Drought stress tolerance and photoprotection in two varieties of olive tree

Abstract

The olive tree (Olea europaea L.) is adapted to tolerate severe drought and high irradiance levels. Relative electron transport rate (J), photosynthetic efficiency (in terms of F _v /F _m and Φ_PSII), photochemical (qP) and non-photochemical quenching (NPQ) were determined in 2-year old olive plants (cultivars ‘Coratina’ and ‘Biancolilla’) grown under two different light levels (exposed plants, EP, and shaded plants, SP) during a 21-day controlled water deficit. After reaching pre-dawn leaf water potentials of about -6.5 MPa, plants were rewatered for 23 days. During the experimental period, measurements of gas exchange and chlorophyll fluorescence were carried out to study the photosynthetic performance of olive plants. The effect of drought stress and high irradiance levels caused a reduction of gas exchange, J, Φ_PSII and F _v/F _m and this decrease was more marked in EP. Under drought stress, EP showed a higher degree of photoinhibition, a higher NPQ and a lower qP if compared to SP. Coratina was more sensitive to high light and drought stress and had a slower recovery during rewatering. The results confirm that photoprotection is an important factor that affects photosynthetic productivity in olive, and that the degree of this process varies between the cultivars. This information could give a more complete picture of the response of olive trees grown under stressful conditions of semi-arid environments, and could be important for the selection of drought-tolerant cultivars with a high productivity.     

Biomimetic transport of simple olive biophenol and analogues through model biological membranes by differential scanning calorimetry.

The different interactions of p-hydroxybenzoic acid (1), a simple biophenol (BP) found in olives and their food products, and its substitute analogues, benzoic (2), anisic (3), and toluic (4) acids, with a model membrane represented by dimyristoylphosphatidylcholine (DMPC) multilamellar vesicles (MLV) was studied by differential scanning calorimetry (DSC). The influence of their different lipophilic character on transfer and absorption processes through an aqueous medium into a lipid bilayer was also investigated. DSC experiments allowed monitoring of the interaction of BP with biomembranes by considering the effects exerted on the thermotropic behavior of DMPC multilamellar and unilamellar vesicles at different pHs (4 and 7.4). The examined compounds affect the transition temperature (T(m)) of phospholipid vesicles, causing a shift toward lower values, which is modulated by the molecular fraction entering into the lipid bilayer, as well as by their molecular interaction with the lipids. Kinetic calorimetric measurements were performed on suspensions of blank liposomes immediately after being added to fixed weighed amounts of powdered compounds and after increasing incubation periods at 37 degrees C. T(m) shifts, due to molecular dissolution and transfer of the compounds into the membrane surface occurring during the incubation time, were compared with those determined by a fixed molar fraction of free compounds directly dispersed in the membrane. The results show that the kinetic process, involved in molecular release, transfer through aqueous medium, and uptake by the model membrane surface, is influenced by lipophilicity as well as by pH, acting on the acid solubility and membrane disorder, allowing us to gather useful information on the BP intake process of olive derived foodstuffs.     

Policosanol contents and compositions of wheat varieties

Policosanol (PC) is the common name for a mixture of high molecular weight (20-36 carbon) aliphatic primary alcohols, which are constituents of plant epicuticular waxes. Wheat germ oil has been reported to improve human physical fitness, and this effect is attributed to its high PC, specifically its high octacosanol (OC) content. Although the PC composition of wheat leaves has been studied extensively, information on PC content and composition of wheat grain fractions is scarce. The objective of this study was to examine the PC contents and compositions of wheat grain fractions of 31 varieties grown in Oklahoma. PC compositions of the samples were identified using a gas chromatograph coupled with a mass spectrometer. The PC content of wheat bran was higher than that of the germ, shorts, and flour. The Trego and Intrada varieties had the highest PC content among the 31 wheat varieties studied. Tetracosanol (C24), hexacosanol (C26), and OC (C28) were the major PC components in all varieties. This study showed that wheat varieties grown under identical growing conditions and management differ significantly in PC content and composition.     

Discrimination of storage conditions and freshness in virgin olive oil

Virgin olive oil samples stored in the light at ambient temperature, in the dark at ambient temperature, and at low temperature in the dark for 12 months both with and without headspace were separated into recognizable patterns with stepwise linear discriminant analysis. The discrimination with variables volatile and phenolic compounds, free fatty acid (FFA), peroxide values, K232, and K270 revealed a departure of stored oil from freshness and showed significant (p < 0.01) differences between storage conditions. Virgin olive oil stored at low temperature had characteristics closest to fresh oil while oil stored in the light showed the largest departure from freshness. Parameters that exclusively and significantly (p < 0.01) discriminated storage conditions were identified as potential markers of the storage condition. In the presence of oxygen, hexanal was a marker of storage in the light, FFA was a marker for dark storage, and markers of low-temperature storage were acetic acid and pentanal. In the absence of oxygen, octane was the marker for storage in the light whereas tyrosol and hexanol were markers of virgin olive oil stored in the dark, with no marker indicative of low-temperature storage. E-2-Hexenal, K232, and K270 were identified as markers of virgin olive oil freshness.     

Chemical authentication of extra virgin olive oil varieties by supervised chemometric procedures.

This work has focused on discriminating extra virgin olive oils from Sabina (Lazio, Italy) by olive fruit variety (cultivar). A set of oils from five of the most widespread cultivars (Carboncella, Frantoio, Leccino, Moraiolo, and Pendolino) in this geographical area was analyzed for chemical composition using only the Official Analytical Methods, recognized for the quality control and commercial classification of this product. The obtained data set was converted into a computer-compatible format, and principal component analysis (PCA) and a method based on the Fisher F ratio were used to reduce the number of variables without a significant loss of chemical information. Then, to differentiate these samples, two supervised chemometric procedures were applied to process the experimental data: linear discriminant analysis (LDA) and artificial neural network (ANN) using the back-propagation algorithm. It was found that both of these techniques were able to generalize and correctly predict all of the samples in the test set. However, these results were obtained using 10 variables for LDA and 6 (the major fatty acid percentages, determined by a single gas chromatogram) for ANN, which, in this case, appears to provide a better prediction ability and a simpler chemical analysis. Finally, it is pointed out that, to achieve the correct authentication of all samples, the selected training set must be representative of the whole data set.     

Small branches of olive tree: a source of biophenols complementary to olive leaves

The extraction of biophenols (BPs) from small branches (fibrous softwood) of olive tree accelerated by microwave assistance is proposed for the first time. Under optimal working conditions, no further extraction of the target analytes was achieved after 10 min, so complete removal of them within this interval was assumed (amounts ca. to 19000, 1000, 2000, 900, and 700 mg/kg of oleuropein, verbascoside, tyrosol, alpha-taxifolin, and hydroxytyrosol, respectively; the three last BPs are absent in branch-free olive leaves). The extracts required no cleanup or concentration prior to injection into a chromatograph-photodiode array detector assembly for individual separation-quantification. Extraction from this raw material was also implemented in continuous and discontinuous-continuous extractors using ultrasound assistance and superheated liquids, respectively, as auxiliary energies, and the results were compared with those obtained by microwave-assisted extraction. The simultaneous extraction of small branches and leaves from olive tree provided extracts with a higher variety of BPs, but either extracts richer in oleuropein and verbascoside without tyrosol, alpha-taxifolin, and hydroxytyrosol or rich in these three BPs can be obtained by separate extraction of leaves and branches, respectively.     

Intraspecific classification of water-melon under cultivation

Summary The ecogeographical classification of water-melon eliciting the principles governing the development of the above crop is presented. 10 ecogeographical groups were singled out differing in morphologic-anatomical characters and physiological properties of varieties. Based on statistical analysis the groups are included into 3 geographical types: the Russian, the Asiatic and the Eastern types. The idea is suggested on the initial position occupied by the Asiatic type in the evolution of water-melon.

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Die intraspezifische Klassifikation der kultivierten Wassermelonen

Zusammenfassung Die ökogeographische Klassifikation der Wassermelonen wird anhand der Evolutionsprinzipien dieser Kulturart dargelegt. 10 ökogeographische Gruppen werden aufgeführt, die sich durch morphologisch-anatomische Merkmale und physiologische Eigenschaften ihrer Sorten unterscheiden. Auf der Grundlage statistischer Analysen werden die Gruppen drei geographischen Typen zugeordnet: russischer, asiatischer und östlicher Typ. Es wird angenommen, daß vom asiatischen Typ die Evolution der Wassermelonen ausging.

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Changes in chloroplast pigments of olive varieties during fruit ripening

Changes in chlorophyll and carotenoid pigments of five olive (Olea europaea L.) varieties destined for milling were investigated at six consecutive ripening stages. There was a manifest dependence between olive variety, moment of picking, and chloroplast pigment composition of the fruits. Although the content of chlorophylls and carotenoids differed with fruit variety, ripening always involved their gradual loss, which becames more pronounced with increased presence of anthocyanin compounds. The relative rates of disappearance of chlorophylls and carotenoids were markedly different between varieties, implying that the catabolism of these pigments takes place at a relative rate inherent to each variety. The varieties less rich in pigments showed the most extreme behavior. The highest relative rate of disappearance was observed in fruits of the Blanqueta variety, and the lowest was observed in those of Arbequina. The chlorophyll a/chlorophyll b ratio remained practically constant during ripening, with a value very similar for Hojiblanca, Picual, Cornicabra, and Blanqueta, but much higher for Arbequina, implying that the structure of the photosynthetic apparatus is different in the latter variety. In the five varieties studied, lutein was the slowest carotenoid to be degraded, so that its percentage in the fruits increased with ripening, whereas beta-carotene was the fastest to disappear. In ripe fruits covered with anthocyanins, chloroplast pigments were retained in both skin and pulp, with the rate of disappearance being much higher in the latter.     

基于近红外光谱技术的淡水鱼品种快速鉴别

为探索淡水鱼品种的快速鉴别方法,该文应用近红外光谱分析技术,结合化学计量学方法,对7种淡水鱼品种的判别分类进行了研究。采集了青、草、鲢、鳙、鲤、鲫、鲂等7种淡水鱼,共665个鱼肉样品的近红外光谱数据,经过多元散射校正(multiplicative scatter correction,MSC)、正交信号校正(orthogonal signal correction,OSC)、数据标准化(standardization,S)等20种方法预处理,在1 000~1 799 nm范围内分别采用偏最小二乘法(partial least square,PLS)、主成分分析(principal component analysis,PCA)和BP人工神经网络技术(back propagation artificial neural network,BP-ANN)、偏最小二乘法和BP人工神经网络技术对7种淡水鱼原始光谱数据进行了鉴别分析。结果表明,近红外光谱数据,结合主成分分析和BP人工神经网络技术建立的淡水鱼品种鉴别模型最优,模型的鉴别准确率达96.4%,对未知样本的鉴别准确率达95.5%。模型具有较好的鉴别能力,采用该方法能较为准确、快速地鉴别出淡水鱼的品种。     

Analysis of total contents of hydroxytyrosol and tyrosol in olive oils

The most abundant phenolic compounds in olive oils are the phenethyl alcohols hydroxytyrosol and tyrosol. An optimized method to quantify the total concentration of these substances in olive oils has been described. It consists of the acid hydrolysis of the aglycons and the extraction of phenethyl alcohols with a 2 M HCl solution. Recovery of the phenethyl alcohols from oils was very high (<1% remained in the extracted oils), and the limits of quantification (LOQ) were 0.8 and 1.4 mg/kg for hydroxytyrosol and tyrosol, respectively. Precision values, both intraday and interday, remained below 3% for both compounds. The final optimized method allowed for the analysis of several types of commercial olive oils to evaluate their hydroxytyrosol and tyrosol contents. The results show that this method is simple, robust, and reliable for a routine analysis of the total concentration of these substances in olive oils.     

Flavanol and bound phenolic acid contents in different barley varieties

Different barley varieties, consisting of hulled and hull-less types, of normal, waxy, and high amylose starch, as well as two-rowed and six-rowed types, were analyzed for their main proanthocyanidins and bound phenolic acids. Variations in proanthocyanidin and phenolic acid contents were studied in different barley types as well as inter-relationships between the phytochemicals and polysaccharides. The main flavanols found in the analyzed barley varieties were two dimeric as well as four trimeric forms in addition to catechin. The total amount of flavanols ranged from 325 to 527 microg/g of fresh weight of barley flour. No evident associations were found between variations in proanthocyanidin levels and different barley types. The total amount of phenolic acids ranged from 604 to 1346 microg/g of fresh weight of barley flour, with ferulic acid as the dominating acid. The amount of phenolic acids varied according to occurrence or lack of hull, with significantly higher levels in the hulled varieties.     

Fatty acid, triacylglycerol, and phytosterol composition in six Tunisian olive varieties

The physicochemical and stability properties as well as the fatty acid, triacylglycerol, sterol, and triterpenic dialcohol compositions of Tunisian olive oil varieties were analyzed. On the basis of our results, we classified all of the monovarietal oils into the extra virgin category. Oleic and linoleic acids were the most useful fatty acids to discriminate three cultivars, Neb Jmel, Chétoui, and Ain Jarboua, from the others. Of the six monovarietal virgin olive oils analyzed, the main triacylglycerols were OOO, POO, PLO plus SLL, and OLO, which was expected given the high oleic acid and low linoleic and linolenic acids content observed in total fatty acids. In total, these accounted for more than 80% of the total HPLC chromatogram peak area. The main sterols found were beta-sitosterol, Delta5-avenasterol, and campesterol. The statistical analysis showed significant differences between oil samples, and the obtained results showed a great variability in the oil composition between cultivars, which is influenced exclusively by genetic factors.     

Virgin olive oil quality classification combining neural network and MOS sensors

A model based on neural networks has been designed to detect lampante virgin olive oils, a category of olive oil that cannot be consumed without a previous refining process according to the current regulation of the European Communities. The response of 7 metal oxide sensors analyzing 114 olive oil samples has been used in the design, training, and internal validation of the neural network with only 4.5% error in validation. The designed mathematical model, the equations of which are fully described, has been validated also with an external set of 13 samples of diverse varieties and geographical origins with 100% correct classification.     

四个茶树品种的氟吸收累积特性比较研究

评价4个茶树品种的氟吸收富集能力差异,为有效降低茶叶中氟含量和茶叶生产中推广低氟品种提供参考依据。以前期初选出的4个不同氟含量茶树品种的一年生无性系茶苗为材料,采用溶液培养的方法,研究各品种的短期吸收动力学参数差异、 氟吸收累积动态及累积能力差异。结果表明,在低氟浓度生长环境下,茶树对氟的吸收符合Michaelis-Menten动力学方程Vi=VmaxCi/（Km+Ci）描述,表现出主动吸收过程,茶树各部位对氟的吸收累积能力表现为成熟叶根茎; 随着氟浓度的增加,茶树对氟的吸收逐渐表现出了明显的被动吸收现象。茶树各部位对氟的吸收累积能力表现为成熟叶茎根;中茶102品种对氟的吸收累积能力及对氟的耐受性与中茶108相比有较大的差异,中茶108对氟具有比较稳定的低吸收累积特性,而中茶102则对氟表现出了较强的吸收累积特性,龙井43与乌牛早则介于两者之间。中茶108具有稳定的低氟吸收累积特性,可以作为低氟品种推广。     

树木年轮中养分元素含量的平均值及其角分布

Tree rings for analysis were selected from Cedrus deodara growing on a yellow-brown soil in Nanjing City, Pinus massoniana growing on a red soil in the red soil field station at Yintan, Jiangxi Province, and Pinus massoniana growing on a yellow-brown soil in a mining area in Nanjing. Cd, Pb, Cu, Mn, Zn, K and P contents were analysed and average values as well as angular distributions were determined. In cases where the relative deviation was below 0.30, it would be appropriate to use average values to represent the element contents in the tree rings. However, for large standard deviations, the values of the angular distribution would better describe the element contents of rings. The element contents of the environment, particularly the soils, could be obtained from these values.     

Comparative study of virgin olive oil quality from single varieties cultivated in Chile and Spain

Olive tree varieties that were cultivated only in the Mediterranean basin a few decades ago are now planted in the Southern Hemisphere as well. The chemical composition of the oils produced in countries as far distant as Spain and Chile are affected by differences in latitude and climate. In this work, seven monovarietal virgin olive oils from Chile (Arbequina, Barnea, Frantoio, Koroneiki, Leccino, Manzanilla and Picual) have been characterized by the chemical compounds responsible for taste (phenols) and aroma (volatiles). The oils were produced in five regions of Chile, and the concentration values of some chemical compounds were related to the geographical location of the olive tree orchards. Virgin olive oils from the major cultivars, Arbequina and Picual, were characterized in comparison with the same monovarietal oils produced in Spain. The concentration values of fourteen volatile compounds showed significant differences (p < 0.05) between the oils produced in Spain and Chile. Concerning the phenol composition, main differences were found on the secoiridoids derivatives of oleuropein and ligstroside, apigenin and luteolin.     

种植果树对土壤物理性状的双重效应

在渭北果区选择不同园龄(<10 年、10~20 年、>20 年)果园, 分层测定0~60 cm 土层土壤容重、土壤坚实度、土壤含水量以及表层土壤团聚体组成等物理性状, 进一步分析了果园土壤物理性状随园龄的变化特征。结果表明: 土壤容重在0~30 cm 土层随园龄增长而降低; 在30 cm 以下土层随园龄增长而增加, 超过了健康园艺土壤的质量标准1.30 g·cm^-3; 与休闲农田相比, 种植果树可降低10~30 cm 土层土壤容重; 但30 cm 以下土层土壤坚实度急剧增大, 接近或达到了限制根系延伸的土壤质量标准1 000 kPa; 与休闲农田相比, 种植果树对于降低17.5~27.5 cm 土层的坚实度具有明显作用。果园表层土壤团聚体状况整体较差, 水稳性优势团聚体直径为0.5~0.25 mm, >0.25 mm 水稳性团聚体含量随园龄增加而增大, >20 年果园比<10 年果园高1 倍。种植果树对表层土壤具有明显的保护和改善作用, 却在深层发生着紧实化和坚硬化过程。果树对土壤物理状况的双重效应体现在对0~30 cm 土层土壤结构具有改善作用, 对30 cm 以下土层土壤结构有破坏作用。果园土壤“深层的隐蔽性退化过程”影响着果树根系健康生长, 应当给予极大关注。     

Effect of olive ripeness on the oxidative stability of virgin olive oil extracted from the varieties picual and hojiblanca and on the different components involved

The initial stability of virgin olive oil depends on various factors, among which are the variety and the degree of fruit ripeness. The former, which genetically determines the composition of the olive and its oil, also marks, to some extent, its stability. However, oil stability changes as the olive ripens, so it is obvious that the degree of ripeness is an important factor. The oils were obtained by the Abencor system. Acidity, peroxide index, UV absorption at 232 and 270 nm, sensory analysis, fatty acid composition, tocopherols, phenolic compounds, orthodiphenolic compounds, sterols, pigments, and oxidative stability were determined, and the results were analyzed statistically. During ripening there was a decrease in all of the parameters studied except linoleic acid, Delta-5-avenasterol, and oil content, which increased. Virgin oils showed very good correlation between stability and the concentrations of total phenols, o-diphenols, tocopherols, chlorophyll pigments and carotenoids, linoleic and linolenic acids, total sterols, beta-sitosterol, and Delta-5-avenasterol.     

Discrimination of olive oils and fruits into cultivars and maturity stages based on phenolic and volatile compounds

Olive oil and fruit samples from six cultivars sampled at four different maturity stages were discriminated into cultivars and maturity stages. The variables-volatile and phenolic compounds-that significantly (p < 0.01) discriminated cultivars and maturity stage groups were identified. Separation by stepwise linear discriminant analysis revealed that Manzanilla olive cultivar was separated from cultivars Leccino, Barnea, Mission, Corregiola, and Paragon, whereas cultivars Corregiola and Paragon formed a cluster. The volatile compounds hexanol, hexanal, and 1-penten-3-ol were responsible for the discrimination of cultivars. All maturity stages were discriminated, with the separation of early stages attributed to oil phenolic compounds, tyrosol and oleuropein derivatives, whereas the volatile compounds (E)-2-hexenal, hexanol, 1-penten-3-ol, and (Z)-2-penten-3-ol characterized the separation of all maturity stages and in particular the late stages. Hexanol and 1-penten-3-ol characterized the separation of both cultivars and maturity stages.