فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 33 (بهار 1394)

To evaluate the effects of quality of irrigation water and kinds of fertilizer on yield and some cumin’s physiological parameters, a split-plot experiment in randomized complete block design with three replications was conducted at the Research Farm of Zabol University. Main factor was two levels of water irrigation, fresh and natural saline water (EC: 4.180 dS.m-1) and the sub-plots consisted of control, NPK fertilizer, manure and their combination. Analysis of plant growth parameters were performed according to the four times samplings. The results indicated that increasing the concentration of soluble salts in water irrigation until 4.180 dS.m-1 resulted in significant decrease in dry matter, biomass duration, crop growth rate, relative growth rate, relative water content of shoots and roots and yield; It was also showed that application NPK-fertilizer at rate 40:20:15 kg.ha-1 combined with manure with 20 ton.ha-1 can improve growth characters, RWC and yield of cumin as compared to the use of fertilizer separately. The highest dry matter (0.544 g. per plant) were obtained from integrated fertilizer and saline water irrigation treatments at 105 days after sowing. It also emphasized that balanced supply organic fertilizers of micro and macro nutrients for plants can reduce application of chemical fertilizer in fields, without reducing of growth characters and yield of cumin.

Salinity and waterlogging are two abiotic stresses decrease plants yield. In this research¡ the effects of soil salinization and waterlogging having concentrations of calcium (Ca)¡ potassium (K)¡ magnesium (Mg) and sodium (Na) and K:Na ratio in corn (Zea mays cv. single cross 704) root were studied under greenhouse conditions. A factorial experiment with two factors on the basis of completely randomized design with three replications was performed. The factors under study were: waterlogging duration in five levels (0¡ 2¡ 4¡ 8¡ 20 days) and soil saturate extract salinity in four levels (0.11¡ 2¡ 4¡ 8 dS/m). A loamy sand soil for plant growth substrate and NaCl salt for establishing the levels of salinity was used. The salinity and waterlogging factors were imposed simultaneously to the plants from the five-leaf stage of plant growth period. The plants were harvested 60 days after sowing and the concentrations of Ca¡ K¡ Mg and Na in corn root were determined by dry ashi method. The results showed that by increasing the level of NaCl salinity in the soil¡ the K concentration and K:Na ratio of corn root were decreased significantly but concentrations of Ca¡ Mg and Na in corn root were increased significantly. The Mg and Na concentrations of root in waterlogged conditions were significantly lower than that of non-waterlogged conditions but the K and Ca concentrations of root in waterlogged conditions were significantly greater than non-waterlogged conditions. However¡ the effects of soil waterlogging duration on the Ca¡ K¡ Mg and Na concentrations and Na:K ratio of root were dependent on the level of NaCl salinity in the soil. The results demonstrated that even short periods of soil waterlogging had considerable long-term effects on the concentrations of Ca¡ K¡ Mg and Na and K:Na ratio in corn root under saline and non-saline conditions.

Salinity is one of the main stresses that have negative effectcs on seedling growth, and plant production. It inhibits growth of plants through disturbance of the balance between production of ROS and antioxidant defense mechanism which results in oxidative stress. Because, arginine is a vital regulator of physiological and developmental processes the effect of different concentrations of arginine pretreatment of the plant on alleviation of oxidative stress induced by salt 50 and 100Mm NaCl was investigated. Arginine pretreatment increased chlorophyll a, b, carotenoid and seedling growth under salinity condition. Results also showed that salt stress increased proline, protein, H2O2, soluble sugar and the activity of ascorbate peroxidase, guaiacol peroxidase and catalase. Pretreatment of plants with Arg reduced proline, soluble sugar, H2O2 and antioxidant enzymes activity content significantly. The conclusion is that in garden cress plants, pretreatment with concentration of 5 µM and 10 μM arginine may protect cress under salinity stress, probably through the contracting with ROS and or induction of anti-oxidative enzymes.

To quantify the response of some morpho-physiological traits of Echinacea purpurea to thr application of zinc sulfate and ascorbic acid under water deficit, an experiment was carried out in split plot factorial based on RCBD with three replications at the Agricultural Research Station of Islamic Azad University, Tabriz Branch in 2011-12. Experimental factors consisted of water stress as the main factor with three levels (irrigation after70mm evaporation, irrigation after120mm evaporation and irrigation after 170mm evaporation from class A pan), Secondary factor consisted of: application of microelement with two levels (control and application of zinc sulfate 0.005 concentration) and ascorbic acid with four levels (not application, application of 50 mg/l of ascorbic acid, application of 100 mg/l of ascorbic acid and application of 150 mg/l of ascorbic acid). The results showed that the effect of water deficit on purple coneflower caused significant differences in diameter of stem, number of flowering branch, stomata density, zinc concentration of aerial parts plant, fresh weight, relative water content of leaf, LAI, proline concentration, crop growth rate, relative growth rate and net assimilation rate. Comparison of means for water deficits between the different levels of drought stress showed that the maximum LAI, with 2.85, belonged to control. Comparison of means for interaction effects between drought stress and application of zinc sulfate revealed that the maximum proline concentration belonged to spraying plants with zinc sulfate at irrigation after 170mm evaporation from class A pan with 10.16 mg/g.fw. Minimum proline concentration was due to without applying zinc sulfate in complete irrigation (control) with 0.08 mg/g.fw. Maximum crop growth rate with 6.77 g/m2.day was was related to control and the minimum, with 4.16 g/m2.day, to irrigation after 170mm. Maximum relative crop growth rate, with 0.19 g/m2.day, belonged to control and the minimum, with 0.14 g/m2.day, to irrigation after 170mm. Maximum net assimilation rate, with 2.64 g/m2.day, belonged to control and the minimum, with 1.91 g/m2.day, to irrigation after 170mm. The results indicated that application of ascorbic acid, as an antioxidant, may decrease the harmful effects of drought stress on some traits (NAR, CGR, RGR, and RWC) of purple coneflower.

Drought one of the most important global threats against bread wheat production. In order to identify physiological traits associated with drought tolerance, 52 bread wheat varieties were cultured under two normal and drought stress condition in a randomized complete block desigen with three replications. RWC (in three independent times), leaf rolling, leaf silvering, days to flowering, days to maturity and stem reserve remobilization were investigeted. Also in a pot experiment osmotic adjustment of the varieties were measured at seedling stage. varieties Star and Bezostaya had the highest RWC (0.79 and 0.78, respectively). Osmotic adjustment in Rasol and Unknown11 were highest (0.58 and 0.56, respectively). Varieties Tipik, Unknown11 and Azar2 showed the least decrease in thousand grain weight after spraying with KI (4.8, 5.5 and 5.5, respectively). Also varieties Dez, Gaspard and MV-17 have the highest degree of leaf silvering and varieties Niknejad, Star and Kohdasht under drought stress were able than the other varieties bring their leaves to form a rolling and cope with water deficit. Under drought stress, Varieties Alborz, Zagros and Inia were observed premature than the other varieties and Gaspard and Kaslojen varieties were observed late mature than the other varieties. Altogetehr varieties Kohdasht, Star and Bezostaya can be used as genetic resources for leaf water retention under drought stress condition for imjproving other varieties. Also as Azar2 and Unknown11 had highest amount of thousand grain weight under normal condition and simoultanously showed high ability in stem reserves remobilization they can be selected as parents in crosses for improving these traits.

To evaluation the response of some maize hybrids to water deficit stress, a field experiment in 2010 was conducted using a split-plot plan on the basis of complete randomized block design with four replications at the Agricultural Research Station, University of Tabriz (Khalatpoushan). Main plots consisted of three different irrigation regimes (non-stress, mid-stress and sever-stress) and sub plots of 14 maize hybrids. Results showed significant differences among hybrids and irrigation regimes for all traits studied. Analysis of variance revealed significant differences among hybrids and also irrigation levels for all traits except ear diameter. The best model for stepwise regression based on all traits at the average of conditions, indicated that four responsible traits like number of rows per ear, 300-grain weight, number of grains per row and number of leaves per plant remained in model, which justified 83 percent of the total variations in yield performance. The path analysis showed that the number of rows per ear had the highest direct effect on yield. Based on principal component analysis the first component had a major factor on the weight of 300 seeds, plant height, ear length, flag leaf area, ear diameter and corn cob diameter and the second component had a big factor on plant dry weight, number of kernels per row, number of leaves per plant, number of rows per ear and grain yield. Principal component analysis (PCA), based on all of traits studied determined two principal components that could justify the 78 percent of vaiations. In this research the first component named as the growth-morphological factor and second component named as the yield factor.

Light is one of the growth-reducing factors in mixed cropping and agroforestry systems. Therefore, an experimental field was conducted to justiffy the effect of light intensity on two lentil cultivars. It was performed in a factorial experiment based on randomized complete block design with three replications at Agricultural Research Station of Ilam University during 2012-2013 cropping season. The factors under study consisted of shading in four levels (0 shading, 25, 50, 75 and 100% of shadings) and two cultivars lentil (Lens culinaris Medic) (Ziba and ILL4400). Results showed that physiologic traits were significantly affected by cultivar × shading intraction. Ziba cultivar had the highest chlorophyll a and b content in 100% shading. Carotenoid content, relative water content and leaf area index also increased with increasing in shading. The highest and lowest carotenoid and relative water contents were observed in 100% shading × ILL4400 cultivar and control treatment × Ziba cultiva, respectively. The highest leaf specific weight observed in control treatment × Ziba cultivar and decreased with increasing shading. Grain yield decreased with increasing shading. The highest and lowest mean grain yield, 2522 kg.ha-1 and 1137 kg.ha-1, were observed in control treatment × Ziba cultivar and 100% shading and ILL4400 cultivar, respectively. Based on the results of this study, Ziba cultivar had the highest leaf area index, relative water content and chlorophyll a in higher shading treatments; hence, it can perform better than ILL4400 in mixed cropping and agroforestry systems where the light is limited factor.

Drought stress is a major cause of reduction in crop production. According to the role of various plant parts, especially the spike photosynthesis in grain filling and the regulatory roles of IAA in formation of grain yield, a split plot-factorial experiment based on randomized complete block design (RCBD) with three replications was conducted at the experimental field of the Campus of Agriculture and Natural Resources, University of Razi, Kermanshah, in 2010-2011 growing season using two wheat cultivars (Marvdasht and Pishtaz). Results indicated that water stress after pollination significantly decreased grain yield and 1000 grain weight but it did not affect grain no. spike-1, number of fertile and infertile spikelet per spike and spike length as compared well-watered conditions. Drought stress caused 25.7 and 22.6 percent reduction in grain yield and 1000 grain weight of varieties under study respectively. Cultivars differed in grain no. spike-1, 1000 grain weight, number of fertile and infertile spikelet per spike and spike length significantly. Water stress also reduced grain yield of Marvdasht cultivar (31.8%) as compared to Pishtaz cultivar (18.7%). Pishtaz cultivar possessed larger spikes which resulted in grain yield increase under drought stress. Photosynthesis of spike during grain filling stage increased yield under well watered condition by 42.5% and under post-anthesis drought stress by 23.8%, respectivly. Foliar application of IAA did not have any effect on yield reduction when photosynthesis was stopped. This shows the importance of spike photosynthesis in increasing grain yield.

To investigate the effect of different amounts of wheat stubbe residues and urea fertilizer levels on yield and yield components of maize (Zea mays L.) SC. 704, an experiment was carried out, at the Agricultural Research Station, University of Agriculture and Natural Resources Ramin Khuzestan, during the growing season of 2007. The experiment was split plot based on randomized complete block design with two factors and four replications. The treatments consisted of four levels of nitrogen, as main factor, and six different amounts of wheat residues, as subplot factor. Main plot treatments were: a1= 425, a2= 450, a3= 475 and a4= 500 kg/ha urea fertilizer and subplot treatments were: b1= the all wheat residues (100%), b2= 75, b3= 50 and b4= 25 % of wheat residues, b5= without straw and stubble, b6= burning of wheat residues. The resulats revealed that the effects of urea fertilizer and wheat stubble rate on all traits under study and intractions on seed number per ear and ear number per unit area weresignificant. It was also indicated that high levels of wheat residues reduced corn seed yield and its components. The results also showed that turning under the 50-75 percent residue into the soil before planting corn and not using stubble not only don’t reduce seed yield and its components , they also increase in the long run soil organic matter.

Effects of salt stress (NaCl) on fresh weight, pigment content and superoxide dismutase (SOD), peroxidase (POX), and catalase (CAT) activities in nine genotypes of pinto bean exposed to two levels of NaCl )0 and 400 mM( were studied. A factorial experiment on the basis of completely randomized design was carried out in laboratory conditions. Salinity stress increased carotenoids in the leaves while it decreased chlorophyll a and total chlorophyll significantly. Salinity reduced by 24.31% fresh weight. Electrophoretic analyses were performed by using 8% slab polyacrylamide gels. For each isozymic band the “density × area” scores onto gels were evaluated by MCID software as enzymatic activity. Three isozymes were observed for each of SOD and POX and one for CAT. Salt stress increased activities of all observed enzymes. Application of salt stress increased activities of SOD1, SOD2 and SOD3. Their activity increment was estimate to be 26.31, 13.89 and 17.64 percent respectively. POX1, POX2 and POX3 activity increment, were also estimated to be48.38, 21 and 43.02 percent respectively. In the case of CAT it was 43.85 percent. Antioxidant enzymes activity increment could be important strategy for reducing the damage caused by oxidative stress.

DSSAT-CMS computer model simulates growth, development and crop production under the management conditions such as variation in soil moisture, soil carbon, soil nitrogen and nitrogen leaching. In this study, first CERES-Maize model with 20% moisture depletion and then grain yield and biomass of corn at harvesting time were calibrated. Calibration coefficients for corn single cross 260 were P1=169, P2=0.386, P5750, G2=775.9, G3=8.82 and PHINT39.20. Results showed that the model estimates grain yield and biomass in normalized mean root of error squares (RMSEn), Wilmot agreement index (d) and correlation (R2) coefficient at 18, 90 and 82 percent and 29, 84 and 84 percent respectively. Therefore, CERES-Maize model has the high precision in simulation of these two traits and also simulation was desirable in Shiraz region. The model simulated grain yield better than biomass. In general, the model can be used for irrigation and nitrogen management in the region.