Ultraviolet irradiation induces accumulation of isoflavonoids and transcription of genes of enzymes involved in the calycosin-7-O-β-d-glucoside pathway in Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao

Isoflavonoids are a group of phenolic secondary metabolites found almost exclusively in leguminous plants. Formononetin, calycosin and calycosin-7-O-β-d-glucoside (CG) are isoflavonoid products in the CG pathway. Accumulation of the three isoflavonoids plus daidzein and expression of six genes of enzymes involved in the CG pathway were studied in Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao with ultraviolet (UV) irradiation. Our results showed that (1) main isoflavonoids in roots, stems and leaves were CG, daidzein and calycosin, respectively; they accumulated significantly under the induction of UV irradiation during 8 days but their content declined later; (2) expression of six genes of enzymes involved in the CG pathway was inhibited slightly at early stage but the expression was increased greatly afterward; (3) chalcone synthase, chalcone reductase and chalcone isomerase were expressed to their individual maximum level within shorter hours than were cinnamate 4-hydroxylase, isoflavone synthase (IFS) and isoflavone 3'-hydroxylase and (4) more calycosin but less daidzein accumulated in leaves. IFS was highly expressed in leaves, which might lead to high accumulation of the common precursor of daidzein and 2,7-dihydroxy-4'-O-methoxy-isoflavanone, the latter of which would be converted to formononetin, calycosin and CG via a series of reactions. Little daidzein accumulated in leaves, which suggested that rather than be converted to daidzein, the 2,7,4'-trihydroxyisoflavanone was probably more easily caught by 2-hydroxyisoflavanone 4'-O-methyltransferase and hence provided more precursors for formononetin. The findings were discussed in terms of the influence of UV irradiation in the accumulation of isoflavonoids.     

膜荚黄芪与蒙古黄芪幼苗的光能利用及其耐光性研究

以盆栽膜荚黄芪和蒙古黄芪幼苗为试验材料,测量2种黄芪叶片的光合速率、叶绿素荧光参数、光能利用率及耐光性等指标的日变化,以探讨它们的光能利用、热耗散以及耐光性差异.结果表明:(1)随着太阳光合有效辐射的日变化进程推进,2种黄芪的初始荧光(F0)、非光化学淬灭(NPQ)、PSⅡ调节性能量耗散量子产最(YNPQ)先升高后降低...     

中国植物区系地理及植物生态地理中值得讨论的若干名称问题

本文提出在植物区系分区中用“亚洲东部森林植物亚区”及“横断山脉—喜马拉雅山脉森林植物亚区”代替原来“中国—日本森林植物亚区”及“中国—喜马拉雅森林植物亚区”两名称;对植物生态地理中的“中国亚热带植被带”中引入“温亚热带”、“中亚热带”及“暖亚热带”三亚带名称,代替原来称为“北亚热带”、“中亚热带”及“南亚热带”三亚代的名称。同时在“中国温带植被带”中也引入“寒温带”、“温带”、“暖温带”三亚带名称,代替“北”、“中、“南”亚热带及温带植被亚带的名称,以避免对南、北两半球的亚热带与温带及其亚带的混淆的称谓。     

干旱胁迫下沙枣和孩儿拳头叶绿素荧光特性研究

以沙枣和孩儿拳头2年生盆栽苗为材料,采用称重控水的方法设置对照（土壤含水量为25.6%~27.2%）,轻度胁迫（19.2%~20.8%）,中度胁迫（12.8%~14.4%）,重度胁迫（6.4%~8.0%）4个梯度,研究了干旱胁迫对沙枣和孩儿拳头色素含量和叶绿素荧光特性的影响。结果表明：（1）随着干旱胁迫的加剧,两物种叶绿素a含量,叶绿素a/b比值,总叶绿素含量呈下降趋势,且叶绿素a对干旱胁迫的反应较叶绿素b敏感,但两物种叶绿素b含量和胡萝卜素含量变化规律不一致。（2）随着干旱胁迫的加剧,孩儿拳头F_m、F_v呈下降趋势,沙枣相反,但两物种F₀呈增加趋势,F_v/F₀、F′_v/F′_m呈下降趋势,F_v/F_m差异不显著;PhiPS2、ETR、qP先升高后降低,NPQ则先降低后升高。（3）虽然两物种表现出较强的抗旱性,但在重度干旱胁迫下（6.4%~8.0%）,光合色素含量、叶绿素荧光参数受到较大影响,推测此时的土壤水分含量为两物种光合色素、光系统Ⅱ的耐受极限;物种间相比,孩儿拳头更为敏感,在今后的园林管护中,要根据土壤水分状况和物种间的差异做好园林灌溉。     

蒙古黄芪潜在分布区预测的多模型比较

根据蒙古黄芪（Astragalus membranaceus（Fisch.）Bge.var.mongholicus（Bge.）Hsiao）123个样本点数据和19个环境数据,采用4种生态位模型对蒙古黄芪在中国的潜在适生区进行综合分析,并采用受试者工作特征曲线ROC和Kappa统计量,比较不同模型的预测效果。结果显示：4个模型预测精度良好,一致性显著。AUC值均达到0.8以上,Kappa值均达到0.6以上;其中DOMAIN模型的AUC值和Kappa值均最大,说明该模型的预测精度最佳,预测结果最稳定。潜在适生区的预测结果发现,GARP模型预测的最适宜区范围最广;MAXENT和BIOCLIM模型预测结果较为相似;DOMAIN模型预测结果比较分散。4个模型预测结果均表明西北一带可以作为蒙古黄芪栽培引种的主要产区。蒙古黄芪潜在适生区主要分布于中国北纬33°以北地区;最适宜区主要分布于甘肃、宁夏、陕西、山西、河北和内蒙古等地区。     

两种黄芪主根内部构造和有效成分含量变化规律的研究

对膜荚黄芪和蒙古黄芪主根内部结构和有效成分含量变化规律的研究发现,由于两种黄芪个体发育节律的不同,其主根内部结构和养分累亦遵循各不同的变化规律,有效成分黄芪甙和总多糖含量亦随这种营养生长和生殖生长交替规律的不同而变化,并且与养分的积累与消耗呈正相关,两种有成分的含量在萌动期前和枯萎期后达到高峰。     

银柴胡离体培养与毛状根诱导技术初步研究

以银柴胡茎段为外植体,经消毒获得无菌再生材料后,筛选发根农杆菌介导毛状根诱导产生的最适条件。结果显示：最适的无菌消毒方法为：70%酒精浸5 s,0.1%升汞消毒3 min,获得了银柴胡离体培养材料;以发根农杆菌A4菌株介导的银柴胡毛状根诱导过程中,与叶片和不带腋芽茎段相比,带腋芽茎段为最适转化外植体,用OD600=0.8的菌液侵染茎段15 min,共培养3 d,800 mg/L头孢噻肟钠除菌,其诱导率及诱导密度最高,分别为100%和4.7,为最适诱导条件。研究结果说明在适合条件下,银柴胡带腋芽茎段适于诱导毛状根。     

氮离子注入对蒙古黄芪多倍体诱导的影响

利用二倍体蒙古黄芪种子为材料,以低能氮离子束为诱变源,将化学诱导与物理诱变相结合,探索出一套高效的多倍体诱导新方法。研究结果表明：氮离子注入种子后表现出明显的生物学效应;氮离子注入与秋水仙素联合诱导黄芪多倍体的效果很明显。氮离子注入剂量为2.6×10¹⁶ N⁺/cm²,秋水仙素浓度为100 mg·L^-1,培养5 d诱导率最高为44.4%;氮离子注入剂量为5.2×10¹⁶ N⁺/cm², 秋水仙素浓度为150 mg·L^-1,培养10d的诱导率最高为46.2%;二者均高于对照组秋水仙素浓度为100 mg·L^-1培养15 d的最高诱导率13.9%。利用细胞染色体计数鉴定多倍体为四倍体。     

Effects of progressive drought stress on the physiology,antioxidative enzymes and secondary metabolites of Radix Astragali

The dried roots of Radix Astragali are widely used in traditional Chinese medicine, and flavonoids present in the root of this herb have been implicated in its bioactivity. We subjected 2-year-old Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao to a progressive drought stress over 14 days of water withholding and studied the physiological and biochemical responses and secondary metabolite accumulation. Results indicated that drought stress reduced relative water content, reduced yield, but increased electrolyte leakage, malondialdehyde, proline and soluble sugar content. Mild and moderate drought stress enhanced some antioxidative enzyme activity to protect plants from damaging, but antioxidative enzyme activity was limited by severe stress. The calycosin-7-O-β-d-glycoside and ononin content of plant roots was enhanced with degree of drought stress, whereas calycosin and formononetin levels did not differ significantly until 14 days. These results demonstrate that Radix Astragali can adapt to water stress by up-regulating antioxidant enzymes and accumulation of osmotic agents, and a certain degree of drought stress can enhance accumulation of some flavonoids, potentially facilitating higher yields of pharmacological activity of calycosin-7-O-β-d-glycoside production.     

渗透胁迫和外源脱落酸对梭梭幼苗生理特性的影响

水分、渗透胁迫和外源脱落酸（ＡＢＡ）对旱生植物梭梭幼苗的某些生理特性存在显著影响。梭梭幼苗有很强的吸水能力,渗透胁迫下脯氨酸含量增加,其细胞膜相对透性对渗透胁迫不敏感,在脱水过程中具有较强的持水能力,外源ＡＢＡ加强了梭梭幼苗的抗渗透胁迫和抗脱水的能力。     

用抑制差减杂交法分离和克隆梭梭幼苗受渗透胁迫诱导相关基因的cDNA片段

以Hoagland溶液培养的梭梭幼苗(H)为对照群体,甘露醇处理的梭梭幼苗(M)为目标群体,进行抑制差减杂交.用经过H cDNA差减的M cDNA构建了一个含有大约400个独立克隆的差减文库;采用差减前的H cDNA和M cDNA以及正向/反向差减杂交后的cDNA为模板标记探针,对随机挑取的100个重组质粒进行差示筛选,获得了21个阳性候选克隆.从这些阳性候选克隆中随机挑取了8个进行Northern blot分析,证实其中3个候选克隆代表了在M中特异表达或表达增强的基因,序列分析和同源性比较表明它们与逆境胁迫有关;而另外5个候选克隆无Northem杂交信号,推测它们为低丰度转录本.     

膜荚黄芪种子中2种几丁质酶的分离纯化及活性测定

运用传统的层析技术对膜荚黄芪种子中两种几丁质酶进行分离纯化,并对分离纯化中各个步骤得到的蛋白进行了活性研究.结果表明:(1)粗提液的硫酸铵沉淀经再生几丁质亲和柱和凝胶过滤层析Sephadex G-75得到几丁质酶A.(2)粗提液的硫酸铵沉淀经离子交换色谱DE-52、CM、凝胶过滤层析Sephadex G-75得到几丁质酶B.(3)几丁质酶A、B的比活性分别为35.6 U/mg和4.1 U/mg.(4)从膜荚黄芪种子中分离纯化的几丁质酶A和B均为糖蛋白,含糖量分别为6.1%和5.8%.(5) SDS-PAGE显示,几丁质酶A、B的分子量分别为35.5 ku、39.6 ku;凝胶过滤层析测定几丁质酶A、B的分子量分别为36.9 ku、40.8 ku;表明几丁质酶A、B均为单亚基蛋白.     

白花丹参与丹参活性成分积累比较研究

研究了山东产丹参（Salvia miltiorrhiza Bge．）、白花丹参（Salvia miltiorrhiza Bge．f．alba）不同生育阶段脂溶性与水溶性成分含量的动态变化,对活性成分积累过程进行数学模拟。结果表明：白花丹参脂溶性成分积累有两个高峰期,分别在7月底和10月底,丹参脂溶性成分的积累高峰在7月底;白花丹参和丹参水溶性成分的积累高峰期均出现在6—7月份。两年生白花丹参活性成分高于丹参;两种丹参的迷迭香酸含量均以地上部为高,其他活性成分均以地下部为高;白花丹参与丹参根中丹酚酸B的含量积累方程分别为y=-8．105X＋81．047和y=-13．777X＋117．917,即随着植株的不断发育,丹参根部丹酚酸B的含量呈下降趋势。该研究结果可为丹参栽培及其质量控制提供理论依据。     

2种黄芪幼苗对缺硫胁迫的生理响应机制

以药用植物膜荚黄芪（Astragalus membranaceus（Fisch.）Bge.）及其变种蒙古黄芪（Astragalus membranaceus Bge.var.mongholicus Hsiao）幼苗为材料，在水培条件下研究了两种黄芪幼苗在不同程度缺硫条件下的生物量积累、光合参数、次生代谢产物积累等的变化规律。结果显示：与供应Hoagland全营养液相比，低硫和无硫供应处理均显著抑制了两种黄芪幼苗根系和地上部的伸长生长以及生物量的累积，并且引起了植株叶片失绿变黄、根系褐变等一系列缺硫症状。此外，缺硫还导致了两种黄芪幼苗叶片叶绿素含量降低以及光合参数下降、全株各部位细胞膜脂过氧化程度增加。相对膜荚黄芪而言，不同程度缺硫对蒙古黄芪生长发育的影响较小。进一步研究发现，在低硫或无硫条件下，膜荚黄芪植株各部位总酚含量出现了明显下降，而蒙古黄芪根系和叶片总酚含量却因缺硫处理而显著升高。同时我们还发现，硫营养缺乏诱导了蒙古黄芪叶片非光化学能量耗散的升高以及植株各部位主要异黄酮物质的大量积累。我们推断，营养液中硫元素供应的减少引起了黄芪幼苗硫营养不良，影响了植株叶绿素合成，降低了植株的光合能力，并同时引起了全株的氧化胁迫，最终使得黄芪幼苗生长发育受到抑制；蒙古黄芪在缺硫胁迫下提高了光保护能力，合成了较多的异黄酮类物质，有效缓解了缺硫胁迫对其生长的影响，从而在面对缺硫胁迫时比膜荚黄芪表现出了更强的耐性。     

温水浸种对蒙古黄芪种子萌发特性的影响

研究温水浸种破除蒙古黄芪（Astragalus membranaceus Bge.var.mongholicus（Bge.） Hsiao）种子休眠的适宜条件,采用恒温和变温2种浸种方式,测定蒙古黄芪种子在不同时间、不同温度梯度条件下的发芽率、发芽势和发芽指数。结果表明,温水浸种破除蒙古黄芪种子休眠的效果显著,变温浸种效果略优于恒温浸种。不同温度破除休眠效果排序依次为60℃> 70℃> 80℃,其中60℃变温浸种2 min和5 min的发芽率分别为对照的2.87倍和2.31倍。浸种时间、浸种温度均可显著影响蒙古黄芪种子萌发,与对照相比,随着浸种时间增加,发芽率总体呈现出先急速升高后逐渐降低的趋势;发芽指数与浸种温度极显著正相关;浸种温度与发芽势和发芽指数均显著正相关。本研究结果表明温水浸种可以提高种子发芽率,保持种子活力。     

Quantities and types of ectomycorrhizal and endophytic fungi associated with Betula platyphylla var. japonica seedlings during the initial stage of establishment of vegetation after disturbance

Ectomycorrhizal and endophytic fungi of Betula platyphylla Sukatchev var. japonica Hara seedlings were investigated by bioassay using soils from sites where the surface layer had been removed by destructive disturbances. Soil samples were taken from sites A, B, C and D, where 1, 2–3, 4–5, and 7–8 years, respectively had passed since disturbance. Naturally regenerated B. platyphylla var. japonica seedlings grew at sites C and D, but not at sites A or B. The percentages of ectomycorrhizal formation in seedlings were significantly lower in the soils from site A (4%) and site B (13%), compared to those in the soils from site C (53%) and site D (37%). The numbers of ectomycorrhizal morphologic types in sites A, B, C, and D were eight, five, one, and seven, respectively. The same dominant type of ectomycorrhiza was found in sites C and D, and this type was different from those in sites A and B. The frequencies of colonization of seedling roots by endophytic fungi, especially Mycelium radicis atrovirens Melin (MRA) in soils from sites A and B were 31 and 33%, respectively; these frequencies were significantly higher than those for site C (0%) and site D (2%). During the initial stage of establishment of vegetation following disturbance, the quantities and types of ectomycorrhizal fungi in the field that have the potential to associate with B. platyphylla var. japonica might rapidly change after invasion of the host plant. Ectomycorrhizal fungi seemed to compete with endophytic MRA fungi for colonization of the roots of B. platyphylla var. japonica seedlings.     

独根草不同部位几种化学成分的分析比较

为评价独根草这一药赏两用植物,对独根草根、茎和叶中粗灰分、粗纤维、粗脂肪、还原糖、部分矿质元素及活性成分(多糖、绿原酸和总黄酮)进行了测定分析.结果表明:独根草叶中粗灰分、粗纤维、粗蛋白、粗脂肪及还原糖的含量分别为10.11％、8.02％ 、9.54％、9.91％和6.53％;Fe、Zn、Cu、Mn、K、Na、Ca和P等矿质元素含量分别为284、132.8、1.07、19.5μg/g、7.01 mg/g、169.38μg/g、221.9 μg/g和300.5 μg/g;还含有2.00％的绿原酸、6.98％的总黄酮,以及3.29％的粗多糖.叶中各成分含量多高于茎和根,证明其主要药用成分在叶;而茎和根均含有多种元素和活性成分,有一定的药用价值,是一种可以全株入药的药赏两用植物.     

超声辅助酸水解提取山里红叶中牡荆素的工艺优化

采用正交法优化山里红叶中牡荆素的超声辅助提取工艺。通过盐酸浓度、提取时间、固液比、超声功率、超声温度、乙醇浓度6种影响因素的单因素实验,研究它们与牡荆素提取得率之间的规律趋势;应用正交设计优化试验,研究盐酸浓度、提取时间、固液比和超声功率对山里红叶提取牡荆素得率影响大小,并确定最佳提取工艺。研究结果表明：当盐酸浓度为2 mol·L^-1、提取时间为40 min,固液比为1：20、超声功率为500 W、超声温度为50℃、乙醇浓度为50%时,效果最佳,得率为2.603 mg·g^-1;盐酸浓度具有较大显著性,且各因素影响顺序为：盐酸浓度 > 超声功率> > 提取时间 > 固液比。