Current and future potential distributions of three Dracaena Vand. ex L. species under two contrasting climate change scenarios in Africa

Forest undergrowth plants are tightly connected with the shady and humid conditions that occur under the canopy of tropical forests. However, projected climatic changes, such as decreasing precipitation and increasing temperature, negatively affect understory environments by promoting light‐demanding and drought‐tolerant species. Therefore, we aimed to quantify the influence of climate change on the spatial distribution of three selected forest undergrowth plants, Dracaena Vand. ex L. species, D. afromontana Mildbr., D. camerooniana Baker, and D. surculosa Lindl., simultaneously creating the most comprehensive location database for these species to date. A total of 1,223 herbarium records originating from tropical Africa and derived from 93 herbarium collections worldwide have been gathered, validated, and entered into a database. Species‐specific Maxent species distribution models (SDMs) based on 11 bioclimatic variables from the WorldClim database were developed for the species. HadGEM2‐ES projections of bioclimatic variables in two contrasting representative concentration pathways (RCPs), RCP2.6 and RCP8.5, were used to quantify the changes in future potential species distribution. D. afromontana is mostly sensitive to temperature in the wettest month, and its potential geographical range is predicted to decrease (up to ?63.7% at RCP8.5). Optimum conditions for D. camerooniana are low diurnal temperature range (6–8°C) and precipitation in the wettest season exceeding 750 mm. The extent of this species will also decrease, but not as drastically as that of D. afromontana. D. surculosa prefers high precipitation in the coldest months. Its potential habitat area is predicted to increase in the future and to expand toward the east. This study developed SDMs and estimated current and future (year 2050) potential distributions of the forest undergrowth Dracaena species. D. afromontana, naturally associated with mountainous plant communities, was the most sensitive to predicted climate warming. In contrast, D. surculosa was predicted to extend its geographical range, regardless of the climate change scenario.     

Organocatalyzed solvent free an efficient novel synthesis of 2,4,5-trisubstituted imidazoles for α-glucosidase inhibition to treat diabetes

A new and efficient solvent free synthesis of 2,4,5-trisubstituted imidazoles (3a–3j) was achieved by N-acetyl glycine (NAG) catalyzed three components condensation of aldehydes, benzil and ammonium acetate. Our synthetic methodology accommodated a range of various substituted alkyl and aryl aldehydes. Evaluation of α-glucosidase inhibitory activity of these imidazole derivatives revealed that most of them presented good α-glucosidase inhibition at low micro-molar concentrations. Among the synthesized compounds, compound 3c, bearing the ortho-hydroxy phenyl substituent at position 2 displayed the highest inhibitory activity with an IC₅₀ value 74.32 ± 0.59 μM. In silico molecular docking for all compounds and computational studies of the most active compound 3c were also performed.     

病毒侵染对西伯利亚百合DNA甲基化的影响

采用基于AFLP的甲基化敏感扩增多态性(MSAP)技术,用10对引物对侵染百合花叶病毒和丛簇病毒的西伯利亚百合植株和无毒植株进行DNA甲基化水平和模式分析.结果发现,西伯利亚百合无毒植株和病毒侵染植株的平均甲基化水平分别为40.1%和31.5%;平均全甲基化率分别为13.0%和9.7%;半甲基化率分别为27.1%和21.8%.研究表明,百合DNA甲基化多以半甲基化的形式存在;病毒侵染导致百合植株DNA甲基化水平降低,且对整体甲基化水平、全甲基化水平和半甲基化水平均产生了影响;说明病毒侵染百合后植株出现的症状在一定程度上与DNA甲基化存在关联.     

胡瓜钝绥螨对太平洋细须螨的捕食效能初步研究

胡瓜钝绥螨Amblyseius cucumeris Oudemans能捕食为害蝴蝶兰的害螨---太平洋细须螨Tenuipalpus pacificus Baker的卵、幼螨、若螨和成螨。室内研究了胡瓜钝绥螨雌成螨对太平洋细须螨卵、幼螨、若螨的捕食功能反应。结果表明,随着太平洋细须螨密度的增加,胡瓜钝绥螨雌成螨对太平洋细须螨的捕食数量也随之上升,捕食功能反应曲线符合Holling II型方程。胡瓜钝绥螨雌成螨对太平洋细须螨卵的控制能力显著强于对幼螨和若螨的控制能力,a/Th值分别为165.8、79.2和63.8。在猎物密度一定时,由于胡瓜钝绥螨个体间存在相互竞争和相互干扰作用,随着捕食螨密度的提高,捕食螨平均捕食量逐渐减少。     

蜻蜓凤梨开花相关基因AfFPF1初步研究

FPF1 (flowering-promoting factor 1)是参与植物开花期遗传控制的重要家族之一.迄今为止,人们对蜻蜓凤梨中FPF1家族了解有限.本研究以热带花卉蜻蜓凤梨为材料,基于转录组测序数据,克隆获得AfFPF1基因.该基因编码的蛋白含103个氨基酸,分子质量为12.06 kD.AfFPF1转录本在蜻...     

淡黄花百合的组织培养与快速繁殖

以淡黄花百合的鳞片为外植体进行试管培养,筛选出各培养阶段适宜的培养基分别为:(1)丛生芽诱导,MS 6-BA 2.0 mg/L NAA 0.2 mg/L 蔗糖3%;(2)继代增殖,MS 6-BA 1.5 mg/L NAA 0.1 mg/L 蔗糖3%;(3)生根及小鳞茎生长,1/2 MS NAA 0.5～1.0 mg/L 蔗糖3% 活性碳0.1%,1/2 MS NAA 0.5 mg/L 蔗糖6% 活性碳0.1%.     

宁夏豆科2种新记录植物

报道了宁夏豆科2种新记录植物,高山豆(Tibetia himalaica(Baker)Tsui)和兴隆山棘豆(Oxytropis xin-glongshanica C.W.Chang).     

宜昌百合根尖染色体C-带分析

利用Giemsa C-带方法对宜昌百合（Lilium leucanthum(Baker) Baker）进行研究。结果表明：宜昌百合（L. leucanthum）的染色体数目为2n＝2x=24,单套染色体的条带总数目为21条。其带型公式为：2n＝24＝6C+2CI+2I+2CI⁺+2CI⁺+4I⁺+2I⁺+2T⁺+2I+S。宜昌百合（L. leucanthum）每条染色体上都显示出显著的特征带,且带纹的深浅差异明显。宜昌百合（L. leucanthum）的强带主要集中在着丝点及附近区域。通过Giemsa C-带方法可以将宜昌百合（L. leucanthum）的每条染色体区分开。     

浙贝母鳞茎衰退过程的解剖学研究初报

采用徒手制片、石蜡切片和电子显微镜技术,系统而深入地研究了浙贝母（ＦｒｉｔｉｌｌａｒｉａｔｈｕｎｂｅｒｇｉｉＢａｋｅｒ）鳞茎衰退过程中的形态、组织结构和细胞内部的变化情况．看到了大分子物质进行运输时采用集装囊泡形式的可能性。进一步论证了胞间连丝作为细胞间原生质通道的观点．