萌发及发芽势的影响多表现为抑制作用,随浓度升高而增强,但当超过一定浓度以后抑制作用有所下降。各浓度处理液对胚根胚轴生长的抑制作用表现为随浓度升高而增强,在较低浓度时对胚轴的生长表现为一定的促进作用。     

秋水仙素诱导川贝母(Fritillaria cirrhosa D.Don)愈伤组织多倍体的研究

应用组织培养技术对川贝母（Fritillaria cirrhosaD.Don)进行多倍体诱导。结果表明：组织培养条件下,将川贝母愈伤口组织在培养基中添加一定浓度的和为水仙素处理一段时间,或者经一定浓度的和为水仙素浸泡一段时间后再培养,均可诱发川贝母多倍体的产生,但以前者效果较好。在秋水仙素浓度为1000mg/L。处理5d的条件下,诱导率最高达70%。细胞染色体鉴定结果为：四倍体染色体数为2n=4x=48,而二倍体的染色体数为2n=2x=24。     

Studies on Chemical Constituents of Fritillaria thunbergii Miq.

In our previous papers, it was reported that peimine, peiminine, eduardine and three new alkaloids, zhebeinine, zhebeirine, zhebeinone, were isolated from the bulbs of Fritillaria thunbergii Miq. In consecutive investigation of the plant, an additional new alkaloidal glucoside, 5α , 14α -cevanine-6α , 20β-dihydroxyl-3β-O-β-D-glucoside, named zhebeininoside (Ⅰ) and aknown picropodophyllotoxin (Ⅱ) were isolated. The structure of zhebeininoside was determined on the basis of spectral analysis and chemical reaction. Picropodophyllotoxin was firstly isolated from Fritillaria plants.     

A Karyological Study on Three Taxa of Fritillaria

This paper deals with karyotype analysis of three taxa of Fritillaria, i. e. F. thunbergii (from Yinxian and Zhoushan), F. thunbergii var. chekiangensis, and F. anhuiensis. The results show that all the three taxa are diploid (2n = 24) and their karyotypes are different. The karyotype formulae may be summarized as follows: F. thunbergii: Yinxian, 4m(lsc) +4st(lsc) ^l) +16t(lsc) ; Zhoushan, 2m+2sm+12st(lsc) +8t(2sc) . F. thunbergii var. chekiangensis2m+2sm+8st (2sc) +12t (4sc). F. anhuiensis 2m+2sm+8st (2sc) + 12t (５sc). There are many secondary constrictions in all the three taxa of Fritillaria studied, but the numberand positions of secondary constrictions are quite different in different taxa.     

Flavonoids and isoflavonoids of chemotaxonomic significance from Glycyrrhiza pallidiflora (Leguminosae)

Chemical studies were carried out on the root of Glycyrrhiza pallidiflora (Leguminosae), a licorice of no medicinal or commercial value. Two isoflavone glycosides, wistin and ononin, were isolated as major constituents from the methanol extract. A series of chromatographic separations of the acetone extract yielded isoflavone aglycones (afromosin, 2′,7-dihydroxy-4′-methoxyisoflavone and formononetin), flavanones (liquiritigenin and 4′,7-dihydroxy-6,8-diprenylflavanone), an isoflavan [(-)-vestitol], a pterocarpan [(-)-medicarpin], chalcones (echinatin and isoliquiritigenin), dibenzoylmethanes (licodione and 2′-O-methyl-licodione), a flavone (4′,7-dihydroxyflavone), a 3-arylcoumarin (2′-7-dihydroxy-4′-methoxy-3-arylcoumarin), and a new isoflav-3-ene (2′-7-dihydroxy-4′-methoxyisoflav-3-ene). The co-occurrence of the retrochalcone echinatin and the biogenetically related licodione and 2′-O-methyl-licodione is of particular interest, and suggests that this species is closely related to G. echinata and G. inflata. The biogenesis of the retrochalcone is also discussed in relation to its significance in the chemotaxonomy of sects Echinatae and Bucharicae of the genus Glycyrrhiza.     

Slippery flowers as a mechanism of defence against nectar-thieving ants

Background and AimsThe great diversity of floral characteristics among animal-pollinated plants is commonly understood to be the result of coevolutionary interactions between plants and pollinators. Floral antagonists, such as nectar thieves, also have the potential to exert an influence upon the selection of floral characteristics, but adaptation against floral antagonists has attracted comparatively little attention. We found that the corollas of hornet-pollinated Codonopsis lanceolata (Campanulaceae) and the tepals of bee-pollinated Fritillaria koidzumiana (Liliaceae) are slippery to nectar-thieving ants living in the plant’s habitat; because the flowers of both species have exposed nectaries, slippery perianths may function as a defence against nectar-thieving ants.MethodsWe conducted a behavioural experiment and observed perianth surface microstructure by scanning electron microscopy to investigate the mechanism of slipperiness. Field experiments were conducted to test whether slippery perianths prevent floral entry by ants, and whether ant presence inside flowers affects pollination.Key ResultsScanning electron microscopy observations indicated that the slippery surfaces were coated with epicuticular wax crystals. The perianths lost their slipperiness when wiped with hexane. Artificial bridging of the slippery surfaces using non-slippery materials allowed ants to enter flowers more frequently. Experimental introduction of live ants to the Codonopsis flowers evicted hornet pollinators and shortened the duration of pollinator visits. However, no statistical differences were found in the fruit or seed sets of flowers with and without ants.ConclusionsSlippery perianths, most probably based on epicuticular wax crystals, prevent floral entry by ants that negatively affect pollinator behaviour. Experimental evidence of floral defence based on slippery surfaces is rare, but such a mode of defence may be widespread amongst flowering plants.     

Commercial Harvesting Has Driven the Evolution of Camouflage in an Alpine Plant

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