Mostafa Mobli

SALINITY TOLERANCE OF BERMUDAGRASS (CYNODON SPP. L.C. RICH.) CULTIVARS AND SHOOT NA, K AND CL CONTENTS UNDER A HIGH SALINE ENVIRONMENT

Summary Increasing need for salt-tolerant turfgrasses continues due to population growth in arid and semi-arid regions where potable water is limited, while soil and existing water sources are salty. Bermudagrass (Cynodon spp. L. C. Rich) is widely used in these areas. Therefore, this experiment was conducted to evaluate the salt-tolerance of ten cultivars of bermudagrass under a high saline soil and water environment. Five salinity levels of irrigation water (3.30, 6.93, 10.2, 14.8 and 17.8 dS m–1) were prepared and 30 pots were surfaced-irrigated at each salinity level for 1 year. Overall top growth, root growth, K content and K:Na ratio were reduced by 75%, 45%, 77% and 94.5%, respectively; while leaf-firing, shoot Cl and shoot Na concentrations were increased by 4%, 498% and 356%, respectively, when the salinity increased from 3.3 dS m–1 to 17.8 dS m–1. Regarding the salt-tolerance of cultivars, ‘Tifway’ was superior in top growth, percentage leaf-firing, Na uptake and K:Na ratio, ‘ISF2’ in root growth, and ‘Tifdwarf’ in Cl uptake. Although ‘Tifway’ showed the greatest reduction in root dry weight, it had the lowest level of leaf-firing and lowest reduction in top growth, which could be due to having the lowest Na uptake. Cultivars exhibited marked differences in their response to salinity; however, no mortality was observed, indicating that all cultivars tolerated the salinity levels used in the experiment.

Effects of auxins and application methods on root regeneration of Pistacia mutica seedlings

Summary Beneh (Pistacia mutica F. & M.) is a native tree of Iran. It can be used as a rootstock for pistachio cultivars due to its adaptibility to severe environmental conditions and resistance to some pests and diseases. The very low percentage seedling survival following transplanting has been a major problem in using this wild species as a rootstock for pistachio cultivars. This study was conducted to test the effects of different concentrations of indolebutyric acid (IBA) and naphthalene acetic acid (NAA) and application methods on root regeneration of transplanted bare-rooted beneh seedlings. IBA at 1000 or 2000 mg l–1 regenerated more roots, developed longer roots, increased root fresh and dry weight and increased the survival rate of seedlings more than other treatments. Auxin was more effective in increased root regeneration of beneh seedlings when applied using the root-dip method than as a top spray or drench into the growing media. There was a significant interaction between auxin concentration and method of application so that, in most cases, using 2000 mg l–1 IBA by the root dip method enhanced the effect of IBA, while this effect at 500 mg l–1 NAA was eliminated or reversed when applied using the drench method. It was concluded that application of IBA at 1000 or 2000 mg l–1 by the root-dip method would help the survival of seedlings following transplanting.

Relationships between Fruit Mineral Nutrients Concentrations and Some Fruit Quality Attributes in Greenhouse Cucumber

ABSTRACT The objective of this investigation was to determine nutritional and performance quality indices of greenhouse cucumber (Cucumis sativa L.) in relationship with fruit nutrient concentrations. Fruit firmness showed a positive correlation with fruit calcium (Ca) concentration (r = 0.66; P < 0.01). Ascorbic acid and citric acid concentrations in the fruit were positively influenced by potassium (K) concentration. There was a negative correlation between the fruit pH and phosphorus (P) concentration (r = −0.54; P < 0.01). The greenish color intensity (−a) of the fruit skin was positively correlated (r = 0.58; P < 0.01) to the magnesium (Mg) concentration. On the other hand, the basic tint of color (H) was lower in the fruits with higher K concentration. The mean nitrate concentration in the greenhouse cucumber was about 2.5 times higher than the World Health Organization (WHO) standard limit that shows high potential health risks. Potassium was the most important effective element on cucumber quality.

Effects of different growing media on vegetative and reproductive growth of bell pepper

ABSTRACT A soilless pot experiment was conducted to investigate the effects of different growing substrates on vegetative and reproductive growth of bell pepper. The growing substrates consisted of: rice hull (100%), perlite (100%), coarse saw dust (100%), rice hull (75%)+zeolite (25%), perlite (75%)+zeolite (25%), saw dust (75%)+zeolite (25%), rice hull (50%)+perlite (50%), saw dust (50%)+perlite (50%), and rice hull (50%)+saw dust (50%) (by volume). Results showed that for all measured vegetative traits the highest and lowest amount was related to the plants grown in the perlite+zeolite and pure rice hull or saw dust, respectively. Results also showed that using perlite+zeolite as the media produced the highest fruit number and yield, while plant grown in the saw dust+zeolite produced the lowest fruit number. According to the results, adding zeolite and perlite to rice hull or saw dust in most cases, significantly increased the pepper yield compared with their pure treatments.

Comparison of anti-oxidant activities and fruit quality attributes in four sweet bell pepper (Capsicum annuum L.) cultivars grown in two soilless media

ABSTRACT This work was carried out to study the effects of two soilless media consisting of 80:20 [volume/volume (v/v)] mixtures of mosspeat and perlite, or cocopeat and perlite, on fruit quality and anti-oxidant activities in four cultivars of bell pepper (Capsicum annuum L.): ‘Traviata’ (green), ‘Inspratian’ (red), ‘Aracia’ (orange), and ‘Taranto’ (yellow). The results showed that the composition of the medium had a significant effect on the anti-oxidant composition and activities of the bell pepper fruit. Plants grown on 80:20 (v/v) mosspeat and perlite had significantly higher pericarp firmness, titratable acidity, total phenolic compound concentrations, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, and the hydroxy free-radical (•OH) scavenging ability. Fruit on plants grown on 80:20 (v/v) cocopeat and perlite had significantly higher vitamin C concentrations. Among the four cultivars tested, ‘Inspratian’ (red) was superior in more factors including pericarp thickness, dry matter content, titratable acidity, total soluble solids content, total phenolic concentration, DPPH scavenging ability, and vitamin C concentration. There was a significant interaction between cultivar and soilless medium composition, indicating that the response of bell pepper cultivars varied in the different media. The results of the present study highlight the importance of comparing soilless media in terms of their effect on fruit crop quality and anti-oxidant activity.