Study of Effects of Root Temperature, Corm Size, and Gibberellin on Underground Organs of Saffron (Crocus sativus L.)

Hypocotyledon explants of Eucalyptus camaldulensis Dehnh., E. froticetorum E. Muell, and E. viminalis Labill were cultured on LS medium with three hormonal treatments at 24 °C and were used to produce calluses and roots. The nonstructural carbohydrates were extracted. These sugars were quantitatively and qualitatively analyzed based on spectrophotometry, thin-layer chromatography, and gas-liquid chromatography. Hormonal treatment with a combination of 0.88 μM BA, 2.6 μM NAA, 2.8 μM IBA, and 0.9 μM 2, 4-D which produced the dark woody callus, induced the highest growth rate. Whereas in 20 μM 2, 4-D the light-fresh callus were produced. At IBA 10 μM the explants produced too much root. The major sugars in the nonhydrolyzed soluble sugar extraction were sucrose and glucose and a small amount of rhamnose, fructose, ribose, and glucuronic acid. Also, in this fraction, there was no galactose. In the hydrolyzed fraction, there was no galactose, whereas glucose and fructose, which were produced from sucrose, were the major sugars in this fraction. In hydrolyzed nonstructural polysaccharide fractions, galactose, glucose, mannose–arabinose, xylose, and one uronic acid appeared in all treatments and species. In contrast to sugars in intact plants of the Eucalyptus tree, there was no galactose in the hydrolyzed soluble sugar fraction in the tissue culture extractions, but it appeared in the hydrolyzed nonstructural – -polysaccharides fraction of explant extractions. The absence of galactose in the hydrolyzed or unhydrolyzed-soluble extraction sugars could serve as a marker or an indicator for the optimum conditions of growth of explants.

Identification of resistant chickpea lines against pathotypes causing Ascochyta blight disease in Iran

The identification of resistance sources against Ascochyta blight pathotypes is necessary for use in chickpea breeding programs. Plant breeders accept screening of crop germplasm as a useful gene pool against biotic and abiotic stress. Ascochyta rabiei is one of the most important constraints to chickpea production in most areas of the world, especially in Iran. In this study, reactions of 420 chickpea accessions and 97 lines and cultivars from Ferdowsi University of Mashhad were evaluated to find resistant sources against six pathotypes of Ascochyta rabies by artificial infection using mix spore suspension in field and greenhouse conditions during two years (2003 and 2004). In the first step, the seeds were sown in the field and inoculated using a mixed spore suspension of six pathotypes in five to seven leaf stages. Humidity and temperature were regulated using a mist irrigation system during the week after inoculation to distribute the disease in the field. The disease severity was scored on a scale of one to 9 when susceptible line death. In this step, 63 accessions with scales 2 to 4 showed high resistance levels against the pathotypes. These accessions were inoculated again by the spore suspension in the greenhouse at different developmental stages, i.e., planting, flowering, and podding. The disease symptoms were scaled two weeks after each step of inoculation. Nine accessions showed high resistance levels in the greenhouse. The average disease severity was higher in the greenhouse than in the field. The differentiation of resistant and susceptible accessions was correctly performed in the podding stage. According to field and greenhouse evaluations two desi accessions (MCC54 and MCC523) and six Kabuli accessions (MCC496, MCC133, MCC299, MCC528, MCC3.11, and MCC142 were resistant against six pathotypes of ascochyta blight. These accessions can be used as resistant sources in chickpea breeding programs.

Allelopathic effects of essential oils of Zhumeria made on Wheat (Triticum aestivum ) and Tomatto (Lycopersicon esculentum)

In this investigation, the effects of different concentrations of essential oils prepared from leaves of Zhumeria majidae on seed germination and seedling growth of Lycopersicon esculentum and Triticum aestivum were studied. Besides, the effects of essential oils on leaf chlorophyll content and peroxidase activity in the roots of the above plants were investigated. In post-emergence treatment, the effects of different concentrations of essential oils on the fresh and dry weight of the above plants were studied. Essential oils prepared from the leaves of Zhumeria majidae inhibited seed germination and seedling growth. In wheat, in the presence of 50 and 100 percent stock solution, the seed germination rate was reduced to zero. Using different concentrations of essential oil as post-emergence treatment reduced both fresh and dry weight in the plants tested. The most inhibitory action was observed on the dry weight of Lycopersicon esculentum. The amount of chlorophyll was reduced in all post-emergence-treated plants. The activity of peroxidase enzyme extracted from the above plant roots in Lycopersicon esculentum was increased and that in Triticum aestivum was reduced.

Journal of Biology