نشریه روابط خاک و گیاه
پیاپی 37 (بهار 1398)

To investigate the effects of nutrient-solution concentrations of potassium (K) and calcium (Ca), as well as different ratios of K/Ca, on growth and flowering of lisianthus (Eustoma grandiflorum) under soilless culture conditions, a factorial experiment was conducted with two factors including two K levels (300 and 400 mg/L) and three Ca levels (80, 100 and 160 mg/L). Results showed that K= 400 mg/L increased leaf number and plant height by 10% and 5% more than K= 300 mg/L, respectively. But, did not affect shoot or root’s fresh and dry weight. The highest plant height (45.6 cm) was obtained in 100 mg/L of Ca and the highest fresh root weight was observed in 160 mg/L of Ca. The effect of K×Ca interaction was significant on the number of leaves and branches. The highest number of leaves (40.3) was observed in K=400 and Ca=160 mg/L treatment. The interaction effect of Ca×K had significant effect on traits related to flowering. The highest number of flowers (16.4), number of flowering shoots (4.7) and flower diameter (49.5 mm) were observed in K=400 and Ca=100 mg/L or K=400 and Ca=80 mg/L (K/Ca ratios of 4 and 5); while, the flower longevity was the least (10.3 days). The highest flower longevity was observed with K=300 and Ca=100 mg/L. The best nutrient solution treatment for yield and durability of flowers was K=300 and Ca= 80 mg/L (K/Ca=3.7).

In order to investigate the effects of seed priming by salicylic acid (SA) and Paclobutrazol (Pa) on parsley, as a medicinal plant, under drought stress, a factorial experiment, based on completely randomized design with four replications, was performed at the Research Greenhouse and Laboratory of Department of Horticulture, University of Mohaghegh Ardabili. Experimental treatments included five levels of priming (seed priming by 100 and 200 mg/L concentrations of SA and 100 and 200 mg/L of Pa and control (no priming)) and three levels of drought stress (25, 50 and 100% of field capacity (FC) moisture content). Results showed that seed priming had significant effect on plant height, shoot and root dry weight, proline content, stomatal conductance and potassium content of parsley (p≤0.05). Seed priming by 100 and 200 mg/L SA increased plant dry weight by 14 and 8%, respectively, as compared to control. Seed priming by 100 and 200 mg/L Pa reduced plant dry weight by 1 and 11%, respectively, as compared to control plants. Drought stress decreased all vegetative growth traits of parsley. But, proline and soluble protein contents of leaves were increased. Maximum proline content of leaves (2.4 µg/g fresh weight) was for 25% field capacity moisture content and the lowest proline content (1.06 µg/g fresh weight) was observed for 100% field capacity moisture content. Seed priming by salicylic acid, having positive effect on growth and physiological traits, led to higher resistance against drought stress, as compared to Paclobutrazol

This research was aimed at investigating the effects of foliar application of calcium silicate and sodium silicate on growth and biochemical characteristics and leaf elements of chrysanthemum. This study was conducted as a factorial with completely randomized design and silica source at two levels (calcium silicate and sodium silicate) and concentration of silica at five levels (0 (control), 50, 100, 150 and 200 mg/L) in soil medium, with three replications. At the end of the growth stage, fresh and dry weight of leaf, stem, flower and root, flower diameter, number of flowers, total protein content, soluble sugars and also leaf elements’ concentrations such as nitrogen, potassium, phosphorus, zinc, manganese, iron, copper and silicon were measured. Results showed that foliar fertilization of plant with silica caused to increase the fresh and dry weight of leaf, stem, flower and root, flower diameter, number of flowers, total protein content and soluble sugars. Also, concentrations of chrysanthemum leaf elements such as nitrogen, phosphorus, potassium and zinc were increased, but concentrations of iron, manganese and copper were decreased. The concentration of 150 mg/L sodium and calcium silicates was suitable for improving morphological and reproductive characteristics and also for improving adsorption of nitrogen, potassium, manganese, iron and copper. But, for improving the adsorption of zinc and silica, the best concentration of both silicates was 200 mg/L

Water supply in arid and semiarid regions of the world is a serious problem in crop production. Grafting may enhance water stress resistance and plants growth. In order to evaluate the effect of different cucurbit rootstocks (Flexifort, Shintoza and ungrafted cucumber) and water stress (40, 60, 90% of field capacity) on morphologic traits and yield of greenhouse cucumber (Cucumis sativus L. var. Nagen 792), an experiment was conducted as split plots design based on randomized complete blocks with three replications in 2016. Results showed that plant dry weight, leaf and stem fresh weight, number of nodes and root moisture content in Flexifort rootstock as compared to ungrafted plants was increased by 91, 53, 58, 28 and 7%, respectively. Root volume in the Shintoza and Flexifort rootstocks was almost twice as much as the ungrafted plants and its volume decreased with increasing water stress. Plant dry weight, leaf and stem fresh weight, number of nodes, root volume and leaf and root moisture content were decreased significantly with increasing water stress. Maximum leaf area and marketable yield were obtained in Flexifort rootstock irrigated with 90% of field capacity and minimum leaf area and marketable yield were obtained in ungrafted plants irrigated with 40% of field capacity. These results suggest that grafted plants on Flexifort and Shintoza have better growth and yield than ungrafted plants under water stress conditions

Chrysanthemum aphid (Macrosiphoniella sanborni) is one of the most important pests of chrysanthemum (Chrysanthemum morifolium); while there is little information about the interaction of chrysanthemum and chrysanthemum aphid. In the present study, interaction of different chrysanthemum cultivars and aphid populations was assessed through evaluation of morpho-physiological traits. For this purpose, 14 chrysanthemum cultivars were cultivated in a greenhouse at Isfahan University of Technology, Isfahan, Iran, using a factorial experiment in a completely randomized design with three replications. According to the results of analysis of variance, presence of aphid significantly affected all measured plant’s growth parameters. The studied traits showed negative responses to stress conditions. The highest reduction effect was related to photosynthesis. Also, the respiration rate was increased in relation to photosynthesis among the infected plants. In addition, presence of the pest reduced the proportion of open buds to total buds on the plant, decreased plant height and delayed flowering period among the infected plants. Although the growth of aphid population in different cultivars was not exactly the same during different days, but the trend was relatively similar. Despite the relatively high number of aphids on the flowers of “Ordibehesht” cultivar, they still had good quality. Overall, based on the results of this study, aphids can significantly affect the chrysanthemum plant's vegetative and reproductive growth

Sunlight, as a natural resource, is an important factor in agriculture, which is supplied indefinitely and without any charge by the sun. But some phenomena such as cloudy weather or shortening the length of the day throughout the year, cause restrictions on access to this important source. This is very important for cultivation in controlled environments such as greenhouses, which usually produce off-season. This paper is aimed at evaluating the economic exposure of artificial lighting to increase cucumber production to compensate for the lack of light due to weather cloudiness. For this purpose, by using daily meteorological data of the study area and cucumber production from one of the greenhouses in Hamadan city, which didn’t have artificial lighting system, the damage of cloudy hours was assessed. Daily time series data were collected for the period of April 2007 to July 2010, and the amount of crop reduction per hour of cloudiness was estimated by using an autoregressive distributed lag model (ARDL). Results showed that on the average, in each production period, atmospheric cloudiness has 3.8% negative effect on greenhouse cucumber production. On the other hand, based on this research’s findings, compensating for the lack of sunlight due to atmospheric cloudiness by artificial lighting in this area isn’t economically feasible, and the benefit/cost ratio is 0.11

The aim of this study was to examine how timing of supplemental lighting and different light combinations affect the vegetative and reproductive responses of petunia (Petunia × hybrida Super cascade Blue). This experiment was designed as a factorial based on a randomized complete blocks design with three replications. After being in the greenhouse for 12 hours, the plants received supplemental lighting at two different times (from 6 p.m. to 10 p.m. and 10 p.m. to 2 a.m.) by the usage of various combinations of red light (R, 625 nm) and blue light (B, 467 nm) including 100% R, 15% B : 85% R, 30% B : 70% R and high pressure sodium lamp (HPS, serving as control). Results showed that there was not significant interaction between light combination and the timing of supplemental lighting on vegetative characteristics. Plants under 30% B : 70% R light ratio had the highest foliage fresh weight (15.73 g) and dry weight (0.86 g), root fresh weight (1.13 g) and dry weight (0.3 g), average height of lateral shoots (6.63 cm), Chlorophyll a, b, total  and  carotenoids contents (1.03, 0.35, 1.38 and 0.44 mg/g FW, respectively) and the plants under 15% B : 85% R light ratio had the highest height of central stem (14.4 cm), leaf area (313.07 cm2), number of leaves (80.5) and number of lateral shoots (9.83). Also, results revealed that there was significant interaction between timing of supplemental lighting and light combination on the flowering time, and the shortest time to flowering (56 days after sowing) was obtained under 30% B : 70% R light ratio from 10 p.m. to 2 a.m