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.

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.

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.

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.

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.

油梨根际土壤微生物群落及其共生网络对根腐病的响应

【目的】为研发根腐病绿色综合防控技术提供理论依据,有效推进油梨树种产业发展。【方法】本研究以百色市林业科学研究所的健康和根腐病发病油梨植株根际土壤为研究对象,并利用基于16S核糖体RNA(rRNA)和内部转录间隔区(ITS)扩增子高通量测序技术,分析健康和染病植株根际细菌和真菌群落结构、组成及多样性差异,比较细菌和真菌群落结构及其相互作用,确定土壤病原菌和有益菌的变化。【结果】染病植株相对于健康植株,根际细菌和真菌群落结构和多样性均没有显著性变化。变形菌门Proteobacteria、酸杆菌门acidobacteria、放线菌门actinobacteria、拟杆菌门bacteroidetes和绿弯菌门chloroflexi是油梨根际土壤优势细菌类群,子囊菌门ascomycota和担子菌门basidiomycota是油梨根际土壤优势真菌类群。在门分类水平、纲分类水平以及属分类水平上,细菌和真菌群落组成有明显的变化,但随着分类水平降低,群落组成变化越明显。此外,健康和染病油梨根际细菌群落α多样性显著高于真菌群落,而健康与染病之间细菌群落结构差异小于真菌。细菌物种之间的相互作用比真菌网络物种间的相互作用更紧密,并且负连接百分比和关节类群数量更多,细菌网络的稳定性更高。同样,油梨根际土壤细菌群落相对于真菌群落表现出更高的生态位宽度和生态位重叠。对根腐病有反应的细菌和真菌,如芽孢杆菌Bacillus、假单胞杆菌pseudomonas和溶杆菌lysobacter和球囊菌纲glomeromycetes,由于其在染病油梨根际土壤中的相对丰度均高于健康土壤,可以被视为相关的生物防治菌。【结论】根腐病并不会使油梨根际细菌和真菌群落结构和多样性发生显著性变化,但会使得一些有益菌的相对丰度增加,并且细菌比真菌对根腐病具有更高的抵抗力。

牛油果主要病虫害及其防治

概述世界各地牛油果的主要害虫种类(蝇类、蛾类、蚧类、螨类,半翅目和鞘翅目类)、主要病害种类(根腐病、炭疽病、疮痂病等真菌性病害以及细菌性软腐病和溃疡病)和病虫害防治现状。近年来国内牛油果种植面积快速扩张,文章提出从科学合理选园、加强检验检疫、合理选种、选择适宜防治措施等方面来预防和防治牛油果病虫害。

南宁3个油梨品种开花物候期与花粉活力分析

为进一步了解油梨(Persea americana)开花物候期特征和不同油梨品种花粉活力的差异,以‘哈斯’('Hass')、‘平克顿’('Pinkerton')和‘富尔特’('Fuerte')3个油梨品种为试验材料,观察3个品种在南宁地区的开花物候期,并采用醋酸洋红染色法和TTC法和对3个品种的花粉活力进行测定。结果表明,在南宁地区,3个油梨品种的开花物候期集中在1月中旬—3月下旬,花期为26~37天;‘富尔特’开花最早,‘平克顿’次之,‘哈斯’最晚;3个品种单花开放和闭合的时间存在差异。采用醋酸洋红染色法时,3个品种的平均花粉活力为75.70%~87.07%,均较高;‘哈斯’和‘富尔特’的平均花粉活力均显著高于‘平克顿’。采用TTC法时,3个品种的平均花粉活力为50.22%~55.33%,均较低,且差异不显著。采用两种方法测定花粉活力,‘哈斯’的平均花粉活力均较高。研究结果可为南宁地区油梨种植品种配置和杂交育种等提供参考。

牛油果果实发育过程中营养物质含量变化研究

为确定牛油果的最佳采收期,阐明牛油果生长发育过程中营养物质的累积变化规律。该文采用电感耦合等离子体发射光谱法、灼烧法、茚三酮柱后衍生离子交换色谱法、回流提取法和GC-MS联用技术,研究了‘HASS’‘V3’和‘V4’3个品种牛油果果实中粗脂肪、氨基酸、矿质元素以及灰分在6—12月间的含量变化。结果表明:(1)3个品种牛油果中油脂的主要成分均为油酸,其中‘HASS’和‘V4’果实中的粗脂肪含量在12月达到峰值,而‘V3’果实中的粗脂肪含量则在10月达到峰值,之后有所下降。(2)3个品种牛油果中均含有17种氨基酸,包括7种人体必需氨基酸、2种儿童必需氨基酸以及8种人体非必需氨基酸,其中‘HASS’和‘V3’果实中的17种氨基酸含量在11月达到峰值,而V4的则在10月达到峰值。(3)3个品种牛油果中均含有磷(P)、钾(K)、钙(Ca)、镁(Mg)、锌(Zn)、铁(Fe)、锰(Mn)、铜(Cu)、钠(Na)9种矿质元素,其中P、K、Zn、Fe、Na含量在10—12月累积至最大,其余4种矿质元素变化规律不明显。(4)灰分含量变化规律与粗脂肪相似。综上认为,3个品种牛油果的营养物质均在10月达到最佳值,可以根据需求进行采收。该研究结果为确定牛油果的最佳采收时间提供了科学依据。

海南白沙和儋州油梨叶部及果实炭疽病菌的鉴定

【目的】明确海南省白沙县和儋州市油梨种植基地的油梨叶片和果实的病原菌种类,为该病害的准确鉴定和田间防治措施的制定提供理论依据。【方法】在海南省白沙县和儋州市的油梨种植基地调查炭疽病的发生情况并采集病叶和病果,通过组织分离法和单孢分离法获得纯化分离株,并对纯化菌株进行致病性测定,结合形态学和分子生物学对所得菌株进行病原菌种类鉴定。【结果】从采自白沙县的14份病叶种分离的得到3株菌株,儋州市的10份病叶中分离获得6株分离物以及自白沙市采集的5份病果中分离出的1株真菌,经致病性测定,菌株HNBSL01、HNDZL02和HNBSF03为致病菌,且均与田间症状一致。根据3种致病菌的菌落、分生孢子和附着胞的形态特征可初步判断引起油梨叶片和果实炭疽病的病原菌均为炭疽菌属(Colletotrichum sp.);多基因(ITS-ACT-TUB2-CHS-1-GAPHD-HIS3)联合分析构建系统发育树分析结果显示,病原菌HNBSL01与暹罗炭疽菌(C.siamense)的同源性为81%、HNDZL02与果生炭疽菌(C.fructicola)的同源性为100%、HNBSF03与长直孢炭疽菌(C.gigasporum)的相似性达100%。【结论】引起海南白沙县和儋州市油梨种植基地叶片和果实炭疽病的病原菌为暹罗炭疽菌(C.siamense)、果生炭疽菌(C.fructicola)和长直孢炭疽菌(C.gigasporum),其中,C.gigasporum为国内首次报道引起油梨果实炭疽病的病原菌。

不同地区油梨种子的主要化学成分分析

为油梨品种选育及种子中化学成分在食品、医药等行业的应用提供参考,采用直接灰化法、蒽酮法和指示剂滴定法等方法检测海南(儋州、白沙)、云南(瑞丽)和广西(南宁)16份油梨种子资源的含水量、灰分、可溶性糖、可滴定酸、可溶性蛋白质、总酚和总黄酮7种化学成分,并对国内油梨资源与国外油梨品种Hass进行比对。结果表明:7种化学成分含量在大部分油梨资源间呈显著性差异(P<0.05)。含水量、灰分和总酚含量在16份油梨资源间差异较小,而可溶性糖、可滴定酸、可溶性蛋白质和总黄酮含量在16份油梨资源间差异较大。与其他15份国内油梨资源比较,Hass种子含水量[(55.76±0.15)g/100g FW]和可溶性糖含量[(0.69±0.03)g/100g FW]最低,灰分含量[(0.99±0.02)g/100g FW]最高,可滴定酸含量[(1.80±0.00)g/100g FW]较低,其他成分处于中间水平。

7个油梨品种(系)果肉的脂肪酸含量及其相关性

为油梨果肉油脂开发和品质育种奠定基础,采用索氏提取法和气质联用法对国内油梨品种(系)RN-1、RN-5、RN-11、RN-12、RN-15、RN-16和国外品种Hass等果肉的含油量和脂肪酸成分进行测定,并进行相关性与聚类分析。结果表明:7个油梨品(系)果肉含油量为5.04~8.75g/100g FW,且差异显著(P<0.05),其中RN-5的含油量最高,达8.75g/100g;果肉均含有8种脂肪酸成分,在大部分油梨品种(系)间差异显著(P<0.05),相对含量为棕榈酸(30.87%)>油酸(29.48%)>亚油酸(26.58%)>棕榈油酸(9.96%)>亚麻酸(1.30%)>硬脂酸(1.16%)>花生酸(1.02%)>肉豆蔻酸(0.23%)。不饱和脂肪酸相对含量为62.80%~70.60%,其中油酸相对含量大于30%的品种(系)3个,为RN-1、RN-15和RN-16;亚油酸相对含量大于25%的4个,为RN-1、RN-5、RN-12、RN-15和RN-16;棕榈油酸相对含量大于10%的3个,为RN-5、RN-11和Hass。亚麻酸与花生酸的相对含量呈极显著正相关,肉豆蔻酸与亚油酸呈显著正相关。基于8种脂肪酸成分相对含量聚类,RN-1、RN-5、RN-11、RN-16和Hass聚为一组,RN-12和RN-15各为一组。油梨果肉具有较高含油量和适宜的脂肪酸含量,其中RN-5在油脂开发和品质育种上具有较好的开发利用前景。

90份鳄梨种质资源AFLP遗传多样性分析

【目的】本研究对采自中国云南德宏、保山、西双版纳、普洱、红河和缅甸克钦邦、掸邦地区共90份鳄梨种资资源进行遗传多样性分析,为其新品种选育和种质创新提供参考依据。【方法】采用CTAB法提取鳄梨叶片基因组DNA,利用扩增片段长度多态性分子标记技术,对90份种质资源的基因组DNA进行酶切、连接、预扩增、选择性扩增,电泳分离,银染显色。电泳结果得到"0,1"矩阵,使用POPGENE 32软件计算每对引物的多态性条带、多态性比率、有效等位基因数、遗传多样性指数等指标,同时使用NTSYSpc-2.11F计算种质间遗传相似系数,根据相似性系数进行UPGMA聚类分析和PCA主效应分析,对鳄梨种质资源进行分类。【结果】从24对AFLP引物组合中,筛选出8对扩增条带清晰、多态性高的引物组合,8对引物共扩增出1 165个条带,其中多态性条带有1 163个,多态位点百分率为99.83%;有效等位基因数(Ne)平均1.294 4个;Nei’s基因多样性指数(H)平均0.209 5;Shannon信息指数(I)平均0.353 0。根据遗传相似系数进行聚类分析,在遗传相似系数0.752处可划分为4个类群,第Ⅰ类群有1份保山种质70号;第Ⅱ类群有24份种质;第Ⅲ类群有1份西双版纳种质59号;第Ⅳ类群有64份种质。在遗传相似系数0.763处可将第Ⅳ类群划分为3个亚群(A、B和C)。用PCA法对90份鳄梨种质AFLP标记结果进行主效应分析,显示了不同种质的分类位置,主效应分析结果与分子聚类结果基本一致,呈一定的地域性分布规律。【结论】90份种质资源的遗传多样性较为丰富,59号和70号相对特殊,在种质创新中应给予重点关注。

油梨基因组DNA提取、SSR-PCR反应体系优化及引物筛选

旨在建立稳定可靠的油梨(Persea americana Mill)叶片DNA的提取方法和SSR-PCR反应体系及筛选出稳定的油梨SSR多态性引物,为开展油梨种质SSR分子标记提供遗传研究的基础。以油梨叶片为试材,比较3种油梨叶片DNA提取方法 ;利用L16(45)正交实验设计对油梨SSR-PCR反应体系进行优化;利用优化的反应体系筛选引物;同时,选取5对多态性引物对45份油梨种质进行PCR扩增,进一步检测该优化体系的稳定性。结果表明,常规2×CTAB法、改良2×CTAB法和植物DNA提取试剂盒法等3种DNA提取方法中,改良2×CTAB法对油梨基因组DNA的提取效果最佳;获得最优反应体系为:20μL总反应体系中,含约40 ng DNA模板、1.5 mmol/L Mg^(2+)、0.15 mmol/L d NTPs、0.5 U Taq DNA聚合酶、0.5μmol/L引物;以此体系为基础进行引物筛选,从73对油梨SSR引物中筛选出了30对扩增条带清晰的多态性引物,说明该反应体系可用于油梨SSR标记的进一步研究;稳定性检测获得的谱带清晰,表明该优化反应体系是稳定可靠的。由此可见,改良的2×CTAB法可用于油梨叶片DNA的大量样本提取,优化后的SSR-PCR反应体系及筛选出的30对多态性引物可用于油梨SSR标记的进一步研究。

基于转录组测序的油梨EST-SSR引物开发

利用转录测序技术,开发油梨表达序列标签-简单重复序列(EST-SSRs),为SSR标记在油梨种质资源鉴定、品种选育及遗传连锁图谱构建奠定基础。采用Illumina二代测序的技术,共获得37 639条无冗余的序列,对其进行SSR搜索,共获得6 419条简单序列重复(SSR)。利用Primer 3.0软件设计SSR引物,并以11份油梨种质筛选多态性引物。基于转录组序列开发出的EST-SSR的分布频率为17.05%。在油梨EST-SSR中,单核苷、二核苷和三核苷的重复占主导,占总数的99.07%。单、二、三核苷酸重复单元分别占总SSR的37.47%、31.80%和29.80%;出现频率最高的二核苷酸重复基元是AG/CT,占总数的29.15%,出现最高的三核苷酸重复基元为AAG/CTT,占12.01%。随机选择315个SSR位点合成引物,经11份油梨种质筛选鉴定,227对引物可扩增获得产物,有效扩增率为72.06%;其中34对引物表现出良好多态性,占有效引物的12.78%,占总引物的10.79%。在34对多态性引物中,每对引物扩增等位基因数2～12个。利用高通量测序开发SSR引物有较好的实用性,开发获得的34个具有多态性的油梨SSR标记可用于研究油梨及其相关近缘物种的遗传变异。

鳄梨组织培养繁殖体系优化研究

为满足市场需求,以鳄梨饱满茎段为外植体采用组织培养方法进行优质种苗繁育,对于该种的产业发展和应有具有重要意义。试验筛选了无菌株体系建立、诱导潜伏芽萌发、丛生芽继代增殖和生根培养较适培养基配方。结果表明:诱导鳄梨无菌株系建立较适培养基为WPM+1.0 mg·L-16-BA+0.3 mg·L^(-1)NAA+0.5 mg·L-1ZT+2%蔗糖+0.2%活性炭+0.65%琼脂;诱导潜伏芽萌发较适培养基为WPM+2.0mg·L^(-1)6-BA+0.5mg·L^(-1)NAA+1.0 mg·L^(-1)ZT+2%蔗糖+0.2%活性炭+0.65%琼脂,诱导出芽率达到54%;丛生芽继代增殖培养较适培养基为WPM+3.0 mg·L-16-BA+0.3 mg·L^(-1)NAA+1.0 mg·L^(-1)ZT+2%蔗糖+0.2%活性炭+0.65%琼脂,增殖率达到3.70;幼苗生根较适培养基为1/2WPM+0.5 mg·L^(-1)IBA+0.5 mg·L^(-1)NAA+2%蔗糖+0.2%活性炭+0.65%琼脂,生根率达到90%。炼苗移栽60 d后成活率为96%。该试验获得的培养基配方,可培养出完整植株,短期内获得大量优质种苗。

油梨PaWRI1和PaWRI2基因的克隆、序列分析及表达研究

以‘哈斯’油梨(PerseaamericanaMill.)为试材,通过RACE及RT-PCR技术分别克隆得到2个AP2/EREBP类转录因子WRI1和WRI2基因的c DNA全长,分别命名为PaWRI1(GenBank登录号:MH367865)和PaWRI2(GenBank登录号:MH367866)。其中,PaWRI1基因全长为1 396 bp,含1 155 bp开放阅读框,编码384个氨基酸;PaWRI2基因全长为1 782 bp,含1 287 bp开放阅读框,编码428个氨基酸。PaWRI1和PaWRI2基因属于AP2/EREBP类转录因子家族,其编码氨基酸序列中分别均存在2个和1个典型的AP2/ERF DNA结合位点。实时荧光定量PCR检测结果表明:在油梨果实发育过程中,果肉中PaWRI1基因的相对表达量始终快速上升,PaWRI2基因的相对表达量先少量下降,而后缓慢上升;PaWRI1基因相对表达量变化与油脂积累的变化较一致,PaWRI2基因相对表达量变化与油脂积累的变化不一致。因此,推测在油梨果实发育过程中,果肉中PaWRI1基因可能参与调控油脂积累过程。

高效液相色谱法定性定量测定油梨果实中的可溶性糖成分

分析油梨果实可溶性糖成分及含量,为以后深入分析、利用其成分提供一定理论基础。对所采集的3份油梨,应用高效液相色谱仪测定其可溶性糖组分及含量。结果显示,3份油梨果肉中的可溶性总糖含量为(13.19±0.32)^(25.94±0.98)(mg/g FW),其可溶性糖由甘露庚酮糖、甘露庚糖醇、果糖及葡萄糖等4个成分组成,以甘露庚酮糖为主;可溶性总糖、甘露庚酮糖、甘露庚糖醇、果糖及葡萄糖含量在3份油梨果肉中差异均显著。3份油梨种子中的可溶性总糖含量为(20.47±0.52)^(29.41±0.60)(mg/g FW),其可溶性糖同样由甘露庚酮糖、甘露庚糖醇、果糖及葡萄糖等4个成分组成,以甘露庚糖醇为主;可溶性总糖、甘露庚酮糖、甘露庚糖醇、果糖及葡萄糖含量在3份油梨种子中差异均显著。3份油梨果肉和种子之间可溶性总糖和各可溶性糖成分平均含量差距大小依次为:甘露庚糖醇>果糖>甘露庚酮糖>葡萄糖>可溶性总糖。