一个柚新种质的亲缘关系鉴定

该研究以1个疑似柚新品种——‘迷你红柚’为实验材料,利用植物形态学观察、花粉电镜观察以及ISSR分子标记技术,以确定‘迷你红柚’与‘琯溪蜜柚’、‘邓肯葡萄柚’之间的关系。(1)从形态学观察可以看出:‘迷你红柚’果实的外形特征与‘邓肯葡萄柚’较相似,但与‘琯溪蜜柚’有较大的差别;而且‘迷你红柚’嫩叶的形态学特征与‘琯溪蜜柚’和‘邓肯葡萄柚’均有不同。(2)电镜观察发现:‘迷你红柚’花粉的萌发孔沟、花粉沟与‘琯溪蜜柚’和‘邓肯葡萄柚’相似,但花粉大小、外壁网眼与‘琯溪蜜柚’和‘邓肯葡萄柚’均有不同。(3)聚类分析结果表明,‘迷你红柚’和‘邓肯葡萄柚’遗传关系最近,但又有一定距离。研究认为,‘迷你红柚’不同于‘琯溪蜜柚’和‘邓肯葡萄柚’,极有可能是柚的一个新品种。     

柚类品种遗传相互关系的RAPD标记研究

利用22个经筛选在样品间具多态性的10碱基随机引物,对柚 [Citrus max ima (Burm.) Merr.] 的主要品种及柚的一个野生近缘种云南红河橙 (C. hongh eensisY. M. et al.)、一个栽培近缘种葡萄柚 (C. × paradisi Macfad) 共79个样品的总DNA进行PCR扩增.在样品间共产生164条RAPD标记带,其中多态性带134条,多态性百分率为81.71%;以NTSYS-pc (Version 1.80)软件计算样品间的Jaccard遗传相似系数,并进行UPGMA聚类分析.结果表明野生近缘种云南红河橙及栽培近缘种葡萄柚与柚三个种种内聚合良好,种间分异明显,为柚分类上的地位奠定了遗传学基础.特异性RAPD分子标记的研究为柚类品种的鉴定提供了重要指标.     

柑橘胚性愈伤组织总多酚含量影响因素的研究

研究了甲醇水溶液浓度和浸提时间、品种/基因型、培养时间对柑橘胚性愈伤组织总多酚含量的影响。结果表明,用40%的甲醇溶液在55℃水浴条件下浸提30min,柑橘胚性愈伤组织总多酚的得率最高;总多酚含量受品种/基因型的影响,在所比较的6个柑橘品种/基因型暗柳橙、椪柑、默科特橘橙、无酸甜橙、锦橙和红马叙葡萄柚中,暗柳橙胚性愈伤组织的总多酚含量最高;总多酚含量随培养时间的改变而变化,在培养40d时各品种/基因型胚性愈伤组织的总多酚含量均达到最大值。     

脱水速率和降温速率对葡萄柚种子超低温保存的影响

以新鲜葡萄柚(Citrus paradise)种子为材料,使用3种脱水速率处理至约20%含水量,然后用饱和盐溶液平衡至10种不同的含水量,再进行简化的二步法超低温保存;同时,以经过15 ℃、50%相对湿度(RH)条件脱水至含水量约12%的葡萄柚种子为材料,使用程序降温仪进行5个降温速率和3个预冷温度的传统二步法超低温保存。结果表明,葡萄柚种子对脱水敏感,种子含水量越低,成苗率越低。而且,脱水速率越快,对种子的损伤越大,成苗率呈现75% RH>50% RH>15% RH;冷冻处理对种子有进一步的伤害,含水量6%～8%的种子超低温保存效果最佳,但脱水速率对超低温保存的种子成苗率的影响不明显。用传统二步法超低温保存葡萄柚种子,与预冷对照相比,经液氮冷冻的种子成苗率都有明显下降。在预冷对照组中,-2.5 ℃·min^-1降温速率的种子成苗率最高,在冷冻保存中-0.5 ℃·min^-1和-0.25 ℃·min^-1的降温速率最有利于超低温保存。预冷温度从-40 ℃降至-60 ℃,未超低温处理种子的发芽率降低,但超低温处理种子的发芽率提高。     

葡萄柚种子无菌苗组培快繁体系的建立

以葡萄柚种子在无菌条件下萌发的幼苗作为外植体供体,子叶切断作为丛生芽初代诱导培养的接种材料,以MT作为基本培养基,通过调节不同植物生长调节剂及其浓度组合、不同质量浓度的蔗糖,选择最佳初代培养基、继代培养基和生根培养基,对葡萄柚组培快繁技术体系进行研究。结果表明:(1)葡萄柚种子经预处理后,先用75%酒精表面灭菌15 s,再用0.1%Hg Cl2浸泡20 min的消毒效果最好,污染率为18.33%,萌发率为89.91%;(2)初代培养的最适培养基为MT+1.0 mg·L-16-BA(6-苄氨基腺嘌呤)+0.2 mg·L-1IBA(吲哚丁酸)+0.2 mg·L-1GA(赤霉素)+蔗糖40 g·L-1,腋芽诱导率较高,为93.33%;(3)浓度为0.2 mg·L-1的GA能提高初代培养的腋芽诱导率,但还达不到显著水平;(4)继代培养的最适培养基为MT+0.5 mg·L-16-BA+0.2 mg·L-1IBA+0.2 mg·L-1GA+蔗糖40 g·L-1,丛生芽增殖系数达到4.25,芽深绿色,茎粗壮,节间较长,生长旺盛;(5)浓度为0.2 mg·L-1的GA能显著提高继代培养的增殖系数;(6)最适合继代培养的蔗糖浓度为40 g·L-1,丛生芽长势极好;(7)最佳生根培养基为1/2 MT+NAA 0.2 mg/L+蔗糖40 g·L-1+AC 0.1%,生根率达68.89%,根粗壮;(8)生根苗移栽30 d后成活率在75%以上。该研究建立了葡萄柚的组织培养快繁技术体系,为葡萄柚的规模化生产提供了可行的技术依据。     

风靡全球的葡萄柚

春节期间,在北京和上海等大城市的水果市场上,几乎同时推出了一种新的水果——美国葡萄柚,并赫然标明产地佛罗里达州。观其外形,与我国国产的柚子相比,并无多大差异,只是体积小许多,宛如成年男子的拳头般大小。别看其貌不扬,但其身价不菲,每公斤售价16—20元,冠盖百果之上乘,并有风糜全国之势。19世纪初叶,当葡萄柚刚被引入美国佛罗里达州种植时,这种似柚非柚、似橙非橙的小乔木并未引起人们多大的注意。佛罗里达是美国东南部伸向大西洋的一个半岛,地处北亚热带,位于北纬25°—31°之间,终年阳光普照,雨量充沛,气候温暖湿润,植物繁茂,拥有大…     

热浸处理减少长期贮藏的伏令夏橙的冷害

对于可能减少柑桔冷害危险性的诸多因素,人们已做了许多研究。如对果实年龄、果实在树冠所处的位置、生长调节剂处理、乙烯处理、果皮损伤、塑料包装以及预贮处理等研究,都表明对柑桔类果实冷害程度有影响。此外,葡萄柚采后用涕必灵(TBZ)和苯菌灵处理,也减少了冷害发生。但是,关于伏今夏橙(Citrus sinensis)长期贮藏期间如何减轻冷害强度及其方法,有价值的资料却很少。     

柑桔种质资源谷氨酸草酰乙酸转氨酶同工酶研究

本文分析了125份柑桔属、枳属、金柑属和指来檬属种质资源的谷氨酸草酰乙酸转氨酶同工 酶(GOT)。新发现了GOT-1的两个等位基因B和C。宽皮柑桔的GOT同工酶颇为一致(仅两个例 外),表明可能有共同的起源。酸橙的GOT同工酶较复杂,可能有多种起源,其中朱栾和小红橙的起 源可能与宜昌橙或香橙有关。在单胚种柚中发现了6种GOT基因组合。宜昌橙存在着两种GOT同工酶类型。本文讨论了甜橙、酸橙、葡萄柚、香橙、柠檬等种类的可能起源。     

葡萄柚中糖基转移酶对槲皮素及其类似物催化机制探讨

研究了葡萄柚中糖基转移酶(FGT)作为催化酶,以UDP-葡萄糖、UDP-N-乙酰-D-氨基葡萄糖、UDP-甘露糖为糖基供体,槲皮素、柚皮素、柚皮苷为糖基受体,研究糖基化合成情况。通过高效液相、质谱及核磁共振氢谱对产物反应进行检测。确定了槲皮素与UDP-葡萄糖、UDP-N-乙酰-D-氨基葡萄糖可以发生糖基化反应,生成的槲皮素糖苷分子量分别为464、505。根据核磁结果鉴定,所得到的产物结构分别为槲皮素-3-O-β-D葡萄糖苷、槲皮素3-O-β-D-N-乙酰-D-氨基葡萄糖苷。以FGT酶为催化酶,对槲皮素进行了糖基化修饰。     

两个菜用枸杞品种的生长特性及品质分析

对两个菜用枸杞品种的主要生长特性、营养成分及食用性研究表明,大叶品种嫩芽平均产量显著高于小叶品种;大叶品种较耐高温,小叶品种较耐低温;生产上可进行大、小叶品种搭配种植,能有效提早和延长采收期,从而提高单位面积产量和经济效益。此外,小叶品种嫩芽的蛋白质、VitC含量高于大叶品种。两个品种风味各具特色,其适宜的消费群体亦有所差异。     

Effect of artemether alone and in combination with grapefruit juice on hepatic drug-metabolising enzymes and biochemical aspects in experimental Schistosoma mansoni

Artemether is an efficacious antimalarial drug that also displays antischistosomal properties. Grapefruit juice increases the oral availability of a variety of the CYP3A4 substrates. This study was designed to evaluate the effect of repeated administration of grapefruit juice with artemether on the hepatic activities of cytochrome P-450 (CYP450) and cytochrome b5 (cyt b5), on the serum levels of some biochemical enzymes and antischistosome efficacy. Results showed that administration of grapefruit juice alone induced more inhibition in the hepatic activities of CYP450 and cyt b5 than that produced by Schistosoma mansoni infection. Moreover, it enhanced degeneration of eggs and accelerated healing of the pathological granulomatous lesions. Treatment of S. mansoni-infected mice with artemether at a total dose of 300 mg/kg resulted in total and female worm burden reductions of 66.7 and 90.1%, respectively, hence protecting the host from damage induced by schistosome eggs. Treatment of S. mansoni-infected mice with artemether at 150 mg/kg reduced the total and female worm numbers by 43.3 and 54.4%, respectively, thus somewhat ameliorating hepatic granulomatous lesions compared with the infected untreated group. This was associated with no change in the hepatic activities of CYP450 and cyt b5 and in the serum levels of total protein, albumin, globulin and alanine aminotransferase compared with the uninfected control group. Coadministration of grapefruit juice with the lower dose (150 mg/kg) of artemether eliminated eggs and granulomatous reactions. In this group, the inhibitory effects of grapefruit juice on CYP450 and cyt b5 were apparent but serum liver enzymes were unchanged compared with the uninfected control group. Coadministration of grapefruit juice with artemether achieved complete protection of the host from damage induced by schistosomal infection.     

What Do Mexican Fruit Flies Learn When They Experience Fruit?

Mexican fruit flies learn fruit characteristics that enable them to distinguish familiar fruits from novel fruits. We investigated whether mature Mexican fruit flies learn fruit color, size or odor. We found no evidence that female flies learn fruit color or size after experience with host fruit, including oviposition. However, green fruit and fruit models were more attractive than yellow and red fruit and fruit models regardless of previous experience. Females with grapefruit experience were more attracted to fruit models with extract of either grapefruit peel or pulp, than to models without extract. Females with no experience with grapefruit were not attracted to models treated with grapefruit extract. These results indicate that females learned fruit odor during exposure to grapefruit.     

Evidence for host plant preference by Iphiseiodes quadripilis (Acari: Phytoseiidae) on Citrus

In this study, we present field and laboratory evidence on the preference of Iphiseiodes quadripilis (Banks) for grapefruit (Citrus paradisi Macfadyen) leaves compared with sweet orange (Citrus sinensis (L.) Osbeck) leaves. This preference was confirmed in four orchards whether leaf samples were taken from either border trees of contiguous grapefruit or sweet orange or interior row trees with both citrus species in adjacent rows. Iphiseiodes quadripilis was most abundant in grapefruit trees in spite of the greater abundance of the Texas citrus mite, Eutetranychus banksi (McGregor) (Acari: Tetranychidae) in sweet orange trees. Similar preference responses were observed in laboratory tests using a Y-tube olfactometer whether I. quadripilis were collected from sweet orange or grapefruit. Iphiseiodes quadripilis collected from grapefruit trees showed significant preference for grapefruit over sweet orange leaves in contact choice tests using an arena of alternating leaf strips (12 mm long × 2 mm wide) of sweet orange and grapefruit. However, I.␣quadripilis collected from sweet orange trees did not show preference for either grapefruit or sweet orange leaves. Based on these results, grapefruit leaves foster some unknown factor or factors that retain I. quadripilis in greater numbers compared with sweet orange leaves.     

Identification of Xanthomonas citri ssp. citri host specificity genes in a heterologous expression host

We provide the first conclusive evidence that Xanthomonas axonopodis pv. citri Asiatic strain (Xac-A) and, in particular, Xac-A^w, a unique citrus canker A strain isolated from Key lime in Wellington, Florida, induces a hypersensitive reaction (HR) in grapefruit leaves. Using the heterologous tomato pathogen X. perforans , as a recipient of the Xac-A^w genomic library, we identified a 1599-bp open reading frame responsible for HR in grapefruit, but not Key lime, and designated it avrGf 1. Xac-A^wΔ avrGf 1 produced typical, although visibly reduced, citrus canker symptoms (i.e. raised pustules) in grapefruit and typical canker symptoms in Key lime. We also determined that the X. perforans transconjugant carrying an Xac-A^w hrpG elicited HR in grapefruit and Key lime leaves, and that xopA in X. perforans was partly responsible for HR. Xac-A transconjugants carrying the X. perforans xopA were reduced in ability to grow in grapefruit leaves relative to wild-type Xac-A. The X. perforans xopA appears to be a host-limiting factor. An avrBs3 homologue, which contained 18.5 repeats and induced HR in tomato, was designated avrTaw . This gene, when expressed in a pustule-minus Xac-A^w, did not complement pustule formation; however, pthA^w , a functional pthA homologue, complemented the mutant strain to produce typical pustules in Key lime, but markedly reduced pustules in grapefruit. Both avrBs3 homologues, when expressed in a typical Xac-A strain, resulted in typical citrus canker pustules in grapefruit, indicating that neither homologue suppressed pustule size in grapefruit. Xac-A^w contains other unidentified factors that suppress development in grapefruit.     

Amounts and variation in grapefruit juice of the main components causing grapefruit–drug interaction

A method for the determination of three furocoumarins containing two new chemicals (GF-I-1 and GF-I-4) in commercially available grapefruit juice and grapefruit itself was developed using high-performance liquid chromatography (HPLC). These components isolated from grapefruit juice have 5-geranyloxyfurocoumarin dimer structures showing extremely high affinities for a form of cytochrome P450 (CYP3A4). Considerable differences were observed on the contents among commercial brands and also batches. The contents were determined to be 321.4±95.2 ng/ml GF-I-1, 5641.2±1538.1 ng/ml GF-I-2 and 296.3±84.9 ng/ml GF-I-4 in twenty-eight white grapefruit juices. These chemicals were not detected in beverages from orange, apple, grape and tangerine, except that trace amount of GF-I-2 and GF-I-4 were found in lemon juice. The average levels of these furocoumarins were lower in the juice from red grapefruit than a white one. The highest level of these components were found in the fruit meat.     

黄猄蚁对柚子花期害虫的影响

于2008年3月柚子花期,将柚园划分为两个区域,一个区域引迁黄蚁,另一个区域不做处理作为对照。在2个区域分别选取20个枝条共40枝,对柚子花期主要害虫(柑桔花蕾蛆、蓟马)及健叶率进行调查。结果表明:对照区柑桔花蕾蛆和蓟马的虫口密度及虫花率都显著高于处理区,而且虫口数量一直保持在较高的水平;有黄蚁存在的情况下,柚子树花蕾蛆的有虫花率减少了70%～80%,蓟马有虫花率减少了近60%,健叶率增加了30%左右。建议在今后害虫综合防治中,充分认识到黄蚁对害虫的防治作用,通过保护和引迁黄蚁来有效防治害虫。     

Preparation of Acetylated Grapefruit Peel Polysaccharide

Grapefruit peel polysaccharide has antioxidant, antitumor, hypoglycemic and other biological activities, and chemical modification can further improve the properties of the polysaccharide. Acetylation modification of polysaccharides has the advantages of simple operation, low cost and little pollution, and is widely used at present. Different degrees of acetylation modification have different effects on the properties of polysaccharides, so it is necessary to optimize the preparation technology of acetylated grapefruit peel polysaccharides. In this article, acetylated grapefruit peel polysaccharide was prepared by acetic anhydride method. With the degree of acetyl substitution as the evaluation index, combined with the analysis of sugar content and protein content in the polysaccharide before and after modification, the effects of three feeding ratios of 1:0.6, 1 : 1.2 and 1 : 1.8 (polysaccharide: acetic anhydride, mass/volume) on acetylation modification were explored through single factor experiments. The results showed that the optimum ratio of material to liquid for acetylation modification of grapefruit peel polysaccharide was 1:0.6. Under these conditions, the degree of substitution of acetylated grapefruit peel polysaccharide was 0.323, the sugar content was 59.50 % and the protein content was 1.038 %. The results provide some reference for the study of acetylated grapefruit peel polysaccharide.     

Fatty acids of triglycerides from Citrus juice sacs

The fatty acid composition of trigylcerides from oranges, grapefruit, lemons and limes, was determined by GLC. Each species possessed its own intrinsic fatty acid pattern which might be used to differentiate it from the other species. The five major acids in all species were palmitic, palmitoleic, oleic, linoleic and linolenic. Collectively these acids comprised greater than 92% of the total acid content. Lemons were distinguished from all other species by their higher 16/16:1 ratios while grapefruit showed the highest total percentage of 16 and 16:1 acids. Lemons and limes contained higher percentages of branched-chain acids than oranges and grapefruit.     

Low temperature induction of invertase activity in grapefruit flavedo tissue

Invertase activity increased in the flavedo tissue of ‘Marsh’ grapefruit (Citrus paradisi Macf.) when trees were exposed to cold hardening temperatures and decreased at dehardening temperatures. Invertase activity also increased in the flavedo of detached fruit stored at 5δ. Reducing sugar levels paralleled invertase activity while sucrose levels were inversely related to invertase levels. The mechanism by which low temperatures induce invertase activity in grapefruit flavedo tissue was not determined. However, results indicated that a proteinaceous inhibitor, similar to the one found in potato tubers, is not involved in the regulation of invertase activity in flavedo tissue of grapefruit.