野花椒内生真菌Diaporthe perseae次生代谢产物及其抗炎活性

目的研究野花椒内生真菌Diaporthe perseae次生代谢产物及其抗炎活性。方法Diaporthe perseae发酵提取物的次生代谢产物采用硅胶、Sephadex LH-20、TLC、HPLC进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。对分离得到的部分化合物进行抗炎活性筛选。结果从中分离得到13个化合物,分别鉴定为蜜环菌酮(1)、2-(4-羟基苯基)乙酸乙酯(2)、N-(2-苯乙基)乙酰胺(3)、4-羟基苯甲醛(4)、环(S-脯氨酸-R-亮氨酸)(5)、环(S-脯氨酸-S-异亮氨酸)(6)、环(S-脯氨酸-R-缬氨酸)(7)、3β,5α-二羟基-6β-乙酰基麦角甾-7,22-二烯(8)、3β,5α-二羟基-10α-甲基-6β-乙酰基麦角甾-7,22-二烯(9)、3β,5α,9α-三羟基-(22 E,24R)-麦角甾-7,22-二烯-6-酮(10)、3β,5α-二羟基(22 E,24R)-麦角甾-7,22-二烯-6-酮(11)、(22 E,24R)-ergosta-7,9(11),22-三烯-3β,5α,6β-三醇(12)、5α,6α-epoxy-24(R)-methylcholesta-7,22-dien-3β-ol(13)。化合物5~7抑制NO释放的IC 50值分别为59.37、41.73、58.98μmol/L。结论所有化合物均为首次从该内生真菌中分离得到,化合物5~7为抗炎活性成分。

Toxicological Study of the Hydroalcoholic Extract of a Recipe of Three Plants Used in Traditional Togolese Medicine

This work consisted of assessing the toxicity of a recipe of three plants used in traditional Togolese medicine. Acute and sub-acute toxicity was assessed according to OECD chemical test guidelines n˚423 dated December 17, 2001 and n˚407 dated October 3, 2008 respectively. Cytotoxicity was assessed using the 3-(4,5-dimethylthiazolyl-2-yl-2,5-diphenyltetrazolium bromide (MTT) test. No significant toxicity was observed after 14 and 28 days, although a dose-dependent decrease in creatinemia was observed in male rats (the recipe to be used to moderate creatinine levels). Cytotoxicity was without effect on NCM 365 cells. The results obtained justify the use of the recipe in traditional medicine.

Triterpenoid of avocado (Persea americana) seed and its cytotoxic activity toward breast MCF-7 and liver HepG2 cancer cells

Objective:To determine the structure of triterpenoid isolated from avocado seeds and the cytotoxic effect on MCF-7 and Hep G2 cells.Methods:The powder sample was macerated with ethanol,followed with separation of the extract by column chromatography.The target compound was monitored on thin layer chromatography plate and reagent Lieberman–Buchard.The isolated compound was characterized by spectral analysis,mainly ultraviolet,infrared,and liquid chromatographymass spectroscopy and their spectroscopic data with those reported in literature were compared.In vitro cytotoxic activity was investigated against Vero,MCF-7,and Hep G2 cell lines using MTT assay.Results:A triterpenoid compound was isolated from ethanol extract.The extracts,fraction(F3),and the isolated compound showed a significant cytotoxic activity against all investigated cell lines.MTT assay showed that the triterpenoid isolate inhibited cell proliferation of MCF-7 and Hep G2 cell line with the IC50 values of 62 mg/m L and 12 mg/m L,respectively,and was safe to normal cells.Conclusions:The results of the present study reveal that triterpenoid from avocado seeds have the potential for further development as anticancer agents.

Impact of Oriental Fruit Fly Postharvest Treatments on Avocado

The detection in August 2015 of the Oriental Fruit Fly (Bactrocera dorsalis Hendel, Diptera: Tephritidae) in the Redland area in Miami-Dade County, Florida triggered a quarantine that restricted the movement of fruit fly host material in an approximately 99-square mile (256-square kilometer) area. The quarantine affected 4000 acres of fruit bearing commercial avocado groves. Approved post-harvest treatments for B. dorsalis and avocado included in the USDA Treatment Manual were acceptable for immediate certification and movement of fresh avocados from the quarantine area. However, it was unknown if Florida avocados would meet quality standards (US combination grade) after the treatments. Three post-harvest treatments that combine methyl bromide fumigation and cold storage periods were tested on six avocado varieties from Florida. The treatments differed in the durations of the fumigation and cold treatment periods. A seven day transit period at 8.3°C (47°F) was added to account for the time when the fruit leaves the packing house until it is sold by retailers. None of the six varieties had met the US combination grade after the treatments and transit period. Treated fruit exhibited both internal (pulp) and external (skin) damage. Damage was attributed to the fumigation component of the treatment, but the six varieties tolerated the cold portion of the treatment. Damage by fumigation ranged from 26% - 100%. In general, the longer the fumigation period the worse the effect. The need for alternative post-harvest treatments for Florida avocados is discussed.

Persea americana attenuates inflammatory response associated with hyperlipidemia in ovariectomized and irradiated rats by regulating MMP-3/TIMP-1 levels

Objective:To explore the effect of Persea americana supplementation on inflammation,oxidative stress,and lipid profiles in ovariectomized rats fed with a high-fat diet and exposed to radiation.Methods:The control group was sham operated,while groups 2-5 were ovariectomized and fed a high-fat diet.Groups 4 and 5 were exposed toγ-radiation(1 Gy/week for 5 weeks)after ovariectomy.Groups 3 and 5 were treated with 1 mL/250 g/day of Persea americana for one month.Serum levels of estrogen,alanine aminotransferase,aspartate aminotransferase,cholesterol,triglycerides and lipoproteins were measured.Additionally,hepatic oxidative stress,inflammatory and fibrogenic markers were evaluated.Results:Persea americana treatment reduced the oxidative stress markers as well as the levels of triglyceride,total cholesterol,and low-density lipoprotein cholesterol,which in turn lowered hepatic fat accumulation.Moreover,it suppressed hepatic inflammatory mediators(interleukin-6,tumor necrosis factor-α,and C-reactive protein)and downregulated pro-fibrogenic markers(transforming growth factor-βand tissue inhibitor of metalloproteinase-1).Conclusions:Persea americana provides protection against ovariectomy,and gamma radiation-mediated hepatic inflammation not only through its antioxidant,anti-inflammatory,lipid-lowering effect but also by modulating the fibrogenic markers.

Avocado and Cardiovascular Health

Avocado is a fruit which had a caloric density of 1.7 kcal per gram and a half unit (~70 g) is composed by 114 kcal, 4.6 g of fibers, 345 mg of potassium, 19.5 mg of magnesium, 1.3 mg of vitamin E and 57 mg of phytosterols. Approximately 75% of fiber’s avocado contents are considered insoluble and 25% are soluble. The avocado contains lipids that consist of 71% from monounsaturated fatty acids (MUFA), 13% from polyunsaturated (PUFA) and 16% from saturated fatty acids (SFA). Recent researches have shown that avocado may improve hypercholesterolemia and may be useful in the treatment of hypertension and type 2 diabetes mellitus (T2DM). This way, avocado plays an important role in the cardiovascular health. This review summarizes the potential benefits of avocado consumption in the prevention of cardiovascular risk factors and metabolic diseases.

Genetic diversity of <i>Persea bombycina</i>from goalpara district of Assam, India

Assam of the northeastern region of India is unique in terms of its rich biodiversity and multiple ethnicity of its people. The impact of the resultant socio-religio-cultural diversity is also reflected in the diverse traditional ways of silkworm farming. We report the genetic diversity of Persea bombycina “Som” from different locations of Goalpara district of Assam, India, where random amplified polymorphic DNA (RAPD) marker was used in this study. RAPD analyses of ten genotypes of “Som” from Goalpara district of Assam, India with B19 RAPD primer generated 86 bands, showing an average of 8.6 bands per sample and 30.2% (26 bands) of these were polymorphic. The number of bands per accession ranged from 5 to 10 with a mean of 8.6 and the size range of the amplified bands was 250 - 6000 bp. In a UPGMA phenetic dendrogram based on Jaccard’s coefficient, the P. bombycina accessions showed a high level of genetic variation, as indicated by genetic similarity and revealed 10 “Som” genotypes in to three major clusters. This study may be useful in identifying diverse genetic stocks of P. bombycina, which may then be conserved on a priority basis. The RAPD primer used in this study was able to distinguish all the 10 genotypes of “Som” plants, which can be used to assess genetic diversity.

Antidiabetic potential of methanol extracts from leaves of Piper umbellatum L. and Persea americana Mill.

Objective: To determine inhibitory activity of methanolic leaf extract of Piper umbellatum and Persea americana(P. americana)(traditionally used in Cameroon against diabetes) on β-glucosidase, β-glucosidase, maltase-glucoamylase, aldose reductase and aldehyde reductase activities, enzymes involved in starch digestion or diabetic complications. Methods: The methanol extracts from Piper umbellatum and P. americana were prepared by maceration. To assess relative efficacy of these extracts, the determination of concentrations that were needed to inhibit 50% of enzyme activity was done, whereas, gas chromatography-mass spectrum was used to identify components from extracts that may be responsible for the activities. Results:The tested extracts strongly inhibited β-glucosidase, maltase-glucoamylase, aldose reductase and aldehyde reductase activities with IC50 ranging from(1.07 ± 0.03) to(31.77 ± 1.17) μg/mL.Among the tested extracts, P. americana was the most active against sensitive enzymes(IC50 of1.07 ± 0.03 to 15.63 ± 1.23). But, none of the extracts showed interesting inhibitory effect against β-glucosidase as their percentage inhibitions were less than 16%. From gas chromatographymass spectrum analysis, 10 and 8 compounds were identified in Piper umbellatum and P.americana extracts respectively, using NIST library 2014. Conclusions: Results of this study provide the scientific credential for a prospective usage of these plants to treat diabetes.

Genetic Transformation Studies on Avocado Cultivar “Hass” (Persea americana)

The use of traditional breeding for improvement of avocado cultivars is time consuming, hence other methods such as genetic transformation by Agrobacterium is indispensable to adopt. The strain GV3850/pBI121gave best transformation outcome compared to five other binary vectors (AGL1/pCGP904;AGL1/pBI121;GV3850/pCGP904;LBA4404/pCG-P904 and LBA4404/pBI121) under different pH and acetosyringone concentrations. The optimal condition for reliable transformation was by using 200 μM acetosyringone and a pH of 5.2. Transformed embryonic shoots co-cultivated with GV3850/pBI121 were tested using the histochemical x-gluc assay. Further analysis was conducted by polymerase chain reaction using specific primers for the reporter gene (GUS).

Analysis of Sesquiterpene Distributions in the Leaves, Branches, and Trunks of Avocado (<i>Persea americana</i>Mill.)

Avocado is a commercially valuable fruit crop cultivated in tropical and subtropical climates throughout the world. Taxonomists recognize three horticultural races of avocado, consisting of Mexican (Persea americana var. drymifolia), Guatemalan (P. americana var. guatemalensis), and West Indian (P. americana var. americana) varieties. Published research that attempted to differentiate among the horticultural races by using leaf chemistry found that sesquiterpene content was only useful for discrimination of pure Mexican from Guatemalan and West Indian, but not to distinguish between Guatemalan and West Indian races. This study presents a sampling method for analysis of sesquiterpenes from avocado leaf, branch and trunk samples. Our results indicate that sesquiterpene content from leaves and small diameter branches (2.5 cm) was highly variable;however, sesquiterpenes were much less variable within wood from larger diameter branches and trunk samples, providing information representative of avocado varietal differences. In addition to chemotaxonomic applications, information on sesquiterpene content of avocado wood is needed for identification of host-based attractants for a new avocado pest, the redbay ambrosia beetle (Xyleborus glabratus). This insect vectors a fungal pathogen that causes laurel wilt, a lethal vascular disease that currently threatens avocado production in south Florida, USA. Females of X. glabratus identify appropriate host trees based on emissions of terpenoids, particularly α-copaene. Our results are discussed in terms of how proximo-distal distributions of sesquiterpenes may function as host-location cues by this invasive wood-boring pest.

Development of a Technical Itinerary for the Production of Avocado (Persea américana Mill.) Seedlings with Biofertilizers

The cultivation of fruit trees generally requires a nursery phase during which the young seedlings are monitored and treated to improve their ability to adapt to the environment. This leads to the production of seedlings that are used to create orchards. It consists of four essential steps or operations: 1) The germination phase of the seeds in germinators for the production of rootstocks;2) Transplanting into pots or bags;3) Fertilisation in order to obtain seedlings of a satisfactory vigour (stem diameter) ready for grafting. The nursery phase requires a good understanding and mastery of plant regeneration and fertilisation techniques. In Cameroon, the demand for avocado (Persea americana) fruits is increasing, but the supply is not keeping up with this demand. After a summary monograph on the production practices of avocado seedlings in the Yaounde area, this work aims to optimise the aforementioned three steps in order to obtain seedlings of sufficient sizes for grafting. Three factors are considered in this study: 1) The substrate (Substrate), whose effects are evaluated by the germination rate (GR), the daily average germination (DAG) and the root volume of seedlings (RootV). 2) The transplanting date (TransD), determined by considering three dates including 40 (Trans40), 65 (Trans65) and 75 (Trans75) days after sowing, and 3) Fertilisation using biological fertilisers, evaluated by testing four fertilisation levels, Fert1 (10 gr of 20-10-10 plus 10 gr fowl droppings), Fert2 (Acaulospora tuberculata), Fert3 (Gigaspora margarita) and Fert4 (Mixed mycorrhizal strains of Gigaspora margarita and Acaulospora tuberculata). This third factor is evaluated by growth parameters including leaf area (LeafA), chlorophyll index (ChlorInd), gain in Plant height (GainPltH) and plant diameter (GainPltD). The trial took place in the First Seed company, a seed production unit located in the Simbock district of Yaounde for the field phase, and the Biological Control Laboratory of the Institute of Agricultural Research for Development (IRAD), Nlolbisson, Yaounde. Two trials were conducted, the first with the objective of determining the best substrate with a completely randomized block design in 2 replications, three substrates/replication. The second trial was done with a factorial design (Split plot) with three replicates, the main factor being the Transplanting Date (TransD) and the second factor the biological fertilizer. Data were separated using least significant difference at 5% treshhold. Results indicate a highly significant effect of substrate on RootV (p = 5.00E-03). This effect translated by an increase of 49.42% and 19.53% of root volume on sawdust respectively to sand and soil. Sawdust (100%) and soil (98%) affect germination by 8 days reduction over sand and the germination rate on these two substrates is higher than the one on sand (92%). The early transplanting (TransD40) allows a better growth of the seedlings in terms of stem length and the collar diameter. The only observation variable that stands out for the early nursery stage fertilisation is leaf area, which shows significant differences between the 4 fertilisation formulae tested. The chlorophyll index and leaf area are also strongly correlated with the seedling growth parameters. Our results show that the early transplanting stage (40 days after planting) combined with a germination on white sawdust should be proposed to reduce the production cycle of grafted seedlings in association with early application of biofertilisers or organic fertilizer.

Hydro-Ethanol Extract of Persea americana Fruit Pulp Ameliorates Dyslipidaemia and Cardiotoxicity Exerted by Alloxan-Induced Diabetes Mellitus

Diabetes-induced dyslipidaemia has been associated with an increased risk of atherosclerosis and coronary heart diseases. Persea americana fruit has been reported to possess anti-diabetic properties. Therefore, this study assessed the lipid profile and likely cardio-protective effects of hydroethanolic extracts of P. americana fruits in alloxan-induced diabetic Wistar rats. Thirty-five male rats (150 ± 30 g) were divided into 5 groups (n = 7) and treated orally as follows;groups I-II were normal animals treated with distilled water (0.3 ml/day) and P. americana (300 mg/kg) only respectively. Animals in groups III-V were made diabetic using alloxan monohydrate (100 mg/kg i.p.) and treated orally with distilled water (0.3 ml/day), P. americana (300 mg/kg) and glibenclamide (5 mg/kg) respectively for 21 days. Fasting blood glucose level was monitored prior to, after induction of diabetes mellitus, and on day 21 post-treatment, respectively. Thereafter, retro-orbital blood samples were collected after anaesthesia and analysed for insulin, total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL), high density lipoprotein (HDL) levels, apolipoproteins A1 and B, superoxide dismutase (SOD) and catalase activities, reduced glutathione (GSH), Vitamin C and malondialdehyde levels, respectively. VLDL, atherogenic index (AI) and ApoB/A1 ratio were estimated mathematically. Pancreatic and cardiac structures were also investigated using Haematoxylin and Eosin stains. Treatment with P. ameriacana extracts reduced (p P. americana treated diabetic group. The hydro-ethanol fruit extract of Persea americana attenuates diabetes induced dyslipidaemia and reduces the susceptibility to cardiac impairment in experimental diabetes mellitus.

Effect of Avocado （Persea Americana）, Cabbage （Brassica Oleracea） and Ginger （Zingiber Officinale） on Rat Liver and Thyroid Injuries Induced by CCI4 （Carbon Tetrachloride）

Avocado, Cabbage, and Ginger are a part of a regular human diet and have antioxidant, and antitumor effects. The effect of AVOE （avocado）, GE （Ginger） and CE （Cabbage） extracts separately on liver NO （nitric oxide）, MDA （malondialdehyde）, as well as serum AST （aspartate aminotransferase）, ALT （alanine aminotransferase）, total bilirubin, TC （total cholesterol）, T.G （triglyceride）, HDL cholesterol （high-density lipoprotein）, LDL cholesterol （low-density lipoprotein）, TSH （thyroid-stimulating hormone）, T3 （Triiodothyronine）, T4 （Thyroxine） in rats treated and untreated with CC14 （carbon tetrachloride） was studied. The levels of NO, MDA, as well as serum AST, ALT, total bilirubin, TC, T.G, LDL, and TSH, showed an elevation while, HDL, T3 and T4 showed the decline in rats treated with CC14 as compared to control. Treatment of rats with AVOE and GE pre, during, and post CC14 administration improve NO, MDA, as well as serum AST, ALT, total bilirubin, TC, T.G, HDL, LDL, TSH, T3, T4 as compared to CC14. Treatment of rats with CE pre, during, and post CC14 administration did not improve in the thyroid hormones and lipid profile levels as compared to CC14. These findings suggest that avocado and ginger treatment exerts a protective effect on metabolic disorders by decreasing oxidative stress.

Hepato-Preventive Effects of Hydroethanolic Leaves Extract of <i>Persea</i>Americana, Mill (Lauraceae) “Avocado” against Antouka Super^®Induced Damage in Male Japanese Quail (<i>Coturnix coturnix</i>Japonica)

The present study was undertaken to evaluate the protective effects of Hydroethanolic leaves extract of Persea americana (HEPA) against Antouka Super®(AS) induced hepatotoxicity in male Japanese quail. In total, 40 immature male Japanese quails aged 28 days were used and divided equally into 5 groups. The groups were designed as the control group (received only a 10 ml/kg of distilled water) and the AS group (75 mg/kg b.w). Other three groups received AS (75 mg of AS/kg b.w) plus HEPA (50, 100, and 200 mg/kg b.w/day respectively) by the oral route. After 60 days of the experiment, the crushed liver was performed to obtain homogenate. The protective effects of HEPA on the biochemical parameters, oxidative stress biomarkers and histology changes in the liver were evaluated. The results indicated that AS treatment caused significant alterations in the clinical signs and behavior. It induces the increase in the content of Urea, Creatinine, Protein, AST and ALT in liver tissues and serum. The activities of enzymatic oxidative stress markers such as Superoxide Dismutase (SOD);Catalase (CAT) and Total Peroxidase (POD) also showed significant perturbations in AS-treated quails. Histopathological examination of the liver of AS-treated quails revealed liver lesions characterized by moderate to severe degenerative changes showing a number of hepatocytes undergo fatty changes, focal aggregation of the lymphocytes, multiple necrotic changes and inflammatory infiltrate. The administration of HEPA however, markedly ameliorated the toxicity of AS by protecting the levels of aforesaid biomarkers to near normal levels. These results suggested that HEPA due to its phytochemical constituents with antioxidant properties possesses significant effects against AS-induced toxicity. However, these effects were more pronounced at a dose of 200 mg/kg bw.

基于荧光SSR标记的鳄梨种质资源遗传多样性

本试验对滇缅地区鳄梨种质资源遗传多样性进行了研究,为鳄梨种质资源保存、评价与利用提供了参考。本研究对采自中国云南德宏、保山、西双版纳、普洱、红河、缅甸克钦邦和掸邦地区共90份鳄梨资源利用毛细管电泳法进行荧光SSR-PCR产物检测,并利用所得结果评价鳄梨遗传多样性水平。7对SSR引物对90份鳄梨资源进行扩增,得到72个等位基因,不同引物扩增的等位基因差异较大,从5到14个不等,平均每个位点含10.29个等位基因。主要等位基因频率在0.238 9~0.811 1之间,平均值为0.434 9;观测杂合度在0.022 2~0.766 7之间,平均值为0.431 7;期望杂合度在0.314 1~0.877 0之间,平均值为0.692 7;多态性信息指数在0.273 2~0.859 9之间,平均值为0.653 5。UPMGA聚类分析表明,遗传相似系数介于0.1~1.0之间,平均值为0.46,在阈值0.41处可分为4大类群。本研究为新品种选育促进产业健康发展和开发利用该地区独特鳄梨资源提供帮助。

油梨蒂腐病菌对油梨果实活性氧代谢的影响

活性氧(reactive oxygen species,ROS)在植物病害发育中扮演重要角色,揭示油梨蒂腐病发病过程中ROS代谢变化规律对于深入了解致病机制和抗病育种具有重要作用。本研究探究了L.theobromae侵染油梨果实期间ROS产生和消除系统的变化特征。研究发现,病原菌L.theobromae在侵染早期诱导了ROS的产生并激活寄主油梨ROS消除系统。随着病情的发展,油梨的抗氧化能力不断削弱,致使ROS积累,促使丙二醛的产生。另外,病原菌L.theobromae的侵染在接种后2~5 d降低了油梨果实中SOD和CAT酶的活性以及AsA和GSH的含量。这些研究发现表明病原菌L.theobromae的侵染引起的病情发展可能归因于ROS消除能力的减弱以及ROS的合成,积累的ROS引起了细胞膜脂的过氧化,破坏了细胞膜的结构,从而导致抗病能力的丧失。反过来,这些ROS也会促进病害的发展。在本研究中,对L.theobromae侵染引发的ROS代谢变化以及其与病情发展的关系进行分析,为后续抗病育种提供一定的理论参考。

基于3S技术贵州省油梨种植区规划

本研究基于3S技术,全面、系统、精细地规划了贵州油梨种植区范围及面积,旨在为国内油梨产业健康、有序发展提供科学依据。本研究采用1995年至2014年贵州省主要气象站点的气象资料及海拔图、坡度图和土地利用图,结合油梨的生物学特性及其对气候环境的要求,分析影响贵州油梨发展的关键时期和关键因子,建立经度、纬度、海拔、坡度等地理因子与关键因子关系模型,从而确定贵州油梨的最适种植地域及面积。贵州油梨种植适宜区总面积为1.090 244×105 hm2,共分布在贵州赤水市、习水县、兴义市、望谟县、黎平县、镇宁县、关岭县、安龙县、罗甸县、晴隆县、普安县、兴仁县、贞丰县、荔波县、紫云县、平塘县、册亨县共17个市(县)。将油梨种植适宜区分为两种类型:优势区和一般区,其中种植优势区的面积为9.560 127×104 hm2,占87.69%,总体分布在南盘江流域、北盘江流域及红水河流域范围内;一般种植区的面积为1.342 313×104 hm2,占12.31%,分布在赤水河流域、都柳江流域、漳江流域。将3S技术应用到农业布局区划中,可准确、高效的指导农作物的未来发展区域。本研究成果可为贵州油梨产业种植结构调整和发展布局提供科学依据。

两个油梨品种转录组SSR特征比较分析及其分子标记开发

本研究通过对‘哈斯’(Hass)与‘福尔特’(Fuerte) 2个油梨品种转录组中SSR位点特征进行比较分析,设计引物并验证其多态性,为油梨开发新的SSR分子标记提供数据基础。利用MISA软件分别从油梨品种‘Hass’和‘Fuerte’的转录组数据中发现SSR序列6 449个和6 312个。统计结果显示,二核苷酸重复类型数量最多,占‘Hass’和‘Fuerte’SSR总数的48.44%和48.32%,AG/CT为出现频率最高的核苷酸重复基元,在‘Hass’中共2 477个(38.41%),在‘Fuerte’中共2 478个(39.26%);各核苷酸重复类型在5次重复中出现的次数最多,‘Hass’品种中为1 539次,占比为23.86%,在‘Fuerte’中为1 543次(24.45%);两个品种最优势的10个微卫星类型相同;‘Hass’品种特有重复基元26种,‘Fuerte’品种特有重复基元32种。用Primer 3.0软件为‘Hass’、‘Fuerte’油梨转录组SSR序列成功设计出13 686、13 398对引物。随机选择25对引物对8份油梨种质资源进行多态性检测,分别得到11和10对多态性引物,多态性比率分别为44%和40%。本研究结果表明,两个油梨品种微卫星分布特征基本一致,油梨转录组可作为开发SSR分子标记的有效来源,得到的大量SSR标记可为油梨的遗传多样性分析、亲缘关系鉴定及分子标记育种提供理论依据。

Occurrence of Persea Mill. from the Siwalik Forest of Darjeeling, Eastern Himalaya： Paleoclimatic and Paleogeographic Implications

Fossil leaf remains of two new species of Persea Mill., belonging to the family Lauraceae collected from the lower part of the Siwalik sediments（Gish Clay Formation of Sevok Group, Middle Miocene） of Darjeeling foothills of eastern Himalaya, are described. The new species are Persea miogamblei sp. nov. and Persea neovillosa sp. nov.. On the basis of leaf architecture（size, shape and venation pattern） fossil leaves described in this article closely resemble modern leaves of Persea gamblei（King ex Hook. f.） Kosterm. and Persea villosa（Roxb.） Kosterm.. The geographic distribution of the fossils and their modern counterparts are discussed and on that basis tropical evergreen vegetation with a warm and humid climate at the time of deposition of the Siwalik sediments is suggested in contrast to the present day tropical deciduous vegetation in this area. The present finding also suggests probable migration of these lauraceous taxa to Southeast Asia.

Bird-plant interactions and vulnerability to biological invasions

Aims Species interactions regulate the invasiveness of non-native species and as declines of native tree species escalate,exotic tree species that offer supplementary resources to animal seed-dispersers should expand their distributions as they fill ecological roles.Our primary objective was to forecast impacts from an imminent biological invasion(laurel wilt disease)by quantifying resources provided by native(threatened)and exotic fruits(disease-resistant)and associated bird foraging preferences.Methods In the southeastern USA,we tested for redundancy among the resources provided by native and exotic fruits to overwintering birds.Comparisons between abundant subcanopy species Persea borbonia(native)and Cinnamomum camphora(exotic)were paramount considering the widespread disease-induced decline of P.borbonia,and the biological and phylogenetic similarities between these species.Across two winter survey periods,we quantified fruit removal and documented bird species using motion-activated cameras in the field.Physical and chemical fruit characteristics were also quantified.Important Findings Foraging bouts on both P.borbonia and C.camphora fruits were documented for four native bird species.There was no difference in selectivity between fruit types during Year 1 of our survey,but there was a significant preference for C.camphora fruit in Year 2;the change in preference was correlated with significantly lower temperatures in Year 2.While the pulp/seed ratio and moisture content differed,the nutritional content of fruit pulp(g/100 g)was similar between fruit types.Given the apparent redundancy among these native and exotic fruit resources,we forecast increases in the consumption and dispersal of exotic propagules following the widespread laurel wilt disease-induced decline of P.borbonia and other native fruit bearing members of Lauraceae.This empirically based prediction is among the first to document exotic forest pathogens as indirect threats to native bird-plant interactions and potential facilitators of exotic plant invasion.