Journal of Plant Biological Sciences
Year:2010 | Volume:1 | Issue:1-2|Papers Count:8

Many studies have been carried out both to produce ectomycorrhiza in axenic culture media and to investigate the impact of this symbiotic system on the plants. However, no investigation has been conducted on the effect of ectomycorrhizas on mineral concentration of pistachio when mycorrhizal and non-mycorrhizal plants exposed to different amounts of Mg. Ectomycorrhizal pistachio plants were produced using Agaricus bisporus, along with non-mycorhhizal plants were grown under sterilized condition in conical flasks where they were treated with four concentrations of MgSO4 prepared from Hogland nutrient solution with half of its concentration. After plant harvesting the concentration of Ca, Mg, P, Fe, K, Na, Zn, Mn and Cu of plants were measured. Colonization rate had increased in mycorrhizal plants when they exposed to higher Mg rates. The concentration of the above cations increased significantly in mycorrhizal plants in comparison to non-mycorrhizal plants. In ectomycorrhizal plants the excess amounts of Mg of high concentrations did not move to the shoots and was accumulated in the roots. The results were discussed with especial reference to the role of ectomycorrhizas in plant nutrition.

Plants use complicated mechanisms to respond stress, using proteins involve in signaling pathways for detoxification. The results of SDS-PAGE in the present study showed down regulation of proteins with 20, 26 and 50 KDa in stem-leaf and 30 and 75 KDa in roots in tomato cultivar Isfahani. Two-dimensional electrophoresis of proteins in leaf extract under salt stress showed differences in intensity of expression of some protein spots compare to the control. These spot proteins can be categorized into 2 groups: 1- protein spots up regulated or down regulated under salt stress 2- protein spots which appeared or disappeared under salt stress. It can be concluded that salt stress directly or indirectly affects on metabolism.

The effect Zn deficiency on growth, leaf pigments and photosynthesis was studied in red cabbage (Brassica oleracea L. var. capitata f. rubra) plants under three different light conditions including 100, 200 and 400 mmol m-2 s-1 in hydroponic medium either with adequate (725 pM free Zn activity) or low (30 pM free Zn activity) Zn supply. Dry matter production of shoot and root was reduced by low Zn supply up to 95% and 63% respectively, but increased with increasing light intensity. Low Zn supply caused reduction of shoot growth up to 80% under low light intensity (100 mmol m-2 s-1), while this reduction was only 24% for plants grown under higher (400 mmol m-2 s-1) light conditions. Significantly lower Zn was allocated to shoot than roots in Zn deficient compared with Zn sufficient plants. Leaf chlorophyll and carotenoids content decreased in Zn deficient plants but anthocyanins and phenolics accumulated under these conditions. Zn deficiency did not cause any damage to PSII reaction centers but caused inhibition of both photochemical and non-photochemical quenching demonstrating reduction of electron use in dark reactions and lower heat dissipation in low Zn plants. Stomatal resistance was elevated in Zn deficient leaves that led to reduction of CO2 assimilation rate and transpiration.

The inflorescence and floral ontogeny of Phytolacca americana have been studied using epi-illumination light microscopy. Our result revealed that flowers initiate acropetaly in racemous inflorescence with helical order. Each flower was subtended by a bract and two bracteoles. The perianth composed of 5 sepals which are formed helically in a 2/5 sequence. 10 stamens are arranged in five pairs opposite to sepals and their initiation follows sequential order. The number of carpels corresponds with the number of stamens in the inner androecial whorl. In mature flowers basal portion of the carpel became fused, while the distal portion, which contains style, remained free. Unusual characters that have been observed include: initiation of additional flowers at the base of bracts and bracteoles, formation of the extra stamens outside the inner stamens and doubling of inner stamens which result in increase of stamens and carpels. Our data in regard to the androecial ontogeny support existence of diplostemony as an ancestral type in the Phytolaccaceae, and therefore suggest that P. americana occupies a basal position in Phytolaccaceae.

The genus Onobrychis Miller is a large genus belonging to Fabaceae family and comperises 9 sections. The genus is distributed mainly in north temperate regions, but centers of its diversity are in the eastern Mediterranean area and south-western Asia. Many species of the genus are cultivated as fodder or for ornamental value. Onobrychis sect. Hymenobrychis DC. with about 12 species is one of important sections of the genus. In this study, chromosome number of 5 species belonging to the section, Onobrychis sintenisii Bornm., Onobrychis subnitens Bornm., Onobrychis chorassanica Bunge, Onobrychis hohenackeriana C. A. Mey. and Onobrychis michauxii DC. were analyzed. This report is the first cytogenetic analysis of these taxa. Results showed that all taxa are diploid and possess 2n = 2x = 14 chromosome number.

Copper is a micronutrient which its, deficiency can alter essential functions in plant metabolism. On the other hand, excess copper is present in certain regions and environments, and can be potentially toxic to plants causing phytotoxicity by the formation of reactive oxygen species that damage cells. In this study, we examined the effect interactions between various concentrations of sodium nitroprusside (SNP) solution (0, 50, 100, and 200 µM) and different levels of Cu (50, 100, and 200 mM CuSO4) on the growth and morphology of Garden Cress (Lepidium sativumL.). The results showed that SNP treatment increased roots and shoots fresh weight, as well as the contents of chlorophyll a, b, total chlorophyll and carotenoids in all of the L. sativum plants under Cu Toxicity, as compared with the control plants. SNP treatment decreased malondialdehyde and other aldehyde in shoots and roots of the plants treated with copper, as compared with the control plants. In this study, determined that medium concentrations of SNP solution (50 and 100 µM) had good effects on improvement of physiological effects in plants under Cu toxicity.

Alkaloids are variable substances and are classified according to their chemical and biochemical properties. Tropane alkaloids such as atropine and scopolamine which are ornitine derivatives are the most important alkaloids of Atropa belladonna. In this study the plant leaves was gathered from three stations of Vaz-Chamestan area in north of Iran in different seasons. Alkaloids were extracted from leaves’ powders three times from every sample. Total alkaloid of extracts was determined by UV spectrophotometer (258 nm). HPLC analysis was performed to determine atropine and scopolamine content of samples three times a sample. Soil samples were studied also for texture, pH, EC, etc. The most soil porosity and C/N ratio were observed in 3rd station and the least one in the first station. All of soils were mildly alkaline without salinity. Height of station had significant influence on total alkaloid contents and the common influence of height – season of sampling also was significant. Atropine content always was higher than scopolamine. There was also seen significant correlation between some soil properties and alkaloid content in some cases. Total alkaloid contents had always significant correlation with atropine and scopolamine contents.