مجله تولید و فرآوری محصولات زراعی و باغی
سال هشتم شماره 3 (پاییز 1397)

Dust is considered as one of the most widespread air pollutants. The objective of the study was to analyze the effect of dust load on the leaf attributes of the nut pistachio tree (Pistacia vera L.) planted in Badrood region (Kashan, central Iran) with a relatively high aeolian dust pollution. Some leaf characteristics including specific leaf area (SLA), relative water content (RWC), leaf nitrogen content (LNC), leaf phosphorus content (LPC), total chlorophyll content (TCC), total soluble sugars (TSS), ascorbic acid (AC) and air pollution tolerance (IPTI) indices were evaluated. Increasing of dust load led to aggravation of state of stress in most of the parameters studied. However, IPTI and AC indices were increased with increasing the dust load. Even though all studied traits were affected by the dust load but RWC, LNC, TCC were amongst those that were less affected and SLA, AC, IPTI, TSS and LPC were more influenced by different quantities of dust load. It may be concluded that the long-term exposer of the plant photosynthetic surfaces to dust particles leads to significant changes in biochemical and biophysical attributes, which can lead to a decrease in pistachio productivity.

Salinity is known as one of the most important abiotic factors that limit growth and yield of crop plants. This research was conducted to evaluate the effect of mycorrhiza symbiosis on physiological responses of Solanum lycopersicum against salinity stress. Three Solanum lycopersicum genotypes with and without mycorrhiza fungi and three levels of salinity stress (non-saline (control), mild (4 dSm-1) and severe saline (7 dSm-1) were examined in a randomized complete block design in Lisimeter pools in greenhouse condition. Some physiological traits at flowering initiation and yield of the examined genotypes at physiological maturity were estimated. Mycorrhizal symbiosis in the presence of non-saline water led to notable increase in plant dry mass. Severe salinity led to significant increase in colonization percentage. Primo Rio treated with mycorrhiza indicated the greatest leaf and root area and root volume. Non-inoculated plants were proven to contain greater flavonoid contents when grown in the presence of severe salinity. From the gathered data, it can be concluded that mycorrhizal symbiosis may leave positive influence on leaf area (i.e. photosynthetic source) and root area and volume (i.e. leading to  enhancement of mineral absorption), and hence withstanding tomato against salinity stress. Grande op and Primo Rio appeared to be salt-sensitive and salt-tolerant genotypes, respectively.

In order to evaluate the reaction of foreign genotypes and the indigenous cultivars of barley against drought and study their biochemical traits, eight genotypes with two barley cultivars were surveyed in a randomized complete block design with three replications in two states of sufficient irrigation and non-sufficient irrigation regimes (drought) at the Faculty of Agriculture, Shiraz University, Shiraz, Iran in the cropping year 2013-2014. The main factor included drought stress and complete irrigation treatments; the sub-factors included genotypes and barley cultivars. The results showed that drought reduced the content of chlorophyll a, chlorophyll b, and carotenoids in all genotypes, causing 18.9, 26.2 and 12.6% reduction in these traits, respectively. The chlorophyll a/b ratio in this study was increased under drought stress conditions. The least reduction in the concentration of pigments was related to Youssef genotype and genotypes 79 and 120, which were considered tolerant. The activity of superoxide dismutase, catalase and peroxidase enzymes was also increased significantly under drought stress. The results also showed that the catalase enzyme had a low activity among the enzymes examined in the study; therefore, it played a role in the plant protection against drought stress, while the peroxidase enzyme was recognized as the best biochemical criterion for drought tolerance. The highest activity of this enzyme in the drought stress conditions was obtained in Yousef (74.44%) and the genotype 120 (72.61%); on the other hand, the lowest activity in the stressed plants was found to be in Basil (50.78%). In general, the genotypes 95 and 120, with the mean grain yield of 8809.7 and 8925 kg ha-1, were recognized as the best genotypes in both non-stress and drought stress conditions. Therefore, drought could have a different effect on the biochemical traits of barley genotypes, and this difference was probably related to their stress tolerance.

This study was designed and implemented to investigate the yield and agronomic characteristics in three differently maturing corn (Zea mays L.) hybrids (SC704, SC500, and SC260) using four nitrogen (N) levels (0, 80, 160, and 240 kg N ha-1, from Urea, N= 45%). The experiments were conducted in Zabol (South-West of Iran) and Isfahan (Central Iran) in 2014 and 2015, respectively, using a split-plot arrangement in a randomized complete block design with three replications. Results revealed that the interaction effects of nitrogen × hybrid × location on the number of grain per ear, 1000-grain weight, nitrogen fertilizer use efficiency and grain yield were significant at 1% level. The interaction effects of nitrogen × hybrid on ear length, stem diameter, plant height, grain protein and dry mass yield were significant. Increasing the nitrogen application rate from 80 to 240 kg N ha-1 was found to increase ear length, stem diameter, plant height, 1000-grain weight, SPAD, grain protein and dry mass yield while it increased the nitrogen use efficiency. Increasing the nitrogen application rate from 80 to 160 kg N ha-1 was found to increase number of grains per ear and grain yield. The threshold level of nitrogen fertilizer requirement based on a 50% maize yield loss were determined to be 178 and 200 kg ha-1, respectively, in SC704 grown in Isfahan and Zabol, respectively. While the latter values were 164 and 192 kg ha-1 for SC500, and 150 and 186 kg ha-1 for SC260. It can be concluded that the SC500 had the highest grain yield at 160 kg N ha-1 in Zabol, and SC704 at 160 kg N ha-1 in Isfahan.

Foxglove (Digitalis sp.), as an ornamental and medicinal plant, is used for treatment of heart congestive disorders. Use of plant cell and tissue culture can be effective in large scale micropropagation and stable production of medicinal compounds. In this study direct and indirect regeneration methods in two species of this genus (D. purpurea and D. lanata) were investigated in response to different concentrations of auxin and cytokinin. In indirect method (regeneration through callus), regeneration occurred only in D. lanata in response to 3mg L-1 BAP, and no regeneration observed in callus of D. purpurea. Use of 13 different combinations of plant growth regulators for direct regeneration from node explants showed that the best regeneration in both species occurred in MS medium supplemented by BAP. Number of shoots produced in direct method in D. purpurea was more than that of D. lanata.  The response of explants of D. lanata to different treatments was faster. The results showed that phenol production in node culture of both species was much less than leaf culture in indirect regeneration. Rooting was rapidly achieved even in mediums without auxins and 1 mg L-1 Zeatin. Rooted plantlets transported into the soil and acclimated in greenhouse. Taking to the account of low phenol production and high number of shoots in direct regeneration, this method could be suggested for the micropropagation of foxglove.

This research was designed and implemented to determine the effect of different irrigation regimes on the grain yield, dry matter, tiller number per unit area, degree of maturity, panicle harvest index, percentage of leaf rolling, day to 50% flowering, and the physiological maturity of rice genotypes, using a split plot randomized complete block design in two years (2014 and 2015). Four irrigation regimes (every 1, 3, 5 and 7 days of irrigation) were assigned to the main plots and 12 rice genotypes were in the subplots with three replications. The results showed that irrigation regimes, genotypes and interactive effects of these two factors had a significant impact on all measured traits at the 1% probability level. All genotypes tended to produce the most grain yield in the second irrigation regime (the three-day irrigation interval); genotype IR 81025-B-327-3, with 6555.10 kg ha-1 of grain yield, out-performed the remaining genotypes in this level of irrigation regime. Also, the second irrigation regime (the three-day irrigation interval) had the highest amount of dry matter, tiller number, degree of maturity, and panicle harvest index. Considering the positive and significant correlation between these traits and grain yield, their increase could be regarded as one of major reasons for the increase in the grain yield at the second irrigation regime (the three-day irrigation interval). The degree of maturity with day to 50% flowering and physiological maturity were decreased with increasing irrigation intervals; the latter modifications could be regarded as a defense mechanism to avoid drought

This experiment was conducted in a greenhouse at Isfahan University of Technology, Isfahan, Iran in 2014 to evaluate 20 wheat cultivars (Navid, Pishtaz, Karaj, Kavir, Tajan, Karun, sholeh, Bahar, Khoshki 11, Gasparood, Sepahan, Sorkh tokhm, Chamran, Ghods, Shariar, Omid, Sistan, Alamut, Marvdasht and Shiraz) under two carbon dioxide concentrations (the ambient 360 and the enriched 700 µM) and two salinity levels (0 and 150 mM NaCl). Treatments were arranged as a factorial in a completely random design with three replications. The results showed that salinity decreased potassium concentration in shoots (27%) and roots (39%), chlorophyll a and b concentrations (27 and 30%, respectively), carotenoids concentration (21%), plant height (39%), leaf area (32%), root volume (40%), shoot and root dry weight (30% and 23%, respectively); however, it increased sodium concentration in the shoots and roots (36%). The extent of salt-induced decreases in the shoot dry weight of the evaluated cultivars ranged from 8 to 46%. Karaj and Marvdasht cultivars were the most and the least sensitive cultivars to salinity under both ambient and enriched carbon dioxide concentrations, respectively. The elevated carbon dioxide concentration increased potassium concentration in the shoots (except Sholeh, Ghods and Gasparood) and roots, chlorophyll and carotenoids concentrations, plant height, leaf area (except Shahriar), root volume, shoot (except Sistan and Omid), and root dry weight; however, it decreased sodium concentration in the shoots and roots. The highest and the lowest increases in the shoot dry weight under non saline condition were obtained for Karaj and Alamut (23 and 6%, respectively); under saline conditions, they were found in Chamran and Kavir (66 and 3%, respectively). The results obtained from this experiment showed that the elevated carbon dioxide concentration positively influenced the growth of most cultivars. This effect was more pronounced under saline conditions, indicating that carbon dioxide enrichment could alleviate, at least in part, the negative effects of salinity.

Coriander is an annual plant belonging to Apiaceae family that its yield is affected by drought stress. Three experiments (normal irrigation regime, sudden drought stress and gradual drought stress) were conducted according to a randomized complete block design with three replications in 2015 to introduce the most drought tolerant Iranian coriander ecotypes based on several economical traits, aiming at improving them in next generations, using univariate and multivariate tolerance indices. The economic traits having high heritability and high correlation with the yield and fruit essential oil content were used to calculate multivariate index of the Membership Function Value for Drought Stress (MFVD) and multivariate graphical analysis based on Principal Component Mediated Multivariate Index (PCAMMI). Also, genotype by environment interaction was traced for normal and stress experiments. The ecotypes, traits and indices were categorized and their occurrence in the environments was showed using a Heatmap graphical mapping. Stable genotypes and suitable indices were identified. High variation was observed among ecotypes. Stress Tolerance Index and Geometric Mean Productivity indices were suitable for identification of genotypes belonging to group B, and Tolerance Index and Mean Productivity indices were suitable for identification of genotypes belonging to group C. The multivariate index of MFVD and thousand fruit weight was categorized into the same group. Therefore, this index was not effective for separating ecotypes. Ecotypes were grouped using the PCAMMI graphical technique. In sudden drought stress, ecotypes 6, 12 and 14, and in gradual drought stress, ecotypes 1, 2, 3, 5, 8, 11 and 13 were grouped in group A.

To study the effect of mulch and two irrigation levels on olive cultivar ‘Manzanila’, two experiments were conducted. The first experiment evaluated the effect of seven types of mulch in plant-less pots; the second one was conducted on olives as a factorial according to a complete randomized design with 4 replications. In this experiment, seven mulch types (gravel mulch, pistachio shell mulch, wheat straw mulch, de-oiled olive pomace mulch, super absorbent polymer, organic-based emulsion polymer, and control (no mulch)) in the presence of two irrigation levels (control: irrigation to reach 100% of field capacity) and water stress (irrigation to reach 50% of field capacity) were investigated. The results showed that mulching decreased surface evaporation rate and improved soil water content, keeping the underneath soil moist longer than bare soil; the best types of mulch for conserving soil water were de-oiled olive pomace mulch and pistachio shell mulch. The results of the second experiment indicated that the shoot water potential and the olive chlorophyll index were decreased significantly in the water stressed treatment; however, using pistachio shell mulch improved the latter traits under stress conditions. The stomatal size and stomatal density were also affected by irrigation conditions; on the other hand, mulch usage, especially de-oiled olive pomace mulch, could decrease drought effects in drought stress conditions, improving leaf conditions for photosynthesis, and growth. All types of mulch in the experiment increased stomatal conductance in the water stress treatment (50% of crop capacity), as compared to the control (100% of crop capacity). Overall, the results showed that the application of pistachio shell mulch and de-oiled olive pomace mulch could be a suitable criterion to reduce the damaging effects of drought stress in olive.

Most researches on wheat and barley breeding for salt tolerance have focused mainly on excluding Na+ from different tissues but the results of some experiments suggest that contribution of Na+ exclusion to salt tolerance is overshadowed by other physiological responses. Three bread wheat cultivars differing in salt tolerance (Arg, Tajan and Baharan) and one barley cultivar (Nik) were employed to assess tissues Na+ concentration and K+/Na+ ratios as a criterion for salt tolerance using a factorial experiment based on a randomized complete block design with three replications. Three levels of NaCl (0, 75 and 150 mM NaCl) were imposed as the salinity treatment when the leaf 4 was fully expanded. Salinity decreased root dry weight, root K+, shoot K+ and shoot K+/Na+ ratio and increased root and shoot Na+. Shoot Na+ concentrations of barley and salt tolerant cultivar of wheat (Arg) were greater than Tajan and Baharan under salinity stress.  There was no meaningful relationship between Na+ exclusion and salt tolerance in the examined wheat cultivars and Nik barley cultivar. Shoot K+/Na+ ratio was found to be the most responsive trait to salinity and no significant differences were observed between the wheat cultivars and Nik barley cultivar under salinity conditions in this aspect. Given the negative effects of salinity on root growth, it seemed that the major factor in root dry weight losses of the present wheat cultivars and Nik barley cultivar was due, mainly, to the osmotic effect of salt. The results of this experiment suggest that Na+ exclusion does not necessarily confer salt tolerance. It, hence, seems breeding for salt tolerance needs to select for traits related to both Na+ exclusion and other physiological responses, most likely those associated with tissue tolerance.