Abstract: As a cool weather crop, lettuce (Lactuca sativa L.) is very sensitive to the changes in temperature during growth. This study investigated the textural, compositional and some biochemical changes in the outer and inner leaf tissues of two crisphead lettuce cultivars ('Bittsu' and 'Cisco') harvested in different seasons. The result demonstrated that in colder months, the crispiness of lettuce leaves reduced significantly and higher amount of sugars, organic acids and ammonia were accumulated. In general, between the two cultivars, 'Bittsu' contained higher amount of sugars and organic acids, while 'Cisco' contained higher amount of ammonia. However, inner leaf tissues contained higher amount of ammonia than outer leaf tissues in both cultivars. The level of fructose was found to be higher than glucose and sucrose in all cases while malic acid was the main component in organic acid fraction. The activities of ammonia-assimilating enzymes such as glutamine synthetase (GS; EC 184.108.40.206) and asparagine synthetase (AS; EC 220.127.116.11) either decreased or nearly remain constant depending on the tissue types during the colder months. Outer leaf portion showed higher GS activity than inner leaf tissues. However, both of aminating and deaminating activity of glutamate dehydrogenase (GDH, EC 18.104.22.168) decreased in the outer leaves whereas deamination activity slightly increased in the inner leaf tissues during warmer harvest months.
Alaa Eldin Khalil Omar
Department of Horticulture, Faculty of Agriculture, Kafr El-Sheikh University, Kafr El-Sheikh 33516, Egypt
Abstract: This study was conducted during two successive seasons (2005 and 2006); in the experimental farm of Faculty of Agriculture, Kafr El Sheikh University; with the aim to investigate the influence of arbuscular mycorrhizal fungi (AMF) inoculation and irrigation intervals on growth of grapevine nurslings cv. Ruby King. Two mix mycorrhizal fungi including Glomus fasiculatum and Glomus mosseae were used for inoculation. The AMF inoculated and non-AMF nurslings were irrigated at 3, 6 and 9 days interval. The results showed that a combined treatment of AMF inoculation and irrigation at 3 days intervals recorded the highest values in terms of length of main root, total root length, root volume, root dry weight (%), top/root ratio, number of fine roots (< 2 mm), number of small roots (2-5 mm), number of leaves and leaf area per nursling. These results are of practical importance, as they highlight the potential of using mycorrhizal fungi inoculation for root development and growth improvement in grapevine nurslings and hence increases its adaptability upon transfer from the nursery to the open field.
Ji Heun Hong, Sung Kee Hwang, Guk Hoon Chung, and A. Keith Cowan
Biotech Institute, GlonetBU, Doosan Corporation, Yongin 449-795, Korea; AKConsulting, Grahamstown 6140, South Africa.
Abstract: The effect of foliar applications of lysophosphatidylethanolamine (LPE) on 'Thompson Seedless' (Vitis vinifera L.) was evaluated to determine the suitability of this plant amendment aid as a management tool in table grape production. LPE at 10 mg L-1 was sprayed on vines at two different stages of berry growth and development. Treatments were: 1) 4 weeks after fruit set; 2) 6 weeks after fruit set; and 3) 4 and 6 weeks after fruit set. Soluble solids content (SSC) of berries at all harvest dates was significantly higher for vines treated with LPE compared to the control. Titratable acidity (TA) gradually decreased during ripening, and by the third harvest, TA of berries from vines treated with LPE was lower than that of control. All the treatments resulted in higher fruit firmness when compared to control. However, there were no significant differences in firmness of berries from vines given LPE treatment at different stages of growth. LPE treatment increased berry size, although no significant difference in size between single and sequential applications of LPE was observed. These results indicate that LPE may play a role in plant hormone-associated regulation of berry growth and development.
Esmaeil Chamani, Daryl C. Joyce, Behroz Esmaeilpour
Department of Horticulture, Faculty of Agriculture, University of Mohaghegh Ardabili, Ardabil, Iran.
Key words: Dianthus caryophyllus 'Lunetta', preharvest, postharvest, Thidiazuron, vase life.
Abstract: Experiments were conducted to determine the effects of Thidiazuron (TDZ) applied at preharvest stage under glasshouse conditions on Dianthus caryophyllus 'Lunetta'. Thidiazuron at 0, 1, 10, 100, and 1000 uM was applied as a foliar spray arranged in completely randomized design. Time to flowering was recorded, and relative stem length, total nitrogen and tissue water content were measured at harvest. Postharvest vase life, relative fresh weight changes, and solution uptake were also measured. TDZ treatments decreased relative stem length compared to the control (0 uM). TDZ treatment tended to decrease total nitrogen and water content of tissues slightly, but not significantly (P > 0.05). TDZ at 100 uM significantly increased the vase life of cut carnation flowers compared to the control. TDZ treated flowers tended to maintain higher relative fresh weight, with positive differences for the 100 uM TDZ treatment being apparent at day 5, 7 and 9 of vase life. Solution uptake was higher in TDZ treated flowers.
NasserAlKhalifah, E.Askari, andA.E. Shanavaskhan,
King Abdulaziz City for Science and Technology (KACST), Post Box 6086, Riyadh 11442, Saudi Arabia.
Abstract: With the increasing number of turfgrass cultivars, development and use of reliable identification methods is becoming important. Random amplified polymorphic DNA (RAPD) markers along with morphological markers proved useful for cultivar identification. Seven turfgrass cultivars encompassing four bermudagrass and three zoysiagrasses were grown under uniform greenhouse conditions and their key diagnostic features were described. Bulk samples of leaves were collected from each cultivar and subjected to RAPD analysis using standard protocols. Out of the 35 Operon primers used, 20 detected polymorphism among the cultivars. 'Nagissa' and 'Miyako' zoysiagrasses showed close genetic relationship as compared to the rest of the cultivars. They had the highest value in the similarity matrix for Nei and Li's coefficient (0.802) while one variant of Miyako clustered with Bermuda-1. Tifgreen Bermuda and Bermuda-2 also clustered together while 'Tifway' stood apart. Analysis of the morphological data showed that the variant of ' Miyako' belonged to the Zoysia genus but its genetic affinity with Bermudagrass needs to be explained. Within and between species, the cultivars having similar leaf-texture showed a tendency to cluster together.
B. Sinha and J. Tarafdar
Department of Plant Pathology, Bidhan Chandra Krishi Viswa Vidyalaya, Mohanpur, Nadia-741252, West Bengal, AICRP on Tuber Crops, Directorate of Research, BCKV, Kalyani, West Bengal. India.
Key words: Sweet potato, viruses, symptoms, NCM-ELISA, coat protein
Abstract: The natural occurrence of sweet potato virus disease (SPVD) in 26 Indian sweet potato cultivars was evaluated at Horticultural Experimental Field of the B.C.K.V. University, West Bengal during 2004-2005 seasons based on the possible symptoms and serology. The leaves from virus suspected plants were indexed for viruses by nitrocellulose membrane enzyme-linked immunosorbent assay (NCM-ELISA) and coat protein study. Disease incidence was highest in Pol-4-9 during 2004 (12.87%) and 2005 (25.19%). Results were confirmed in several seropositive plants with higher incidence and diversity of viruses. Sweet potato feathery mottle virus (SPFMV), sweet potato cauliflower mosaic like virus (SPCaLV), Sweet potato mild speck virus (SPMSV) and C-6 virus were detected serologically in single or mixed infections in many leaf samples of the cultivars. The frequency of C-6 virus was very high (73.07%) followed by SPCaLV (34.61%), SPFMV (26.92%) and SPMSV (23.07%). Attempt was made to characterize the virus coat protein of the partially purified virus from the leaves with most frequently observed symptoms. Protein analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed a major protein band of 65 kDa, and 38 kDa which were assumed to be the viral coat proteins of associated virus. Minor protein bands of 24 kDa were also observed. The viral protein degraded upon storage at 4?C over time to yield a protein band of 22 kDa.
Erdinc Bal and Demir Kok
Namik Kemal University, Horticulture Department, Agricultural Faculty, Tekirdag/Turkey.
Abstract: Muskule grape variety which has table and late maturing attributes, was used for this study. Storage of table grapes requires stringent control of gray mold, which is caused by Botrytis cinerea Pers. In spite of the fact that the use of sulfur dioxide (SO2) in controlling gray mould is common practice, it has some advantages and disadvantages. Thus, physical, natural organic elicitors and biological methods have been used for delaying decays. In this study, UV-C (0.25kJ m-2), salicylic acid (1, 2, 3mM) and Na2S2O5 (0.4g powdered sodium metabisulfate pads) treatments were used to reduce quality losses during the cold storage of Muskule grape. Treated clusters were placed into polyethylene container and packaged with polyethylene bags having 10.5 a thicknesses and stored at 0?1 oC and 90?5% relative humidity throughout 100 day. At the end of 100 day, weight loss (%), soluble solids content (%), titratable acidity (g 100 mL-1), pH of fruit juice, sensory evaluation, view of cluster skeleton and decay rate (%) were determined at 20 days interval. SA (3mM) + UV-C combined treatment and SA (3mM) treatment were found to be effective depending on examined criterion.
A. Uzun, O. Gulsen, Y.AkaKacar, V.Aras, A. Demirel, M. Bircan, S. Paydas andA. Yildiz
Alata Horticultural Research Institute, Erdemli, Mersin, Turkey-33740;Department of Horticulture, University of Cukurova, Adana, Turkey-0'330.
Abstract: Molecular markers are the most widely used tools in cultivar and species identification. The objective of this study was to characterize some Turkish and European cultivars and new apricot cultivars derived by hybridization between Turkish and European apricot cultivars using RAPD markers. Five new, two local cultivars, and four promising hybrids from Turkey, and 13 cultivars from Europe, North America, South Africa were characterized. Sixty RAPD primers produced 57 polymorphic and 79 monomorphic markers, totaling 136. All the 136 markers were used to construct a dendogram based on UPGMA. All cultivars were distinguished from each other with the similarity value ranging from 0.90 to 0.96. Known hybrids were grouped between or close to either one of parental genotypes. This study may imply narrow genetic diversity among the most widely grown apricot cultivars in the world.
Odiaka Ngozi Ifeoma, Akoroda Malachy and Odiaka Emmanuel
Department of crop Production, College of Agronomy, University of Agriculture, Makurdi, Benue State, Nigeria, Department of Agronomy, University of Ibadan, Ibadan, Oyo State, Nigeria; Cooperative Exten?sion Centre, University of Agriculture, Makurdi, Benu
Key words: Telfairia occidentalis Hook. F., fluted pumpkin, gender, production, constraints, poverty, profit, sustainability, Nigeria.
Abstract: Gender roles in telfairia leaf production were investigated in Makurdi using a survey based questionnaire administered to 50 farmers to identify gender-disaggregated roles in telfairia production. The survey showed that women have major role as producers and marketers of telfairia leaves. Women and girls provided 80.0% of labour requirements for hole digging, sowing, irrigation, weeding, harvesting and marketing. The men cleared land and dug holes while girls and boys in primary and secondary schools assisted in weeding and hole digging. The results also revealed that a typical telfairia farm using N10,650.00 (US$84.5 at N126/dollar) worth of seeds produced 16.5 t/ha of leaves valued at N212,400.00 (US$1,685.7) with 85.0% profit. Seed accounted for 60.7% of total cost of production, while irrigation cost was 20.3%. A minimum take-off fund of N210,572 (US$1671.2) was needed to give revenue of N386,000 (US$2920.6) and a gain of 83% per hectare. Total fruit equivalent of fruits/shoots produced 2,056 fruits and the price of fruit equivalent of fruits/ shoots produced N514,000 (US$4079.4) with a gain of 144%. Two major constraints to leaf production were high cost of quality seeds (36.1% of respondents) and water pumps (13.9% of respondents). Women participation in telfairia vegetable production, marketing and utilization in Makurdi can provide a means of livelihood and appreciable income for women in rural and urban areas, which is capable of sustaining the running of the home and enhancing the living standards of women.
Vijay Paul and G.C. Srivastava
Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi-110 012, India.
Key words: Solanum lycopersicon, minerals, pericarp, ripening, tomato, fruit
Abstract: Two contrasting varieties of tomato (Solanum lycopersicon L.) fruits i.e. 'Pusa Gaurav' (slow ripening type) and 'Pusa Ruby' (fast ripening type) were examined for Ca, P, K, Zn, Cu and Mn contents in the fruit's pericarp portion. Fruits were examined either at different ripening stages during their maturation on the plant itself or at different intervals during storage when harvested at green mature stage. Ca was found to be higher in 'Pusa Ruby'. 'Pusa Gaurav', on the other hand, showed higher content of P, Zn, Cu, Mn but low K in comparison to 'Pusa Ruby'. The roles of these minerals were explained towards their stabilizing effect on plasma membrane and cell wall along with their involvement in the antioxidative system and thereby determining the rate of ripening.
T. Prabu, S.D. Warade, M.A. Jatkar and P.H. Ghante
Department of Horticulture, Mahatma Phule Krishi Vidyapeeth, Rahuri, College of Horticulture, Pune -411 005,Depart-ment of Plant Pathology, Mahatma Phule Krishi Vidyapeeth, Rahuri -413 722. India.
Abstract: Okra germplasm, consisting of 85 accessions, which included cultivars, related species and their inter specific hybrids was screened for two seasons, while their amphidiploids, backcrosses and F3 generations were screened for one season for powdery mildew resistance (Erysiphe cichoracearum DC) under severe field epiphytotic conditions. Only the wild species A. caillei-2 and A. moschatus-1 were found immune while two biotypes of A. tetraphyllus, A. manihot spp. manihot, A. manihot spp. tetraphyllus, A. manihot (L.) Medikus and A. angulosus were found highly resistant to powdery mildew in both seasons. A. tuberculatus-1, A. caillei-1, A. ficulneus and cultivars of A. esculentus were susceptible. Reaction of inter specific hybrids, backcrosses and amphidiploids revealed that the resistance in A. caillei-2, A. angulosus and A. manihot spp. tetraphyllus were partially dominant. Further, it was observed that in F3 generations, only the lines of A. caillei -2 inter specific hybrid derivatives (lines derived from hybrids having A. caillei-2 as one parent) were found highly resistant to powdery mildew.
Iran's Pistachio Research Institute, Qazvin Station, No.''8, Beheshti Blvd. Agri. & Natural Resources Research Center, Qazvin, Iran.
Key words: Pistachio, chilling injury, growth degree day, flowering, fruit development
Abstract: Chilling threshold and growth degree day (GDD) of two main pistachio pistillate cultivars were determined. Layout was factorial based on a complete randomized design with three factors, two cultivars (Qazvini and Ouhedi), 5 thermal levels (+2, 0, -2, -4 and -6 oC) and three developmental stages including dormant bud, swelling bud and fully bloomed flowers for chilling studies. Critical temperature for reversible tissue colour change was determined as -4oC at bud stage, -2oC at blooming bud and +2oC at flower. Decreasing temperature down to two more degrees (e.g. -6 oC at bud) could shift the damage into the irreversible browning injury. For GDD measurements, three factors, including cultivar, thermal accumulation (calculation based on +4.5oC) and phenological stages were considered. Kernel filling period varied in two cultivars; Ouhedi's bigger kernel required more time to grow fully and more growth degrees day. Qazvini needed 2561.044 GDD and 138.5 days for total bearing period (flowering to harvest), and 623.363 GDD and 30 days for kernel filling period. Ouhedi needed 2917.823 GDD and 160 days for total period, and 730.61 GDD and 33.5 days for kernel filling.
S.N. Saxena, S Janjharia,A.K. Sharma, R. Sharma and G. Singh
Plant Biotechnology Centre, Rajasthan Agricultural University, Bikaner-334006
Abstract: Capparis deciduas is an important constituent of desert ecosystem, however, due to population pressure on the land their stands are reducing at an alarming rate. Establishment through root suckers and seeds being very slow and cumbersome, remains the major bottleneck for their reestablishment in the area. Thus, realizing the constraint, a rapid and efficient micropropagation protocol for multiple shoot regeneration employing shoot tip explant was developed. The protocol is more efficient and reproducible than reported earlier. Maximum number of explants (100%) responded on Murashige and Skoog (MS) medium supplemented with 6-benzyl amino purine (BAP) 7 mg L-1 and naphthaline acetic acid (NAA) 0.1 mg L-1 while number of shoots per explant were maximum (8.5) on alone BAP 7 mg L-1. Regenerated shoots could be rooted best on MS medium supplemented with indole butyric acid (IBA) 1 mg L-1. Rooted shoots could be hardened and transplanted in to the field.
A.P. Silva, A. Santos, J. Cavalheiro, C. Ribeiro, F. Santos and B. Gon?alves
'CECEA - Centre for Agricultural Sciences and Engineering, University of Tras-os-Montes e Alto Douro, Apt. '0'3, 500'-80' Vila Real, Portugal, Department of Plant Science and Agricultural Engineering; CETAV - Centre for Technological, Environmental and Li
Abstract: Chemical composition (crude protein, crude fat, starch, neutral detergent fibre - NDF and free a-amino acids) of six hazelnut cultivars (Butler, Ennis, Fertile de Coutard, Grossal, Merveille de Bollwiller and Segorbe) was investigated. Genotype significantly affected fruit nutritive value. Crude protein ranged from 12-17 g 100 g-1 dry weight (dw) in cultivar Ennis and Merveille de Bollwiller, respectively; crude fat was 50-62 g 100 g-1 dw in cvs. Fertile de Coutard and Butler; starch varied from 1.0 to 2.4 g 100 g-1 dw in cvs. Segorbe and Butler; and NDF was 8-14 g 100 g-1 dw in cvs. Merveille de Bollwiller and Ennis. Total free a-amino acids content ranged from 144 mg 100 g-1 dw (cv. Segorbe) to 413 mg 100 g-1 dw (cv. Butler). The essential amino acids content varied between 23 mg 100 g-1 dw (cv. Butler) to 55 mg 100 g-1 dw (cv. Merveille de Bollwiller). Alanine was the main amino acid found (62% of total amino acids) and methionine was the lowest (0.3%). Based on the available data on the phytochemical content of hazelnuts, including the data presented in this study, there is a high likelihood that this fruit will provide positive health benefits.
Abstract: For a citrus grower to choose the right clementine cultivar for a given region or market, it is very important to know the characteristics of that cultivar particularly in terms of the development of its internal as well as external quality attributes. In particular, it is very important to know when the maturity index is attained along with the rate of color change, sugar accumulation, acid dissipation, firmness loss, etc. This paper describes the results obtained for several quality attributes (rind color, firmness, juice content, juice titratable acidity and soluble solids content) of seven clementine cultivars sampled at different stages of maturity. All of the cultivars reached minimum maturity index (sugar / acid ratio greater than 7.0) by early November. The rate of rind color change is significantly influenced by picking period and is the main attribute that differs among most of the clementine cultivars. In addition, 'Guerdane', the new clementine cultivar, is the only cultivar that matures much later (January-February) and has the characteristics of a late-maturing cultivar both internally (juice quality) and externally (rind color).
Oyetunji, O.J. Kabeya, M, Shiwachi, H.
Department of Botany and Microbiology, University of Ibadan, Nigeria. International Institute of tropical Agriculture (IITA), Ibadan, Nigeria.
Key words: D. alata, D. rotundata Poir, cultivars, IBA, mini tuber, root formation, vine cuttings, survival, white yams.
Abstract: The multiplication ratio for seed yam production is very low compared to other tuberous crops. Seven clones of Dioscorea rotundata Poir (white yam) were evaluated for production of mini tubers from their vine cuttings. Three to four nodes leafy vine cuttings were prepared from the middle portion of the lateral branches collected from mother plants 127, 134 and 141 days after planting (DAP). The lower portion of these nodes were wounded with a clean razor blade and then dusted with 1.0% Indole-3 butyric acid (IBA) powder in order to promote rooting. The mini tubers were harvested 115 DAP. The developed mini tubers varied in sizes among the tested cultivars from 1.9 to 4.2g. The weights were found to be genotype dependent. The survival rate of the planted vine cuttings ranged from 31.1 to 77.1% while the average total number of roots per vine ranged from 5.1 to 5.8. The average number of tubers per vine was 1.8 ?0.8. If these number and weights of mini tubers can be obtained from propagation of vine cuttings, there will be tremendous increase in propagating material thereby making yam cultivation less expensive and also allowing the ware yam only for consumption and other uses.
A. Moreira, L.A.C. Moraes, J.C.R. Pereira and C. Castro
'Embrapa Cattle Southeast, Rodovia Washington Luiz, Km 234, C.P. 339, 13560-970, Sao Carlos, Sao Paulo State, Brazil; 2Embrapa Western Amazon, C.P. 3'9, 69011-970, Manaus, Amazonas State, Brazil; 3Embrapa Soybean, C.P. 23', 8600'-970
Abstract: Banana cultivation is ranked as one of the agricultural activities of greatest economic importance and social significance in Brazil. The area under banana cultivation in Brazil (516,000 ha) is larger than India and Ecuador, leading countires in production, but with rather lower productivity due to lack of adequate crop management, particularly fertilizer application. The objective of this work was to investigate the rate of nutrient retranslocation and the effect of fertilization on the yield and uniformity of banana bunches cultivated in central Amazon region. Two field experiments were conducted in a xanthic Ferralsol (dystrophic Yellow Latosol) - predominant soil of the region, examining: a) the nutrient translocation rate in twelve plants; and b) the efficiency of zinc use, in a completely randomized blocks in split plot design with four rates of ZnSO4 (0, 30, 60 and 120 g plant1 cycle1) and two application times (in the hole together with the seedling or applied in the fifth month after planting), with four replicates. Under the local edaphoclimatic conditions, the results show that N, P, K, Mg and Cu have a high retranslocation rate. The plant yield was influenced by the rates of ZnSO4, with the most efficient application method being in the planting hole. Results indicated that at high concentrations, zinc had mobility in the phloem from the leaves to the fruits. The proposed critical leaf zinc concentration at the start of inflorescence was 12.9 mg kg-1 for the third leaf.
Miguel A. del Amor and Francisco M. del Amor
Consejeria de Agricultura y Agua de la Region de Murcia. Plaza Juan XXIII. 30008 Murcia, Spain. Instituto Murciano de Investigacion y Desarrollo Agrario y Alimentario. C/Mayor s/n. 30150 La Alberca. Murcia. Spain.
Key words: Yield, crop quality, total soluble solids (TSS), drought, stress, Solanum lycopersicon L.
Abstract: Field studies were conducted to compare the yield and fruit quality of processing tomatoes in surface and subsurface drip irrigation, with 100 and 50% of crop evapotranspiration (ETc). The results showed that when irrigation was reduced by 50% ETc the subsurface treatment showed higher water content at root depth compared with the on-surface treatment. At 50% ETc subsurface irrigation yield increased by 66.5% compared with the surface treatment. However at 100% ETc no significant difference in total fruit yield was observed between irrigation methods. The superficial and water-stressed treatment increased the pH and the acidity of the fruits but the subsurface treatment did not show differences with respect to the full-irrigation treatments. Our results show that the subsurface drip irrigation method could be reasonably applied for processing tomato when water resources are limited.
John H. Mirandaand Richard Williams
School of Agronomy and Horticulture Science, The University of Queensland, Gatton, Qld.4343, Australia. Present address: Brisbane South Lifestyle Support Services, 48 Duke Street Kangaroo Point, Q 4169
Key words: Carbon dioxide enrichment, air flow, photo system II, photochemical efficiency of PS II (FV/FM), photosynthetic photon flux (PPF), photoinhibition, dry weight, chlorophyll and nitrogen.
Abstract: The influence of light quality and carbon dioxide concentration on the development of photosynthetic functional structures of strawberry leaves in vitro was examined. We assessed the photochemical quenching parameter of chlorophyll a photochemical efficiency of photo system II (PSII) of strawberry leaves in vitro in a factorial set up. The main effects of light quality; averaged over CO2 enriched, air flow and closed systems, increased the initial chlorophyll fluorescence value from 485 for yellow light developed PS II system of leaves to 1142 for white light (control) developed ones. The photochemical efficiency of PSII significantly increased from 0.64 under white light to 0.80 for yellow light developed leaves. The leaves developed under blue light were similar to that of control white light for many chlorophyll fluorescence parameters except the initial chlorophyll fluorescence level. The increase in photochemical efficiency of PSII of strawberry leaves can be attributed to lower initial fluorescence values. Under blue light the total dry weight and total chlorophyll content were increased. The possible role of high mercury peak of white light and photoinhibition during development in vitro is discussed.
Yu Zhou and Bal Ram Singh
Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02747 USA.
Abstract: Cranberry callus was successfully induced from cranberry (Vaccinium macrocarpon Ait, Ericaceae) leaves by using Gamborg's B5 medium containing phytohormones at 25oC in the dark. Anthocyanin-producing cranberry callus was obtained only under conditions of continuous light exposure. Red light and UV light exposure of the callus enhanced anthocyanin content by 41.3 and 29.3%, respectively. The light-dependent anthocyanin production in the callus was regulated by temperature. Anthocyanin content in the callus decreased 81.1% at 42oC, 58.9% at 37oC, 47.0% at 30oC, and increased 10.4% at 4oC, compared to the callus maintained at 25oC after 48 hours of incubation at the given temperature. A temperature decrease of 10oC from 25 to 15oC resulted in a critical increase of the anthocyanin production in the callus, irrespective of differences in pH of culture medium. The growth of the callus cultured in medium at pH 7.0 was 6.2-fold higher than in the same medium at standard pH of 5.8.
Abstract: Response of low-chill peach cultivar 'Premier' to early forcing culture was studied. Three-year-old trees were forced in a glasshouse from 15 November, 1 and 15 December and 1 and 15 January. Symptoms of insufficient chilling were detected when forcing was started from 15 November and 1 December. Bud break was delayed and sporadic. The flower and leaf buds forced from 15 December and 1 and 15 January rapidly burst within 15 days after the onset of the treatments. The final burst rate exceeded 70%. Generally, flowering started 10-15 days after flower bud burst. The size of the flowers from the trees forced from 15 November and 15 January was smaller than that recorded at other forcing times. Earliest harvest started under forcing from 15 December and 1 January. These results suggested that by using this low-chill cultivar, forcing could be initiated from mid-December, more than one month earlier than for high-chill cultivars, with complete dormancy release, in this region.
H. Kitazawa, T. Asao, T. Ban, Y. Hashimoto, T. Hosoki
United Graduate School of Agricultural Sciences, Tottori University, Koyama-cho Minami, Tottori, Tottori 680-8553, Japan; Faculty of Life and Environmental Science, Shimane University, Kamihonjo, Matsue, Shimane 690-1102, Japan; Department of Soil Science
Abstract: In order to mitigate the autotoxicity in growing plants in closed hydroponic systems, the effects of foliar applications of 2,4-dichlorophenoxyacetic acid (2,4-D) and 1-naphthaleneacetic acid (NAA) on the growth of strawberry were investigated. Although the growth of strawberry plantlets was not affected by the auxin treatments in the fresh nutrient solution, the auxin treatments recovered the growth in the used nutrient solution. Benzoic acid, a compound reportedly accumulating in the reused nutrient solution of strawberry hydroponics, resulted in a significant decrease in the growth of strawberry plantlets at 50 uM concentration, compared to the growth in the nutrient solution without benzoic acid. Mitigation of the growth inhibition caused by the previously used nutrient solution or addition of the high concentration of benzoic acid in the fresh solution was demonstrated by immersing strawberry leaves in the auxin solutions (0.45 and 4.5 uM 2,4-D or 5.4 and 54.0 uM NAA) for two seconds before transplanting. The number of flowers and harvested fruits, and the fruit yield of strawberry plants grown in the greenhouse for about 33 weeks were reduced by the non-renewing the nutrient solutions. These values recovered in the 5.4 uM NAA treatment and were not significantly different from the control (renewal of the nutrient solution). These results suggested that reductions in the number of flowers and the yield of strawberry in closed hydroponic systems appear to be related to the allelochemicals exuded by the plant itself. The auxin such as NAA would avoid the growth reduction of strawberry caused by autotoxicity. The 5.4 uM NAA treatment may be the most effective for alleviating autotoxicity of strawberry and increasing the yield.
Yueju Wang, Michael Wisniewski, Richard Meilan, Sandra L. Uratsu, Minggang Cui,Abhaya Dandekar and Leslie Fuchigami
Department of Horticulture, Oregon State University, Corvallis, OR, 97331- 7304, USA; USDA-ARS, 45 Wiltshire Road, Kearneysville, WV, 25430-9606, USA, Forestry & Natural Resource Department, Purdue University, West Lafayette, IN, 47907-2072, USA, Departme
Key words: Superoxide dismutase, oxidative stress, salt stress, transgenic tomato.
Abstract: Production of reactive oxygen species (ROS) is associated with a number of physiological disorders in plants. Superoxide dismutase (SOD) catalyzes the breakdown of superoxide (O2-) into O2 and H2O2 and provides the first line of defense against the toxic effects of elevated levels of ROS. The effect of increased expression of Mn superoxide dismutase (Mn-SOD) on salt stress tolerance was studied using transformed tomato (Lycopersicon esculentum cv. Zhongshu No. 5) plants. Northern blots confirmed expression of the heterologous Mn-SOD in transgenic plants. Strong Mn-SOD enzyme activity was detected by native PAGE in transformed plants. Transgenic plants showed resistance to the superoxide-generating herbicide methyl viologen (MV, 10-4 M). The total SOD activity was one and one half- to two-fold higher, and APX (ascorbate peroxidase) activity was six to seven fold higher in transgenic, than in wild-type (WT) plant under MV stress. Germination of transgenic tomato seeds at a NaCl concentration of 150 mM was greater than wild-type seeds. When exposed to salt stress, roots of transgenic plants were less stunted and leaf injury was lower than that observed in WT plants. Also, the total APX activity of transgenic plants was 4 to 5 fold higher than that of WT under NaCl (200 mM) stress.
James T. Cole and Janet C. Cole
Department of Horticulture and Landscape Architecture, Oklahoma State University, Stillwater, OK 74078-6027, USA
Abstract: Tolerance of field- and container-grown lilyturf (Liriope muscari (Decne.)), (Liliaceae) and four species of ornamental grasses (Poaceae), perennial quaking grass (Briza media L.), Japanese bloodgrass (Imperata cylindrica (L.) Beauv. 'Red Baron'), river oats (Chasmanthium latifolium (Michx.) Yates) and dwarf fountain grass (Pennisetum alopecuroides (L.) Spreng. 'Hameln'), to five preemergent herbicides (isoxaben, oryzalin, oxadiazon, oxyfluorfen, and prodiamine) was evaluated. Grasses were planted in the fall of 1997 and in the spring of 1998. Herbicides were applied to the fall planting in the spring of 1998. The April, 1998 plantings received herbicide applications within two or 45 days after planting. Herbicides were applied within two days of planting in May and June of 1998. All species in the field and containers were damaged most by oxyfluorfen, followed by oxadiazon; however, injury was not as severe with oxadiazon as with oxyfluorfen. The oxadiazon-treated plants recovered more quickly than oxyfluorfen-treated plants. Plants were least damaged by prodiamine, oryzalin, and isoxaben. Field-grown Japanese bloodgrass, dwarf fountain grass and lilyturf were generally less damaged when herbicide was applied in June, regardless of planting date or herbicide applied than by the April herbicide application. Prodiamine, oryzalin, or isoxaben caused few phototoxicity symptoms in the species tested, but oxyfluorfen and oxadiazon caused unacceptable injury.
Faculty of Agriculture, Shahid Chamran, University, Ahwaz, Iran.
Key words: Allium cepa, Aspergillus niger, cultivars, life storage, onion
Abstract: In Khuzestan (South Iran), onion bulbs are usually formed and harvested in spring and consumed either in the same season or during summer while some of these are kept for seed production. In order to study the losses in onion bulbs under hot store conditions, an experiment was conducted in autumn 2002 and spring 2003. The data were collected on five cultivars being produced at Shahid Chamran University, two local cultivars and three of those under commercial cultivation. The collected bulbs were kept in 30 x 50cm boxes, 15 cm in height. The experiment was replicated three times in completely randomized design. Data on change in number, weight of the healthy bulbs and decayed bulbs were recorded every 15 days. No bulb root was produced during the storage when maximum, average and minimum temperature were 48, 33 and 25oC, respectively with the average relative humidity (RH) of 30%. As far as storage life was concerned, there was a significant difference among the varieties. Compared to both the local and market bulbs, those produced at Shahid Chamran University showed more storage life. Another important finding of this research was that 50% of the local and university bulbs remained unspoiled after 120 days, whereas the Taxes Yellow Grano, Taxes Early Grano and G1 had the short storage life; 50% of the stock were destroyed after 60 days. In the present study, Aspergillus niger was found to be the most important factor responsible for onion decay in hot stores of Khuzestan.
Maria Remedios Cigales Rivero and Octavio Perez Zamora
Centro Universitario de Investigacion y Desarrollo Agropecuario Universidad de Colima. Km 40Autopista Colima-Manza-nilloTecomdn, Col. 28100Mexico.InstitutoNacionaldeInvestigacionesForestales, Agricolas y Pecuarias. Campo Experimental Tecomdn.
Abstract: In cantaloupe farming (Cucumis melo L.), the production of export quality fruit require nutritional indicators that allow an adequate management of nitrogen fertilization and irrigation water supply. This study with cantaloupe muskmelon was carried out to test four nitrogen fertilization treatments and three levels of soil moisture tension under field conditions. Nitrate content (N-NO3) in the cellular extract was evaluated as an indicator of nutritional status. Significant correlation was found between the lowest nitrate concentrations in the petiole sap and the N fertilization doses in three different sample periods. The effect of soil moisture tension on nitrate concentration varied in both years; this was attributed to soil temperature differences. Results showed that it is feasible to establish outcome predictions of yield and quality of the fruit based on the nitrate concentration in petiole sap, concluding that this is an adequate indicator of the nutritional status of the cantaloupe plant. However, its use as a guide for managing fertilization and irrigation must include a permanent follow up of the crop that evaluates the effects of environmental factors in plant growth and uptake of the nutrients.
P.l. Garriz, H.L. Alvarez, G.M. Colavita and M.S. Gajdos
Faculty of Agriculture, Comahue National University, c.c. 85, 8303 Cinco Saltos, R.N., Argentina.
Abstract: Thinning is a central management activity in the production of high quality fruit required for the domestic and export market. Early thinning of fruit trees is important since it influences fruit size and the time of application affects flower bud formation for the following season. Furthermore, finding organic blossom thinners is a major challenge as hand thinning is a costly practice. At the High Valley region of Argentina (lat. 38?56' 67?59'W), lime sulphur was evaluated as flower thinner on 'Abbe Fetel' (Pyrus communis L.) pear trees trained to palmette leader. Treatments were 1) control, and 2) 7 % lime sulphur applied at 30 % bloom, using an orchard sprayer. Fruit diameter (FD) was recorded two weekly (n=20 per date and treatment). At 144 days after full bloom (DAFB), or initial commercial harvest, fruit weight and the maturity indices were determined. Fruits were then graded into size categories. Growth equations were developed using non linear regression and mean separations were computed with Student's t-test. The lime sulphur sprays significantly increased mean FD, starting from 115 DAFB. Logistic model best fitted the fruit growth vs. time curves. Percentage of fruits with <65mm diameter was 25 % for the control and 5.26 % for lime sulphur treatment. Treatment 2 increased final fruit weight by 16.5 %, as compared to the untreated pears. At 144 DAFB, thinned trees showed firmer fruits than the controls (64.4 vs. 61.7 N) and there were no statistical differences among treatments in soluble solids concentration and starch index. Consequently, data indicated that lime sulphur at 7 % was an effective flower thinning agent to enhance 'Abbe Fetel' pear seasonal fruit growth and quality.
G. Talluto, V. Farina and R. Lo Bianco
Dipartimento S.En.Fi.Mi.Zo., Sezione di Frutticoltura Mediterranea, Tropicale e Subtropicale, Universitd degli Studi di Palermo, Viale delle Scienze 11, 90128Palermo, Italy.
Key words: Canopy size, crop load, deficit irrigation, fruit growth, fruit quality, leaf area, shoot length, stomatal conductance, yield.
Abstract: We investigated the vegetative and productive responses of 'Golden Delicious' apple (Malus domestica Borkh.) trees to fixed partial rootzone drying under the dry climate of central Sicily. Soil water content (SWC), stomatal conductance, yield, fruit quality, fruit growth, and vegetative growth of conventionally irrigated trees (CI), where drip emitters on both sides of each tree were left open, were compared to that of fixed partial rootzone drying (FPRD) trees where only one side of the rootzone was irrigated for the entire season thus receiving 50% of the CI irrigation water. The irrigation season started on 31 July and ended on 13 September, 2004. Wet and dry rootzone sides showed significantly different SWC from 16 August until 14 September, whereas stomatal conductance of CI and FPRD trees differed significantly starting on 24 August. Relative growth rate of CI fruit was higher than that of FPRD fruit on 27 and 31 August, but fruit size was similar during the entire sampling period and at harvest. Trees of the two treatments had similar yields, number of fruits, crop load, fruit:leaf ratio, fruit quality, tree height, wood fresh and dry weight, canopy spread area, volume and density, shoot length and number, internode length, and leaf area. FPRD trees had higher yield efficiency, thinner shoots, lower leaf water content, higher canopy density and leaf dry weight and specific leaf weight than CI trees. Our observations suggest the extent of possible water savings without loss of yield and fruit quality using this partial rootzone drying strategy in 'Golden Delicious' apple orchards of central Sicily.
Department of Crop, Soil & Pest Management, Federal University of Technology, PMB 704, Akure, Nigeria
Key words: Bell pepper, fertigation, hydraulics, stomata, canopy, leaf potential, water uptake
Abstract: The effect of fertigation regimes on water transport properties (soil, plant and canopy resistances) through the plant to the canopy in the Soil-Plant-Atmosphere-Continuum (SPAC) was studied in bell pepper in a Mediterranean climate. The treatments consisted of fertigated drip irrigation in factorial combinations of three levels (amounts) of water application (daily, twice and once weekly) and application frequencies (2, 6 and 10 times per fertigation event). Leaf water potential and stomatal conductance were monitored while whole plant hydraulic conductance was estimated by the evaporative flux method, using the Ohm's law analogy (the slope of the water potential difference (Ay) versus sap fluxes). Canopy conductance (inverse of resistance) was estimated from vapour pressure deficit (vpd) and transpiration flux. Differences in the intervals between fertigation events altered the environment for root development and affected soil moisture status, stomatal conductance (gs), leaf water potential (lwp), transpiration (sap) flux, and xylem and canopy water transport capacities in bell pepper. The components of the resistance elements in the SPAC differed under the fertigation treatments. Total plant resistance (Rp) increased with transpiration flux in a linear manner in addition to a proportional decrease in stomatal (gs) and canopy conductance (gc). Canopy component constitutes the least resistance (greatest conductance) to the flow of water, estimated soil resistance was much lower than total resistance to the flow of water, and the highest within plant resistance is contained in the root system which constituted a predominant part of total plant resistance. Bell pepper has an efficient xylem sap transport system, maintains gs and plant water status under variable soil moisture regimes. Bell pepper water use is affected by soil environment, plant architectural and xylem traits. The mechanisms underlying differences in water use and plasticity of physiological functions in bell pepper under variable fertigation regimes appeared to be offered through changes in the magnitudes of component resistances of the water transport pathways in the SPAC. The implications of knowledge of the magnitudes of the resistances to water flow pathway in the SPAC to irrigation management is discussed.
Zdenka Premuzic, Hemilse E. Palmucci, Juan Tamborenea and Martin Nakama
Catedra de Quimica Analitica, Catedra de Fitopatologia, lnvestigador alumno. Facultadde Agronomia de la Universidad de Buenos Aires (FAUBA) Av. San Martin 4453. Capital Federal (1416), 4lnstituto de Floricultura -INTA-CASTELAR. De los Reserosy
Abstract: Disinfection by chlorination was applied to the solution of a soilless closed system of Lactuca sativa varieties, Gallega and Mantecosa. The aim was to study the effect of the addition of different doses of chlorine on the production (fresh weight and dry matter), quality (nitrates, vitamin C and nitrogen contents), and phototoxicity to lettuce (chlorosis) with regard to the chemical properties of the solution (pH, electrical conductivity EC and chlorides). Four treatments were applied: 0.55, 5.5 and 11 mg L-1 (ppm) of chlorine and a control without addition of chlorine. The 11 mg L-1 treatment produced a decrease in production of Gallega, presenting a 40 % lower fresh weight than the control. Both varieties presented high contents of nitrates. Gallega presented the maximum values (2920- 8158 mg kg-1) and showed values under the permissible limit with the 0.55 and 5.5 mg L-1 treatments. Mantecosa showed lower maximum values (3787- 5291 mg kg-1), although with all the values above the limits of permission. The contents of nitrogen for both varieties exceeded the levels of sufficiency in all the treatments. This fact was related to the high nitrogen supply provided by the fertirrigation that contributed to the high nitrate contents. Gallega presented larger contents of vitamin C (19.3-28 mg.100g-1) than Mantecosa (15.3?19.98 mg 100g-1). Chlorination did not affect the chemical properties of the solution (pH and EC remained between the appropriate range for the species). Chloride contents in the nutrient solution were larger at the 11ppm doses; however the values remained under the toxicity levels for the species. For both the varieties, 0.55 mg L-1 treatment produced the higest fresh weight and vitamin C contents and the lowest nitrate contents and toxicity symptoms (chlorosis), while 11 mg L-1 treatment resulted more chlorosis and necrosis of leaves, diminishing the commercial quality of the plants.
Brian A. Krug, Brian E. Whipker, Ingram McCall and John M. Dole
Department of Horticulture Science, Box 7609, North Carolina State University, Raleigh, NC 27695-7609
Abstract: Flurprimidol preplant bulb soaks (10 to 40 mg L-1) were applied to tulip (Tulipa sp. L.) bulbs for growth control. Three tulip cultivars ('Page Polka', 'Prominence' and 'Red Present') were used to determine if the efficacy of flurprimidol varied by cultivar. Flurprimidol was compared to paclobutrazol (50 and 100 mg L-1) and uniconazole (10 and 20 mg L-1). Flurprimidol preplant bulb soaks significantly (P < 0.05) controlled tulip plant height during the greenhouse forcing when applied to 'Page Polka' and 'Prominence' at concentrations > 15 mg L-1 and > 10 mg L-1, respectively. A concentration of 40 mg L-1 was needed to control plant height during the postharvest evaluation for 'Page Polka' while concentrations > 15 mg L-1 controlled postharvest plant height for 'Prominence'. No control during forcing or postharvest was provided by any concentration tested on 'Red Present'. The differences observed indicate that the efficacy of flurprimidol as a preplant bulb soak varied with cultivars. In order to determine optimal cultivar doses, growers will need to conduct their own tulip cultivar trials, with flurprimidol concentrations ranging between 10 and 40 mg L-1.
Faculty of Agriculture, The University of Tabriz, PO Box 51664, Tabriz, Iran
Key words: Ni, cucumber, N, yield, quality, urea, nitrate
Abstract: The effects of Ni concentrations in the nutrient solution on the yield, quality and N assimilation of cucumber plants were evaluated in plants grown either with urea or nitrate as the sole N source. The cucumber plants (Cucumis sativus cv RS189 and Vikima) were treated with two N sources, urea and nitrate as NaNO3 at 200 mg L-1, and three concentration of Ni as NiSO4.6H2O (0, 0.5, and 1 mg L-1). Treatments were arranged in a randomized block design with six replicates. The highest concentration of Ni in the leaves (1.2 mg kg-1 DW) was observed in the urea-fed plants at 1 mg L-1 Ni concentration. Addition of Ni up to 0.5 mg L-1 had no effect on the fruit Ni concentration in the both urea and nitrate-fed plants. Ni supplement (0.5 mg L-1) increased the yield significantly (10 and 15% in RS189 and Vikima, respectively), in urea-fed plants but decreased when 1 mg L-1 Ni applied to the solutions. Nitrate-fed plants had higher percentage of total soluble solids compared to urea-fed plants. Nitrate concentration of the fruits in urea-fed plants in both cultivars was approximately 50% less than those nitrate-fed plants. The reduction of nitrate concentration in the fruits became more pronounced as the Ni concentration increased in the solution. The rate of photosynthesis (Pn) in urea-fed plants continuously increased with the increase of the Ni concentration in the solution. Both N concentration and NR (Nitrate Reductase) activity of young leaves were higher in urea-fed plants at 0.5 mg L-1 Ni concentration. Ni supplements enhanced the growth and yield of urea-fed plants by the increase of Pn, N concentration and NR activity. It can be concluded that Ni supplements (0.5 mg L-1) improves yield, quality and NR activity in urea-fed cucumber plants.
EmiliaAtanasova, Ivanka Mitova, Ilko Dimitrov and Ira Stancheva
N. Poushkarov Institute of Soil Science, National Center of Agricultural Sciences, 7-Shosse Bankya str. 1080 Sofia, Bul?garia; Acad. M. Popov Institute ofPlant Physiology, Bulgarian Academy of Sciences, Acad. G. Bonchev str., Bl. 21, 1113 Sofia, Bulgaria
Key words: Head cabbage, quality parameters, foliar fertilization, fertilizer application
Abstract: The influence of different fertilizer sources on head cabbage (Brassica oleracea var. capitata, cv. Pructor) yield and quality was studied. The field experiment was carried out on alluvial - meadow soil (fluvisol -FAO)pH 6.5. The trial included mineral fertilizer, farmyard manure and foliar fertilizer. The highest yield values were obtained with mineral fertilization. The best quality parameters in the cabbage leaves - dry weight, total soluble sugars, cellulose, vitamin C and nitrates content were obtained in the treatments with foliar fertilization followed by the treatments with organic fertilization. The observed decrease of N and K residuals after the harvest of head cabbage crop in comparison with the initial soil reserves indicated complete absorption of fertilizers supplied and this is a very important result from ecological point of view.
A. Deljou, O. Karami and P. OstadAhmadi
Department of Biotechnology, Faculty of Agriculture, Bu-Ali Sina University, Hamadan, Iran.
Abstract: The effect of sucrose concentration was investigated on callus induction and differentiation of embryogenic callus derived from petal explants of carnation cultivar Nelson'. Embryogenic calli were produced on MS culture medium containing 9 uM 2,4-dichlorophenoxy acetic acid (2,4-D), 0.8 uM 6-benzyladenine (BA) and different concentrations of sucrose alone or in combination with sorbitol. In constant osmotic potential medium, number of explants containing embryogenic calli was significantly enhanced by increasing the sucrose concentration. Somatic embryos were induced on a hormone-free media containing various concentrations of sucrose alone or in combination with sorbitol. Different sucrose concentrations from 50 to 150 mM significantly increased somatic embryos. No callus and embryo formed when sorbitol was the sole carbon source. In the presence of a constant sucrose concentration, increasing the osmotic potential with sorbitol led to increase in the frequency of somatic embryos. In medium containing low concentration of sucrose (50 and 100 mM), reduced development of embryos was recorded. 90% of somatic embryos were regenerated to form the entire plantlets when they were transferred onto the half-strength MS culture medium containing 3% sucrose. Plantlets also continued to grow under greenhouse condition.
Paul B. Francis and C. Robert Stark, Jr.
Division of Agriculture Faculty, University of Arkansas atMonticello, P.O. Box 3508, Monticello, Arkansas 71656, USA
Abstract: Field studies were established in 2004 and 2005 to determine the effects of transplant drench and foliar applications of organic-complex Ca, B, K amendments and a yield enhancement product, 'Perc PlusTM', on the flowering, fruiting, fruit yield and market value of Italian-cv. 'Classica' and large-fruited cv. 'Amelia' tomato (Lycopersicon esculentum Mill.). Treatments were an organic yield enhancement applied as a transplant drench and then foliar 7 days later (TD); once a week foliar amendments of organic-complex Ca, B, and K nutrients beginning at first bloom for 4 weeks (FA); a combination of the drench and foliar treatments (TD+FA); and a control (CON). Fruit-set of 'Classica' was significantly higher for the FA and TD+FA than the other treatments in 2004, however there was no effect on yield and quality of harvested fruit. Flowering and fruit-set of 'Amelia' were not affected by drench and/or foliar amendments in either year. Total fruit yield and quality of the treated plots were not significantly different than the CON for either cultivar or year.
K.P. Baiyeri and E. Ortese
Department of Crop Science, University of Nigeria, Nsukka, Nigeria; Department of Crop Science, Akperan Orishi College of Agriculture, Yandev, Benue State, Nigeria.
Key words: Bananas and plantains, genotypic differences, nutrient uptake.
Abstract: Six genotypes comprising a landrace and a hybrid from each of the three Musa major genomic groups were evaluated in a soilless potting mix. Effect of genotype on most of the growth parameters was non-significant. But the uptake (total quantity accumulated, distribution pattern and tissue concentration) of N and K was significantly (P < 0.05) influenced by genotype (G), age of plant at sampling (AP) and G x AP interaction. Dessert bananas had higher N uptake while 'PITA 22' (a plantain hybrid) demonstrated an exceptional propensity for K uptake. Nitrogen and potassium concentration varied with tissue, genotype and age of plant at sampling. Nitrogen concentration in roots and leaves decreased with plant age while it increased in the corm. Potassium concentration in roots, corm and leaves increased progressively with plant age in all the genotypes. Significant differences in the quantity of N and K accumulated per plant, even though all the genotypes were planted in the same potting mix, suggested differential nutrient mining capacity of the genotypes. Implying that nutrient uptake and consequently nutrient demand varies with genotype, supplemental application would vary accordingly. The study suggested that genotype that had higher nutrient uptake will impoverish the soil faster, and thus require more external nutrient inputs to maintain/restore soil productivity.
Dewoowoogen P. Baclayon, Toshiyuki Matsui, Haruo Suzuki and Yusuke Kosugi
Department of Applied Biological Sciences, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan
Abstract: Sugars play indispensable roles in many metabolic processes in plants. In broccoli, the level of sugars, particularly sucrose, rapidly decline few days after harvest. This study investigated the influence of exogenous application of 10% (w/v) sucrose to broccoli heads during storage at 20oC. Hydration of the head was slowed down by sucrose treatment compared with the non-treated heads which gained weight by about 5% of the initial value at the end of the experimental period. Furthermore, sucrose application enhanced ethylene production as well as respiration rate. Glutamine synthetase (GS; EC 22.214.171.124) activity was higher in the florets of sucrose-treated heads but, like the non-treated heads, the activity continuously declined until the end of the storage period. The relatively higher GS activity during the early period of storage caused the delay of the onset of ammonia accumulation by about a day. In the branchlet portion, GS activity was higher in the sucrose-treated heads until day 2 but declined thereafter. The decline in GS activity in this portion, however, did not result to ammonia accumulation.