Most Cited Scientia Horticulturae Articles
Volume 127, Issue 2, December 2010, Pages 93-105
Lee, J.-M. | Kubota, C. | Tsao, S.J. | Bie, Z. | Echevarria, P.H. | Morra, L. | Oda, M.
Vegetable production with grafted seedlings was originated in Japan and Korea to avoid the serious crop loss caused by infection of soil-borne diseases aggravated by successive cropping. This practice is now rapidly spreading and expanding over the world. Vegetable grafting has been safely adapted for the production of organic as well as environmentally friendly produce and minimizes uptake of undesirable agrochemical residues. The number and size of commercial vegetable seedling producers has increased markedly reflecting the increase in farmers' preferences for grafted seedlings of high-quality and better performance. In addition to the widely recognized advantages of disease tolerance and high crop yields, grafting technology is also highly effective in ameliorating crop losses caused by adverse environmental conditions such as low soil temperature and high soil salts, especially under protected cultivations where successive cropping or continuous farming is routinely practiced. Grafted seedlings are much favored in hydroponics farming systems where the chances of rapid spread of noxious diseases, once infected, is high. Active research has been focused to develop efficient rootstocks and handy grafting tools. In addition, researchers are eager to develop grafting machines or robots to reduce the higher price of grafted seedlings. The quality of grafted transplants is extremely important to maximize high-quality crop yield. Use of grafted vegetables has increased with the increased use of improved soil mix or substrate, farmer's preferences for better seedlings, efficient management of nursery systems, lower prices of grafted seedlings, and efficient nationwide delivery and/or transportation system. Improved grafting methods to cut down the labor cost for grafting and subsequent handling of plug-grown grafted transplants will contribute further to the increased use of grafted vegetables worldwide. © 2010 Elsevier B.V.
Reactive oxygen species, antioxidant enzyme activities and gene expression patterns in leaves and roots of Kentucky bluegrass in response to drought stress and recovery
Volume 120, Issue 2, April 2009, Pages 264-270
Bian, S. | Jiang, Y.
The objective of this study was to investigate accumulation of reactive oxygen species, antioxidant enzyme activities, and gene expression patterns of antioxidant enzymes of Kentucky bluegrass (Poa pratensis L.) under drought stress and recovery. Grass (c.v. Midnight II) was subjected to soil drying for 5 d and then rewatered for 1 d in growth chambers. Drought stress increased superoxide (O 2 -) production of leaves and hydrogen peroxide (H 2O 2) content of the leaves and roots. Recovery enhanced leaf O 2 - production and root H 2O 2 content. Lipid peroxidation of the roots increased 4.5-fold and 2.4-fold under drought stress and recovery, respectively. Drought stress increased the leaf activities of ascorbate peroxidase (APX, EC 220.127.116.11), monodehydroascorbate reductase (MDHAR, EC 18.104.22.168), dehydroascorbate reductase (DHAR, EC 22.214.171.124), and the root activities of catalase (CAT, EC 126.96.36.199), glutathione reductase (GR, EC 188.8.131.52) and MDHAR, while reducing the root activities of superoxide dismutase (SOD, EC 184.108.40.206) and DHAR, respectively. The increased leaf activities of APX, MDHAR, DHAR and the root activities of MDHAR and CAT were observed after rewatering, compared to the control. For the leaves, the expressions of iron SOD (FeSOD), cytosolic copper/zinc SOD (Cu/ZnSOD), chloroplastic Cu/ZnSOD, and DHAR were down-regulated by drought stress but recovered to control level after rewatering, while the expressions of GR and MDHAR were up-regulated and remained that levels after recovery. For the roots, the expressions of cytosolic Cu/ZnSOD, manganese SOD (MnSOD), cytosolic APX, GR, and DHAR were down-regulated under drought stress but recovered except for GR and DHAR, while MDHAR expression was up-regulated. No differences in CAT transcript abundance were noted among the treatments. Antioxidant enzymes and their gene expressions may be differentially or cooperatively involved in the defense mechanisms in the leaves and roots of Kentucky bluegrass exposed to drought stress and recovery. © 2008 Elsevier B.V. All rights reserved.
Volume 127, Issue 2, December 2010, Pages 172-179
Rouphael, Y. | Schwarz, D. | Krumbein, A. | Colla, G.
In horticultural industry, the focus has traditionally been on yield. However, in recent years consumers interest in the quality of vegetable products has increased worldwide. Vegetable quality is a broad term and includes physical properties (1), flavor (2), and health-related compounds (3). Grafting vegetable plants onto resistant rootstocks is an effective tool that may enable the susceptible scion to control soil-borne diseases, environmental stresses and increase yield. However, in these cases, the characteristics of the three areas might be affected by grafting as a result of the translocation of metabolites associated with fruit quality to the scion through the xylem and/or modification of the physiological processes of the scion. Possible quality characteristics showing these effects could be fruit appearance (size, shape, color, and absence of defects and decay), firmness, texture, flavor (sugar, acids, and aroma volatiles) and health-related compounds (desired compounds such as minerals, vitamins, and carotenoids as well as undesired compounds such as heavy metals, pesticides and nitrates). There are many conflicting reports on changes in fruit quality due to grafting and whether grafting effects are advantageous or deleterious. The differences in reported results may be attributable in part to different production methods and environments, type of rootstock/scion combinations used, and harvest date. This report gives an overview of the recent literature on the effects of grafting on fruit vegetable (Solanaceae and Cucurbitaceae) quality including physical properties, flavor and health-related compounds of the product. The review will conclude by identifying several prospects for future researches aiming to improve the product quality of grafted vegetables. © 2010 Elsevier B.V.
Volume 119, Issue 3, February 2009, Pages 275-279
Özgen, M. | Serçe, S. | Kaya, C.
In this study, phytochemical and antioxidant properties of anthocyanin-rich mulberry species of Morus nigra L. (black mulberry) and Morus rubra L. (red mulberry) fruits harvested from across Turkey were investigated. Fruit color, total phenolics (TP), total monomeric anthocyanin (TMA), titratable acidity (TA), and individual sugar and organic acid compositions were determined. Total antioxidant capacity (TAC) of fruits was assessed by both the trolox-equivalent antioxidant capacity (TEAC) and the ferric reducing antioxidant power (FRAP) assays. Black mulberry exhibited higher TP, TMA, TAC and TA when compared to red mulberry. The average TP contents of M. nigra and M. rubra were 2737 and 1603 μg gallic acid equivalent in g fresh weight basis (GAE/g fw), respectively. M. nigra had the richest amount of anthocyanin with an average of 571 μg cy-3-glu/g fw. Overall, TAC averaged 10.5 and 12.0 mmol TE/L by the TEAC and FRAP methods, respectively. We found that FRAP, TEAC, TP and TMA were significantly correlated (r = 0.64-0.99) with each other. Fructose (5.27 g/100 mL) and glucose (5.81 g/100 mL) were determined to be the major sugars in both mulberries. M. nigra displayed a higher TA (2.05 g/100 mL) than M. rubra (0.78 g/100 mL), with citric acid as the major acid. © 2008 Elsevier B.V. All rights reserved.
The influence of arbuscular mycorrhizal colonisation on key growth parameters and fruit yield of pepper plants grown at high salinity
Volume 121, Issue 1, June 2009, Pages 1-6
Kaya, C. | Ashraf, M. | Sonmez, O. | Aydemir, S. | Tuna, A.L. | Cullu, M.A.
This study investigated the effects of arbuscular mycorrhizal (AM) colonisation by Glomus clarum on growth and fruit yield of pepper (Capsicum annum cv. 11B 14) grown at high salinity. The experiment was conducted in pots containing a mixture of perlite and sand (1:1, v/v) under glasshouse conditions. Treatments were: (1) no added NaCl without arbuscular mycorrhizae (NS-AM), (2) no added NaCl with arbuscular mycorrhizae (NS + AM), (3) added 50 mM NaCl without arbuscular mycorrhizae (S1-AM) and (4) added 100 mM NaCl without arbuscular mycorrhizae (S2-AM), (5) added 50 mM NaCl with arbuscular mycorrhizae (S1 + AM) and (4) added 100 mM NaCl with arbuscular mycorrhizae (S2 + AM). The NaCl treatments reduced pepper shoot and root dry matter, and fruit yield compared with the non-saline treatments. The concentrations of N, P and K, in the leaves were significantly reduced by salinity stress, however, mycorrhizal colonisation of the salt-stressed plants restored leaf nutrient concentrations to the levels in non-stressed plants in most cases. AM inoculation improved pepper growth under salt or saltless conditions and reduced cell membrane leakage. © 2009 Elsevier B.V. All rights reserved.
Volume 119, Issue 2, January 2009, Pages 208-211
Bhatia, R. | Singh, K.P. | Jhang, T. | Sharma, T.R.
True-to-type clonal fidelity is one of the most important pre-requisites in micropropagation of crop species. Genetic fidelity of in vitro raised 45 plants of gerbera (Gerbera jamesonii Bolus) derived from three different explants, viz., capitulum, leaf and shoot tips, was assessed by 32 ISSR markers, for their genetic stability. Out of 32 ISSR markers, 15 markers produced clear, distinct and scorable bands with an average of 5.47 bands per marker. The markers designed from AG motif amplified more number of bands. The markers anchored at 3′ ends produced high number of consistent bands than unanchored markers. Fifteen ISSR markers generated a total of 3773 bands, out of which 3770 were monomorphic among all the clones. The Jaccard's similarity coefficient revealed that out of 45 clones derived from different explants, 44 were grouped into a single large cluster alongwith the mother plant with a similarity coefficient value of 1.00, whereas one clone (C38) remained ungrouped. The clones derived from capitulum and shoot tip explants did not show any genetic variation, whereas, one of the leaf-derived clones exhibited some degree of variation. © 2008 Elsevier B.V. All rights reserved.
Volume 121, Issue 2, June 2009, Pages 176-181
Łata, B. | Trampczynska, A. | Paczesna, J.
The quali-quantitative distribution of phenolic compounds varies considerably between apple flesh and peel, but the concentration of phenolics is substantially higher in the peel than flesh. Because the peel comprises only a small percentage of the entire fruit weight, its significance as a donor of phenolics is disputable. We assessed the contribution of the peel to the total phenolic yield of 19 apple cultivars. Calculations were based on the weight of the whole fruit and the peel (which is frequently discarded) and the concentration of individual phenolic compounds. On average, 8, 24, 32, 50 and 66% of chlorogenic acid, (+)-catechin, (-)-epicatechin, phloridzin, and rutin, respectively, were present in the peel, which constitutes about 6-8% of the whole apple weight. With the exception of chlorogenic acid, 50% or more, on average, of the above phenolics were present in the peel of 'Granny Smith', 'Idared', 'Red Rome', 'Jonamac' and 'Gloster' apples; the highest percentage was found in 'Starking Delicious' apple peel (82%). The lowest peel contribution to total phenolic content per whole apple ranged between 26 and 29% and was observed in 'Pilot', 'McIntosh' and 'Prima' apples. Presented results may be useful for further investigations of the relationship between phenolics and agronomical parameters or future selection of apple genotypes having improved nutritional quality when consumed as fresh or as processed apple products. © 2009 Elsevier B.V. All rights reserved.
Effects of proline on antioxidant system in leaves of grapevine (Vitis vinifera L.) exposed to oxidative stress by H2O2
Volume 119, Issue 2, January 2009, Pages 163-168
Ozden, M. | Demirel, U. | Kahraman, A.
Although proline is one of the major computable organic solutes that accumulate in many plant species in abiotic stresses, a hot debate continues about whether proline accumulation is a reaction to abiotic stress, or a plant's response is associated with stress tolerance. The effects of proline on antioxidative system in grape leaves of Vitis vinifera L. cv., 'Öküzgözü' exposed to oxidative stress by H2O2 was investigated. Endogenous proline, hydrogen peroxide (H2O2), malondialdehyde (MDA) concentrations, percentage of electrolyte leakage (EL), and some of the antioxidant enzyme activities; such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (POD) were measured spectrophotometrically. Inhibitory effect of H2O2 on antioxidant enzyme activities, MDA, and EL was found. In the presence of proline, SOD and CAT activities decreased, while POD and APX activities increased. Proline pre-treatment resulted in a decrease in cellular H2O2 content, MDA, and EL, while cellular concentration of proline increased. Based on the finding, it was suggested that proline and H2O2 could play an important role in oxidative stress injury of grapevine leaves grown in vitro culture. Also, proline might have a direct positive effect on antioxidant enzyme system, membrane phase change, MDA, and EL. Crown Copyright © 2008.
Volume 122, Issue 4, November 2009, Pages 507-520
Chugh, S. | Guha, S. | Rao, I.U.
Orchids are among the most diverse of the flowering plant families, with over 800 described genera and 25,000 species. Orchids are prized for their beautiful long lasting flowers exhibiting an incredible range of diversity in size, shape and colour. Today growing orchids is more than just a hobby, it is an international business covering around 8% of the world floriculture trade and has the potential to alter the economic landscape of a country. Large-scale multiplication of exquisite and rare hybrids using tissue culture techniques has helped orchids occupy a position as one of the top ten cut flowers. As orchids are outbreeders, their propagation using seeds leads to the production of heterozygous plants. Hence, protocols providing regeneration from various vegetative parts of the plants are needed. Though orchid micropropagation has shown spectacular development in the recent years, the wide spread use of micropropagation is believed to be still limited due to problems like exudation of phenolics from explants, transplantation to field, somaclonal variation etc. We endeavour to include the major investigations on explant-based orchid tissue culture starting from the pioneering works of Rotor [Rotor, G., 1949. A method of vegetative propagation of Phalaenopsis species and hybrids. Am. Orchid Soc. Bull. 18, 738-739] followed by Morel [Morel, G., 1960. Producing virus-free cymbidiums. Am. Orchid Soc. Bull. 29, 495-497] and Wimber [Wimber, D.E., 1963. Clonal multiplication of cymbidiums through tissue culture of the shoot meristem. Am. Orchid Soc. Bull. 32, 105-107] to date. © 2009 Elsevier B.V. All rights reserved.
Impacts of water stress on gas exchange, water relations, chlorophyll content and leaf structure in the two main Tunisian olive (Olea europaea L.) cultivars
Volume 119, Issue 3, February 2009, Pages 257-263
Guerfel, M. | Baccouri, O. | Boujnah, D. | Chaïbi, W. | Zarrouk, M.
Leaf structural adaptations for the reduction of water loss were examined in two olive (Olea europaea L.) cultivars (Chemlali and Chétoui) growing under water stress conditions. Leaf measurements included leaf tissue thickness, stomatal density, trichome density, specific leaf area, leaf density, water relations, and gas exchange. We found considerable genotypic differences between the two cultivars. Chemlali exhibited more tolerance to water stress, with a thicker palisade parenchyma, and a higher stomatal and trichome density. Chemlali leaves also revealed lower specific leaf area and had higher density of foliar tissue and lower reduction in net CO2 assimilation rate. The mechanisms employed by these two cultivars to cope with water deficit are discussed at the morpho-structural level. The morphological and structural characteristics of the leaves are in accordance with physiological observations and contribute to the interpretation of why the olive cv. Chemlali is more drought-tolerant than cv. Chetoui. Furthermore, from the behaviour of Chemlali plants we consider this cultivar very promising for cultivation in semi-arid areas. © 2008 Elsevier B.V. All rights reserved.
Grafting as a tool to improve tolerance of vegetables to abiotic stresses: Thermal stress, water stress and organic pollutants
Volume 127, Issue 2, December 2010, Pages 162-171
Schwarz, D. | Rouphael, Y. | Colla, G. | Venema, J.H.
Due to limited availability of arable land and the high market demand for vegetables around the world, cucurbit (cucumber, melon, and watermelon) and solanaceous (eggplant, pepper and tomato) crops are frequently cultivated under unfavourable soil and environmental conditions. These include thermal stress, drought and flooding, and contamination by persistent organic pollutants. Plants exposed exhibit various physiological and pathological disorders leading to stunted growth and severe loss in fruit quality and yield. One way to avoid or reduce losses in production caused by adverse soil chemical and physical conditions and environmental stresses in vegetables would be to graft them onto rootstocks capable of reducing the effect of external stresses on the shoot. This review gives an actual overview how grafting can alleviate the adverse effects of environmental stresses on vegetable's crop performance at agronomical, physiological, and biochemical levels. Implications for the selection and breeding of stress-tolerant rootstocks are discussed. © 2010 Elsevier B.V.
Differential effect of cultivar and harvest date on nectarine colour, quality and consumer acceptance
Volume 120, Issue 1, March 2009, Pages 41-50
Iglesias, I. | Echeverría, G.
The influence of nectarine cultivar and the harvest date on fruit colour, fruit size, fruit quality parameters, and consumer acceptance were assessed. The analyses were carried on cultivars with different fruit taste (acidity and sweetness), from 5-years-old trees at the IRTA-Experimental Station of Lleida (Spain). The six cultivars were grouped in three pairs in which each had a similar commercial harvest date. Each pair comprised by a non-acid cultivar and an acid cultivar, except the pair of 'Big Top®' and 'Mesembrine®', which included two non-acid cultivars. The nectarines were harvested at 8 days intervals on five harvest dates, three of which were before the commercial harvest date, one at commercial harvest and another 1 week after commercial harvest. On all of the harvest dates the non-acid cultivars always presented a more intensity of red skin colour than the acid cultivars, and they developed red colouration earlier. Compared to non-acid, acid cultivars showed also a greater differences in red colour between the exposed side and the shade side of the fruit. The evolution of fruit weight and of soluble solids content over the different harvest dates was similar for both groups of cultivars. Acid cultivars showed a significantly faster decrease in fruit firmness, especially evident in the case of early season cultivars as 'Alicecov'. The sugar-to-acid ratio of the non-acid nectarines was 2-3 times higher than with the acid cultivars. The consumer acceptance was always greater for non-acid than for acid cultivars, even at early or advanced stages of fruit maturity. © 2008 Elsevier B.V. All rights reserved.
Genetic diversity and relationships within Citrus and related genera based on sequence related amplified polymorphism markers (SRAPs)
Volume 121, Issue 3, July 2009, Pages 306-312
Uzun, A. | Yesiloglu, T. | Aka-Kacar, Y. | Tuzcu, O. | Gulsen, O.
Sequence related amplified polymorphism (SRAP) markers were used to detect molecular marker polmorphisms among 86 citrus and their relatives in Aurantioidea. Twenty-one SRAP primer combinations produced a total of 376 polymorphic fragments with an average of 17.9 per primer combination and an average polymorphism information content (PIC) of 0.86. The unweighted pair group method arithmetic average (UPGMA) analysis demonstrated that the accessions had a similarity range from 0.28 to 1.00 with a mean of 0.64. The subtribe Clauseninae (tribe Clauseneae) separated from the subtribes of the tribe Citreae. The subtribe Balsamocitrinae (tribe Citreae) was the most distant from the others. In the Citrinae, 'primitive citrus fruit trees' and 'near citrus fruit trees' groups did not clearly separate from each other but all genera in these groups were distinct. On the other hand, subgenus Papeda and subgenus Citrus were not separated clearly in the dendrogram. C. maxima, C. medica and C. reticulata separated into three distinct clusters in agreement with three 'true basic species' thesis. Similarity-based analyses supported the theory of few ancestral species in Aurantioidea. © 2009.
Volume 121, Issue 4, August 2009, Pages 447-450
Koca, I. | Karadeniz, B.
Seven wild and ten cultivated blackberries (Arapaho, Bartin, Black Satin, Bursa 1, Bursa 2, Cherokee, Chester, Jumbo, Navaho, and Ness), and six lowbush (Vaccinium arctostaphylos) and four highbush (Vaccinium corymbosum) blueberries fruits (Ivanhoe, Jersey, Northland, and Rekord) were analyzed for total anthocyanins, total phenolics, and antioxidant activity as ferric reducing antioxidant power (FRAP) in this study. The respective ranges of total anthocyanin and total phenolic contents of the tested samples were: blackberries, 0.95-1.97 and 1.73-3.79 mg g-1 and blueberries, 0.18-2.94 and 0.77-5.42 mg g-1. FRAP values varied from 35.05 to 70.41 μmol g-1 for blackberries, 7.41 to 57.92 μmol g-1 for blueberries. Wild blackberries had the highest FRAP values while wild blueberries had the highest total phenolic and total anthocyanin contents. A linear relationship was observed between FRAP values and total phenolics for blueberries (r = 0.981). The anthocyanin pigments in samples were isolated and characterized by high-performance liquid chromatography (HPLC) with UV-visible detection. Cyn-3-glu was the predominant anthocyanin in all blackberry fruits. © 2009 Elsevier B.V. All rights reserved.
Volume 127, Issue 2, December 2010, Pages 147-155
Colla, G. | Rouphael, Y. | Leonardi, C. | Bie, Z.
Salinity is one of the major abiotic stresses that reduce plant growth and crop productivity in many vegetable production areas of the world. Grafting can represent an interesting tool to avoid or reduce yield losses caused by salinity stress in high-yielding genotypes belonging to Solanaceae and Cucurbitaceae families. Grafting is an integrative reciprocal process and, therefore, both scion and rootstock can influence salt tolerance of grafted plants. Grafted plants grown under saline conditions often exhibited better growth and yield, higher photosynthesis and leaf water content, greater root-to-shoot ratio, higher accumulation of compatible osmolytes, abscisic acid and polyamines in leaves, greater antioxidant capacity in leaves, and lower accumulation of Na+ and/or Cl- in shoots than ungrafted or self-grafted plants. This report gives an overview of the recent literature on the salinity response of grafted plants and the mechanisms of salt tolerance in grafted plants related to the morphological root characteristics and the physiological and biochemical processes. The review will conclude by identifying several prospects for future researches aiming to improve the role of grafting in vegetable crops grown under saline conditions. © 2010 Elsevier B.V.
Volume 120, Issue 2, April 2009, Pages 271-275
Bettaieb, I. | Zakhama, N. | Wannes, W.A. | Kchouk, M.E. | Marzouk, B.
The effects of water deficit on vegetative growth, fatty acids and essential oil yield and composition of Salvia officinalis aerial parts were investigated. Plants were treated with different levels of water deficit (C, MWD and SWD). Results showed important reductions of the different growth parameters. Drought decreased significantly the foliar fatty acid content and the double bond index (DBI) degree. This later was provoked mainly by a strong reduction of linolenic acid proportion and the disappearance of palmitoleic acid. Besides, moderate deficit increased the essential oil yield (expressed as g/100 g on the basis of dry weight) and the main essential oil constituents were camphor, α-thujone and 1.8-cineole which showed an increasing under moderate water deficit. © 2008 Elsevier B.V. All rights reserved.
Investigation of physico-chemical properties and antioxidant activity of twenty Iranian pomegranate (Punica granatum L.) cultivars
Volume 126, Issue 2, September 2010, Pages 180-185
Tehranifar, A. | Zarei, M. | Nemati, Z. | Esfandiyari, B. | Vazifeshenas, M.R.
Pomegranate is one of the native fruits of Iran which contains high genetic resources, but there are insufficient information regarding properties of the fruit. The objective of the present study was to investigate the physcio-chemical characteristics and antioxidant activity of twenty pomegranate cultivars grown in Iran. This study showed that there were significant differences among the cultivars in all measured factors except the length/diameter ratio of fruit. The fruit weight, skin percentage, aril percentage and juice percentage were within the range of 196.89-315.28g, 32.28-59.82%, 37.59-65% and 26.95-46.55%, respectively. The total soluble solids content varied from 11.37 (°Brix) to 15.07 (°Brix), pH values from 3.16 to 4.09, titratable acidity content from 0.33g 100g -1 to 2.44g 100g -1 and total sugars content from 13.23g 100g -1 to 21.72g 100g -1. The results also showed that the values of ascorbic acid ranged from 9.91mg 100g -1 to 20.92mg 100g -1. The total anthocyanins content was observed in pomegranate cultivars between 5.56 mg 100g -1 and 30.11mg 100g -1. The level of total phenolics was varied from 295.79mg 100g -1 to 985.37mg 100g -1. The antioxidant activity of pomegranate cultivars was found between 15.59 and 40.72%. These data demonstrated that the cultivar was the main parameter which influences the physico-chemical properties and antioxidant activity in pomegranates. © 2010 Elsevier B.V.
Volume 127, Issue 2, December 2010, Pages 156-161
Savvas, D. | Colla, G. | Rouphael, Y. | Schwarz, D.
The response of grafted vegetables to stress conditions owing to the nutrient status, and the presence of heavy metals in the root environment may be different than that of self-rooted plants, depending mainly on the rootstock genotype. Several studies have indicated that some rootstocks are capable of restricting the uptake and/or the transport of heavy metals (e.g. Cd, Ni, Cr) and micronutrients (e.g. Cu, B and Mn) to the shoot, thereby mitigating the stress caused by excessive external concentrations of them. However, other mechanisms driven by the root system, such as detoxification of harmful elements or hormonal signals modifying gene expression in the scion, seem to be involved in the mitigation of stress caused by excessive external nutrient or heavy metal concentrations. On the other hand, the uptake and/or utilization efficiency of macronutrients (N, P, K, Ca and Mg) by plants may be enhanced by grafting onto some rootstocks. This is ascribed mainly to the root characteristics of these rootstocks, which are more vigorous than those of highly productive cultivated varieties. However, other mechanisms implicated in the efficiency of active nutrient absorption by the roots, as well as signals arising from the scion, which are mainly governed by sink demand, may also enhance nutrient uptake and utilization. The higher efficiency of some graft combinations of fruit vegetables to take up and utilize nutrients may mitigate yield losses owing to shortages of these nutrients in the root environment of plants and restrict nutrient losses due to leaching. Nevertheless, it is important to specifically test each grafting combination and not merely each rootstock for its ability to ameliorate nutrient or heavy metal stress because in many instances the responses depend on the rootstock/scion combination. This report gives an overview on the prospects and restrictions of grafting as a means to minimize the negative effects of heavy metals, excessive nutrient availability, nutrient deficiency, and alkalinity stress on vegetable crop performance taking into consideration agronomical, physiological and biochemical aspects. © 2010 Elsevier B.V.
Volume 125, Issue 3, June 2010, Pages 211-217
Flores, F.B. | Sanchez-Bel, P. | Estañ, M.T. | Martinez-Rodriguez, M.M. | Moyano, E. | Morales, B. | Campos, J.F. | Garcia-Abellán, J.O. | Egea, M.I. | Fernández-Garcia, N. | Romojaro, F. | Bolarín, M.C.
The possibility of applying grafting to improve fruit quality has been scarcely investigated. Different shoot tomato (Solanum lycopersicum) genotypes were grafted onto distinctly-different tomato rootstocks and the effect of the rootstock on two important fruit quality parameters, soluble solids content (SSC) and titratable acidity (TA), was studied under both non-saline and saline conditions. Increased SSC and TA in fruits from grafted plants grown under saline conditions were observed on different grafting combinations. One of these rootstocks (cv. Radja) was able to induce increases in both fruit yield and fruit quality traits of the scion. When recombinant inbred lines (RILs) from the crossing of the cultivated tomato and wild tomato (Solanum cheesmaniae) were tested as rootstocks, using the commercial hybrid 'Boludo' as scion, the rootstock also improved SSC and TA when grafted plants were grown under non-saline conditions. On the whole, these results show the effectiveness of grafting with respect to upgrading of fruit quality in tomato, which is of great importance as grafting is a rapid and efficient alternative to achieve this goal. © 2010 Elsevier B.V. All rights reserved.
Physico-chemical and antioxidant properties of six apple cultivars (Malus domestica Borkh) grown in southern Brazil
Volume 122, Issue 3, October 2009, Pages 421-425
Vieira, F.G.K. | Borges, G.D.S.C. | Copetti, C. | Amboni, R.D.D.M.C. | Denardi, F. | Fett, R.
The objective of this study was to compare the physico-chemical properties and antioxidant activity of six apple cultivars grown in southern Brazil. Apple peel color, dry matter, total soluble solids, pH, total sugars, titratable acidity, total phenolics, total monomeric anthocyanin and total antioxidant activity were measured in the apple cultivars Imperatriz, Daiane, Fred Hough, Fuji Suprema, Galaxy and Baronesa. The results showed great quantitative differences in the composition of the apple cultivars. Of all the cultivars, the peel of Galaxy was slightly more red-colored and that of Fred Hough was the least red-colored. The dry matter varied from 15.24% (Galaxy) to 19.55% (Fuji Suprema), the soluble solids content was between 11.8 (Fred Hough) and 14.0 (Daiane) °Brix, pH values varied from 3.90 (Imperatriz) to 4.27 (Fred Hough), the total sugar content (g 100 g -1) ranged from 11.54 (Imperatriz) to 14.78 (Fuji Suprema) and the titratable acidity content (g 100 g -1) varied from 0.20 (Baronesa) to 0.36 (Imperatriz). The total phenolic content (GAE 100 g -1 fresh matter) observed in the apple cultivars was between 105.4 (Baronesa) and 269.7 mg (Imperatriz). The values of the total anthocyanin content (mg 100 g -1 FM) ranged from 4.79 (Fred Hough) to 41.96 (Galaxy). The highest total antioxidant activity was observed in Imperatriz (739 μmol TEAC 100 g -1 FM), while the lowest value was found in Fuji Suprema (335 μmol TEAC 100 g -1 FM). There was a strong correlation between total monomeric anthocyanin content and all peel color measurements and between antioxidant activity and total phenolic content. The results suggested that genotype is the main factor that determines the composition of bioactive compounds in apples and this provides important information on how to make the best use of the apple cultivars investigated. © 2009 Elsevier B.V. All rights reserved.
Application of chlorophyll fluorescence for the diagnosis of salt stress in tomato "Solanum lycopersicum (variety Rio Grande)"
Volume 120, Issue 3, May 2009, Pages 367-372
Zribi, L. | Fatma, G. | Fatma, R. | Salwa, R. | Hassan, N. | Néjib, R.M.
To study the response of tomato (Solanum lycopersicum cv. Rio Grande) to salinity, the effect on plant growth, water relations, stomatal conductance and Chlorophyll fluorescence was investigated. Tomato plants were grown in peat culture under controlled conditions and submitted during 28 days to saline stress ranging from 0 to 25, 50, 100, 150 and 200 mM of NaCl. At the end of the experiment period, plant growth was significantly decreased with increasing salinity. During the three weeks following the application of NaCl, stomatal conductance (g s) and water potential (ψ w) decreased gradually with the increase of salinity. Indeed, salinity treatment showed no changes in all chlorophyll fluorescence parameters. In the fourth week, the water potential and stomatal conductance decreased significantly. PSII photochemistry in light-adapted leaves was modified in salinity-stressed plants; while in dark-adapted leaves, there were no changes in the maximum quantum efficiency of the PSII photochemistry. The strong correlations between the foliar content of Na + and Chl a fluorescence characteristics (the actual PSII efficiency (Φ PSII), the photochemical quenching (q p), the non photochemical quenching (NPQ), and the linear electron transport rate (ETR)) suggest that these parameters can be used to screen genotypes for salt tolerance. © 2008 Elsevier B.V. All rights reserved.
Polyamines enhance chilling tolerance of cucumber (Cucumis sativus L.) through modulating antioxidative system
Volume 122, Issue 2, September 2009, Pages 200-208
Zhang, W. | Jiang, B. | Li, W. | Song, H. | Yu, Y. | Chen, J.
Cucumber chilling-resistant cultivar Changchun mici and -sensitive cultivar Beijing jietou were used in this study to investigate the effects of exogenous PAs on protection against chilling injury as well as on changes of physiological features, and the fluctuation of free PAs content in the leaves under chilling stress. Upon chilling treatment, free spermidine (Spd), spermine (Spm) and putrescine (Put) were remarkably induced in the leaves of cv. Changchun mici 1 day after treatment. The induction of Put declined thereafter, whereas Spd and Spm levels increased steadily. In the leaves of cv. Beijing jietou, Put content was increased only at 1 day after chilling while Spd content decreased significantly upon chilling treatment. Chilling reduced soluble protein content, and decreased the activities of antioxidant enzymes, including superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) only in Beijing jietou. However, these changes could be renovated by exogenous application of Put and Spd. It was also found that pretreatment with Put and Spd diminished the increased electrolyte leakage and malondialdehyde (MDA) content caused by chilling in the leaves of both cultivars. Pretreatment of methyglyoxal-bis-(guanylhydrazone) (MGBG), the PAs biosynthetic inhibitor cancelled the effects of PAs in most of the treatments. Moreover, histochemical staining and quantitative measurements showed that exogenous application of Put and Spd eliminated but MGBG exaggerated the hydrogen peroxide (H 2O 2) accumulation caused by chilling stress, especially in leaves of Beijing jietou. Interestingly, Changchun mici was found to contain higher endogenous free PAs contents compared to Beijing jietou. While no significant difference of SOD, POD and CAT activities was found between non-chilling Changchun mici and Beijing jietou seedlings, the former exhibited higher APX activity than the latter. These results suggest that PAs play important roles in the tolerance of cucumber against chilling stress, which is most likely achieved by acting as oxidative machinery against chilling injury. © 2009 Elsevier B.V. All rights reserved.
Effects of fruit bagging on coloring and related physiology, and qualities of red Chinese sand pears during fruit maturation
Volume 121, Issue 2, June 2009, Pages 149-158
Huang, C. | Yu, B. | Teng, Y. | Su, J. | Shu, Q. | Cheng, Z. | Zeng, L.
Red Chinese sand pears (Pyrus pyrifolia Nakai) are particular to China. In order to determine the effects of fruit bagging treatments (including bag types, bag removal patterns and dates) on fruit qualities and to understand the mechanism of coloring of red Chinese sand pears, two experiments were carried out. In the first experiment, fruit of 'Meirensu' were firstly covered by light-impermeable paper bags with different levels of light permeable liners during their early development stage, then, the whole bag were/not removed or only the outer layer of bags were removed 3, 2 or 1 weeks before harvest. Thus, the fruit were/not totally re-exposed or were under different levels of sunlight transmission (80.31% or 34.71%). Non-bagged fruit were used as the control. Bagging treatments significantly affected the concentration of anthocyanin and the visual qualities of pear fruit. Compared to control, fruit re-exposed totally for 2 or 3 weeks accumulated the largest amount of anthocyanin and fruit receiving 80.31% and 34.71% of sunlight for 1-3 weeks could synthesize a little anthocyanin, indicating that high light intensity is imperative for coloring in red Chinese sand pears. Bagging treatments did not affect contents of total soluble sugars, but decreased organic acids contents in fruit. In the second experiment, fruit of 'Meirensu' and 'Yunhongli No. 1' were covered with only one type of light-impermeable bag during the early development stage and totally re-exposed after the bag removal 15 days before harvest. Fruit were then collected at different intervals to trace the time-course of coloring, and related physiology and inner qualities. With increasing time after the bag removal, the concentration of chlorophyll, carotenoid, flavonoid and total phenols changed little, but the concentration of anthocyanin accumulated extremely fast within 10 days after the bag removal in both cultivars and thereafter kept constant. 'Yunhongli No. 1' had higher anthocyanin contents and lower hue angle than 'Meirensu', indicating a higher potential of anthocyanin synthesis. After the bag removal, the sucrose contents and PAL activities increased gradually and correlation analysis revealed that they were highly correlated with anthocyanin accumulation in two cultivars. This study suggests that anthocyanin biosynthesis in red Chinese sand pears is a highly light dependent process and modified by genotypes. Based on the current results, in order to obtain red Chinese sand pear fruit with attractive appearance and good inner qualities, fruit must be covered with light-impermeable bags at the early stage of fruit development and the bag should be removed totally at least 10 days before harvest. © 2009 Elsevier B.V. All rights reserved.
Volume 127, Issue 2, December 2010, Pages 106-111
King, S.R. | Davis, A.R. | Zhang, X. | Crosby, K.
In many parts of the world, grafting is a routine technique used in continuous cropping systems. It was first commonly used in Asia during the late 1920s by grafting watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai) onto pumpkin [. Cucurbita moschata Duchesne ex. Poir] rootstocks. Use of rootstocks can enhance whole plant biotic stress responses by improving plant vigor through vigorous attainment of soil nutrients, avoidance of soil pathogens and tolerance of low soil temperatures, salinity, and wet-soil conditions. The type of rootstock affects scion growth, yield, and fruit quality. Grafting is rare in the United States, due in part to cost and availability of facilities, but with continued loss of quality disease-free farmland along with the phase-out of methyl bromide, vegetable grafting is an attractive option. However, grafting cost, limited grafting facilities, methyl bromide exclusions, shipping costs, and legal issues associated with contracting for grafted plant delivery have caused slow acceptance of this option. This review discusses recent literature on vegetable grafting with a focus on the genetics and breeding of the rootstock, and delves into current issues affecting the grafting industry. Issues affecting acceptance of grafting in the United States and Canada are highlighted. © 2010.
Volume 127, Issue 2, December 2010, Pages 127-146
Louws, F.J. | Rivard, C.L. | Kubota, C.
Grafting is an important integrated pest management strategy to manage soilborne pathogens and other pests of solanaceous and cucurbitaceous crops. Important diseases managed by grafting are caused by fungal pathogens such as Verticillium, Fusarium, Pyrenochaeta and Monosporascus; oomycete pathogens like Phytophthora; bacterial pathogens, particularly Ralstonia; root knot nematodes and several soil-borne virus pathogens. Rootstocks can include intraspecific selections that utilize specific major resistance genes and interspecific and intergeneric selections that exploit non-host resistance mechanisms or multigenic resistance. Rootstock selection has also been documented to impact foliar pests including pathogens, arthropods and viruses. Over-reliance on specific rootstocks in production systems has led to the emergence of new pathogens or shifts in the host specificity of the pathogen population, emphasizing the need for multi-tactic approaches to manage soilborne pathogens. One advantage and associated challenge of grafting is that rootstock selection for disease management is site specific depending on the presence, population structure and dynamics of the pathogen, as well as edaphic, environmental and anthropogenic factors. The use of grafting as an Integrated pest management tool to manage biotic stress will be most successful when carried out with increasing knowledge about the biology, diversity, and population dynamics of the pathogen or other pests and when complemented with sustainable farming system practices. This review highlights major uses of grafting to manage soilborne pathogens, provides some novel information on managing foliar or other soilborne pests (insects, mites, weeds) and offers discussion on future research and applications. © 2010 Elsevier B.V.