مجله علوم و فنون باغبانی ایران
سال هجدهم شماره 2 (تابستان 1396)

Evaluation of morphological characteristics of pollen grains plays an important role in identifying the different male trees cultivars. In this research morphological characteristics of the pollen grains of male date palm trees of eight cultivars including ‘Shahani’, ‘Kabkab’, ‘Zahidi’, ‘Beraem’, ‘Faryab’, ‘Sheikhali’, ‘Fard’ and ‘Jarvis’ were studied using the scanning electron microscope. Results indicated that pollen grains shape of male date palm trees in all cultivars were monad, elliptical, fusiform and have a longitudinal groove. Outer surface ornamentations of the pollen grains (exine) were reticulate, irregular and with different sizes. Also the pollen grains have different dimensions (length and width), weight, number of pores and percentage of germination. So that the highest length of pollen grains in ‘Fard’ cultivar (24.52 μm), the highest width of pollen grains in ‘Zahidi’ (13.24 μm) and ‘Faryab’ (13.20 μm) cultivars, the highest amount of weight of pollen grains in ‘Jarvis’ (22.10 g) and ‘Faryab’ (21.25 g) cultivars, the highest number of pores in the outer surface of pollen grains (18 pores per μm2) and the highest percentage of germination (78.30 %) in ‘Fard’ cultivar was observed. The characteristics of spathe (inflorescence cover) and inflorescence, ‘Zahidi’ cultivar had the highest length of the spathe (77.67 cm), ‘Jarvis’ cultivar had the highest diameter of the spathe (19 cm), ‘Jarvis’ (1619.67 g) and ‘Zahidi’ (1535.67 g) cultivars had the highest spathe weight, ‘Sheikhali’ cultivar had the highest number of strand in the spathe (183.67), ‘Kabkab’ cultivar had the highest length of strand in the spathe (21.05 cm), ‘Jarvis’ cultivar had the highest number of flower in each strand (72.53) and whole spathe (10534.66). Also spathe color was observed brownish in each eight male date palm trees cultivar.

In this study, the trend of mineral uptake by GF677 (Prunus persica × Prunus amygdalus) shoots in response to salinity stress was studied under in vitro conditions. Shoots of GF677 rootstock were subcultured into the Murashige and Skoog (MS) medium containing1 mg/l BA (6-Benzyladenine) and 0.1 mg/l NAA (naphthalene acetic acid) at different concentrations [Zero (control), 40, 80 and 120 mM] of sodium chloride (NaCl) with four replicates for six weeks. Mineral uptake was measured in the GF677 shoots every two weeks. GF677 rootstock continued N and K uptake at concentrations of 40 and 80 mM until six weeks. Phosphorous uptake continued in the control and 40 mM treatments until six weeks. Magnesium uptake decreased in the concentrations of 40, 80 and 120 mM. Iron and Zn uptake decreased in the all salinity concentration. Sodium and Cl uptake increased by increasing salinity levels during the six weeks culture. In general, due to the antagonistic effects of sodium chloride, GF677 shoots could continue to uptake nitrogen, potassium and calcium until the sixth week of culture (except for 120 mM) but did not have the ability to uptake magnesium, iron, and zinc.

Hawthorn is one of the crucial tolerant seedling rootstocks to iron deficiency chlorosis for quince and pear trees in calcareous soils. In this investigation, owing to double seed dormancy, low percentage of seed germination and producing seedling rootstocks, two factorial experiments in a completely randomized design with three replications were conducted to overcome seed dormancy in hawthorn. In the first experiment, the effect of seed scarification with concentrated sulfuric acid (98%) in three times period including 0, 1.5 and 3 hours and four warm-cold temperature treatments on C. atrosanguinea was investigated. In the second one, the germination of seed embryos of C. atrosanguinea were evaluated under different concentrations of potassium nitrate (0, 5000 and 10000 mg l-1) and gibberellic acid (0, 100 and 200 mg l-1) in vitro. The results of first experiment showed that the scarification time and temperature treatments, had significant effects in increasing germination percentage (GP), mean daily germination (MDG), length of hypocotyl and epicotyl, germination index (GI) and Seed viability index (SVI), and reduced the germination rate (T50) and mean germination time (MGT) compared to control. The results of the second experiment indicated that the aapplications of 100 mg l-1gibberellic acid, and 5000 mg l-1 of potassium nitrate significantly increased GP, MDG, GI, SVI and decreased T50 compared to the control.

Soil salinization, resulting from the accumulation of water- soluble salts in the soil, adversely impacts on agricultural production including figs. To investigate the effects of different salinity levels (0.6, 4, 6 and 8 mmhos.cm-1 NaCl) on four fig hybrids, an experiment was performed as factorial based on completely randomized design. The investigated seedlings were offsprings of ‘Sabz’ as maternal parent and four caprifigs namely ‘Pouz Donbali’(P), ‘Khormaei’(K), ‘Shahanjiri’(Sh) and ‘Daneh sephid’(D); (S×P, S×K, S×Sh and S×D). Salinity at level 8 mmhos.cm-1 increased proline (9.18-fold), carotenoids (8.04%) and stomata density (54.13%), and also decreased relative water content (15.24%), starch (39/42%), length (23.68%) and width (24.60%) of stomata and stomata conductance (73.59%) compared with the control treatment. With increasing salinity level to 6 mmhos.cm-1 increased total soluble sugars, Chlb and total Chl in comparison with the control treatment. The most proline, Chla, Chlb, total Chl, carotenoids, total soluble sugars, starch was measured in S×K hybrid, whereas the lowest relative water content was measured in S×D hybrid and the lowest Chlb and total Chl was measured in S × Sh hybrid. Moreover, S × Sh hybrid had the most decrease in stomata length and width and most increase in stomata density under the salinity condition, while the lowest stomata density was found in S×K hybrid. Moreover, the most and lowest changes in the percentage of stomata conductance under treatment 8 mmhos.cm-1 in comparison with the control treatment were found in S×P and S×K hybrids, respectively. Among the studied hybrids, S×K was shown salinity tolerance more than other hybrids and it is possible to use of this hybrid in the salinity soils up to 8 mmhos.cm-1.

In this research water relations, gas exchange and leaf temperature in five almond genotype/cultivars grafted on GN15 rootstock in response to deficit irrigation stress were studied. Factorial experiment was conducted in a completely randomized design with five cultivars (Sahand, Ferragness, 13-40, H and K3-3-1) and three levels of irrigation (available water, 70% and 40% available water) in Horticultural Research Station of Sahand. Results showed relative water content (RWC) decreased from 21% to 32%, leaf water potential (Ψleaf) dropped to -4.8 MPa and electrolyte leakage (EL%) increased from 53% to 59% in sensitive genotypes (K3-3-1 and 13-40). In sensitive genotypes photosynthesis and stomatal conductance decreased 70% till 75% in response to severe deficit stress. Water deficit stress promoted water use efficiency (WUE) up to 6 to 7 folds in drought tolerant genotypes. Leaf temperature difference in the morning and noon (ΔT) significantly decreased in drought tolerant genotypes. Reducing stomatal conductance and the ability to maintain RWC involved in almond genotypes in drought tolerance mechanisms. Negative significant correlation between leaf temperature difference and photosynthesis found. We suggested that ΔT could be used as a simple measurement for determining water stress in almond genotypes and monitoring water stress in the irrigation management of almond orchards. Finally, it was concluded that ferragness cultivar, Sahand and H genotypes on GN15 rootstock better act under severe stress tolerance.

Rootstocks were involved on fruit quality at harvest and post-harvest times. In this experiment, the Yashar mandarin fruit quality on five rootstocks (Sour orange, Citrange, Citromelo, Poncirus and Fling dragon) at harvest and during cold (5oC & 85% RH) and common (7-10oC & 60-70% RH) storages was evaluated during two years. The results showed fruit had the lowest juice percentage at harvest time on Citrange but fruit on citromelo had the highest juice percentage during storage. TI (6.03 to 6.8 at harvest) slightly decreased but EC increased during storage. At harvest time, the TSS/TA ratio was the highest on Sour orange with 9.43 and the lowest with 7.83 on Flying dragon but it increased during storage. Fruits color development on Citrange was not as well as other rootstocks. Fruit on Sour orange has more phenol at harvest time significantly. The amount of vitamin C in peel of fruits that grafted on Flyingdragon were significantly higher than other rootstocks at harvest time and during storage. The amount of antioxidant capacity was varied depending on fruit tissue and rootstock type. According to overall acceptability data, no significant differences observed to 20 days of storage at all rootstocks. With sampling at 40 and 60 days of storage, fruits on sour orange take lower point with 4.67 and 3.67 respectively especially in common storage. Generally, Yashar fruit on poncirus had high nutrition value and juice content during storage.

This research was conducted to study the effect of root and foliar applications of silicon on growth and yield of strawberry under salt stress conditions in soilless culture. Experiment was conducted based on factorial experiment considering the silicon concentration and its application method as the first factor and salinity as the second one with in completely randomized design in 3 replications. Seedlings of Pajero cultivar of strawberry were prepared at 4-5 leaf stage. After transplanting into 3 L plastic pots containing cocopeat and perlite (1:1 v/v). Salinity levels were; 0 mM (as control) and 40mM. NaCl along with applying salinity treatments, silicon treatments were applied using silicic acid as 1 and 2mM as root application every other day and at 4 and 8mM as foliar spraying once per two weeks. Morphological and vegetative traits consisted of shoot and root dry weight, leaf area, greenness index, specific leaf area, leaf nitrogen content and yield, sodium, potassium, chlorine, silicon and nitrogen concentration in strawberry plant were measured and analyzed. The results showed that NaCl of 40 mM in all levels of silicon concentrations reduced all traits, except the sodium content of shoot and root. At both salinity levels, silicon showed a positive effect on growth parameters of strawberry and reduced adverse effects of salinity. It also seems that root application of silicon has a greater impact on controlling the negative effects of salinity compared to its foliar application method.

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.