Fulvic acid mediates chromium (Cr) tolerance in wheat (Triticum aestivum L.) through lowering of Cr uptake and improved antioxidant defense system.

Chromium (Cr) stress is one of the most adverse environmental factors that affect plant growth and food chain contamination. Fulvic acid (FA) is known to enhance the growth and production of crops, but the studies are scare regarding the application of FA on metal tolerance in plants. The effects of FA application on alleviating Cr phytotoxicity in wheat plants were investigated in a pot experiment conducted in sand- and soil-grown plants. Three Cr (0, 0.25, and 0.50 mM) treatments in the form of K2Cr2O7 were applied in both soils with or without foliar application of 1.5 mg L(-1) FA. Plants were harvested after 4 months of treatments, and data regarding growth characteristics, biomass, photosynthetic pigments, and antioxidant enzymes were recorded. FA application increased plant biomass, photosynthetic pigments, and antioxidant enzymes while it decreased Cr uptake and accumulation in plants as compared with Cr treatments alone. We conclude that FA application contributes to decreased Cr concentrations in wheat grains and could be used as an amendment when aiming for decreased metal concentration in plants.

Cadmium-induced upregulation of lipid peroxidation and reactive oxygen species caused physiological, biochemical, and ultrastructural changes in upland cotton seedlings.

Cadmium (Cd) toxicity was investigated in cotton cultivar (ZMS-49) using physiological, ultrastructural, and biochemical parameters. Biomass-based tolerance index decreased, and water contents increased at 500 µM Cd. Photosynthetic efficiency determined by chlorophyll fluorescence and photosynthetic pigments declined under Cd stress. Cd contents were more in roots than shoots. A significant decrease in nutrient levels was found in roots and stem. A significant decrease in nutrient levels was found in roots and stems. In response to Cd stress, more MDA and ROS contents were produced in leaves than in other parts of the seedlings. Total soluble proteins were reduced in all parts except in roots at 500 µM Cd. Oxidative metabolism was higher in leaves than aerial parts of the plant. There were insignificant alterations in roots and leaves ultrastructures such as a little increase in nucleoli, vacuoles, starch granules, and plastoglobuli in Cd-imposed stressful conditions. Scanning micrographs at 500 µM Cd showed a reduced number of stomata as well as near absence of closed stomata. Cd depositions were located in cell wall, vacuoles, and intracellular spaces using TEM-EDX technology. Upregulation of oxidative metabolism, less ultrastructural modification, and Cd deposition in dead parts of cells show that ZMS-49 has genetic potential to resist Cd stress, which need to be explored.

Proptosis: etiology and demographic patterns.

OBJECTIVE: To determine the demographic pattern of patients presenting with proptosis and its etiology. DESIGN: A cross-sectional descriptive study. PLACE AND DURATION OF STUDY: Khyber Institute of Ophthalmic Medical Sciences (KIOMS), Hayatabad Medical Complex, Peshawar from July 2001- December 2002. PATIENTS AND METHODS: Sixty cases of proptosis presenting at KIOMS were included. Thirtysix patients were male while 24 were female. They were divided into two age groups; 0-15 years (paediatric group) and above 15 years (adult group). An elaborate work up plan was formulated for all patients, which included detailed history, clinical examination (ocular, orbital and systemic), radiological and histopathological investigations. RESULTS: Neoplasms (33%) were the most common causes of proptosis in all the patients followed by orbital inflammations (23%), orbital infections (20%), structural abnormalities (12%), vascular abnormalities (7%) and trauma (5%). CONCLUSION: Neoplasms were the most common cause of proptosis in both paediatric and adult group. Proptosis was the cardinal feature and visual deterioration was present in more than half of the patients. Timely referral, early diagnosis and appropriate management can result in reduction of visual morbidity.