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51.
以不同发育时期的长角凤仙花Impatiens longicornuta Y.L.Chen(凤仙花科Balsaminaceae)为材料,利用扫描电镜技术观察了其花器官的分化及其发育过程。长角凤仙花为两侧对称花,具2枚侧生萼片,唇瓣囊状,旗瓣具鸡冠状突起,雄蕊5枚,子房上位,5心皮5室。其花器官分化顺序为向心式,萼片—花瓣—雄蕊—雌蕊原基。2枚侧生萼片先发生,然后近轴萼片(即唇瓣)原基和2枚前外侧萼片原基近同时发生;但是这3枚萼片原基的发育不同步,远轴的2枚前外侧萼片原基的发育渐渐滞后,然后停止发育,最后渐渐为周围组织所吸收,直至消失不见。花瓣原基中,旗瓣原基最先发生,4个侧生花瓣原基相继成对发生,且之后在基部成对愈合形成翼瓣;5枚雄蕊原基几乎同时发生,5个心皮原基轮状同时发生。本文结果支持凤仙花属植物为5基数的花,并进一步证实了唇瓣的萼片来源;此外,研究结果表明花器官早期发育资料对植物系统与进化研究具有重要参考价值。  相似文献   
52.
Impatiens macrantha S. X. Yu&Ying Qin (Balsaminaceae), a new species from Guangxi, China, is described and illustrated. Phylogenetic analysis based on molecular data shows the new species to belong to I. subg. Clavicarpa and to be closely related to I. tubulosa with which it shares succulent stems and racemose inflorescences, but it can be easily distinguished by having a 4 – or 5 – ridged stem, obovate or elliptic leaf blade, and saccate lower sepal. Furthermore, I. macrantha is distinguishable from other Impatiens in China by its obviously larger leaves and flowers. The evidence from morphology and molecular data both support I. macrantha as new to science.  相似文献   
53.
云南凤仙花属新类群   总被引:5,自引:1,他引:5  
记述了云南产凤仙花属(Impatiens L.)19个新种1个新变种。即:长喙凤仙花;怒江凤仙花;德钦凤仙花;德浚凤仙花;片马凤仙花;文山凤仙花;老君山凤仙花;麻栗坡凤仙花;版纳凤仙花;昔马凤仙花;孙氏凤仙花;大关凤仙花;马楠凤仙花;绥江凤仙花;紫溪凤仙花;滇南凤仙花;耳叶棒凤仙花;二甫凤仙花;半坡凤仙花;大甫凤仙花。  相似文献   
54.
报道了中国凤仙花属一新记录种:紫花辐射凤仙花(Impatiens dalaiensis Gogoi&Borah)。该种分布于云南省腾冲县高黎贡山自然保护区,生长在常绿阔叶林下水沟边。本种主要辨别特征为:花轮生,紫色;唇瓣舟状,口部具芒;翼瓣远侧裂片长带状且螺旋扭曲。该种2015年发表时记载模式标本采自印度,而我们将原始文献中记录的模式标本采集点GPS经纬度信息标记于地图上时却发现,地点位于中国西藏自治区察隅县境内,故对原文记述的模式产地信息提出质疑。  相似文献   
55.
The purpose of this study was to evaluate the remediation potential and disturbance response indicators of Impatiens walleriana exposed to benzene and chromium. Numerous studies over the years have found abundant evidence of the carcinogenicity of benzene and chromium (VI) in humans. Benzene and chromium are two toxic industrial chemicals commonly found together at contaminated sites, and one of the most common management strategies employed in the recovery of sites contaminated by petroleum products and trace metals is in situ remediation. Given that increasing interest has focused on the use of plants as depollution agents, direct injection tests and benzene misting were performed on I. walleriana to evaluate the remediation potential of this species. I. walleriana accumulated hexavalent chromium, mainly in the root system (164.23 mg kg?1), to the detriment of the aerial part (39.72 mg kg?1), and presented visible damage only at the highest concentration (30 mg L?1). Unlike chromium (VI), chromium (III) was retained almost entirely by the soil, leaving it available for removal by phytotechnology. However, after the contamination stopped, I. walleriana responded positively to the detoxification process, recovering its stem stiffness and leaf color. I. walleriana showed visible changes such as leaf chlorosis during the ten days of benzene contamination. When benzene is absorbed by the roots, it is translocated to and accumulated in the plant's aerial part. This mechanism the plant uses ensures its tolerance to the organic compound, enabling the species to survive and reproduce after treatment with benzene. Although I. walleriana accumulates minor amounts of hexavalent chromium in the aerial part, this amount suffices to induce greater oxidative stress and to increase the amount of hydrogen peroxide when compared to that of benzene. It was therefore concluded that I. walleriana is a species that possesses desirable characteristics for phytotechnology.  相似文献   
56.

Background and Aims

Local adaptation enables plant species to persist under different environmental conditions. Evolutionary change can occur rapidly in invasive annual species and has been shown to lead to local adaptation. However, the patterns and mechanisms of local adaptation in invasive species along colonization sequences are not yet understood. Thus, in this study the alien annual Impatiens glandulifera was used to investigate local adaptation to distinct habitats that have been consecutively invaded in central Europe.

Methods

A reciprocal transplant experiment was performed using 15 populations from alluvial deciduous forests, fallow meadows and coniferous upland forests, and a greenhouse experiment was performed in which plants from these habitats were grown under treatments reflecting the main habitat differentiators (shade, soil acidity, competition).

Key Results

Biomass production, specific leaf area, plant height and relative growth rate differed between habitats in the field experiment and between treatments in the greenhouse, but not between seed origins. Overall, there was no indication of local adaptation in either experiment.

Conclusions

Since I. glandulifera is a successful invader in many habitats without showing local adaptation, it is suggested that the species is coping with environmental variation by means of high phenotypic plasticity. The species seems to follow a ‘jack-and-master’ strategy, i.e. it is able to maintain high fitness under a wide range of environmental conditions, but performs particularly well in favourable habitats. Therefore, the proposed colonization sequence is likely to be based primarily on changes in propagule pressure. It is concluded that invasive alien plants can become dominant in distinct habitats without local adaptation.  相似文献   
57.
花粉来源影响着植物的生殖成功和种群的遗传结构, 母体效应则有利于子代适应母代经历的环境。然而, 气候变暖背景下, 花粉来源联合母体效应对植物生殖成功的影响仍不明了。该研究以兼性异交的中国特有植物红雉凤仙花(Impatiens oxyanthera)为研究对象, 采用双因素随机区组设计, 设置母代增温(+0 ℃和+2 ℃)嵌套子代增温(+0 ℃、+2 ℃和+4 ℃)共6种实验处理, 探讨不同母代增温条件下子代增温对红雉凤仙花花粉来源限制的影响。结果显示: 红雉凤仙花异交的结实率和种子数均高于自交的相应值, 且随着子代增温幅度提升, 这2个值均呈现不同程度降低, 特别是自交结实率和种子数随子代增温明显降低, 而母代增温则减缓了自交引起的生殖成功率降低的效应。上述结果说明, 红雉凤仙花异交生殖成功率大于自交。子代增温显著降低了兼性异交植物自交的适合度, 母代增温可以减缓这种不利影响, 从而表现出对增温的跨代适应性。  相似文献   
58.
Resource competition is commonly invoked to explain negative effects of invasive plants on native plant abundance. If invasives out-compete natives, global changes that elevate resource availability may interact with invasives to exacerbate impacts on native communities. Indeed, evidence is accumulating that elevated CO2 and N deposition decrease native biomass and simultaneously increase invasive biomass. However, superior competitive ability, and a relative increase in the magnitude of invasive impacts under elevated resource availability, remain to be definitively proven. Using model, multi-species, multi-individual riparian plant communities, where planting density was maintained by replacement of native with exotic individuals, we conducted a greenhouse, competition experiment using native (to the UK) and invaded communities exposed to ambient and elevated CO2 (CO2 experiment) or N availability (N experiment). We tested two hypotheses: (1) invasives are superior competitors to natives at ambient atmospheric CO2 and N deposition; (2) negative effects of invasives on natives are exacerbated under elevated CO2 or N availability. Our results provide some support for the first hypothesis: in the CO2 experiment native biomass was significantly lower in invaded communities. In the N experiment, native biomass was unaffected by the presence of exotics but other characteristics (e.g. root:shoot ratios) were altered. Differences in light availability between the experiments may have modified the effects of the invasives on the native assemblages but our design did not permit us to determine this definitively. The hypothesis that elevated CO2 and N availability benefit invasives at the expense of natives was not supported by our results. This may be explained either because the invasives showed minor responses to the resource manipulations or because native and exotic species were differentially limited by CO2 and N. Our results confirm the expectation that invasives alter the characteristics of native assemblages but lead us to question whether elevated resource availability will magnify these effects.  相似文献   
59.
报道了中国凤仙花属一新记录种——高大凤仙花(Impatiens kerriae Craib)。该种原产于泰国,在中国为首次记录。该文对高大凤仙花的特征进行了详细描述,尤其是对花果特征及花果期进行了重新描述和补充。凭证标本存放于中国科学院西双版纳热带植物园标本馆(HITBC)。  相似文献   
60.
Flexible pedicels are characteristic of birdpollinated plants, yet have received little attention in studies of hummingbird-flower interactions. A major implication of flexible pedicels is that flowers may move during pollination. We examined whether such motion affected interactions between ruby-throated hummingbirds (Archilochus colubris) and jewelweed (Impatiens capensis) by increasing pollen deposition and by altering the effectiveness of nectar removal. For I. capensis, flower mobility enhanced pollen deposition: birds had significantly longer contact with anthers and more pollen deposited on their bills and crowns when foraging at mobile flowers than at flowers that had been experimentally immobilized. In contrast, flower mobility imposed a cost on hummingbirds by significantly increasing their handling times and reducing their extraction rates relative to their interactions with immobile flowers. Field observations indicated that the motion observed during hummingbird visits did not occur when bees (Bombus spp., Apis mellifera) visited I. capensis flowers, which suggests that the mobility of I. capensis flowers is an adaptation for hummingbird pollination.  相似文献   
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