Fino lemon clones compared with the lemon varieties Eureka and Lisbon on two rootstocks in Murcia (Spain)

Six clonal selections of the autochthonous Spanish lemon tress cv. Fino, named Fino 46, Fino 47, Fino 48, Fino 49 and Fino 77, and two foreign varieties Eureka and Lisbon (Citrus limon (L.) Burm. f) grafted on sour orange (C. auramtium L.) and Citrus macrophylla (C. macrophylla Wester) rootstocks were studied in Murcia (Spain). The fruit were harvested for 6 years, and fruit quality and tree size were evaluated after the sixth harvest. Fino 49, Fino 77 and Lisbon trees produced the highest cumulative yield. However, Eureka trees on macrophylla had the highest yield efficiency (cumulative yield/trunk cross-sectional area (TCSA)) due to its small TCSA. There were few differences between Fino group and Lisbon as regards fruit quality; however, Eureka trees on macrophylla produced smaller fruit with a higher concentration of total soluble solids (TSS) and titratable citric acid (TA) than the other varieties. Macrophylla was a better rootstock than sour orange for lemon trees since lemon trees grafted on macrophylla had higher cumulative yield and yield efficiency than those on sour orange. However, sour orange induced the highest TSS and TA in all lemon varieties evaluated.     

柑橘果实糖积累与蔗糖代谢酶活性的研究

研究了脐橙、柠檬果实发育过程中汁胞和果皮内糖含量与糖代谢酶活性的变化。结果表明：不同柑橘品种、不同部位糖积累和相关酶活性变化不同。柑橘汁胞和果皮中还原糖含量均高于蔗糖含量。随着脐橙汁胞中糖分的积累,酸性转化酶(SAd)活性持续下降,至采收时几乎为零,说明SAd 的下降与脐橙汁胞糖分积累有很大关系。柠檬汁胞中的中性转化酶(NI)活性随着果实成熟而下降,在成熟时保持极低水平,而此时SAd 活性则较高,是其它酶活性的6倍以上,表明柠檬汁胞中糖分的利用在果实成熟前与NI活性有极大的关系,在成熟期则与高SAd 活性有关。脐橙和柠檬汁胞间糖组分的明显差异和相关酶的变化动态表明蔗糖合成酶(SS)和转化酶在柑橘汁胞糖代谢中可能起到重要作用。     

Effects of gibberellic acid and cycocel on colouring and sizing of lemon

The effects of autumn applications of GA₃ and CCC on colouring and sizing of ‘Lisbon’ lemon (Citrus limon (L.) Burm. f.) were investigated over a period of 6 years. The implications of regulating the colour and size of lemon on extending its harvest were also assessed.A combination of GA₃ at 10 p.p.m. and CCC at 1000 p.p.m. delayed colouring and arrested growth of lemons, thus extending harvest into late spring by increasing the supply of small-sized premium quality fruit. The effects on colouring could be ascribed to the inhibition of carotenogenesis and the decline in the rate of chlorophyll losses which, although primarily GA₃ effects, were enhanced by CCC. Fruit circumference was reduced and juice content was probably less in the early developmental stages.     

Isolation and expression analysis of differentially expressed genes in stem tissue of the Greek lemon cv. Adamopoulou

Lemon (Citrus limon (L.) Burm. f.) is susceptible to mal secco, a serious vascular disease caused by the fungus Phoma tracheiphila (Petri) Kant. and Gik., as well as low temperatures. The greek lemon cultivar Adamopoulou, thought to be derived from the Portuguese cultivar Lisbon, exhibits enhanced resistance to mal secco and cold as opposed to cv. Lisbon. Suppression subtractive hybridization (SSH) was employed for the isolation of differentially expressed genes in lemon stem tissue. A subtractive cDNA library was constructed and a total of 296 clones were sequenced. The obtained sequences were edited, resulting in 56 non-redundant ESTs. Sequence analysis revealed homology to previously identified genes involved in defense mechanisms against biotic and abiotic stresses, as well as sequences with no significant similarity in the GenBank. Selected ESTs were analyzed by real-time PCR for confirmation purposes. This analysis revealed significant expression differences between the two cultivars for genes expressing allantoinase, ultraviolet-B-repressible protein, 4-coumarate:CoA ligase and other proteins that are known to be upregulated under biotic and abiotic stress conditions.     

Root morphology and the effect of rootstocks on leaf nutrient acquisition of Kinnow mandarin (Citrus nobilis Loureiro × Citrus reticulata Blanco)

The study aimed to understand the root morphological character of 1 year old seedling rootstock of citrus genotypes viz., rough lemon, Karna Khatta, Carrizo citrange, Rangpur lime, Troyer citrange, Jatti Khatti and sour orange as well as to investigate the effect of these rootstocks on the leaf mineral composition of Kinnow. Root morphological traits showed significant genotypic variation. Rough lemon seedlings had a higher root length, projected area, surface area, volume and the number of forks. Sour orange was moderate rootstock of the 7 genotypes for most of the root morphological characters, while citrange rootstocks expressed poor root morphology. The rootstocks also imparted significant influence on the leaf mineral composition. Leaf K, Ca and Mg content was recorded maximum in plants grown on rough lemon seedling, while N, P, Fe, Zn, Mn and Cu concentration was higher on sour orange rootstock. Kinnow trees on Rangpur lime rootstock accumulated more Na in their leaf tissue, where as Troyer citrange restricted the accumulation of Na. Considering the root morphological characters and nutrient accumulation pattern, rough lemon and sour orange for areas free from tristeza virus could be suggested as alternative rootstocks for the studied Kinnow mandarin under similar ecological conditions.     

柑桔体细胞杂种扦插繁殖及其有关性状研究

对３个由原生质体融合产生的柑桔体细胞杂种繁殖特性的研究表明，金柑与甜橙属间体细胞杂种扦插生根成活率较低。甜橙＋宜昌橙以及甜橙＋粗柠檬种间体细胞杂种扦插萌发和生根能力与权及粗柠檬没有显著差异；插条发根平均为２．０条和１．８条，一年生植株根系总长分别为１２２．２ｃｍ和８０．７ｃｍ，与积和粗柠檬均无显著差异；粗柠檬＋甜橙杂种的须根数为３９条，株－１，与权（５４．５条·株－１）差异显著，而宜昌橙＋甜橙种间杂种（４７．７条·株－１）与积差异不显著；体细胞杂种的抗寒性有介于双亲之间的趋势     

脐橙与粗柠檬体细胞杂种果实类胡萝卜素、糖酸遗传的亲本偏向性

 采用高效液相色谱测定柑橘种间体细胞杂种[‘朋娜’脐橙（Citrus sinensis Osbeck）+ 粗柠檬（C. jambhiri Lush）]和其两个融合亲本果实的类胡萝卜素含量，气相色谱测定可溶性糖及有机酸含量，并检测代谢过程中关键基因的表达，比较分析体细胞杂种果实品质遗传及基因表达特点。结果表明，体细胞杂种类胡萝卜素成分及含量均偏向粗柠檬亲本，柠檬酸、苹果酸积累量也偏向粗柠檬；而蔗糖含量处在中亲值；实时定量PCR 技术检测类胡萝卜素代谢途径中的7 个基因，其中4 个基因在‘朋娜’脐橙中的表达量高于粗柠檬，环化途径中番茄红素ε 环化酶基因（CitLcy-e）、玉米黄质环氧酶基因（CitZep）在体细胞杂种中表达量偏向粗柠檬亲本，显著低于‘朋娜’脐橙。可见粗柠檬遗传物质的表达在体细胞杂种中占主导地位。     

3种柑橘实生砧木及其2种体细胞杂种根系解剖结构的比较

采用石蜡切片法和组织离析法分别对3种柑橘实生砧木和2种体细胞杂种的根系木质部和导管分子的解剖构造进行了比较。结果表明：（1）粗柠檬、红橘和枳3种实生砧木根系的木质部和韧皮部呈同心圆环状排列,而‘红橘+枳’和‘红橘+粗柠檬’两种体细胞杂种木质部和韧皮部呈“海星状”排列,结构异常。（2）导管所占的面积和密度,均以生长势较强的粗柠檬为大,以生长势较弱的枳为小;体细胞杂种没有明显规律。（3）柑橘导管分子属于孔纹导管,穿孔板均为单穿孔,大多分布于端壁上;导管分子两端具尾、倾斜、侧壁穿孔等性状的有无及其比例,反映出生长势的差异及其输导能力的强弱。（4）粗柠檬具有较好输导能力的导管分子结构,而枳较差;体细胞杂种根系的导管分子长度和直径都大于其亲本,在导管分子性状上,向不利于输导能力的较原始性状偏移。     

不同柑橘砧木对锦橙果实品质的影响

 2006—2008年连续3年研究11种砧木对铜水72-1锦橙果实品质的影响。结果表明：不同砧木对果实颜色和内在品质均有影响,其中以卡里佐枳橙为砧的果实亮度最好,黄色度值最高,果实最大,果皮最薄;以路比枳为砧的果实红色度值和固酸比（TSS/TA）最高,果皮最厚;以沃尔卡姆为砧的亮度最差,黄色度值、单果质量和可食率最低,中心柱最小;以C35枳橙为砧的中心柱最大且维生素C含量最低;以光皮酸橙为砧的果实红色度最低而可食率最高;以里其16-6枳为砧的果实可溶性固形物（TSS）含量最高;以孙楚沙橘为砧的果实可滴定酸（TA）和维生素C含量最高,而TSS/TA最低;果实TSS和TA最低的砧木为枸头橙。品质综合评价,性状表现较好的为孙楚沙橘、卡里佐枳橙和C35枳橙,而表现较差的为兰普莱檬和沃尔卡姆柠檬。     

A comparison of the response of different citrus fruit cultivars to storage temperature

A comparison was made of the response to storage temperatures (0–17°C) of grapefruit ‘Shamouti’ and ‘Valencia’ oranges, and lemon fruit. There was no chilling injury (CI) and the incidence of rot was relatively low at 12°C or higher for all cultivars. At low storage temperatures, however, pitting and subsequent rot development in grapefruit and in ‘Shamouti’ and ‘Valencia’ oranges were highest at 6°C, while in lemon the incidence of these disorders rose with the decrease in storage temperature, and was highest at 2°C. Grapefruit and ‘Shamouti’ oranges exhibited the highest susceptibility to CI, lemon showed an intermediate susceptibility, and ‘Valencia’ orange a very low one. In grapefruit, severe peel pittings that developed in cold storage were covered by mold rots during cold storage and shelf-life, but in ‘Valencia’ and particularly in ‘Shamouti’ oranges the incidence of decay during cold storage was low. During shelf-life, a pronounced CI-induced increase in the incidence of mold rots was evident. This breakdown during shelf-life may be associated with microscopic peel injuries which are formed during cold storage and covered by mold rots during shelf-life. Increased susceptibility of the cultivar to CI could be correlated with an increase in ethanol content at low temperatures.     

Micropropagation of Darjeeling orange (Citrus reticulata Blanco) by shoot-tip grafting

Summary

Micropropagation of Darjeeling orange (Darjeeling mandarin) was done by shoot-tip grafting on the local rootstocks rough lemon, sour orange and Rangpur lime. Seedlings of these plants were raised in MS medium in standard conditions of temperature, light duration and plant age. Microbuds (0.2 mm long), aseptically excised from the scion, were grafted onto the decapitated rootstock seedlings. The micrografts in culture medium were grown under standard lighting. Rootstock seedlings showed optimum growth at 25–30°C. Optimum growth of the micrografts resulted from treatment in complete darkness for 4 d after grafting followed by exposure to 750 W for 16 h d^?1 for 15 d and 1500–2000 W for 16 h d^?1 for 39 d. The success of micrografting depended on the age of the rootstock seedling which was 21 d, 14 d and 14 d for sour orange, rough lemon and Rangpur lime respectively. The micrografts were then double grafted to the two year old rootstocks seedlings of the respective species and the age of the micrografts for the successful double grafts was also standardized. The survival rate was high with 40 d, 45 d and 45 d micrografts on sour orange, rough lemon and Rangpur lime respectively. The double-grafts were then indexed for tristeza virus and greening disease after six months’ growth in an insect-proof screenhouse and found to be free from these graft transmissible diseases.     

Evaluation of citrus somatic hybrids for tolerance to Phytophthora nicotianae and citrus tristeza virus

Somatic hybridization is a biotechnology tool that can be used in citrus breeding programs to produce somatic hybrids with the complete genetic combination of both parents. The goal of this work was to test the reaction of citrus somatic hybrids that may be useful as rootstocks to trunk and root infections caused by Phytophthora nicotianae van Breda de Haan (P. parasitica Dastur) and to citrus tristeza virus (CTV). The somatic hybrids evaluated were ‘Caipira’ sweet orange (Citrus sinensis L. Osbeck) + ‘Rangpur’ lime (C. limonia Osbeck), ‘Caipira’ sweet orange + ‘Cleopatra’ mandarin (C. reshni hort. ex Tanaka), ‘Caipira’ sweet orange + ‘Volkamer’ lemon (C. volkameriana V. Ten. & Pasq.), ‘Caipira’ sweet orange + rough lemon (C. jambhiri Lush.), ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange (C. aurantium L.), ‘Rangpur’ lime + ‘Sunki’ mandarin (C. sunki (Hayata) hort. ex Tanaka), ‘Ruby Blood’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, and ‘Valencia’ sweet orange + Fortunella obovata hort. ex Tanaka. For P. nicotianae trunk and root infection assays, plants of the somatic hybrids, obtained from 9-month semi-hardwood cuttings, were evaluated and compared with diploid citrus rootstock cultivars after mycelia inoculation in the trunk or spore infestation in the substrate, respectively. ‘Cleopatra’ mandarin + sour orange, ‘Rangpur’ lime + ‘Sunki’ mandarin, ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Ruby Blood’ sweet orange + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Volkamer’ lemon had less trunk rot occurrence, whereas the somatic hybrids ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange, ‘Caipira’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Rangpur’ lime were tolerant to root rot. For CTV assays, plants of the somatic hybrids along with tolerant and intolerant rootstocks were budded with a mild strain CTV-infected or healthy ‘Valencia’ sweet orange budwood. Differences in average scion shoot length indicated that the hybrids ‘Cleopatra’ mandarin + sour orange and ‘Valencia’ sweet orange + Fortunella obovata were intolerant to CTV.     

雪莲果多酚氧化酶性质及其抑制方法研究

从雪莲果块根中提取多酚氧化酶(PPO),对其最适反应pH、最适反应温度、热稳定性进行研究,同时研究了VC、氯化钠、柠檬酸、蔗糖、柠檬汁和橘子汁对PPO活性的影响。结果表明:雪莲果PPO的最适反应pH为6.4,最适反应温度为30℃,在80、90、100℃分别处理300、240、220 s时完全失活。NaCl和蔗糖对雪莲果PPO活力没有影响,VC、柠檬酸、柠檬汁和橘子汁对其有很好的抑制作用,柠檬汁和橘子汁可作为天然抑制剂应用于雪莲果加工中。VC、柠檬酸对PPO的抑制作用高度显著,橘子汁、VC与柠檬酸的交互作用对PPO活性有显著影响。     

柑桔原生质体融合再生出叶肉亲本类型植株

粗柠檬(Citrus jambhiri Lush)叶肉原生质体与哈姆林甜橙(C.sinensis Osbeck)悬浮细胞系原生质经聚乙二醇(PEG)诱导融合、再生的植株中,除体细胞杂种外,发现两棵为二倍体,与其亲本一样,2n=2x=18。这两棵植株叶片形态似粗柠檬。GOT、SOD及POX 3种同工酶分析结果显示,其酶带与粗柠檬基本相同,但个别带纹有差异。本文就这类植株的来源问题作了讨论。     

柑橘果实膳食纤维的研究

以柠檬、玉环柚、椪柑、脐橙、温州蜜柑和胡柚为试材,测定了果皮和果肉中总膳食纤维(TDF)、不溶性膳食纤维(IDF)、水溶性膳食纤维(SDF)、中性洗涤剂纤维(NDF)、酸性洗涤剂纤维(ADF)、纤维素(CEL)、半纤维素(HC)、木质素(Lignin)、总果胶(TP)、原果胶(Protopectin)和水溶解性果胶(WSP)含量。以柚和温州蜜柑为试材,分别测定了不同的发育阶段膳食纤维及其具体组分的含量,总结了不同发育阶段果实膳食纤维的变化情况。结果表明,除柠檬和脐橙果肉的SDF含量稍多于果皮中含量外,其他各组分均是果皮中的含量大于果肉。除果皮中TDF和IDF的品种间变异较小外,其它组分在品种间的变异均较大。除HC外,各组分在果肉中的变异均大于果皮。柠檬果实中TDF、SDF、NDF、ADF、CEL、木质素和WSP含量都高于其它柑橘类水果。柚和温州蜜柑TDF和IDF随着果实的成熟而有所下降,但降幅不明显;而SDF则随着发育阶段的推移而渐渐增加。     

柠檬新品种‘黄绣球’

‘黄绣球’是从沃尔卡姆柠檬芽变培育而来的柠檬新品种。树姿呈开张状,春梢刺少且刺长度适中;嫩叶中间绿色,外缘淡红色;部分成熟叶外缘黄色,中间绿色。果实圆形且表面光滑,幼果果面呈黄绿相间带状条纹,转色期绿色部分变为橙色,果面橙黄相间,完全成熟后果面以黄色为主,留红色斑点。具有较高的观赏价值,适合制作盆景。     

Potential impact of harvesting for the long-term conservation of arboreal marsupials

We used a simulation approach to study the trade-off between forest harvesting and the conservation of arboreal marsupials in managed eucalypt forests of south-eastern New South Wales (Australia). The EDEN gap model is used to predict tree biomass harvested and the resulting shifts in habitat quality (HQ) for arboreal marsupials under different harvesting scenarios. These harvesting scenarios generate a gradient of biomass harvested by varying rotation length and tree retention in different topographic positions. The results suggest that the shape of the curve of reduction of HQ along the harvesting gradient is very sensitive to topographic position and hence to the proportion of topographic units in the landscape. Consequently arboreal marsupial management in logged forests will be region-dependent as each region will have its own pattern of landscape complexity.     

柑橘种间六倍体体细胞杂种开花及其花粉育性

 二倍体锦橙+种间四倍体体细胞杂种HR (哈姆林甜橙+ 粗柠檬) 的种间六倍体体细胞杂种植株移入温室7年后(即2004年) , 有1株六倍体首次开花, 花粉染色活力40.8% , 花粉萌发率3.7%;2006年该植株再次开花, 花粉染色活力为20.3%。由于自然界中没有柑橘六倍体, 本研究是人工的方法创造出可育的柑橘六倍体体细胞杂种植株的首例报道。     

Evaluation of rootstocks for the Cyprus local lemon variety ‘Lapithkiotiki’

The effect of various rootstocks on yield, yield efficiency, tree size and fruit quality of the local lemon variety ‘Lapithkiotiki’ (Citrus limon (L.) Burm. F.) was studied under Cyprus conditions. Total cumulative yield over 13 years of production was the highest on rough lemon (C. jambhiri Lush) followed by that on Volkameriana (C. volkameriana Ten. & Pasq.), Yuma Ponderosa lemon (C. limon (L.) Burm. F.), sour orange (C. aurantium L.), Citrus macrophylla Wester, Morton citrange (C. sinensis cv. Washington navel × Poncirus trifoliata (L.) Raf.), Yuma citrange, Rangpur lime (C. limonia Obs.), Palestine sweet lime (C. limettioides Tan.), C-32 citrange and Citremon 1449 (C. limon × P. trifoliata), although no statistically significant differences were found between sour orange, the commercial rootstock used in Cyprus, and the other above mentioned rootstocks. Next in order as regards to total cumulative yield was Cleopatra mandarin (C. reticulata Blanko.) followed by Carrizo citrange, with statistically significant differences compared with sour orange. Trees on Citrumelo CPB-4475 (C. paradisi Macf. × P. trifoliata) and C-35 citrange died 3–4 years after grafting. Canopy volume was the lowest for trees on Cleopatra mandarin and Carrizo citrange. Yield efficiency A, expressed as total cumulative yield per trunk cross-sectional area, was the highest on C. macrophylla and lowest on Carrizo citrange. Rootstock significantly affected fruit size and weight, rind thickness, juice content, brix, total acids and brix:acid ratio. The results of the present study reveal that the most promising rootstocks that may replace sour orange for the local lemon variety ‘Lapithkiotiki’ under Cyprus conditions are Volkameriana, Yuma Ponderosa lemon, C. macrophylla and Citremon 1449.     

柑桔体细胞杂种植物学性状、生长特性及其扦插繁殖研究

采用宜昌橙和伏令夏橙、金柑和伏令夏橙、哈姆林和粗柠檬融合的3个体细胞杂种,进行高接和扦插繁殖,并以亲本或枳作比较。试验结果表明：体细胞杂种之间的生长量存在显著差异,并均受亲本影响;杂种的叶子植物学性状,与亲本相比,叶形指数变小;杂种的刺生长并不与两亲本均值成正相关;杂种扦插成活率偏向高值亲本,其中两个杂种具有与枳扦插应用一样的潜力。即使两亲本的扦插成活率均为0,而杂种仍有部分扦插成活。