Somaclonal variation with early juice-sac granulation obtained by inter-specific protoplast fusion in citrus

Summary

Six plants with an early juice–sac granulation trait derived from inter-specific protoplast fusions between embryogenic calli of ‘Bonanza’ navel orange (Citrus sinensis [L.] Osbeck) and mesophyll protoplasts of ‘Dahongpao Red’ tangerine (C. reticulata Blanco) were analysed by flow cytometry and by using molecular markers, including simple sequence repeats (SSR) and restriction fragment length polymorphism (RFLP). The results indicated that all six plants were diploids and had inherited their nuclear DNA from the embryogenic callus parent ‘Bonanza’ navel orange. However, an analysis of morphological and fruit characteristics, and measurements of components of the cell walls in the juice-sacs, showed that they were not true-to-type for ‘Bonanza’ navel orange, especially for fruit traits such as juice-sac granulation and navel structure. These results confirmed that these plants were not hybrids, and were more likely to be somaclonal variants that arose during the regeneration of the navel orange protoplasts. These plants will provide material for studying the mechanism of granulation in juice-sacs, a common phenomenon during the storage of pummelo and other citrus fruits.     

广西宽皮柑橘“蓝皮”果产生的生理原因初探

近些年,部分柑橘产区相继报道宽皮柑橘（Citrus reticulata Blanco）果实出现白皮层呈蓝色的“蓝皮”果现象,表现为在白皮层近囊衣侧出现蓝色斑块或蓝色区域。为探明其原因,以广西3个产区采集的‘沃柑’、‘贡柑’和‘马水橘’的正常果及其各自的“蓝皮”果为材料,分别对白皮层中花青苷等类黄酮物质、矿质元素进行了检测和分析;同时,利用GC–MS分析成熟期白皮层和汁胞中可溶性糖和有机酸,以明确风味品质的变化情况。结果表明：该蓝色并非花青苷类和黄烷酮类物质积累所致;成熟期“蓝皮”果白皮层中5种聚甲氧基黄酮的含量显著上升;蓝色白皮层中Ca、Mg、S、Zn、B和Ba含量均与对照有显著差异,但变化趋势没有一致性,基于21种矿质元素含量的OPLS-DA分析可以将“蓝皮”果和正常果区分开,其标志性元素为K,其次是S;蓝色白皮层及其汁胞中的苹果酸和蔗糖含量较正常果均有显著提升。因此,蓝色白皮层的形成可能与逆境胁迫下多种矿质元素络合物或螯合物的积累有关。     

柑桔汁胞离体培养的研究

本试验研究了宽皮柑桔类和甜橙类共７个品种汁胞的离体培养。观察到在相同的培养条件下，两类柑桔汁胞产生愈伤组织的能力不同，甜橙类较易，其幼嫩果实的汁胞比相对较成熟的果实的汁胞更易诱导产生愈伤组织。汁胞离体培养时，愈伤组织的产生对培养基没有严格要求，对添加植物生长调节剂的种类、浓度变化不敏感。     

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。     

Histological examination of callogenesis and adventitious embryogenesis in immature ovary culture of grapevine (Vitis vinifera L.)

Summary

Histological examinations of callogenesis and adventitious embryogenesis in immature ovary culture of grapevine (Vitis vinifera L. ‘Neo Mat’) were carried out during different phases of ontogenetic development. Adventitious embryos and/or embryogenic calli were obtained when immature ovary explants were cultured on a callus induction medium (C medium) for two months followed by transfer of callus-forming explants onto an embryogenesis induction medium (E medium). Microscopic observations of serial sections of the explants revealed that the calli formed on C medium were initiated preferentially from receptacle parenchyma cells. No cell division in the embryo sac was observed and most of them degenerated four weeks after the onset of culture. Two to four weeks after transfer of the explants onto E medium, calli characterized by dense cytoplasm, conspicuous nuclei and thick cell walls were newly formed in the initially-formed, receptacle-derived ones. Proembryos simultaneously developed in the newly formed calli, indicating that they were embryogenic calli. Cell division of embryo sacs was never observed even on E medium, and adventitious embryos and embryogenic calli were hence of somatic origin. Adventitious embryos developed asynchronously and passed through globular, heart, torpedo and cotyledonary stages. These adventitious embryos germinated and developed into plantlets following their transfer onto a plant growth regulator-free medium.     

The Rough Fruit Condition of the Shamouti orange—Connections with the Endogenous Hormonal Balance

The rough peel disorder is characterized by excessively thick rough peel and large fruit sizes and is found in Shamouti orange fruits growing under less than optimal conditions such as heavy, soils, low relative air humidity, and on sour orange rootstock. Affected fruit is not fit for export.

Appreciably more cytokinin-and gibberellin-like activities were found in both external (flavedo) and internal (albedo) peel tissues of rough than of smooth oranges at a very young fruitlet stage (May-June), when peel growth was at its peak (both cell divisions and elongation) and the rough fruit disorder was developing. At this stage no consistent differences could be detected in the level of native auxins or ABA like inhibitors. Higher cytokinin and gibberellin levels were also found in rough mature peel (November) when peel growth of rough peel is resumed. On the basis of these and other data a causal relationship between the endogenous regulator balance and the control of peel roughness is suggested.     

重庆开县柑橘冬季树冠覆膜对落果及果实品质的影响研究

通过对开县长沙锦橙柑橘果园实施35．55 hm2柑橘冬季树冠覆膜防冻试验,并对该果园防冻后柑橘果实进行落果数、果实可食率、果汁率、枯水个数、可溶性固形物（TSS）含量、维生素c（vc）含量、总酸（TA）含量的测定,发现采取树冠覆膜的柑橘落果数、果实果汁率、可溶性固形物（TSS）含量、维生素c（vc）含量、总酸（TA）含量均显著减少,而果实可食率、枯水个数均没有显著的变化。     

沙田柚在不同砧木上的早期表现

供试品种为沙田柚,砧木材料２８个,以酸柚砧作对照,研究了不同砧木上沙田柚树体生长发育,产量的早期表现。经过７年的观察分析,初步认为关云大叶枳,江津大叶枳,多花枳,朱砂柑、摩洛哥酸橙对沙田柚有早结,矮化作用。定植后第３年试花,第４年开始结果,结果最多的是关云大叶枳,株产达４个,树体高度比对照矮１１．８％￣２１．０％,产量比对照高２４０％￣６００％,其余砧木都比对照结果迟。     

Asymmetric growth of citrus fruit peel induced by localized application of gibberellins in lanolin pastes

Lanolin pastes containing 0.02–1.0% gibberellin A₄₊₇(GA₄₊₇) were applied to one side of developing citrus fruitlets and caused thickening of the peel in the proximity of the treated zone. Enlargement of albedo (= the white portion of citrus peel) cells was involved, as revealed by scanning electron microscopy. The flavedo (= the coloured portion of the peel) and the pulp were not affected by the hormone. Gibberellin A₃ was slightly less active than GA₄₊₇. Cultivars with a naturally thick peel, such as ‘Marsh’ grapefruit (Citrus paradisi Macf.) and ‘Shamouti’ orange (Citrus sinensis (L.) Osbeck) responded more strongly than thin-peel cultivars. The role of gibberellins in the differential growth of citrus fruit tissues is discussed.     

采用流式细胞仪分析柑橘愈伤组织的细胞周期

细胞周期分析可为研究柑橘愈伤组织理化诱变提供依据。试验以暗柳橙、长沙橘、澳洲指橘、纳维来特脐橙等4种培养多年的柑橘愈伤组织为试材,使用流式细胞仪分析其特定时间段的细胞周期,进而找到柑橘愈伤组织理化诱变的最佳时期即分裂最旺盛时期。结果表明,待测4种基因型柑橘愈伤组织在继代2周时处于分裂最旺盛时期,它们的S期时相比例分别为22.4%、21.9%、21.0%和22.9%。同时发现,待测的4种柑橘愈伤组织生长周期长短与再生能力有一定的相关性。极易再生的暗柳橙生长周期最短,易再生的长沙橘、澳洲指橘次之,丧失再生能力的纳维来特脐橙生长周期最长。     

Physico-Chemical Profiling of Promising Sweet Orange Cultivars Grown Under Different Agro-Climatic Conditions of Pakistan

Sweet oranges are produced on large scale all over the world and demanded due to less number of seeds and are better juice quality. A study was carried out with the objective to characterize promising sweet orange cultivars for better quality fruits production under different agro-climatic conditions of Punjab (Pakistan). Fruits of three promising sweet orange (Citrus sinensis L. Osbeck) cultivars viz. ‘Blood Red’, ‘Musambi’ and were harvested from commercial citrus groves at five different locations. Starting from Multan, in the direction of increasing altitude, four more sites viz. Sahiwal, Faisalabad, Sargodha and Chakwal were selected after every 100–150?km distance. Fruits were evaluated in terms of different physical and biochemical characters. Results showed significant influence of climatic conditions on physico-chemical properties of the cultivars at all the locations. Fruits harvested from Multan and Sahiwal showed higher fruit weight, diameter and peel weight. More juicy fruits with higher vitamin C content were produced under mild temperature environmental conditions of Chakwal. Overall, ‘Musambi’ fruits had more total soluble solids and reducing and total sugars. ‘Musambi’ was found to be good source of bioactive compounds i.?e. vitamin C and total phenolic content, had the maximum antioxidant activity as compared to ‘Blood Red’ and ‘Succari’ and may be explored as potential cultivar in Sargodha and Chakwal.     

Characteristics of citrus fruits in relation to granulation

A study was conducted in different citrus cultivars to observe the incidence and degree of granulation, and to measure polyphenol oxidase (PPO) activity and phenolic content pattern in relation to granulation. Standard procedures were followed to observe the incidence and degree of granulation, phenolic content pattern, PPO activity and pheno-physicochemical fruit characteristics of citrus fruits. Across all citrus cultivars studied, 25% of the fruit were affected by granulation to the degree of about 10%. In general, granulated fruit were larger in size than normal fruit, and were inferior in quality characteristics. Among different citrus cultivars, ‘Kaula’ mandarin had highest incidence of granulation (62.5%), followed by ‘Mosambi’ sweet orange (43.6%) and the least in ‘Kagzi’ lime (12.2%). Phenolic content and polyphenol oxidase activity also varied widely among different citrus types, and were significantly higher in normal fruit than granulated fruit. Thus, it appears from the study that PPO plays some role in the occurrence of granulation in citrus.     

柑橘新品种‘华蜜无核贡柑’

‘华蜜无核贡柑’是从‘贡柑’芽变中选育出的无籽柑橘新品种。果实中等大小,单果质量116.3 g,单果种子数1.0粒以内。果实椭圆形,果基乳头状凸起明显;皮薄,橙黄色;果肉橙黄色,味清甜,可溶性固形物含量14.6%,肉质爽脆化渣,品质优。结实早,丰产稳性好,发梢能力较强,3月中下旬盛花,12月下旬至来年1月上旬果实成熟。     

顶空固相微萃取—气质联用技术分析3种柑橘果实的香气成分

采用顶空固相微萃取-气质联用技术对大叶尾张温州蜜柑、锦橙和酸橙3种柑橘果实的香气成分进行分析测定。结果表明,大叶尾张温州蜜柑、锦橙和酸橙果实中分别检测出73、71和66种香气成分,各占总峰面积的85.9%、85.12%、79.82%。主要成分为烃类、酯类、醇类、酮类和醛类化合物。烃类在大叶尾张温州蜜柑中含量最高,酯类物质在锦橙中含量最高,醛类和醇类物质在酸橙中含量最高。3种果实有31种相同的香气成分,独有的香气成分,大叶尾张温州蜜柑15种,锦橙24种,酸橙17种。3种柑橘果实香气成分的种类和含量均存在差异,大叶尾张温州蜜柑的重要特征香气是γ-松油烯,丁酸乙酯和3-羟基己酸乙酯可作为锦橙的重要特征香气,芳樟醇可作为酸橙的重要特征香气物质。     

根癌农杆菌介导的CG1-400-RNase基因转化创制锦橙转基因再生植株

【目的】为了快速有效地利用基因工程的方法获得柑橘无核新种质,【方法】以我国特色多核柑橘优良品种锦橙实生苗上胚轴切段为外植体,采用根癌农杆菌介导法进行能导致种子败育基因CG1-400-RNase的转化;为快速有效地筛选出转化子,在实生苗上胚轴切段转化再生过程中,根据不同发育阶段的组织或器官对抗生素的敏感程度不同采用不同的选择压。【结果】结果表明,在抗性芽再生过程中卡那霉素质量浓度设定为50 mg.L-1,获得的362个抗性芽转入卡那霉素质量浓度为100 mg.L-1的伸长培养基中进行伸长培养后,进行早期PCR检测,获得28个阳性芽;经过不定芽诱导生根或试管嫁接,获得22株完整植株。【结论】再生植株经PCR和Southern杂交检测,获得2株目的基因以单拷贝的形式插入锦橙基因组的转基因植株,为最终获得具有无核性状且可稳定遗传的柑橘新种质奠定了基础。     

Effect of maturity and storage temperature on the development of peteca in lemons (Citrus limon (L.) Burm. F.) cv. Eureka

To evaluate the effect of maturity and storage temperature on the development of the physiological disorder peteca, lemons cv. Eureka were harvested from a grove with northern exposure located in Mallarauco (33°45′ Latitude South) Metropolitan Region of Chile, at 2 levels of maturity (silver or yellow). After storage for 60 d at 3 or 7 °C, under 90% R.H., fruits were evaluated visually for incidence of epidermal and subepidermal peteca. At that time, the concentration of galacturonic acid and degree of methylation were measured in the albedo, and calcium, hydrogen peroxides and total oxalate concentrations, peroxidase and polyphenoloxidase (PPO) activities were determined in the juice and albedo. Yellow lemons at 3 °C developed more epidermal peteca than fruit stored at 7 °C, and that silver fruit stored at 3 and 7 °C, with these last lemons presenting a higher pectin quality than fruit stored at 3 °C. Maturity and temperature interacted significantly on the concentrations of peroxide and calcium in the albedo, which in average were much higher than in the juice, while for PPO and peroxidases, this interaction was highly significant both in juice and albedo, with higher activity in the albedo. These biochemical evaluations suggest that peteca is a result of some kind of stress on the fruit. It is concluded that yellow lemons are more prone to develop peteca than silver fruit. They will develop greater incidence of the disorder when stored at temperatures as low as 3 °C for 60 d, and that this condition affects the degree of methylation in the albedo, which would end up altering the quality of pectins.     

不同种类柑橘的蜡质结构与成分比较

采用扫描电镜和气质联用技术研究纽荷尔脐橙（Citrus sinensis Osbeck‘Newhall’）、南丰蜜橘杨小2-6株系（C. reticulata Blanco‘Yangxiao 2-6’）、红心蜜柚（C. grandis Osbeck‘Hongxin Miyou’）、宫川温州蜜柑（C. unishiu Marc.‘Miyagawa Wase’）、尤力克柠檬（C. limon Burm. F.‘Eureka’）等5种柑橘果皮蜡质结构、含量和组成成分的差异。结果表明：柑橘果皮蜡质由无定型蜡质层及散布其上大小不同的不规则小圆片状蜡质晶体组成;主要化学成分为脂肪酸、饱和烷烃、饱和醛、初级醇、三萜类化合物和小分子代谢产物;纽荷尔脐橙果皮蜡质晶体大小、分布密度、蜡质总量以及除醛外的各蜡质组分含量均要显著高于其它4种柑橘;并且首次从纽荷尔脐橙果皮蜡质中鉴定出了具有保健功能的六甲氧基黄酮。     

Some Studies on the Cuticular Wax of Citrus Fruits

Some preliminary data on the natural wax coat of citrus fruits are presented. Thin-layer and column chromatography showed that the main differences from apple and grape waxes were the relatively higher percentage of esters, the lower percentage of alcohols and the apparent lack of triterpenoids. During fruit development in the Shamouti orange wax production was approximately balanced by surface growth, sos that the amount of wax per unit surface of rind was approximately constant for most of this period. When fruit growth was slowed down by winter temperatures and incipient senescence, the amount of wax per unit surface increased. Wax production continued (possibly at a greater rate) after the fruit had been severed from the tree. Wax removal was enhanced by successive treatments with chloroform. Weight losses of fruit in storage were proportional to the number of wax removals. Packing-house treatments did not remove natural wax but seemed to check its secretion by rind cells.     

柑橘加工鲜食兼用新品种——特罗维塔甜橙的选育

特罗维塔甜橙是从国外引种驯化并经品种比较试验获得的一个加工鲜食兼用的甜橙新品种。果实圆球形至扁圆形,平均单果质量180g,果皮橙黄色至橙红色,鲜艳,油胞大而突起,果肉柔软多汁,汁橙红色,风味浓郁,种子0～3粒,可食率69.1%,出汁率51.6%,可溶性固形物10.5%～13.0%,可滴定酸含量8g/L左右,固酸比13～16,维生素C500mg/L左右,12月下旬成熟,果实挂树延期采收性能良好,可到翌年3月中旬采收,果实耐贮藏。     

Short- and long-term growth of navel orange fruit

Summary

Seasonal patterns of fruit development of young and mature `Bellamy' navel orange trees were measured from mid November to late July. Growth of whole fruit, expressed as fresh or dry weight, was best described by a fourparameter logistic curve (R<sup>2</sup>>0.99). The fresh weight growth curves of fruit from young and mature trees were not significantly different. Dry weights and fresh weights were linearly correlated (R<sup>2</sup>>0.99). The relationship between relative growth rate (RGR) of whole fruit and time was best described by two linear regressions (R<sup>2</sup>>0.98, 0.92, respectively). The two linear phases of RGR did not correspond to ontogenic phases of fruit development as described by Bain (1958). Increases in whole fruit and pulp radii, and whole fruit, pulp, rind and albedo volume during fruit development followed single sigmoidal patterns (four parameter logistic function, R<sup>2</sup> >0.99). Relative changes in the volume of the structural parts of the fruit were small during Stage III of fruit development. Diurnal variations in growth and rind temperature of fruit from young (under continuous irrigation) and mature (under weekly irrigation) `Leng' navel orange trees were recorded during Stage II of fruit development. Inelastic growth measured by LVDTs was described better by diurnal diameter means (max 1 min)/2 than diurnal maxima or minima. Diurnal diameter means of fruit from young trees showed a significant (R² = 0.42, P<0.0001) relationship to daily ambient temperature maxima, and the diurnal growth profiles paralleled the diurnal temperature profiles of the rind. In contrast, the diurnal growth rhythms of fruit from mature trees were insensitive to ambient temperature maxima and the diurnal rhythms appeared to reflect the water status of the tree.