紫花地丁春花与夏花的发育条件

紫花地丁(Viola Patrinii D.C.)是遍生在我国原野上的草花,我国旧文献中已有记载,紫花地丁不仅在春末夏初时开着带有鲜艳紫色花冠的春花,到了盛夏还开着隐蔽而不具花冠的夏花。这种紫花地丁在不同的季节有着开异样花的习性,在我国大学的植物学教材里时常引用。紫花地丁春花与夏花形态上有很大差异,受粉的机构也不同。春花的花梗较长,常伸出叶叢以上,花冠紫色有距,雌蕊的花柱较长,伸入距内,这种花需要蟲媒才能授粉。夏花花梗较短,时常隐蔽在叶片下面,花冠全缺,花柱短而仅剩有两个离距近的雄蕊紧贴在柱头上,花粉在     

紫花地丁两型花相互转变过程中花部形态结构的变化式样研究

紫花地丁(Viola philippica)是具典型开放花与闭锁花混合繁育系统的植物,其两型花的形态差异为花器官发育研究提供了极好的模型。该文以不同光周期下生长的或在不同光周期间调换的紫花地丁植株为研究对象,基于形态解剖学方法,研究了过渡闭锁花的形态结构、开放花到完全闭锁花或完全闭锁花到开放花的变化式样,以及完全闭锁花与过渡闭锁花中不发育雄蕊与花瓣的位置效应。结果显示:该物种在短日照与中日照下均有开放花与过渡闭锁花形成,短日照下大多数花芽为开放花,少数为过渡闭锁花,中日照下大多数花芽为过渡闭锁花,少数为开放花;长日照下全为完全闭锁花。在过渡闭锁花芽中,存在着一系列雄蕊与花瓣数目不同的过渡类型,既有偏向开放花的5雄3瓣的过渡类型,也有偏向完全闭锁花的2雄1瓣的过渡类型。其中,前一种类型在短日照下的过渡闭锁花芽中所占比例较大,而后一种类型在中日照下所占比例较大。另外,过渡闭锁花与完全闭锁花的雄蕊与花瓣发育程度均存在一定的位置效应,其花芽腹侧的下花瓣(对应于开放花的下花瓣)与相邻的2枚雄蕊普遍发育最好,而后花瓣(相对于前花瓣)的发育与完全闭锁花的基本一样,为器官原基状,与后花瓣相邻的2枚雄蕊也普遍最小,而且也最容易发育为无小孢子发生的膜质状结构或原基状结构。同时,将具完全闭锁花的植株置于短日照下或将具开放花的植株置于长日照下一段时间后,重新诱导的花芽经历一系列过渡闭锁花类型后发生花型的相互转变。因此,不同光周期对紫花地丁两型花发育的影响是渐进的,长日照会抑制部分花瓣与雄蕊的发育,短日照能拮抗并破除长日照对雄蕊与花瓣的抑制。     

紫花地丁对盐胁迫的生理反应

为研究盐分胁迫下紫花地丁生理反应,本文以紫花地丁幼苗为试验材料,对不同浓度NaCl处理中的幼苗叶片,进行光合色素、蛋白质、可溶性糖、游离脯氨酸的测定。结果表明,盐胁迫下紫花地丁叶片光合色素含量降低、蛋白质、可溶性糖、游离脯氨酸含量呈先升高后下降的趋势,当处理浓度高于NaCl2%时,各指标与对照之间差异显著。紫花地丁幼苗能够正常生长的抗盐阈值为NaCl2%,可耐低盐胁迫。渗透调节物质是紫花地丁的主要耐盐性指标。     

宝山堇菜(Viola baoshanensis)镉胁迫下的光合作用

利用荧光成像技术研究了自然生长状态下宝山堇菜、紫花地丁镉含量与光合作用间的关系。野外调查表明,宝山堇菜、紫花地丁镉含量差异显著,地上部分镉含量分别为867mg／kg和2mg／kg,相差近450倍;镉转运系数、富集系数,宝山堇菜均大于1,紫花地丁均小于1。叶绿素荧光参数,宝山堇菜Fm、Ik、Pm均显著低于紫花地丁（p=0．05）;两种植物间Fo、Fv/Fm、α均无显著差异。紫花地丁地上部分镉含量与叶绿素荧光参数的相关性较低,宝山堇菜地上部分镉含量与Fm、Pm、Ik达到极显著负相关。Fv／Fm,宝山堇菜、紫花地丁均在0．8左右,与镉的相关性较低,表明其光合作用没有受到镉胁迫。但是,宝山堇菜Fm显著低于紫花地丁,而且与镉呈负相关,表明宝山堇菜叶片Fm会随镉含量的增加而降低,预示镉可能会造成宝山堇菜光系统Ⅱ叶绿素结构破坏或者抑制其电子传递。参数Ik和Pm在两种植物间差异显著及其与宝山堇菜地上部分镉含量显著负相关反映宝山堇菜光耐受能力和电子传递能力在镉胁迫下逐渐减弱。初始斜率α始终维持在较高水平,说明镉胁迫并未对宝山堇菜捕光系统造成显著伤害。结合Fm值的变化和快速光曲线中荧光参数的变化推断镉最有可能会造成宝山堇菜电子传递能力的减弱。     

3种野生地被植物对践踏胁迫的生理生态响应特征

不同强度践踏胁迫下,对3种野生地被植物主要生理生态响应特征进行了研究,结果表明：重度践踏胁迫下匍枝委陵菜的盖度、生物量下降幅度最大,和对照相比分别下降46.58%和43.53%。重度践踏胁迫下车前的纤维素含量最高,比对照增加43.31%。中度践踏胁迫下紫花地丁丙二醛含量积累最少,比对照升高28.57%。紫花地丁叶绿素含量对践踏胁迫响应敏感,轻度践踏可使叶绿素含量提高45.21%（p< 0.05）,重度践踏使匍枝委陵菜和紫花地丁的叶绿素含量分别下降了21.59%和29.37%。践踏胁迫使3种野生地被植物的群体净光合速率下降。综合分析结果为车前最耐践踏,紫花地丁次之,匍枝委陵菜最不耐践踏。     

紫花地丁HPLC指纹图谱研究

目的:建立紫花地丁药材HPLC指纹图谱,提供药材质量控制的可靠方法。方法:采用HPLC方法,以Agi-lent C18(4.6 mm×250 mm,5μm)为色谱柱,甲醇-0.5%醋酸水溶液进行梯度洗脱;检测波长353 nm,流速1.0mL/min。结果:检测了12批不同来源的紫花地丁药材,确立了18个共有峰,建立了紫花地丁对照指纹图谱,计算各被测样品的HPLC指纹图谱的整体相似度,并指认了菊苣苷、七叶内酯、东莨菪素、早开堇菜苷4个特征峰,比较了上述成分在不同药材中的含量。结论:所建立的指纹图谱具有良好的精密度、重现性和稳定性,可作为紫花地丁药材质量控制标准。     

中国石头花属的分类和分布

本文报道我国石头花属植物有18种(其中2新种)1变种,分隶于5组。大多分布西北、华北和东北地区,新疆是我国本属植物的分布和分化中心,种数往东递减。河北石头花、华山石头花、刺序石头花和细叶石头花为我国特有种。     

地丁化学成分的研究

从紫花地丁中首次分得四个有机酸,一个酰胺和一个黄酮甙,其中二十四酰对羟基苯乙胺为一新化合物。     

宝山堇菜（Viola baoshanensis）镉胁迫下的光合作用

利用荧光成像技术研究了自然生长状态下宝山堇菜、紫花地丁镉含量与光合作用间的关系。野外调查表明,宝山堇菜、紫花地丁镉含量差异显著,地上部分镉含量分别为867mg/kg和2mg/kg,相差近450倍;镉转运系数、富集系数,宝山堇菜均大于1,紫花地丁均小于1。叶绿素荧光参数,宝山堇菜F_m、I_k、P_m均显著低于紫花地丁（p=0.05）;两种植物间F_o、F_v/F_m、α均无显著差异。紫花地丁地上部分镉含量与叶绿素荧光参数的相关性较低,宝山堇菜地上部分镉含量与F_m、P_m、I_k达到极显著负相关。F_v/F_m,宝山堇菜、紫花地丁均在0.8左右,与镉的相关性较低,表明其光合作用没有受到镉胁迫。但是,宝山堇菜Fm显著低于紫花地丁,而且与镉呈负相关,表明宝山堇菜叶片Fm会随镉含量的增加而降低,预示镉可能会造成宝山堇菜光系统Ⅱ叶绿素结构破坏或者抑制其电子传递。参数I_k和P_m在两种植物间差异显著及其与宝山堇菜地上部分镉含量显著负相关反映宝山堇菜光耐受能力和电子传递能力在镉胁迫下逐渐减弱。初始斜率α始终维持在较高水平,说明镉胁迫并未对宝山堇菜捕光系统造成显著伤害。结合Fm值的变化和快速光曲线中荧光参数的变化推断镉最有可能会造成宝山堇菜电子传递能力的减弱。     

中国桔梗科一新纪录属——异檐花属

异檐花属Triodanis原产美洲和地中海地区。 在中国为首次报道,我国已知有穿叶异檐花T. perfoliata和卵叶异檐花T．biflora两种,前者采中福建崇安和建宁,后者采自安徽安庆、浙江普陀和福建将乐。     

Chalcone synthase gene lineage diversification confirms allopolyploid evolutionary relationships of European rostrate violets

Phylogenetic relationships among and within the subsections of the genus Viola are still far from resolved. We present the first organismal phylogeny of predominantly western European species of subsection Rostratae based on the plastid trnS-trnG intron and intergenic spacer and the nuclear low-copy gene chalcone synthase (CHS) sequences. CHS is a key enzyme in the synthesis of flavonoids, which are important for flower pigmentation. Genes encoding for CHS are members of a multigene family. In Viola, 3 different CHS copies are present. CHS gene lineages obtained confirmed earlier hypotheses about reticulate relationships between species of Viola subsection Rostratae based on karyotype data. Comparison of the CHS gene lineage tree and the plastid species phylogeny of Viola reconstructed in this study indicates that the different CHS copies present in Viola are the products of both recent and more ancient duplications.     

METABOLISM AND FLOWERING

Two earlier papers have established (1) that the late-flowering chrysanthemum, a typical "short-day" species, flowered in autumn because of a disability in nocturnal translocation which limited the amount of carbohydrate available at the growing-point during the short nights of summer (Grainger, 1938), and (2) that many plants which flower in spring and early summer actually begin the formation of their flower initials in the autumn and winter of the previous year (Grainger, 1939). Such plants might conceivably be "short-day" kinds, since the actual transformation from vegetative to floral organization of the growing-point was accomplished when the days were short. It therefore appears necessary to investigate their relative diurnal carbohydrate metabolism, in order to discover whether it has any causal relationship with the time of actual flower initiation, as was demonstrated for the late-flowering chrysanthemum. The present paper describes the results of such an investigation, and also of certain contributory studies as to the converse effect of flowering upon metabolism, the relative amount of energy used in flowering, and the possible inadequacy of nutrition in very floriferous plants.     

Effects of experimentally imposed climate scenarios on flowering phenology and flower production of subarctic bog species

Climate scenarios for high‐latitude areas predict not only increased summer temperatures, but also larger variation in snowfall and winter temperatures. By using open‐top chambers, we experimentally manipulated both summer temperatures and winter and spring snow accumulations and temperatures independently in a blanket bog in subarctic Sweden, yielding six climate scenarios. We studied the effects of these scenarios on flowering phenology and flower production of Andromeda polifolia (woody evergreen) and Rubus chamaemorus (perennial herb) during 2 years. The second year of our study (2002) was characterized by unusually high spring and early summer temperatures. Our winter manipulations led to consistent increases in winter snow cover. As a result, average and minimum air and soil temperatures in the high snow cover treatments were higher than in the winter ambient treatments, whereas temperature fluctuations were smaller. Spring warming resulted in higher average, minimum, and maximum soil temperatures. Summer warming led to higher air and soil temperatures in mid‐summer (June–July), but not in late summer (August–September). The unusually high temperatures in 2002 advanced the median flowering date by 2 weeks for both species in all treatments. Superimposed on this effect, we found that for both Andromeda and Rubus, all our climate treatments (except summer warming for Rubus) advanced flowering by 1–4 days. The total flower production of both species showed a more or less similar response: flower production in the warm year 2002 exceeded that in 2001 by far. However, in both species flower production was only stimulated by the spring‐warming treatments. Our results show that the reproductive ecology of both species is very responsive to climate change but this response is very dependent on specific climate events, especially those that occur in winter and spring. This suggests that high‐latitude climate change experiments should focus more on winter and spring events than has been the case so far.     

Interspecific competition in Australian honeyeaters—depletion of common resources

Many species of honeyeaters and other nectar-feeding birds occur in most habitats in South Australia. They frequently feed on nectar of the same species of plants. A succession of species of plants provide nectar for birds throughout the year. Nectar is most abundant in winter and early spring and least abundant in summer and autumn. There is more nectar per flower and more flowers in winter and spring. Nectar is often depleted by honeyeaters, and sometimes other visitors (silvereyes, lorikeets and insects) between December and May. It is at times reduced to a level at which it is uneconomical for some species to exploit. There are seasonal movements of honeyeaters into areas of abundant nectar and out of these areas when nectar becomes scarce. Breeding coincides with peak abundance of nectar. Diversity of honeyeaters is probably maintained by an interaction of two types of competition, exploitation and interference. The larger species use the richest sources of nectar and aggressively exclude the smaller species (interference) whereas the smaller species can use poorer sources of nectar because their energy requirements are less (exploitation).     

温带半干旱地区不同管理水平下草坪杂草发生特征的比较研究

2000～2002年对呼和浩特地区不同草坪的杂草种类组成及其危害进行了调查,发现在3个不同管理水平的草坪中共出现80种杂草植物,其中管理水平较差、中等、较好的草坪分别有67种、37种和36种杂草,以菊科、豆科、禾本科植物占优势,不同草坪杂草群落的生活型谱有明显差异.根据危害度指数把草坪杂草分为极度、重度、中度、轻度、弱度危害5个等级,极度和重度危害杂草在管理水平较差、中等、较好的草坪中的种类比例分别为11.95%、21.63%和22.22%;在管理水平较差草坪中,极度危害杂草是早开堇菜和止血马唐,春季和秋季以早开堇菜的危害为主,夏季以止血马唐为主;在管理水平中等草坪中,极度危害杂草是赖草和止血马唐,赖草的高危害期在春秋季节,夏季以止血马唐为主要危害杂草;在管理水平较好的草坪中,极度危害杂草是鼠掌老鹳草、鹅绒委陵菜、赖草、欧亚旋复花,其中鼠掌老鹳草的危害度在整个生长季中占绝对优势.     

A rare continual flowering strategy and its influence on offspring quality in a gynodioecious plant

The majority of angiosperms have a single annual bout of reproduction; species that flower continually throughout the year are rare. Ochradenus baccatus is a gynodioecious, desert shrub whose principal flowering period is associated with the winter rains, although large individuals also remain in flower during the hot, dry summer. The goal of this study was to examine the reproductive consequences of continual flowering in a large population of O. baccatus in Israel. Over the two years of this study, 60% of individuals flowered continuously. The number of fruit and seeds per fruit were greater in winter. Winter seeds were ～12% heavier than summer seeds and had significantly higher germination rates (80 vs. 60%, respectively). Although summer seeds were smaller and less likely to germinate, we propose that the benefit derived from their production lies in their ability to capitalize on the first winter rains. These early rain events provide a head start on establishment and growth in the hostile desert environment. Plants that delay reproduction until the onset of rains risk having their offspring face the dry conditions of spring and summer.     

Flowering and fruiting phenology of a xerochamaephytic shrub community from the mountain of Mallorca (Balearic islands,Spain)

A study of the flowering and fruiting phenology was undertaken for twenty species of the xerochamaephytic communities that characterize the mountain-crest areas of the island of Majorca (Balearic Islands, Spain). The flowering period of the species considered extends from March to November, with the majority flowering during the spring and early summer, and a peak in June. The flowering duration at the species level is longest for Rosmarinus officinalis var. palaui (which flowered in spring and autumn) and was shortest for Genista majorica and Rubia balearica. In this community, three strategies were observed that may serve to reduce interspecific competition between pollinators: 1) pollination specialization of white-pink flowers; 2) high diversification of yellow flower pollinators; and 3) the divergence in flowering time of less common flower colours. The flowering duration of individual plants and whole populations are positively correlated, which may indicate that individuals of each population optimize the time which is phenologically useful. The flowering of the spiny cushion species of the community is characterized by a smaller intraspecific overlap in comparison to the other species examined. This revised version was published online in June 2006 with corrections to the Cover Date.     

杉木天然次生林金龟子多样性及季节动态变化

1　引　言杉木 (Ｃｕｎｎｉｎｇｈａｍｉａｌａｎｃｅｏｌａｔａ(Ｌａｍｂ .)Ｈｏｏｋ .)在我国南方各省有着悠久的栽培历史 ,它生长快 ,材质好 ,在我国林业生产和国民经济建设中占有重要地位。但长期生产实践表明 ,杉木人工林重复连栽会引起地力衰退及生产力下降。影响杉木人工林稳定性的因素很多 ,其中包括地下害虫蛴螬。但有关方面的研究很少 ,只保留在个体生物学和生态学水平上 ,并且许多是室内工作 ,并未把金龟子种群在杉木天然次生林生态系统中分布、发生及季节动态作为一个整体加以研究。本研究工作通过对杉木天然次生林生态系统中金…     

常春二乔玉兰春夏季开花节律及营养效应研究

为系统掌握常春二乔玉兰春夏季开花物候节律,探讨其与营养物质的关系,本研究以6年生常春二乔玉兰为试验材料,观测其年生长发育节律、春夏季开花物候特性以及茎段营养物质的含量变化。结果表明：（1）每年12月始至翌年2月下旬为常春二乔玉兰休眠期。2月下旬花芽膨大生长,并于3月开始春季开花,花期持续约20 d。4月进行营养生长,5月完成花芽分化。5月底部分花芽膨大并于6月开始开花,夏季花期持续约20 d。7~9月为未膨大花芽的发育滞缓期。此外,少量夏季开放的花的基部侧芽再次分化形成花芽。10~12月随着落叶的开始,树体逐渐进入休眠期。（2）常春二乔玉兰营养生长后分化的花芽能够花开两季。春季开花为先花后叶,开花率为100%,开花同步率较高,雌、雄蕊发育正常,为可育花。夏季开花为花叶同放,开花率约为30%,且开花同步率较低,开放的花内雌、雄蕊发育异常,为不育花。（3）春季开花期间可溶性糖和可溶性蛋白呈下降趋势,淀粉含量于开花后期下降;夏季开花期间可溶性糖和淀粉总体呈先降后升趋势,而可溶性蛋白总体呈下降趋势。综上所述,常春二乔玉兰春、夏季开花期内开花模式存在一定差异,其显著节律特征与营养物质含量变化有关,推测低水平的可溶性糖及高水平的淀粉和可溶性蛋白有利于春季开花的启动,而低水平的可溶性蛋白及高水平的可溶性糖和淀粉含量则有利于夏季开花的实现。     

Selective cytotoxicity evaluation in anticancer drug screening of fractionated plant extracts

Chosen to reflect biodiversity in a phylogenetic sense, 100 fractionated plant extracts were screened in vitro for cytotoxicity following extraction and fractionation (polypeptide isolation). Of these 100 extracts, 30 were selected and then characterized preliminarily for antitumor potency and mode of action by testing them on two cell lines and primary cultures of human tumor cells. On the basis of cytotoxicity potency, 10 of the extracts were further characterized for anticancer activity in 10 human tumor cell lines. This final testing resulted in seven potential lead plants with superior evidence of antitumor potential: Colchicum autumnale L. (Colchicaceae), Digitalis lanata Ehrh. and Digitalis purpurea L. (Plantaginaceae), Helleborus cyclophyllus Boiss. (Ranunculaceae), Menyanthes trifoliata L. (Menyanthaceae), and Viola arvensis Murr. and Viola patrinii Ging. (Violaceae). Within a database of antitumor compounds, the activity profiles of the extracts from these seven plants were compared, by correlation analysis, with those of more than 100 other compounds, including 39 standard drugs from different classes of cytotoxic mechanisms. The activity profiles of six of these candidates were uncorrelated with those of the standard drugs, possibly indicating new pathways of drug-mediated cell death.