柠檬皮中香精油溶剂浸提工艺优化

为了研究柠檬(Citrus limonum)皮中香精油提取的工艺条件,采用L16(45)正交试验考察了不同反应条件对柠檬皮中香精油出油率的影响.结果表明,当柠檬皮用量为15 g、石油醚用量为400 mL、提取时间为20 min、提取温度为60℃时,柠檬皮中香精油的出油率达到最高值,为1.92％,各因素对香精油出油率的影响为提取温度＞柠檬皮用量＞提取时间＞石油醚用量.     

陇川柠檬优质高产栽培技术

介绍陇川县柠檬引种、推广种植现状,根据多年柠檬种植的生产经验,总结出柠檬优质高产栽培技术。     

Effects of high-humidity storage on quality,decay and storage life of cherry,lemon and peach fruits

Sweet cherries (Prunus avium (L.) ‘Lambert’ and ‘Blackboy’), lemons (Citrus limon (L.) Burm. f. ‘Lisbon’) and peaches (Prunus persica (L.) Batsch, ‘Summerset’) were stored at 77–83, 90–94 and 95–99% RH (high humidity) at near-optimal storage temperatures after harvest and treatment with fungicides. High-humidity storage did not increase the storage life of peaches held at 0°C, but the life expectancy of cherries (both cultivars) was extended by 7–10 days at 0°C, and of lemons by at least 4 weeks at 10°C when fruit were stored at 95–99% RH compared with levels below 95%. The beneficial effects of high humidity were attributed to retardation of peel desiccation and associated reductions in fruit deformation, peel de-greening, chilling-injury and decay in lemons and to the maintenance of a fresher stalk and a firmer, less shrivelled fruit in cherries. High humidity had no effect on decay in cherries or peaches, but it significantly reduced weight loss and delayed the appearance of shrivel in peaches stored at 0°C. However, after storage at high humidity for 4 weeks, peaches ripened with low rates of C₂H₄ evolution and showed severe low-temperature injury, slight peeling-injury and a poor flavour ex-store.     

Functional Characterization of Citrus Polygalacturonase-inhibiting Protein

A cDNA encoding a polygalacturonase-inhibiting protein gene (SaiPGIPA) was identified from the citrus cultivar Sainumphung (Citrus sp.), one of the most popular cultivars in northern Thailand. SaiPGIPA was expressed in Escherichia coli cells, and the functional properties of citrus PGIP were analyzed. The PGIP fusion protein inhibited by a maximum of about 60% of the endopolygalacturonase activity, and a mixture of the PGIP and fungal endopoly-galacturonase released oligogalacturonides from polygalacturonic acid. The mixture containing the oligogalactur-onides, endopolygalacturonase and PGIP induced expression of the PGIP gene and a chalcone synthase gene in citrus leaves. The mixture also induced resistance in cucumber leaves against Colletotrichum lagenarium. Received 5 September 2001/ Accepted in revised form 20 November 2001     

柠檬种质资源表型性状遗传多样性分析

采用单因素方差分析、相关性分析、主成分分析和聚类分析等统计学方法对13份柠檬种质资源的26个表型性状的多样性进行分析。结果表明：1)26个表型性状变异系数为9.77%～105.44%之间,表现出广泛的变异性;2)表型性状间呈极显著和显著相关性的分别有184对和36对,各性状间存在复杂的相互关系;3)单果重、果实横径、果实纵径等16个性状含有丰富的遗传信息,可作为柠檬优先鉴定内容和重要的评价指标;4)通过聚类分析分为3个组群,其中第1组群可作为选育高品质柠檬品种的亲本,第3组群可作为选育特大果型柠檬品种的亲本。     

广州市沙田柠檬炭疽病病原菌种类的分子鉴定

【目的】明确沙田柠檬炭疽病的病原菌种类,为沙田柠檬炭疽病的田间防治提供指导。【方法】对采集的炭疽病样本进行分离纯化培养,获得 ST2-1、ST2-2、ST2-3、ST3-1、ST3-2、ST3-3、ST4-1、ST4-2和 ST4-3 等 9 株沙田柠檬炭疽病病原菌。分别采用针刺和喷洒接种的方法测定上述菌株的致病性,并分别克隆其核糖体内转录间隔区（ITS）、β 微管蛋白（TUB2）、钙调蛋白（CAL）、肌动蛋白（ACT）、核糖体大亚基（LSU）、甘油醛 -3- 磷酸脱氢酶（GAPDH）和几丁质合成酶 1（CHS1）基因部分片段进行多基因联合鉴定。【结果】ST2-1、ST2-2、ST2-3、ST3-1、ST3-2、ST3-3、ST4-1、ST4-2 和 ST4-3 均 具 有 较 强 致 病 性, 其 中 ST2-1、ST2-2 和 ST2-3 的生物学特征和进化树表明它们属于暹罗刺盘孢菌（Colletotrichum siamense）,ST3-1、ST3-2和 ST3-3 属于兰花刺盘孢菌（Colletotrichum cliviicola）,ST4-1、ST4-2 和 ST4-3 属于果生刺盘孢菌（Colletotrichum fructicola）。【结论】综合形态学特征和分子生物学鉴定结果,引起沙田柠檬炭疽病的病原菌有暹罗刺盘孢菌、兰花刺盘孢菌和果生刺盘孢菌,其中暹罗刺盘孢菌仅分离自沙田柠檬发病的果实,兰花刺盘孢菌和果生刺盘孢菌分离自沙田柠檬发病的叶片,其中兰花刺盘孢菌能在柑橘类植物上引起炭疽病为国际上首次报道。     

冷诱导基因转化柠檬的研究

将包含载体p Ptcor∷8Ptcor8∷YFP的农杆菌EHA105转入到不抗寒的柠檬中,并对转化体系进行了优化。研究结果表明,再生培养基中的6-BA的浓度,卡那霉素(Kan)浓度以及除草剂(Basta)的浓度对柠檬的转化效率有明显影响;再生培养基配方为MT+0.5 mg/L 6-BA,添加75 mg/L kan或10 mg/L Basta时能够有效筛选到抗性芽,并获得了3株转基因柠檬植株,YFP阳性率为3.6%。     

抹梢与修剪对柠檬春花秋熟果调控的影响

对柠檬春花期新梢进行抹除(抹梢);修剪柠檬花期过密花枝,同时抹除抽发的新梢(抹梢+修剪),统计分析有叶枝梢花量、无叶枝梢花量、有叶果量、无叶果量、枝梢叶片数量、单株产量。旨在研究抹梢和修剪处理对柠檬春花秋熟果花果调控的影响,为提高柠檬产量及柠檬的花期调控理论提供科学依据。结果表明:不同处理间柠檬带叶枝梢花量和无叶枝梢花量的差异均不显著;不同处理对柠檬有叶果量和无叶果量影响较大。生理落果完成后,不同处理间有叶果量和无叶果量差异显著,均为修剪+抹梢处理最多,抹梢处理次之,对照最少;不同处理对枝梢叶片数量的影响较小,差异不显著;不同处理间柠檬单株产量差异均达到显著或极显著水平。同一年度不同处理单株产量大小依次为:修剪+抹梢抹梢对照,2010、2011年抹梢处理分别比对照增加45.0%、33.8%,修剪+抹梢分别比对照增加86.2%、71.9%。综合考虑,柠檬春花果修剪+抹梢调控效果最好。