Iranian Journal of Horticultural Science
Year:2012 | Volume:43 | Issue:2|Papers Count:14

Sensitivity of tomato fruit to low temperature and chilling injury limits the storage, handling and marketability of the fruit. As a recommended postharvest treatment, effects of hot water treatment (HWT) on reducing chilling injury and quality traits, variation of tomato fruits during storage life were investigated. Tomato fruits were harvested at mature green stage. They were treated by hot water at 45oC for 15 min, then placed at three storage temperature conditions including 5oC, 13oC, and at a Simulated Condition (SC) of the interval between harvest and consumption by the consumer. Storage period was 43 days. Fruit color, lycopene, weight loss, firmness, enzyme activity of polygalacturonase (PG), ascorbic acid and Chilling Injury (CI) were assessed and evaluated during the experiment. While storage of mature green tomatoes at 13oC developed normal ripening, storage at 5oC and during SC disturbed the normal ripening process. HWT caused delay in surface color development to some extent, resulting in reduction in weight loss and enzyme activity as well as in enhancing ascorbic acid and lycopene contents. It also had a significant effect on reduction of CI in mature green tomatoes. Based on the results, it can be concluded that in tomato as a climacteric fruit, HWT and temperature condition of storage exert significant effects on its storage and shelf life. This study confirmed that 13oC is the optimum temperature for maintenance while HWT is a proper postharvest treatment as regards tomato fruit.

There are about two of millions rainfed fig trees in Estahban. This main location of Iran rainfed production is faced with death and destruction as a result of recent droughts and since rain is the only source of water supplied to the trees in rain-fed conditions. The effects of different levels of water stress on the plants stomata and guard cell response were investigated throughout this work. The experiment was laid out as a 4×4 factorial in a Complete Randomized Design of three replicates. Treatments were comprised of: four fig cultivars (Sabz, Shah-Anjir, Siah and Matti) along with four levels of irrigation: Control with enough water supplying pots (100% of Field Capacity), mild stress (75% of F.C), medium stress (50% of F.C) and severe stress (25% of F.C). The results indicated that the length, width and size of stoma and length, width and size of stoma guard cells were different at different levels of stress and decreased in severe stress treatments. The study revealed that the mere anatomical changes that are caused by periodic drought cannot be determinative of the difference between cultivars.

The aim followed in this research was to determine the effect of Benzyladenin and storage conditions on bulbil formation, germination percentage and growth in Iranian Tareh (Allium ampeloprasum ssp.persicum). Immature inflorecences were treated with different concentrations (0, 10, 50 and 100 ppm) of BA to form bulbils. The experiment was done in RCBD with three replications in Esfahan Center for Research in Agricultural Sciences and Natural Resources. The results revealsed that all concentrations of BA formed bulbils in more than 90 percent of plants except for the case of the control treatment. Then, bulbils were stored in two temperature conditions (31 and 9 centigrade) to evaluate their germination percentage and vegetative growth. It was revealed that the different concentrations of BA and storage conditions had no effect on bulbil germination, but bigger bulbils bore higher germination percentages than the small ones. The temperature treatment exerted no significant effect on vegetative traits, but the different treatments of BA proved significant at a level of 5%. All the bulbils produced viable plants.

In vitro pollen germination and also pollen tube growth dynamics in different pollination treatments under controlled temperature, humidity and photoperiodicity were studied regarding four cultivars (‘Shastomi-e- Do’, ‘Ebrahim-e- Kalajah’, ‘Sefid-e- Rezaeeieh’ and ‘Razi’) under self and under cross-pollination along with three superior genotypes (‘269’, ‘416’ and ‘464’) of apricot. Following 24, 48 and 72 hours after controlled pollination, pistils were fixed in FAA. Subsequently, pistils were rinsed several times with water, and autoclaved in a 5% sodium sulfite to be soflened. After being stained with aniline blue, pistils were examined through fluorescent microscopy. Results indicated significant differences among the studied cultivars for all the traits. The highest and lowest percentages of in vitro pollen germination were observed in cultivars ‘Sefid-e- Rezaeeieh’ and ‘Razi’ respectively. As for the number of germinated pollen grain at the stigma, results revealed significant differences regarding the interaction of cultivars and pollen source. A general decrease in the number of pollen tubes was observed at the end of the style, in a way that the lowest percentage of pollen tubes in the third part of the style was observed under self-pollination. Regarding the pollen tubes either reaching the ovary or not, the results established the self - compatibility of ‘Shastomi-e- Do’ and self - incompatibility in the case of the other studied cultivars.

Oregano (Origanum vulgare L.), a native plant from Iran, belongs to Lamiaceae family. This species is traditionally utilized as sedative, diuretic, sweater and antiseptic, It is also used to treat of gastrointestinal diseases and constipation. Origanum species are widely used in spice industry. In this study, the essential oil of the aerial parts of a subspecies from this plant namely Origanum vulgare ssp. vulgare was isolated through hydro-distillation following its collection from South region of Chalus in its flowering as well as in seed stages. The extracted essential oils were analyzed through GC and GC/MS systems. Nienteen compounds were identified in the extracted essential oil in the flowering stage which constituted about 99% of the total oil. The latter sample was found to be rich in linalyl acetate (27.2%), g-terpinene (16.5%), 3-octanone (10.9%), b-pinene (8.4%) and carvacrol (6.4%). The 22 identified compounds made up 98.6% of the essential oil in seed stage, carvacrol (23.2%), a-pinene (15.8%), b-pinene (10.7%) and trans-caryophyllene (5.3%) constituted the main compounds. According to the GC/MS results, the monoterpenes were characterized as the most predominant essential oil fraction in either stage. The percentages of the other components of the oils were 16.8 and 5.7 for the plant at flowering and at its seed stages, respectively.

Thioredoxins (Trxs) are small heat-stable proteins that are involved in the cell redox regulation and are present in all organisms from prokaryotes to higher eukaryotes. In higher plants, Trxs can be classified into six different groups namely: the chloroplastic Trxs f, m, x, and y, the mitochondrial Trx o and the Trxs h. The Trxs h are represented by a small multigenic family that participate in such multiple processes as cellular protection against oxidative stress. A full-length cDNA coding for a thioredoxin h (VvTrxh3) gene was cloned from grape (Vitis vinifera L. cv. Bidaneh Sefid) leaf tissue through Reverse Transcription Polymerase Chain Reaction (RT-PCR) technique, and then, biochemical, structural and phylogenetic characteristics were analyzed. Nucleotide sequence analysis revealed an open reading frame of cloned VvTrxh3 gene with a length of 345 bp, encoding a protein of 114 amino acid residues. Protein sequence analysis revealed that this gene with thioredoxin fold, contains a typical catalytic site of WCGPC, the calculated molecular mass, and the predicted isoelectric point of the deduced polypeptide of 12.79 kDa and 5.06, respectively. Phylogenetic and multiple alignment studies revealed that this gene is a thioredoxin h belonging to the subclass IA from subgroup I, with a high degree of similarity with plant thioredoxins h.

Apricot belongs to the Rosaceae family and is considered as an economically important Fruit among others. Irregular bearing is a shortcoming in apricot production which is partly due to its limited ecological adaptation. The aim of this study was to investigate the effects of temperature prior to flowering stage on some characteristics as related to flowering organs. In two consecutive years, some traits were recorded in four commercial apricot cultivars namely: ‘Nasiri’, ‘Noori’, ‘Jahangiri’ and ‘Shahroudi’. Results indicated that temperature influenced the plant’s flower reproductive organs, pollen and pistil performance which in turn played an important role on flower fertility. During the first year, pollen germination was considerably low due to a very cold winter while in the second year the final development stage of pistil failed because of becoming confronted with a warm winter. Pistils with shorter style and non-swollen ovaries were observed in some cultivars including ‘Jahangiri’ and ‘Noori’. The two other cultivars produced a higher percentage of normal pistils during the second year. Differences between cultivars would be attributed to carbohydrate storage and sensitivity of ‘Jahangiri’ to warm winters. In ‘Nasiri’ double pistil and multiple ovule percentage decreased during the second year. On the other hand, in year 2007-2008 cultivars exhibited early flowering due to easily meeting the chilling requirement but faced spring frost damage. According to the obtained results, temperature fluctuation affected flower quality in either on year. Continuous cold winter provided more suitable conditions for organogenesis and fruit set in year 2006-2007. In this year, pollen germination decreased because of cold winter but, in total, fruit set was at its optimum level because of good pistil’s performance.

The close to impossible correct controlling of the temperature and light intensity is the main limiting factors of growing plants in the plastic covered greenhouses. Quality and vase life of cut flowers are mostly influenced by greenhouse temperature. Alstroemeria needs cold temperature for growth and flowering. In the current study, the such changes in vase life and flower quality as stem length, the number of flowers per inflorescence, and flower pigmentation in relation with anthocyanin concentration and Phenylalanine ammonia lyase (PAL) activity was investigated for three Alstroemeria cultivars namely: ‘Bordeaux’, ‘Sukari’, and ‘Modena’ during the growing season in summer and autumn in plastic greenhouses.The results indicated that increase in temperature during summer resulted in declining flower quality and vase life, in contrast, cold temperature in late summer and early autumn enhances biosynthesis of anthocyanin and flower pigmentation. There were significant differences observed between Alstroemeria cultivars as regards high temperature during the summer season. In this study, high temperature induced Phenylalanine ammonia lyase (PAL) activity in petals, making one conclude that Phenylalanine ammonia lyase (PAL) enzyme might not be a key enzyme for biosynthesis of anthocyanin in Alstroemeria flowers. With increase in temperature, the number of flowers were shown to decrease in ‘Bordeaux’ cultivar.

Japanese plum (Prunus salicina Lindl.) having originated from China, is now one of the important fruit trees in many countries in the world. Knowledge of genetic diversity among existing germplasms provides the possibility of parental selection in breeding improvement programs. For assessment of genetic diversity and relationship among genotypes in Iran (Ramsar, Velyan Karaj and Mashhad) and four commercial cultivars availabe at the Research Center, Dept. Of Horticultural sciences, University of Tehran, as well as Mirobolan cultivar, eight microsatellite loci were employed. These markers produced a total of 68 bands in the studied genotypes. UDA-005 and UDP98410 loci produced the highest number of alleles (12) while CPSCT026 locus rendered the lowest (4). The average effective allele was recorded 4.1 with a maximum of 6.6 alleles at UDA-005 microsatellite site and a minimum of 2.7 at ASSR71. The average expected heterozigosity in all loci was 0.73 varying from 0.58 at ASSR71 to 0.86 at UDA-005 microsatellite locus. The average observed heterozigosity was 0.49 differing from 0.34 at UDP98410 to 0.71 at ASSR72 loci. Gene flow index (Nm) was 1.22 on the average at all loci showing the exchange of genetic material (seeds, pollen, etc.) among the locations. The mean of Polymorphic Information Content (PIC) being 0.69, indicated high heterozigosity rate among plum genotypes. Cluster analysis based on SMC similarity coefficients and UPGMA method was performed. According to clusters, groups were not in match with the geographical distribution so that genotypes with different distributions were located in same groups but there exicted certain differences between hexaploid and diploid genotypes. Based on the results of similarity matrix, the lowest and the highest genetic similarities were recorded as 0.506 and 0.92 respectively. Average similarity among genotypes recorded as 0.79, corresponding to a previous report with an average similarity whithin the same studied genotypes, using RAPD markers, (0.71).

The effects of different concentrations of salicylic acid as compared with control and as well with distilled water treatment were assessed on induction of resistance to chilling injury and quality of sweet lemon during its storage. For the purpose, sweet lemon fruits were treated by immersion method for 5 minutes in salicylic acid (200, 400 and 600 mg/lit) and then packed in polyethylene bags to be stored in cold storage (4±1oC) for two months. At the end of the storage period, fruits were transferred to 25oC environment for 5 days while the effects of treatments on chilling injury, total soluble solids, ion leakage percentage, vitamin C, weight loss and decay percentage being investigated. Based on the obtained results, salicylic acid decreased chilling injury, preserved quality appearance and prevented water loss of the fruits without any deleterious effect on internal quality. The highest chilling injury occurred in control and the lowest in fruits treated with 400 mg /lit of salicylic acid at low temperature, even after keeping them later at high temperatures. In terms of weight loss and reduction of vitamin C and total acids, significant differences were observed between treated vs. control fruits. Furthermore, no significant differences of total soluble solids (TSS) and pH were found between treated vs. control fruits. In total, treatment with 400mg/lit of salicylic acid showed fruits with the best appearance and the most controlling effect on chilling injury.

The effect of plant growth regulator short time treatments (GA3 and TDZ) on the increase of vase life and qualitative traits of Alstroemeria cultivars ‘Odessa’ and ‘Sacramento’ were investigated. Cut flowers were treated with 24h pulse treatments which included different concentrations of GA3 and TDZ. Cut flowers were later held in preservative solution (Sucrose 2% +Nanosid 2ppm) and then their vase life and qualitative traits evaluated on different days. The results indicated that GA3 300 mM treatment in ‘Odessa’ increased flower longevity while GA3 150 and 300 mM treatments increased leaf longevity. Moreover, GA3 300 mM treatment in ‘Sacramento’ deeply prevent affected the prevention of leaf senescence whereas the preservative solution more conspicuously affected the increase of flower longevity. In addition, 2ppm antibacterial Nanosid diminished the growth of microorganisms in preservative solution, in comparison with control (distilled water) and 2% Sucrose overcome the lack of carbohydrates in respiration process in cut flowers. Relative fresh weight and total soluble solids in stem increased in all treatments except in control. Also, GA3 (50, 150 mM) in ‘Odessa’ and GA3 300 mM in ‘Sacramento’ exhibited the maximum rate of total chlorophyll on the 12th day. Consequently, short duration treatment with 300 mM of GA3 is recommended in increasing the vase life and quality of cut flowers in ‘Odessa’ and ‘Sacramento’. Odessa’ is considered as a superior cultivar over ‘Sacramento’ and Nanosid in preservative solution being acknowledged as an appropriate antibacterial agent.

Barhee is considered as one of the most popular date cultivars worldwide. Its fruits, because of low tannin content and low astringency can be, and are consumed at Khalal stage. Due to its high water content and respiration rate, Khalal date fruit is very perishable and of low storage life. Limited supply, and difficulties involved in marketing of this product, makes one think of new packaging methods to be considered in developing the market for fruits of this cultivar. This study was conducted to evaluate the effects of different packaging methods (control, passive modified atmosphere packaging, modified atmosphere packaging containing ethylene scavenger sachets) and two storage temperatures (5 and 15oC) on the storage life of date fruit cv Barhee harvested at Khalal stage. During 27 days of storage, fruits were analyzed in 3 day intervals and evaluated for different quality parameters including flesh firmness, weight loss, titrable acidity, total soluble solids (TSS), pH, TSS/TA, percentage of Rutab, electrolyte leakage, surface color, antioxidant capacity and phenolic content. Results showed that fruits in MAP treatment with ethylene scavenger sachets experienced the lowest percentage of weight loss (0.42%), lowest percentage of spots turning into Rutab (35%) and maximum tissue firmness. They also experienced low changes in the other marginal parameters tested. Among the two studied storage temperatures, 5oC exerted better effects on the maintenance of quality attributes.

Drying, is one of the important postharvest processes of medicinal plants with an important role played in quality and quantity of the drugs. In this research, in order to study the effect of growing conditions and different drying methods on drying time, essential oil content, color characteristics and microbial load of Dracocephalum moldavica, a Factorial experiment in Randomized Complete Block Design (RCBD) of two factors namely: drying method (five methods) and growing conditions (two conditions), of three replications was performed. The five treatments followed in the drying method were comprised of: 1-sun drying, 2-drying in shade at room temperature, 3-Oven drying at 30oC, 4-Oven drying at 40oC, and 5-Oven drying at 50oC, while the treatments for the growing conditions were:1-cultivation in greenhouse and 2-cultivation in field. The drying process was continued until the moisture content of either about 10% on a wet basis or on a dry basis was obtained. The results indicated the significant effect of treatments on all the evaluated factors. Also for both conditions (field and greenhouse), the minimum drying time (11 and 14 hours) belonged to 50oC for oven treatment while maximum drying time (55 and 73 hours) belonged to drying in shade. The maximum essential oil content (in both conditions)was related to shade drying, while the minimum content achieved at 50oC treatments. Also, it was observed that 50oC and sun drying treatments significantly decreased the plants microbial load.

Use of such natural compounds as essential oils and plant extracts is considered as a safe method in control of postharvest diseases as well as delay in plant tissue senescence. In this study, the effects of clove essential oil and extract was investigated on decay control and on some quantitative characteristics of table grapes during storage. Grape bunches, after having been treated with different concentrations of clove essential oils (0, 50, 100, 150, 300, 450 and 600 ml/L) and as well with extract (0, 150, 300, 450 and 600 ml/L), were kept at 1oC for 40 days. Clove essential oil proved to be effective in decay control, water loss, SSC, browning and shriveling of rachis and against berry shed. Also decrease in berry total phenol content, acidity and softening was delayed, causing increased storage life of fruits. Lower concentrations were more effective in enhancing storage life. Clove extract application, in spite of useful effects, could not be an advisable commercial method for increasing grape storage life, because of its weak decay control, water loss and browning of rachis in all its concentrations.