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1.
Summary During research on the possible differences between theflora urbica in Padua at the beginning of the century and at present times, a considerable concentration of allergy-provoking species has been observed. In addition to the list of these species, this first approach includes some proposals and comments on the ways of managing public and private green areas.  相似文献   

2.
Summary Rye plants carrying B chromosomes with different nuclear and cytoplasmic constitutions have been analyzed at first pollen mitosis. No differences of B chromosome behaviour have been detected. It has been concluded that non-disjunction and preferential distribution are processes controlled by Bs themselves.At second pollen anaphase, B laggards have been observed. Both non-disjunction and B laggards occurred with higher frequency in younger anthers.  相似文献   

3.
Summary Gramineae pollination from a pollen monitoring station located in the eastern suburb of Perugia and meteorological correlations are reported. The data refers to the year 1989. Grass pollen peak pollination was from May to July; in this period the influence of relative humidity and of temperature on pollen concentration was very high. Phenological observations, to identify the time of maximum stamen extension in the most common genera in the area, are also reported. During the period of investigation the counts of pollen grains over four-hour periods showed a regular diurnal rhythm with peaks of concentration in the four-hour period 16.00–20.00. Aerosporological data and meteorological data related to four-hour periods were correlated following different criteria.  相似文献   

4.
The cacti of the American Southwest, defined as the region from southern California to Texas, are surveyed for types of pollination systems and their frequencies. Four types of pollination systems are known to occur in the southwestern cactus flora: bee, hummingbird, hawkmoth, and bat pollination. Two other modes are suspected but not documented: miscellaneous smallinsect pollination and autogamy.—Bee flowers comprise a wide and nearly continuous series of size classes from very small to very large. The large bee flowers, with perianths 5.5 to 12.5 cm in diameter, form a prominent but arbitrarily delimited subcategory in the bee pollination system. Promiscuous flowers and autogamous flowers, if they occur, are included with the medium-sized and small bee flowers in our present classification, due to lack of information, and will have to be separated out when our knowledge is more complete. The overwhelming majority of species in the southwestern cactus flora are bee flowers. Between 39 and 44% of the species are large bee flowers. Another 50 to 56% of the species are classified as medium-sized and small bee flowers; while some of these may turn out to be promiscuous flowers and autogamous flowers, most of them are undoubtedly bee flowers.—Hummingbird, hawkmoth, and bat pollination are conspicuous but statistically minor components of the pollination spectrum, occurring in only one or a few species (see Table 2). Hummingbird pollination has arisen from bee pollination in the Southwest. The species or species groups with hawkmoth and bat pollination, on the other hand, are basically tropical groups which developed their advanced pollination systems in the tropics.Pollination of North American Cacti, V. See alsoGrant & Grant (1979a),Grant & al. (1979),Grant & Grant (1979b),Grant &Hurd (1979).  相似文献   

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Summary Urticaceae pollen monitoring was carried out, in the atmosphere of East Perugia during the summer of 1989. In summer the Urticaceae pollen shows a fluctuating diurnal trend, which was analysed daily over six 4-hour periods. The high peaks of thistaxon were recorded in the middle of the day in July and August, and in the morning in June. The percentage pattern of the daily mean pollen concentration of Urticaceae was compared with mean temperature, wind speed, relative humidity and rain, both in the non-rainy days and rainy ones. The best correlations came out comparing pollen concentration and meteoclimatic parameters during non-rainy days. The interpretation of the influence of rainfalls is very difficult owing to their peculiar features in summer.  相似文献   

7.
A powdery mildew fungus found on Paeonia lutea at the Botanical Garden of Geneva (Switzerland) was identified as Erysiphe hypophylla based on morphological observations. The occurrence of E. hypophylla on Paeonia seemed curious, because host plants of this species have been restricted to a few Quercus species of the family Fagaceae. In this study, we determined the rDNA sequences of the powdery mildew specimens on Paeonia and E. hypophylla on Quercus to confirm the identity of the Paeonia fungus. The three sequences from the specimens on P. lutea were identical to one another in both ITS and 28S rDNA regions and also to the sequences of E. hypophylla on Q. robur, which supports the identification that the fungus on P. lutea is E. hypophylla. However, these sequences were also identical to the sequences of E. alphitoides on Quercus spp. and Oidium mangiferae on mango. This result suggests a possibility that E. hypophylla is conspecific to E. alphitoides. Further study is required to clarify whether E. hypophylla is a synonym of E. alphitoides or a distinct species.  相似文献   

8.
The genetic diversity of the genus Lespedeza is not well known and the phylogenetic relationship of Lespedeza with the genus Kummerowia is unclear. We report the first study in which polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers derived from Medicago, cowpea and soybean were used to assess the genetic diversity of the USDA Lespedeza germplasm collection and clarify its phylogenetic relationship with the genus Kummerowia. Phylogenetic analysis partitioned 44 Lespedeza accessions into three main groups some of which were species-specific and eight subgroups. This data set revealed some misidentified accessions, and indicated that the two species in the genus Kummerowia are closely related to the genus Lespedeza. Morphological reexamination was used to correct the misidentified accessions within the genus Lespedeza. Our results demonstrated that phylogenetic analysis with morphological reexamination provides a more complete approach to classify accessions in plant germplasm collection and conservation.  相似文献   

9.
萜烯合成酶(terpene synthase,TPS)能催化不同的前体物质生成不同的萜类化合物,是合成萜类物质的关键酶。为探究杜鹃花TPS基因家族成员在萜类物质代谢过程中的表达模式,本文基于杜鹃花基因组数据库,利用生物信息学方法对杜鹃花TPS基因(TPS)进行家族成员鉴定;通过云锦杜鹃和诺娃杜鹃两种不同种高山杜鹃的转录组测序结果,结合qRT-PCR、顶空固相微萃取和气相色谱-质谱联用技术,分析两种杜鹃不同发育时期花瓣中TPS家族成员表达水平和代谢物含量变化关系。结果表明,从杜鹃花基因组数据库中共鉴定获得47个RsTPS成员,RsTPS家族成员长度在591-2 634 bp之间,含有3-12个外显子不等,编码196-877个氨基酸;RsTPS家族成员主要分布在叶绿体和细胞质;系统进化分析结果显示RsTPS基因分为5个亚组。通过分析转录组数据得到7个功能注释为TPS的基因家族成员,发现TPS1TPS10TPS12TPS13的表达量在4个时期中呈现出先上升,到盛开期达到顶峰后再下降的趋势。对基因表达量变化与萜类物质含量变化进行相关性分析,发现TPS1TPS4TPS9TPS10TPS12TPS13表达量与云锦杜鹃不同时期花瓣中萜类物质含量变化呈显著性正相关,推测这6个基因家族成员可能是参与云锦杜鹃花香调控的关键基因。  相似文献   

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Summary A comparative study was carried out between aeroallergenic pollen spectra in Trieste and at Lozzo di Cadore. The two localities were found to be different on a five-day running mean basis as to the 8 pollen taxa monitored by the National Aerobiological Monitoring Network managed by the Italian Association of Aerobiology (AIA). In the zone of Lozzo the pollination curve of the spring flowering taxa showed a lag of about one month due to the colder climate. Lozzo di Cadore showed a poor airborne pollen content,Corylus and Graminaceae being prevailing. Trieste has a higher airborne pollen diversity and longer pollination times because of its higher floristic and vegetational complexity. In Trieste the allergenic pollen spectrum showed great quantities ofOstrya, Quercus, Oleaceae, Graminaceae and of ruderal taxa, widespread over the area, due to man's influence.  相似文献   

12.
The embryology ofStegnosperma halimifolium andS. watsonii has been studied in detail. The tapetum is of the secretory type and its cells become multinucleate. Simultaneous cytokinesis in the pollen mother cells follows meiosis. The ripe pollen grains are 3-celled. The ovule is crassinucellate, bitegmic and amphitropous, with the micropyle formed by the inner integument alone. The female archesporium is one celled, and the parietal tissue 3–5 layered. The embryo sac development conforms to thePolygonum type. A central strand, 6 or 7 cells thick, differentiates inside the nucellus and extends from the base of the embryo sac to the chalazal region. The endosperm is nuclear. The embryogeny conforms to the Caryophyllad type. The seed coat is formed by the outer epidermis of the outer integument and the inner epidermis of the inner integument. Based on this evidence and other data, the status of the genus as an independent family,Stegnospermataceae (Stegnospermaceae) is confirmed. Apparently, it forms a connecting link betweenPhytolaccaceae andCaryophyllaceae.  相似文献   

13.
靳明  叶碧碧  庞燕  储昭升  杨琦 《生态学报》2016,36(2):518-524
通过实验室小试研究濒临灭绝物种螺蛳(Margarya melanioides)对舟形藻(Naviculaceae sp.)、菱形藻(Nitzschia sp.)、孟氏颤藻(Planktothrixmougeotii)以及四尾栅藻(Scenedesmus quadricauda)4种典型附着藻类的摄食探讨其摄食生态学特性,调查海菜花(Ottelia acumiuate)养殖塘中藻的群落结构及水体的pH值、光照、溶解氧(DO)、温度等环境,从摄食生态学角度分析,探讨螺蛳在洱海流域恢复的可行性。摄食实验结果显示:螺蛳对实验选取四种藻摄食率关系为舟形藻菱形藻孟氏颤藻四尾栅藻。对舟形藻摄食的影响因素研究结果表明在温度为25℃时其摄食强度最大,摄食率(IR)为(2.19±0.16)mg个~(-1)d~(-1);螺蛳在光照为0-100001x的范围内均有较强的摄食活动,摄食活动最适宜的光照强度区间为1000-20001x,摄食率IR均达到3.0mg个~(-1)d~(-1)以上;溶解氧DO对其摄食活动影响显著,当DO大于3.6mg/L时螺蛳摄食活跃,低于1mg/L时螺蛳基本停止摄食;螺蛳摄食率大小跟螺蛳重量呈显著负相关P0.05。洱海流域海菜花塘水体的调查结果得出海菜花塘的pH值、光照、DO、温度以及藻等环境因子均适合螺蛳生存繁衍,可通过构建海菜花湿地来实现螺蛳的保种与扩增恢复。  相似文献   

14.
C-banding polymorphism was analyzed in 14 accessions of Triticum searsii from Israel, and a generalized idiogram of the species was established. One accession was homozygous for whole arm translocations T1SsS·4SsS and T1SsL·4SsL. C-banding analysis was also used to identify 7 T. aestivum cv Chinese Spring-T. searsii disomic chromosome addition lines, 14 ditelosomic chromosome addition lines, 21 disomic whole chromosome, and 31 ditelosomic chromosome substitution lines. The identity of these lines was further confirmed by meiotic pairing analysis. Sporophytic and gametophytic compensation tests were used to determine the homoeologous relationships of the T. searsii chromosomes. The results show that the T. searsii chromosomes do not compensate well for their wheat homoeologues. The C-banding patterns of T. searsii chromosomes are distinct from those of other S-genome species and from the B-genome chromosomes of wheat, indicating that T. searsii is not a direct B-genome donor species of T. turgidum and T. aestivum.Contribution No. 95-72-J from the Kansas Agricultural Experiment Station, Kansas State University, Manhattan, Kansas, USA  相似文献   

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16.
采用室内土培法,研究了砷胁迫(0,50,100和200 mg/kg)对凤尾蕨属中砷超富集植物大叶井口边草(Pteris cretica var.nervosa)和非砷超富集植物剑叶凤尾蕨(Pteris ensiformis)生物量、株高、叶片内源3-吲哚乙酸(IAA)含量、IAA氧化酶(IAAO)活性、砷含量、抗氧化酶(超氧化物歧化酶SOD、过氧化物酶POD、过氧化氢酶CAT)活性以及细胞膜脂过氧化产物丙二醛(MDA)含量的影响,并用逐步回归法分析了IAA含量与砷含量、抗氧化酶活性、MDA含量之间的关系。此外,研究了100 mg/kg砷处理下IAA、IAAO、3种抗氧化酶和MDA的时间动态。结果表明,与对照(不加砷)相比,加砷处理下大叶井口边草的株高和生物量未出现显著变化,但剑叶凤尾蕨在中、高浓度砷胁迫下则显著降低;中、高浓度砷胁迫均使2种植物叶片含砷量、IAA含量显著增加和IAAO活性显著下降,但这种改变在大叶井口边草中更为显著;加砷处理使大叶井口边草叶片3种抗氧化酶活性维持或增加,剑叶凤尾蕨中SOD和CAT活性虽能维持,但POD活性则显著下降,说明砷胁迫下大叶井口边草具有更强的抗氧化能力。逐步回归分析结果显示,2种植物叶片IAA含量均与砷含量成显著正相关,但在大叶井口边草中,IAA含量还与CAT活性成显著负相关。时间动态研究表明,第13天,大叶井口边草具有最高的IAA含量、最低的IAAO活性以及最低的CAT活性,而剑叶凤尾蕨中的变化规律则不明显。因此,叶片保持较高的IAA含量、较低的IAAO和CAT活性有助于大叶井口边草超量富集砷。  相似文献   

17.
The European spruce bark beetle, Dendroctonus micans Kugelann (Coleoptera, Scolytidae), is one of the most serious pests of oriental spruce (Picea orientalis L.) in Turkey. In this study, we investigated bacterial flora of D. micans collected from different populations of the forests of Eastern Black Sea Region of Turkey from 2002 to 2004. Seven different bacteria were isolated from healthy, diseased and dead specimens based on the color of colony and morphology. According to morphological, physiological and biochemical properties, metobolic enyzme profile by BIOLOG microtiter plate system, and total cellular fatty acid profile by Microbial Identification System (MIS), isolates were identified as Micrococcus luteus, Bacillus thuringiensis subsp. morrisoni, Serratia grimesii, Enterobacter cloaceae, Enterobacter intermedius, Streptococcus sp. and Pseudomonas putida. This is the first study on the bacterial flora of D. micans.  相似文献   

18.
Little is known about how tropical land-use systems contribute to the conservation of functionally important insect groups, including dung beetles. In a study at the margin of Lore Lindu National Park (a biodiversity hotspot in Central Sulawesi, Indonesia) dung-beetle communities were sampled in natural forest, young secondary forest, agroforestry systems (cacao plantations with shade trees) and annual cultures (maize fields), each with four replicates (n = 16 sites). At each site we used 10 pitfall traps, baited with cattle dung, along a 100 m transect for six 3-day periods. The number of trapped specimens and species richness at the natural forest sites was higher than in all land-use systems, which did not significantly differ. Each land-use system contained, on average, 75% of the species richness of the natural forest, thereby indicating their importance for conservation. However, a two-dimensional scaling plot based on NESS indices (m = 6) indicated distinct dung beetle communities for both forest types, while agroforestry systems and annual cultures exhibited a pronounced overlap. Mean body size of dung beetles was not significantly influenced by land-use intensity. Five of the six most abundant dung beetle species were recorded in all habitats, whereas the abundance of five other species was significantly related to habitat type. Mean local abundance and number of occupied sites were closely correlated, further indicating little habitat specialisation. The low dung beetle diversity (total of 18 recorded species) may be due to the absence of larger mammals in Sulawesi during historical times, even though Sulawesi is the largest island of Wallacea. In conclusion, the dung beetle fauna of the lower montane forest zone in Central Sulawesi appears to be relatively robust to man-made habitat changes and the majority of species did not exhibit strong habitat preferences.  相似文献   

19.
动物胃肠道是食物消化和营养吸收器官,对机体健康至关重要。果蝇与哺乳动物的肠道在细胞组成、遗传调控等方面高度相似,是研究肠道发育的良好模型。体外培养细胞中的研究发现,Nprl2通过作用于Rag GTPase,抑制雷帕霉素靶点复合物1(target of rapamycin complex 1,TORC1)的活性,参与细胞代谢的调节。前期报道nprl2突变果蝇具有前胃增大、消化能力降低等肠道衰老相关表型。但对于Nprl2是否通过Rag GTPase调控肠道发育等方面尚不清楚。为了探究Rag GTPase在Nprl2调控果蝇肠道发育中的作用,本研究利用遗传杂交结合免疫荧光等方法对RagA敲减和nprl2突变果蝇的肠道形态、肠道细胞组成等方面进行研究。发现单独敲减RagA可以引起肠变粗、前胃增大等表型,敲减RagA能挽救nprl2突变体中肠道变细、分泌型细胞减少的表型,但并不能挽救nprl2突变体中前胃增大的表型。以上结果表明,RagA在肠道发育中发挥重要作用,Nprl2通过作用于Rag GTPase调节肠道细胞分化和肠道形态,但Nprl2对前胃发育和肠道的消化功能的调节可能通过不依赖于Rag GTPase的机制实现。  相似文献   

20.
Larval digenean parasites were studied in Littorina obtusata (L.) and L. mariae Sacchi & Rastelli at Sawdern Point in West Wales. Shell parameters, ovipositor and shell colour, penis morphology and sex ratios were scored, and the influence of parasitism studied. A total of 7 species of parasites were found, although the prevalence was very low in L. mariae, especially in the females. The parasitic gigantism that has been described in other species of gastropod was not found in this study. Parasitic castration does occur in some infected male L. obtusata, resulting in severe stunting of the penis. However, this phenomena was never observed in L. mariae. The winkle species are congeneric and inhabit broadly similar niches on the shore; their life histories are however quite different — one being annual and the other perennial. This probably affects exposure to infection, and might explain the differing prevalence of the parasites.  相似文献   

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