فصلنامه زیست شناسی گیاهی ایران
سال هشتم شماره 4 (پیاپی 30، زمستان 1395)

The effects of lead (PbCl2) increment, under hydroponic conditions up to 15, 45 and 90 mg/l in presence of EDTA, on some physiological and biochemical traits of one year old saplings of P. nigra and P. alba, were investigated. Six weeks after establishing in target concentration, the amount of lead, biomass, water, soluble sugars, proline, electrolyte leakage, malondialdehyde, and pigments were assessed in different organs. The results revealed that with increasing lead concentration in culture medium in the studied period, the amount of lead in saplings increased, but no effect was observed on their biomass. In both species the magnitude of lead accumulation in root was higher than leaf. P. nigra had more water and less soluble sugars than P. alba. The concentration of soluble sugars increased up to 1.5 times with lead increment in both species, but proline content increased only in P. nigra up to 2 times and remained constant in P. alba. Elevation of electrolyte leakage in saplings of P. nigra in excess lead treatment was accompanied by no change in malondialdehyde content. Concentrations of pigments were not affected by lead, and only the ratio of chlorophyll a to b in P. nigra increased in high lead concentration. In general both species accumulated high extent of lead in their organs. But it seems that P. nigra, at least with respect of enhancing plasma membrane permeability, increasing proline and the ratio of chlorophyll a to b, was more sensitive to this toxic metal in compare with P. alba.

This study was carried out in order to investigate on chromosomal behavior during meiosis in Kerman endemic cotton (Gossypium herbaceum) and VTDL (G. arboretum) species, F1 hybrids of two species and BC4 genotypes. The F1s investigations showed that in 40 percent of tested cells, there was one adjacent quadrivalent. Only in one case there was one lag chromosome at MII and the rest of next meiosis stages were normal. Repeated back crosses (up to BC4) caused to reduce the irregularities. Morphological traits in back crosses, were mostly similar to G. herbaceum and only in few cases were left from G. arboretum species. Since simultaneously breeding for all traits, especially through far hybridization, is not possible at one stage, so the resulted offspring would be great achievement at the early steps of endemic cotton improvement.

Drought is one of the most important factors that limit plant growth and development. In order to study the effect of drought stress in two lines of Triticale Sanabad and ET83-20 as the new man-made cereal, a greenhouse experiment was arranged in a three-replicate completely randomized factorial design. Drought stress was applied as limited irrigation by 30% and 60% of field capacity as a drought condition and 90% of field capacity as a control. One week after applying the stress, some growth criterions and biochemical parameters were evaluated for seedlings. Results of statistical analysis showed that drought stress reduced growth parameters (including dry weight of root and shoot, root length and diameter, root and leaf area) and increased the levels of chlorophyll a, b, total chlorophyll and carotenoid in both lines. However, the pigments contentof ET83-20 had a further increase than the other. The results also showed that proline content as non-enzymatic antioxidant and soluble sugars as osmolytes and antioxidant enzyme activities of superoxide dismutase and guaiacol peroxidase increased under drought stress. However, these increases were more significant in line Sanabad. The damage levels of growth criterions and defence mechanisms show that ET83-20 is less resistance to drought stress than Sanabad. So the line Sanabad could be introduced as a better alternative to wheat bread.

The aim of this study was to examine the effect of salicylic acid on the gene expression pattern of four enzymes; Phenylalanine ammonialyase, Polyphenol oxidase, Peroxidase and Catalase in wheat-Mycosphaerella graminicola pathosystem. For this reason, Salicylic Acid (2mm) were sprayed on wheat in two-leaf stage before inoculation with the fungal pathogen. Sampling of the plants was done at five time points (0, 3, 6, 12 and 24 h) after inoculation. The scanning of genes expression pattern of encoding enzymes were carried out by reverse northern dot blotting method. The results showed that within 24 hours post inoculation the gene expression of these enzymes significantly increased in this tolerant cultivar. SA enhanced the expression of Phenylalanine ammonialyase and Peroxidase genes in all time points. The expression of Polyphenol oxidase was increased by SA after 12h. On the other hand, increasing the expression level of these genes directly increases the activity of the enzymes which indicates direct role of these gens in plant defense system. SA caused a rapid rise in expression of Catalase gene, but this effect was not continued for 24h.

The present study was conducted to evaluate defense and physiological responses of some red and broomscultivars of Sorghum to salinity stress under in vitro culture. Seeds of Sorghum cultivars were cultured on MS (Murashig and Skoog, 1962) medium containing 0, 50, 100 and 150 mM NaCl under in vitro condition. After 2 weeks, the effect of salinity was studied on percentage of germination, growth parameters, photosynthetic capacity (total chlorophyll and carotenoids), total anthocyanin, total felavonoids, reducing sugars, proline, Naﲯ뼉궾 ions, total soluble protein content, ascorbate peroxidase and catalase activities in roots and shoots. According to percentage of seed germination and growth parameters, Red and brooms cultivars were selected as susceptible and resistant to salinity in the study, respectively. The photosynthetic pigments (chlorophyll and carotenoids) and the anthocyanin content decreased by increasing salt levels in both cultivars, while flavonoids increased in three wavelengths 270, 300 and 330 nm. The results showed proline, suger and protein contents increased in roots and shoots of two cultivars by increasing salinity. The content of Na ion increased in the roots of red and brooms cultivars and shoot of Red cultivar. Ratio Na/K increased in roots of two cultivars and shoots of red by increasing salinity. Ratio Na/K in the shoots of brooms cultivar didn’t change significantly under salt stress. Generally in the presence of salt, potassium decreased in roots and shoots of two cultivars. Calcium ion amount in the roots of two cultivars didn’t change significantly under salt stress while it increased in shoots of two cultivars. The CAT activity increased in roots and shoots of two cultivars but APX activity increased in brooms cultivar and decreased significantly in red cultivar.

Pistachio (Pistacia vera L.) with high cultivation in Iran has economic and nutrition importance. In this investigation, the morphological and anatomical traits of the female flower, development of endosperm and cotyledons were studied with cyto-histological techniques and light microscopy. In addition, fruit development was studied in different developmental stages. The results showed each of female flowers in panicle florescence has three-lobed stigma, a large pistil that attached to stigma with short style. One small bract is below 5 sepals in all flowers. Anatomical study reported the pistil have one carpel with single inverse ovule at its ovary. The endosperm is free nuclear firstly and then becomes cellular. Finally, this tissue replaces with cotyledons during embryo development. During the fruit development, the structure of the pericarp differentiated as exo-mesocarp and endocarp. Endocarp development continued until 95 days after full bloom (middle of May), and became hard and lignified in this time.The kernel show no abvious growth at this time but its growth increase after this time and completed in 145 DAF (last of July). Finally, fruit ripening continued and was cmpleted at 165 DAF (last of August) concurrent with harvesting time.

The aim of this research was to identify the plant species, introducing the flora, determination of life forms, and geographical distribution of alpine plants of some part of Alvand Mountain, Hamadan province. This area, with 3750 hectares, situated in north-east of Toyserkan city where the amount of annual precipitation is 420 mm and means annual temperature is 13.4°C. The altitude of this mountain is 3450 m (above sea level). The method of plant collection in this region was classical method of regional plant taxonomic studies. 400 plant samples were collected from different parts of the area between 3000-3450 m during two growing seasons 2009-2010 and are conserved in herbarium of Islamic Azad University, Boroujerd Branch and herbarium of Agricultural and Natural Resources Research Center of Hamadan Province. The life form of plant species was determined by using of Raunkiaer’s method. The position of this area within Iran’s phytogeography classification was studied based on geographical distribution data and references. From 108 identified species in high altitude of Alvand Mountain, 1 Pteridophyte, 80 dicotyledons and 27 monocotyledons are present. These species belong to 33 families and 85 genera. The important families are Asteraceae, Poaceae and Lamiaceae with 12.96%, 12.03% and 10.18%, respectively. Hemicryptophytes with 45 species (41.67%) were the most frequent life form. 65 species (60.18%) belong to Irano-Turanian region; 13 species of them were endemics of Iran which among them, distribution of 2 species (Allium breviscapum Stapf and Astragalus leucargyreus Bornm.) limited to Hamadan province.