Early detection of graft incompatibility in apricot (Prunus armeniaca L.) using phenol analyses

The study investigated the role of phenols in apricot graft incompatibility. Assays of phloem with cambium from 1-year-old apricot trees of cultivars Marlen, Leskora and Betinka which were grafted on the rootstocks of different genetic origin: M-LE-1, Lesiberian, MY-KL-A, Tetra, Penta, Green Gage, Julior, MRS 2/5 and Isthara were analysed with HPLC (together 23 scion/stock combinations). The phloroglucinol, catechin, p-coumaric acid and further non-identified phenols with the retention time 23–25 and 30 min were determined. The content of individual phenol compounds was related to specific cultivar/rootstock combination. The minimum number of statistical significant differences in the phenol content between tissues above and below graft union was established in homospecific combinations (P. armeniaca/P. armeniaca). Cultivars Marlen, Leskora and Betinka differ in the degree of compatibility or incompatibility with rootstocks. The pattern of non-identified phenol 23 in different graft combinations is similar to catechin and p-coumaric acid.     

Adventitious shoot regeneration from hypocotyl slices of mature apricot (Prunus armeniaca L.) seeds: A feasible alternative for apricot genetic engineering

Adventitious shoot regeneration from hypocotyl slices of mature apricot seeds has been achieved with regeneration percentages of 31.7%, 44.4%, and 46.9% for the cultivars ‘Canino’, ‘Dorada’, and ‘Moniqui’, respectively. Regeneration was significantly affected by the parental origin of the explants (P < 0.05) but not by thidiazuron or 3-indolebutyric acid for any of the three cultivars, at the levels tested. None of the other factors studied (basal medium, 2,4 dichlorophenoxy-acetic acid pulses, dark incubation period, or addition of silver thiosulfate) affected significantly shoot regeneration percentage from ‘Canino’ hypocotyl sections. The effect of paromomycin on regeneration was genotype-dependent and different dose–response curves were obtained for each cultivar. While 40 μM paromomycin completely inhibited regeneration from ‘Canino’ sections, some buds were obtained from ‘Dorada’ and ‘Moniqui’ explants. The two aminoglycoside antibiotics tested, kanamycin and paromomycin, showed differing toxicity on ‘Canino’. A lower concentration of kanamycin (20 μM) than of paromomycin inhibited totally adventitious regeneration from ‘Canino’ explants. Agrobacterium-mediated transformation experiments, with the non-oncogenic strain AGL1 harboring the binary plasmid p35SGUSINT, were performed and GUS assays were carried out after four weeks to determinate stable transformation events. The utilization of paromomycin (10 μM) as the selective agent increased significantly both the number of explants that presented at least one transformation event (P < 0.05) and the number of large area or calli expressing the gus gene (P < 0.001), compared with the addition of kanamycin (10 μM). Moreover, when 10 μM paromomycin was added to the medium some massively transformed explants were observed and a chimerical bud was regenerated.     

Apricot (Prunus armeniaca L.) fruit quality attributes and phytochemicals under different crop load

Three apricot (Prunus armeniaca L.) cultivars were subjected to different degrees of fruit thinning during pit hardening. At harvest fruit quality characteristics were assessed, along with phytochemicals’ concentration, such as carbohydrates, phenolic compounds and organic acids. Antioxidant capacity of the pulp was estimated by diphenyl picryl hydrazyl and ferric reducing antioxidant power assays. Thinning improved fruit weight in two of the three cultivars with a subsequent decrease in fruit firmness, without significant effect on total soluble solid content and titratable acidity. The skin color was not influenced by thinning, but carbohydrate concentration and sweetness index increased. Total phenol concentration increased with thinning, without any similar increase of the major individual phenolic compounds detected (neo-chlorogenic acid, chlorogenic acid, rutin, catechin, epicatechin, ferulic acid, p-coumaric acid and caffeic acid). The antioxidant capacity of the pulp was not influenced by thinning. In overall, thinning enhanced the pomological traits of apricot fruits as well as their phytochemical content.     

Phenotypic variability and genetic structure in plum (Prunus domestica L.), cherry plum (P. cerasifera Ehrh.) and sloe (P. spinosa L.)

In the present study, phenotypic variability of 80 plum (Prunus domestica L.) varieties maintained in the French National Plum Collection was evaluated with 19 quantitative traits. In addition, genetic diversity and genetic structure was studied in three plum species (P. domestica L., Prunus cerasifera Ehrh. and Prunus spinosa L.) using chloroplast DNA (cpDNA) markers and five single sequence repeat (SSR) loci. Based on phenotypic traits, some varieties, such as mirabelle plums, grouped together. Bayesian structure analysis was used to identify different genetic groups, whereby damson plums were clearly distinguished from greengage plums. When examining the three species together, a higher level of cpDNA allelic richness was found in P. cerasifera and in P. spinosa than in P. domestica where only five cpDNA haplotypes were detected in the national plum collection, with one main haplotype that accounted for 80% of the varieties studied. P. domestica cpDNA haplotypes tended to group together with P. cerasifera haplotypes whereas most of P. spinosa haplotypes formed a separate cluster. SSR markers were somewhat able to distinguish the three species. These results provide some clues as to the origin of plum and the various plum varieties. Our results also provide useful information for the management of plum genetic resources.     

In vitro shoot regeneration from stored mature cotyledons of sweet cherry (Prunus avium L.) cultivars

Shoot regeneration was achieved from stored mature cotyledons of sweet cherry (Prunus avium L.) in vitro. The influences of different cytokinins (thidiazuron (TDZ) and benzylaminopurine (BA)) and their levels, the dark incubation for the first 10 days of the culture and TDZ pretreatments on shoot regeneration were determined. All varieties regenerated in the presence of TDZ if cotyledons were maintained in darkness for the first 10 days of the culture; however, only three varieties regenerated with low frequencies in the absence of dark incubation. Dark incubation at the early stage of culture was critical for obtaining higher regeneration efficiencies from stored cherry cotyledons. TDZ was more effective than BA in inducing shoot regeneration. The highest regeneration efficiencies were obtained with intermediate concentrations of TDZ (3.6 and 7.2 μM) in combination with dark incubation and the best regeneration frequencies for ‘Vista’, ‘Sunburst’, ‘Tehranivee’, ‘Vouge’ and ‘Heidelfingen’ cotyledons were 70.0%, 53.3%, 23.3%, 30% and 26.6%, respectively.     

日光温室内外金太阳杏光合特性的比较研究

为了探明杏对设施栽培的生理反应,对日光温室内外金太阳杏光合特性进行了比较研究。结果表明,日光温室栽培条件下,金太阳杏单位重量叶片的叶绿素含量增加;光(CO2)饱和点和光(CO2)补偿点降低鸦露地晴天净光合速率Pn日变化呈明显的双峰曲线,温室内也呈双峰线,但双峰出现原因不同。并且研究了影响光合作用的主要生态因子及变化规律,发现净光合速率与胞间CO2浓度、蒸腾作用、气温、叶温、光合有效辐射等因子相关。     

Physico-chemical and antioxidant properties of cornelian cherry fruits (Cornus mas L.) grown in Turkey

Cornus mas L. is a naturally growing dogwood species in Anatolia. In present study, physical, chemical and antioxidant properties of cornelian cherry fruits were studied. The fruit weight was in the range of 0.39–1.03 g, fruit length 14.24–22.20 mm, fruit width 9.59–13.21 mm, flesh/seed ratio 1.34 to 6.72. Hunter L values of the samples ranged between 10.82 and 19.69, and a value was between +6.25 and +15.59, and b value was between +3.46 and +6.64. In addition to the levels of dry matter, soluble solids, pH, total acidity, total sugar content, reduced sugar content, unreduced sugar content, ascorbic acid, total anthocyanin and total phenolics were within the range of 15.88–28.19%, 12.50–21.00%, 3.11–3.53, 1.10–2.53%, 76.80–154.00 g kg⁻¹, 52.80–120.00 g kg⁻¹, 0.00–32.30 g kg⁻¹, 0.16–0.88 mg g⁻¹, 1.12–2.92 mg g⁻¹ and 2.81–5.79 mg g⁻¹, respectively. On the other hand, ferric reducing antioxidant power (FRAP) and EC₅₀ values were between 16.21 mmol g⁻¹ and 94.43 mmol g⁻¹, 0.29–0.69 mg mL⁻¹. Anthocyanin extracts of the fruits were analysed by high-performance liquid chromatography (HPLC) with UV–vis detection. Pelargonidin 3-glucoside was the main pigment found in cornelian cherry fruits.     

Somatic embryogenesis and Agrobacterium-mediated transformation of Japanese apricot (Prunus mume) using immature cotyledons

This study describes a successful method of somatic embryogenesis and genetic transformation using immature cotyledons of Prunus mume. Immature cotyledons from four different developmental stages of eight different P. mume cultivars were used for the experiments to optimize somatic embryogenesis and genetic transformation protocols. Somatic embryogenesis was induced when the explants were cultured on somatic embryo inducing medium consisting of MS basic medium supplemented with 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 μM 6-benzyladenine (BA). They were cultured for 30 days and then transferred to somatic embryo propagation medium containing 0.1 μM α-naphthaleneacetic acid (NAA) and 5 μM BA. It appeared that the developmental stage of the immature cotyledons used as explants was the most important factor for somatic embryogenesis; higher frequencies of somatic embryogenesis were observed when the immature cotyledons were less than 5 mm in length regardless of cultivars. For genetic transformation, the immature cotyledons were inoculated with Agrobacterium tumefaciens EHA101 harbouring a binary plasmid vector with neomycin phosphotransferase II and an intron-interrupted β-glucuronidase gene under the control of cauliflower mosaic virus 35S promoter, and three transgenic plant lines were obtained from inoculated “Sirakaga” immature cotyledons. Transgenic somatic embryos and shoots were selected using 25 mg l⁻¹ kanamycin. Integration of transgenes in the genome of GUS-positive putative transgenic shoots was confirmed by PCR and Southern blot analyses.     

The genotypic effects on the chemical composition and antioxidant activity of sea buckthorn (Hippophae rhamnoides L.) berries grown in Turkey

In this study, chemical composition of berries of 10 sea buckthorn (Hippophae rhamnoides L.) genotypes in Turkey was investigated. The total phenolic content of the berries ranged from 21.31 mg gallic acid equivalents (GAE) per g dry weight basis to 55.38 mg GAE per g. The highest antioxidant activity was 93.54% (similar to the standard BHT at 200 mg/L) and the lowest was 80.38%. There was no correlation (R = 0.688) between the total phenolic content and the antioxidant activity. The major fatty acids in berries were palmitoleic acid (35.48%), followed by palmitic acid (28.13%), oleic acid (22.89%) and linoleic acid (3.96%). Total soluble solid content of sea buckthorn genotypes varied from 10.15 to 14.80%, titratable acidity varied from 2.64 to 4.54%, the pH varied from 2.63 to 2.98 and Vitamin C varied from 19 to 121 mg/100 mL. The average content of minerals in the sea buckthorn berries of different genotypes was 20,800 ppm N, 7100 ppm P, 7260 ppm K, 1960 ppm Ca, 1465 ppm Mg, 32 ppm Zn, 24 ppm Cu, 22 ppm Mn and 7 ppm Fe.     

Effect of synthetic auxins on fruit development of ‘Bing’ cherry (Prunus avium L.)

The main cherry cultivar grown in the warm climate of Israel, ‘Bing’, produces relatively small fruit. Over three consecutive years (2003–2005), application of 50 mg l⁻¹ 2,4-dichlorophenoxypropionic acid [2,4-DP; as its butoxyethyl ester (Power™)], 10 mg l⁻¹ 3,5,6-trichloro-2-pyridyloxyacetic acid [3,5,6-TPA; as the free acid (Maxim^®)], or 25 mg l⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) plus 30 mg l⁻¹ naphthaleneacetic acid (NAA; 0.3% Amigo™), at the beginning of pit-hardening when fruitlet diameter was ca. 13 mm caused appreciable and significant increases in fruit size and total yield, except when the crop load was heavy. Anatomical studies revealed that the main effect of these synthetic auxins was via direct stimulation of fruit cell enlargement. The above auxins had no negative effect on fruit quality, either at harvest or after 1 month of storage at 0 °C, or on return yield in the following year.     

Characterization of lettuce (Lactuca sativa L.) grown with biopesticides and deltamethrin

The purpose of this study was to evaluate the physico-chemical characteristics and the post-harvest loss of mass of curly lettuce (Lactuca sativa L.) cv. Verônica that was grown in a protective environment with applications of biopesticides. The curly lettuce was treated by spraying with neem oil, cassava flour wastewater (manipueira), biofertiliser or the control treatment of deltamethrin. We determined the weight, circumference, dry matter, ash, crude protein, total phenols and minerals profile for the heads of lettuce. After harvesting, the lettuce was packed into opened plastic bags and kept at 5 °C for 5 days to evaluate its weight loss. No differences were observed among the treatments for the physico-chemical parameters. The lettuce that was sprayed with manipueira or biofertiliser had the greatest weight loss during storage. The achievement of similar yields with cheaper products suggests a benefit of using organic bioinsecticides.     

Characterization of Prunus domestica L. in vitro regeneration via hypocotyls

Several important aspects of regeneration of European plum from hypocotyl explants were studied. Multiple shoots were induced and full plants were recovered for a large number of plum varieties. This indicates that European plum species is, in general, very responsive to in vitro regeneration from hypocotyls. Shoot organogenesis could be induced from both mature and immature seed explants but regeneration efficiency was higher when immature seeds were used. Rooting efficiency for varieties with low rooting tendency could be greatly increased by addition of naphthaleneacetic acid in the medium. Primary shoots, when sub-cultured on fresh induction medium, produced multiple shoots at a high frequency and such multiplication could continue for many cycles. The secondary new shoots could be induced for various plum varieties. Plant recovery from the secondary shoots was as efficient as that from the primary shoots. This new system may be an alternative for plum transformation with a potential for increasing transformation efficiency. The system can be used for propagation of transgenic lines and other genetic clones of various varieties.     

Physico-chemical properties and antioxidant capacity of different jujube (Ziziphus jujuba Mill.) cultivars grown in loess plateau of China

The physico-chemical properties and antioxidant capacity of the five main jujube varieties: Junzao, Lingbaozao, Jinzao, Zanhuangzao and Lizao collected from loess plateau of China were determined. The analyzed components included fruit yield, moisture content, total mass per fruit, pH, titratable acidity (TA), reducing sugars, total sugars, total soluble solids (TSS), ascorbic acid, total phenolics content, total flavonoids content and several pure phenolic compounds. The output of the analyses showed higher amounts of ascorbic acid and phenolics in these jujube varieties than in some common fruits. The antioxidative capacity of the jujube extracts, evaluated with the reducing power, the β-carotene bleaching, the 2,2-diphenyl-1-picrylhydracyl (DPPH•), and the 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonicacid) (ABTS•⁺) scavenging methods, showed that the antioxidant activity of the extracts of Lingbaozao was excellent for free radical scavenging and a potent natural antioxidant of commercial value. Statistically significant differences were observed between jujube cultivars investigated with regards to the measured parameters except rutin content of fruit. These results demonstrated that the cultivar was the main factor which influences the physico-chemical properties and antioxidant activity of jujubes.     

Hexanal and 1-MCP treatments for enhancing the shelf life and quality of sweet cherry (Prunus avium L.)

Sweet cherry has a short post-harvest shelf life and this greatly affects the consumer preference and export of fresh fruits. In this study, the effects of pre-harvest application of a hexanal formulation (enhanced freshness formulation, EFF) and post-harvest application of hexanal vapour and 1-MCP on quality parameters and shelf life of sweet cherry were investigated. Cherries subjected to pre-harvest spray with EFF had better color, brightness and firmness than unsprayed cherries even after 30 days of storage at 4 °C. These EFF-treated cherries also showed higher chroma values indicative of enhanced red color. Post-harvest application of either, hexanal vapour, 1-MCP, or a combination of both, enhanced the firmness of cherries. These treatments also resulted in higher levels of superoxide dismutase and ascorbate peroxidase activities. The levels of anthocyanins and phenolic components were either enhanced or maintained during the 30-day storage period. Our results suggest that a pre-harvest application of EFF combined with post-harvest treatment of hexanal and 1-MCP may enhance the quality and shelf life of sweet cherry.     

Metabolism and translocation of 1, 2-14C(2-chloroethyl) phosphonic acid in Prunus persica (L.) Batsch

1,2-¹⁴C (2-chloroethyl)phosphonic acid (¹⁴C-CEPA) translocation and metabolism was studied in short-term experiments on ‘Andross’ peach trees at the end of Stage I of fruit development. The chemical was applied to the fruit surface or to the abaxial surface of the basal leaf of a developing shoot. When the tracer was applied to the fruit, no translocation of the chemical occurred. When the ¹⁴C-CEPA was applied to the leaf, translocation was observed. Thin-layer chromatography (TLC) of the radioactivity recovered in acidic methanol extracts of both fruits and one-year shoots, collected 24, 48 and 96 h after ¹⁴C-CEPA application to the leaf, indicated that the translocation occurred in forms different from the original chemical. Treatment of chromatograms with AgNO₃ and FeCl₃ at 100°C showed that the colour reaction of sugars was associated with the radioactive areas. Therefore it seems likely that the translocation of ¹⁴C-CEPA occurred in sugar-conjugated form. Results of the TLC of ¹⁴C-CEPA before spotting or overspotted with sugars or fruit and leaf extracts, showed that the binding of ¹⁴C-CEPA to sugars is not a metabolic reaction, although the complex, being more stable than the original chemical and biologically active, could have physiological significance in determining long-term responses of tissues to treatments with CEPA.     

Microsatellite characterization of grapevine (Vitis vinifera L.) genetic diversity in Asturias (Northern Spain)

The genetic heritage of the Asturian grapevine (Vitis vinifera L.) has been declining over the past century due to the phylloxera attack and the further abandonment of this culture. In addition, efforts in recent years to restore the Asturian vineyard with the pulling-up of old vineyards and replanting with cultivars endorsed by Cangas Quality Wine regulations are contributing even more to this genetic erosion. The aim of this study was the evaluation and identification of the phytogenetic resources of the Asturian grapevine. A total of 293 accessions were collected in old vineyards and analyzed through nine microsatellite markers. Forty-two different genotypes were obtained, including six profiles with allelic variations. Only 27 cultivars were identified when compared with national and international databases; some of them had not been found in this region before. Homonymies and synonymies have also been detected. These results provide an overview of the status of current grapevine phytogenetic resources in Asturias. Despite the substantial genetic erosion that the Asturian vineyard has suffered, a higher variability than expected has been detected. The finding of new grapevine genotypes is a fact of great importance. The genetic grapevine resources are being drastically reduced all over the world, so this new genetic material has to be included in germplasm banks for its conservation and further agronomical and enological evaluation.     

Effects of cultivar,orchard elevation,and storage on fruit quality characters of sweet cherry (Prunus avium L.)

Fruit quality characters were analysed in the sweet cherry cultivars, Burlat, Van, Tragana and Mpakirtzeika, harvested from low (39–59 m), medium (216 m) or high (490–546 m) elevation sites. The effects of storage for 2 or 4 days at 2 °C and 1 day at 20 °C on the fruit antioxidant contents were also evaluated. Tragana and Mpakirtzeika had greater fruit fresh weight (FW) and total soluble solid content compared to Van and Burlat, the latter being the most red colored. Tragana and Burlat had greater total phenolic content and total antioxidant capacity, measured by DPPH extinction, compared to Mpakirtzeika and Van (mean values 204.4 mg vs. 103.7 mg gallic acid equivalent 100 g⁻¹ FW, and 176.1 mg vs. 79.3 mg ascorbic acid equivalent 100 g⁻¹ FW, respectively). The geographic elevation had a marked influence on the cherry antioxidant content in all studied cultivars, apart from Van, with high elevation orchards producing cherries with greater contents of antioxidant compounds compared to lower elevation orchards. Changes in the antioxidant contents during storage were depended on the cultivar and some times on the orchard elevation. Total antioxidant capacity was significantly correlated with total phenolic content in Tragana, Burlat and Mpakirtzeika, but not in Van; nevertheless this was not the case during storage.     

African spider flower (Cleome gynandra L./Gynandropsis gynandra (L.) Briq.) as a red spider mite (Tetranychus urticae Koch) repellent in cut-flower rose (Rosa hybrida L.) cultivation

Companion planting of Cleome gynandra, of Kenyan origin, in beds of cut-flower roses reduces significantly red spider mite (Tetranychus urticae Koch) infestation without any detrimental effect on productivity or flower quality. The level of reduction is dependent upon the density of the C. gynandra plants with 15 plants in a 1.8 m² bed (8.3 plants m²) being the most effective, planted either around the bed perimeter or within the rows of roses. The relatively high density of C. gynandra plants required may limit the direct application of this technology in export-focused, greenhouse rose production yet may be of significant value as a supplement to other mite-control strategies. The potential benefits of such companion planting for growers of field roses and those involved in some domestic markets are also evident. Research into the nature and extraction of the active, volatile mite-repellant components of C. gynandra is indicated.     

普通杏品种SSR遗传多样性分析

利用来自杏、桃和扁桃的25对SSR多态性引物对66个普通杏品种进行了PCR扩增及变性聚丙烯酰胺凝胶电泳,共检测出284个等位位点,每对引物的等位位点数在3～17之间,平均为11.36。通过NTSYS软件计算得到的Dice相似性系数为0.083～0.987,平均值为0.370,表明中国普通杏种质资源的遗传多样性丰富。UPGMA法聚类将66份材料分为5个组。SSR标记反映出的品种间亲缘关系与根据地理生态类型对杏种质的分类结果基本一致。来自四川和贵州的多数品种独立聚成一组,表现出与其它品种较远的亲缘关系,该地区可能存在特异性较高的种质资源。证实了扁桃基因组SSR引物可用在杏SSR标记的研究中。