جستجوی مقالات مرتبط با کلیدواژه "spermidine" در نشریات گروه "باغبانی"

Nitrogen plays an important role in the uniformity and quality of citrus trees. Several studies previously reported that a low level of nitrogen in citrus trees is generally caused a reduction in yield and fruit quality (Aziz, 1997; Khan et al., 2009). In this regard, applying urea is recommended as the most suitable form of nitrogen for foliar application. The polyamines are included; putrescine, spermidine, and spermine which have been considered as plant growth regulators (Alcazar et al., 2010; Khezri et al., 2010). The role of nitrogen in vegetative and reproductive growth and yield, as well as the correlation between polyamines, flower induction and fruit set in other plants, were proved in previous studies. In this regard, the results of the current study will increase our understanding about the role of polyamines in the morphology of the tree and also the mechanism of regulating the alternate bearing of Kinnow mandarin leading to an approach method to address this problem.

To conduct this study a 17-year-old uniform of Kinnow Mandarin (Citrus reticulate Blanco) grafted onto Bitter orange (Citrus aurantium) rootstock, which grown in a commercial orchard, located in Dezful (Khuzestan Province in Iran). For sampling, the branches which possess leaves and nodes were selected from four sides of each tree, then leaves and nodes were collected at three different time points (one, three, and five weeks post-treatment). Samples were immediately frozen in liquid nitrogen after excision and transported to the Physiology Laboratory of fruit trees within 2h for determining the N fractions and polyamines. The concentration of N in dried leaves and nodes was determined using the colorimetry technique as described by Walling et al. (1989). The experiment was set up as a factorial treatment based on a randomized complete block design with three replications to investigate the effect of different concentrations of urea foliar application (0, 0.75%, 1.5%) on nitrogen and polyamines contents at different time points (Dec 22, Jan 5, Jan 20) followed by evaluating flower characteristics and yield in Kinnow mandarin plant. Data analysis including variance was carried out using MSTATC and SAS software. To compare the mean of polyamines and nitrogen in leaves and nodes, the cut-out method was used, and also for comparison of pistil dimensions, number of flowers, and yields, Duncan's multiple range test (DMRT) was performed.   

Results indicated that polyamines concentration and nitrogen decreased during the period of time and also, in most cases, polyamines concentration was lower in the nodes than the leaves. High levels of polyamines and nitrogen were obtained in leaves and nodes which were treated with the foliar application of 1.5 % urea concentration after Jan 20. The polyamines content in leaves and nodes was greatly dependent on the spraying time and urea concentration used. Spermine (Spm) was the dominant polyamines in leaves and nodes with the highest values of 44.01 nmol/gF.W, 34.41 nmol/gF.W, respectively. Regarding the fact that flower density was higher in trees that treated with urea concentration of 1.5 % after Jan 5 y than other treatments, however, their yield was lower than the trees that treated on Dec 22 with the same urea concentration. This was probably due to the flower abscission as well as the fruit abscission in June. The results of this study showed that the highest yield was obtained with 1.5 % urea concentration after foliar application on Dec 22 compared with other treatments. Regarding the fact that flower differentiation in mandarin occurs during the late January until late February (in Dezful conditions), it can be explained that the foliar application on Dec 22 was performed before differentiation and consequently, the trees have received their required nitrogen. Also, the low-temperature is considered as natural inducer of citrus flowering in the Dezful, likewise, foliar fertilizer application in winter along with the natural factor (low temperature) stimulates flowering in a larger number of buds resulting in increasing the flowering. As nitrogen promotes vegetative and reproductive growth, it can be said that increasing the nitrogen content of leaves followed by transfering to the nodes, increases the number of buds, especially reproductive buds, which leads to an increase in flowering and yield. According to this study, the foliar application of urea in winter with 1.5% concentration can increase yield in Kinnow mandarin trees. Therefore, polyamines can play an important physiological role in flower development of Kinnow mandarin.

In this study, we focused on the effect of the foliar application urea during winter on leaves and nodes of Kinnow mandarin trees and investigated the polyamines, Put, Spm, and Spd contents upon treatments. In conclusion, the application of foliar urea in winter resulted in the significant endogenous increase of polyamines and N in the leaves and nodes of Kinnow mandarin trees. Also, yield, flower density, and pistil diameter were increased by spraying urea. There is a possibility that free polyamines affect on physiological processes.

Today, water scarcity is a critical issue for most countries in arid and semi-arid regions. Due to the difficulty of establishing and maintaining grass in arid areas and in order to investigate the effects of drought and spermidine on Cynodon dactylon L., an experiment was conducted with a double-split plot design based on randomized complete blocks. Treatments included three levels of irrigation: 100% field capacity (without stress), 75% field capacity (moderate drought stress) and 50% field capacity (severe drought stress) and spermidine in three concentrations of 0, 0.5 and 1 mM. During the stress period, the trend of changing the contents of chlorophyll, proline, electrolyte leakage, malondialdehyde, catalase and peroxidase enzymes and growth parameters (fresh and dry weight of shoot and root) was examined at 15-day intervals. The results showed that drought stress decreased shoot fresh weight and increased electrolyte leakage, proline content, lipid peroxidation and peroxidase activity. Spermidine increased chlorophyll content (a, b and total) and decreased contents of proline, lipid peroxidation and peroxidase activity. In general, the results showed that spermidine pre-treatment can alleviate the negative effects of drought stress and increase tolerance of Cynodon dactylon L. to drought stress.

Pistachio (Pistacia vera L.) is an important horticultural crop that has high economic value. Pistachio trees display some physiological disorders including abscission of inflorescence buds, fruit abscission, blankness, non-splitting, early splitting and deformation of nuts. Unfavorable environmental conditions in most pistachio orchards and inadequate nutrition during the flowering time and after flowering has increased these problems in recent years. Polyamines such as putrescine, spermine and spermidine are some low molecular weight polycationic compounds that have been shown to play an important role as growth regulators in different stages of growth and development of buds, flowers and fruits and resistant plants to abiotic and biotic stress. Therefore, the objective of this study was to investigate the influence of polyamines in water scarcity condition on growth, nut traits and yield of ‘Akbari’ pistachio trees. The study was carried out in growing season 2016 in a pistachio orchard (Pistacia vera L. cv Akbari) located in Feyzabad, Mahvelat, Khorasan Province, Iran (34° 40´ N latitude, 58° 25´ E longitude, and around 1253 m above sea level). The climate of the experimental area was arid and semi-arid. The mean annual precipitation was about 171 mm. The irrigation of orchard trees was at 36-day intervals. The experiment was conducted as split plot based on a randomized complete block design with three replications and seven treatments including polyamines spray of Putrescine (Put), Spermine (Spm) and Spermidine (Spd) at concentrations of zero (control), 0.1 and 1 mM on “on” and “off” pistachio trees cultivar Akbari at two-time stages full bloom (FB) and two weeks after full bloom (2WAFB). Leaf chlorophyll index was recorded using the chlorophyll meter (SPAD-502, Konica Minolta, Japan). Leaf area from fully expanded leaves was measured by Digital Leaf Area Meter (LI-3100c). The length and diameter of current-year shoots were measured at harvest time. The percentage of flower bud abscission and fruit abscission were calculated on marked shoots. The yield was calculated by weighting the total dried split nuts separated from each shoot. The data were subjected to analysis of variances (ANOVA) using the SAS software (SAS version 9.1). Difference between means was compared using the least significant difference test (LSD) at 5% level (p ≤ 0.05). Results showed that among the treatments, Put (0.1 and 1 mM) and Spm (0.1 mM) applied in the “on” trees significantly increased leaf chlorophyll index. Also, Put spray at two weeks after full bloom indicated better results in increase of length shoot in ‘on’ trees. All of the polyamines reduced fruit abscission in the “on” trees however, Put at 0.1 and 1 mM concentrations with 11.3 and 11.1% was more effective in decreasing the percentage of fruit abscission compared to other treatments. Fruit abscission of pistachio is assumed to be related to improper fertilization, the dominance of fruits in a cluster or abnormalities of reproductive organs. Polyamines have been suggested to improve fertilization, and subsequent embryo and fruit development. It also has been reported that common precursor of S-adenosylmethionine (SAM) needed for synthesizing both of PAs and ethylene. Thus, it seems that polyamines reduce the abscission of fruits by the improvement of embryo growth and development or by antagonism with ethylene, possibly by competing for S-adenosylmethionine (SAM). Our study indicated that all of the polyamines decreased the percentage of blank nuts in the “off” trees especially two weeks after full bloom. The results showed that Put (0.1 and 1 mM) and Spd (0.1 mM) were very effective in increasing number of nuts per cluster.  Number of nuts per 100 g, split nuts, and kernel percentage did not differ significantly among treatments. Yield variations were not significantly affected by polyamines in in the “off” trees, but in ‘on’ trees, polyamines of Put, Spm and Spd at 0.1 mM concentration by 46.2, 14.6 and 15.2% and at 1 mM concentration by 38.7, 24.7 and 19.9% increased yield compared to control, respectively. Given to correlation results, the positive effect of polyamines on yield improvement in ‘on’ trees was mainly due to the prevention from fruit abscission and enhancement no. of nuts per cluster. Results showed that application of polyamines treatments in ‘off’ trees only on blank nuts and in ‘on’ trees on leaf chlorophyll index, fruit abscission, No. of nuts per cluster and yield was effected. Foliar application of polyamines was more effective in improving traits of shoot length, leaf area and blank nuts two weeks after full bloom compared to full bloom. The results of this study showed that these plant growth regulators, especially putrescine, had the potential to improve growth, yield and reduce physiological problems of pistachio under unfavorable environmental conditions.

Keeping fresh pistachio appearance after harvest had important role in economic value of this produce. In this research, pistachio trees were sprayed with 1 mM of putrescine, spermidine and permine 20 days before harvest. Foliar spraying by distilled water was considered as control. Harvested fruits were coated by chitosan (0 and 1%) and stored at 2±1 oC and 90±5% R.H. The fruits were evaluated at 0, 20, and 40 days of storage. The results showed that hull and kernel firmness, hull and fruit water content, L* index in hull and shell, hue angle and chroma indices, chlorophyll content were decreased during storage but application of polyamines maintained these traits in comparison with control. The results also indicated that combined application of putrescine and chitosan improved these characteristic than alone application of each.

Mango (Mangifera indica) is a tropical fruit native to India whose global production in 2014 reached nearly 45 million tones. Mango is a commercially important fruit and improvement in its storage is of special importance. Mango is a Climacteric fruit whose ripening is done by exogenous or endogenous ethylene. In plants, Polyamines such as spermine, spermidine, and putrescine contradict ethylene because of a common precursor (s-adenosyl methionine (SAM). During ripening, different qualitative and nutritional changes occur in the fruit, e. g. changes in color, tissue softening, accumulation of sugars and organic acids, and great changes in taste, flavor, aroma and plant biochemical materials. Fruit ripening is a complicated process, complementary to fruit development, and a start to its senescence. In general, senescence of a fruit is related to loss of membrane lipids, destabilization of membrane matrix, and lipid peroxidation. Recently, naturally active biological products are applied in a large amount for increasing the storage life and quality of the fruits and delaying their senescence.This study was carried out to investigate the effect of different concentrations of spermidine on the quality and vase life of a local mango variety of Minab.
Healthy fruits, uniform in size, shape, color, and degree of maturity were selected from a mango orchard in Minab and their original physical and chemical characteristics on the first day were measured after washing with water and drying. Statistical analysis of data was done by a general linear model (GLM) with SAS (version 9.1) and mean comparisons were performed using Duncan's multiple range test. Treatment solution in the rate of 0, 0.5, 1, and 2 mM spermidine (SIGMA) was made and its pH was set to 5 using NaOH. One liter of distilled water was used in the control treatment. The treated samples were immersed in solutions of different concentrations of spermidine just once for 30 minutes. During 24-days of shelf life, storage temperature was 15 °C and the relative humidity was 85 to 90 percent. Measurements were on the zero, 8th, 16th, and 24th days. Characteristics such as weight, firmness, flavor index, phenol, ascorbic acid, qualitative characteristics (PH, TA and TSS), and sensory evaluation were measured.
The results showed that physical and biochemical qualities in the control fruit were lower compared to the other treatments. The Polyamine treatment with spermidine, especially at the concentration of 2 mM, significantly maintained weight loss and reduction of vitamin C during storage of fruits. Spermidine treatments increased ascorbic acid and other organic acids in fruit juice and reduced pH. Increased acidity in spermidine treatments of these substances play an active role in coping with storage stress. Moreover, with reduction of tissue respiration, the consumption of organic acids decreased during storage. The results showed that increasing the concentration of spermidine leads to the least decrease in the phenol flesh. Firmness gradually decreased during storage and at the end of shelf life, there was significant difference between the treatments. It was found that treatments with 1 and 2 mM spermidine were the best. Furthermore, the effect of spermidine on the total soluble solid solutions in the flesh of mango fruit was not significant during storage. But skin color, taste, flavor, and aroma index were more favorable. Treatments that delay production of structural lipids led to the production of aromatic volatile substances, which produced a favorable aroma in fruits. It seems that increasing spermidine concentration plays an important role in mango fruit fragrance at the end of shelf-life. The 2 mM spermidine treatment led to the highest total content of phenol and showed the lowest pH in fruit juice.
Spermidine, that is naturally present in animals and plants in particular, belongs to the amine groups. The results indicated that spermidine maintains firmness and extends shelf life of mango fruits and has a significant and beneficial impact on the quality characteristics including weight, color, taste, aroma, and vitamin C during storage. It seems that spermidine of 2 mM concentration has tangible impact on mango fruits and it is recommended in mango store rooms. There is a competition in production of Ethylene and polyamides of spermine, spermidine, and putrescine in plants, due to their common precursor namely S-adenosyl methionine, yet they act oppositely in ripening and senescence processes. Application of polyamides had extraordinary effects on the quality of some fruits during storage.

Salinity stress is one of the most important destructive factors of plant growth and yield, which has very unpleasant effects on plant growth and production in agriculture. Strawberry is a salt-sensitive plant. The aim of this study was to use of polyamines and humic acid (HA) to reduce negative effect of salinity on growth, yield and absorption of minerals elements. For this purpose, a factorial excrement based on randomized block design was conducted in a hydroponic commercial greenhouse with media culture Cocopeat and perlite (equal ratio) in Yasooj suburb. The first factor was polyamines in 5 concentrations (Putrescine (Put) 0, 500 and 1000 mg l-1 and Spermidine (Spd) 500 and 1000 mg 1-1) and humid acid at 0 and 5 g 1-1 concentration. All plants were irrigated with 40 mM NaCl salinity during experiment. Results showed that salinity reduced the growth parameters of strawberry. Application of HA and PAs reduced the harmful effect of salinity stress, although in all traits improved the quantity characteristics. Use of PAs increased the Fe, Ca and K contents in shoot and root of strawberry plant under salinity stress. So use of PAs and HA rescued the absorption of Na in shoot and root of strawberry. In general, results showed the salinity stress caused reduce the growth parameters in strawberry but application of Put and Spd 500 mg 1-1 and HA 5 g 1-1 can reduced the salinity harmful effect and increased vegetative and reproductive traits and absorption of mineral elements under salinity stress.

In order to study the effect of polyamins (PAs) including putrescine (Put) and spermidine (Spd) on growth and quality of olive fruit (Olea europae L. cv. Dezful) an experiment was conducted in Shiraz, Iran (2014 and 2015). Putrescine (0, 2.5 and 5 mM L-1) and Spermidine (0, 1.25 and 2.5 mM L-1) were sprayed on branch units at full bloom (FB) and two weeks after full bloom (AFB). Factorial experiment was conducted in a randomized complete block design with three replications. Fruit number, physical characteristics such as fruit and pit size, weight, length and diameter, fruit color and chemical characteristics such as total phenol content, total carbohydrate and chlorophyll a, b were evaluated. The results showed that Put was very effective on decreasing abscised fruits and increased fruit set at FB. Fruit skin color was affected by the type of PAs applied. Total phenol was generally reduced in fruits obtained from PAs treated trees. Total carbohydrate, N, chlorophyll a and b contents and total chlorophyll increased in PAs treated fruit as compared with control. Applications of Put and Spd significantly increased fruit growth characters such as size, weight, length and diameter but decreased weight, length and diameter of the pits compared with control. The highest effect on physical and chemical characters was observed in Put at 5 mM L-1 treatment.

Pistachio is one of most important horticultural crops in Iran, USA, Turkey and some Mediterranean countries. Some physiological problems such as abscission of inflorescence buds, blankness, non-splitting, early splitting, cracking and nut deformation reduce the pistachio yield and quality.
This experiment were carried out in a commercial 20-year old ‘Ahmad-Aghaii’ pistachio orchard in Rafsanjan, Iran. It was arranged as factorial based on randomized completely block design with three replications.
Results showed that the main physiological problems of pistachio crop were decreased by application of calcium compounds combined with free polyamines. Spray application of the mentioned treatments was more effective at combined stages of 1 and 2 rather than the stages separately. It was resulted that calcium nitrate combined with spermine and spermidine treatments at combined stages of 1 and 2 reduced the abscission of inflorescence buds, blankness, nut deformation and non-splitting. Also, it was found that calcium nitrate combined with spermidine at combined stages of 1 and 2 reduced the percentage of early splitting while splitting and yield were increased.

This experiment was carried out to investigate the effect of polyamines on growth, flowering and corm production of ‘Golden Wave’ and ‘Blue Sea’ cultivars of freesia. For this purpose, freesia plants were sprayed at 35, 70 and 100 days after planting with concentrations of 0.5 and 1 mM of putrescine, spermidine and spermine and distilled water (control). The factorial experiment was performed in a completely randomized design with 3 replications and 2 pots for each replicate. Results showed that spermine treatment delayed flowering time. But spermidine treatment accelerated flowering and also increased leaf length, flowering stem height, inflorescence height, diameter and length of florets and number of lateral stems in both cultivars. Maximum number of corms was obtained in spermidine treatment. But, plants treated with putrescine had more corm weight and diameter than other treatments and control. Polyamines increased leaves nutrient concentration. The highest nitrogen concentration (2.39 and 2.37 percent) was observed in putrescine and spermine treatments and the highest concentration of phosphorus (0.47 and 0.46 percent), potassium (3.1 and 3.03 percent) and zinc (51.31 and 50.3 mg/L) was obtained in spermidine and putrescine treatments. Almost all polyamines increased magnesium concentration of leaves. The results of this study revealed that polyamines, and especially spermidine and putrescine, could increase yield and improved quality of flower and corm of freesia.

In order to investigate the effect of two spermidine concentrations (0.5 and 1 µ M) on in vitro gynogenesis of six onion accessions from Khorasan province this research was carried out. Results showed that the highest and lowest percentage of gynogenesis rate was belonged to M2 and M5 media, respectively. The highest (1.41) and lowest (0.33) percentage of gynogenic embryo were belonged to Roshnavand-e- Birjand and Sefid-e- Naishabur accessions, respectively. The highest percentage of plant regeneration was belonged to Roshnavand-e- Birjand accession in M2 medium culture. Ashkhane-e- Bojnourd and Dargaz accessions had the highest and lowest percentage of plant survival rate (81.25 and 49.8, respectively). Therefore, spermidine in two concentrations of 0.5 and 1 µ M, without other plant growth regulators, had no positive effect on onion gynogenesis and should not be used instead of 2,4-D and BA. Combination of spermidine with other plant hormones could induce gynogenesis in onion.

In spite of attractive appearance, delicious flavour and high antioxidant capacity of strawberry fruit, it has short postharvest life. In this study the effect of fruit dipping in putrescine and spermidine (1 and 2 mM) on postharvest quality and maintenance of strawberry fruit cv. ‘Selva’ was studied. During 10 days storage at 4◦ C, changes of quality attributes including texture firmness, weight loss percentage, surface color, vitamin C content, flesh anthocyanin, total phenolics, antioxidant capacity, titratable acidity, soluble solids content and juice pH were determined at two days intervals. Treatment with putrescine lowered the changes in surface color and fruit weight loss and retarded the fruit softening. Also putrescine and spermidine treated fruits showed higher anthocyanin and antioxidant capacity and lower vitamin C than control fruits. During the storage period of control fruits, titratable acidity showed reducing pattern when pH and soluble solids content increased gradually. While the use of putrescine and spermidine significantly retarded changes of pH and soluble solid concentration.