Alleviation of water and osmotic stress-induced changes in nitrogen metabolizing enzymes in <Emphasis Type="Italic">Triticum aestivum</Emphasis> L. cultivars by potassium

Present communication reports laboratory and pot experiments conducted to study the influence of water and osmotic stress on nitrogen uptake and metabolism in two wheat (Triticum aestivum L) cultivars with and without potassium supplementation. Polyethylene glycol 6000-induced osmotic stress/restricted irrigation caused a considerable decline in the activity of nitrate reductase, glutamate synthase, alanine and aspartate aminotransferases, and glutamate dehydrogenase. Potassium considerably improved nitrogen metabolism under normal water supply conditions and also resulted in amelioration of the negative impact of water and osmotic stresses indicating that potassium supplementation can be used as a potential tool for enhancing the nitrogen use efficiency in wheat for exploiting its genetic potential.     

Pattern of Resource Allocation of Six Plantago Species with Different Breeding Systems

Plantago exhibit great deal of differences in the breeding system. The reproductive effort calculated on the basis of, (i) dry biomass of foliar and floral parts and (ii) seed output-weight (mg) per unit leaf area (cm²), exhibits relation with breeding system. The predominantly inbreeding taxa invest higher reproductive effort compared to their outbreeding allies. In terms of sex allocation strategies, the outbreeding species like P. lanceolata, P. lagopus invest more to the development of floral features and to male functions. On the contrary, inbreeding species such as P. patagonica, P. drummondii, and P. ovata invest greater resources to the female function. Received 13 April 1998/ Accepted in revised form 6 November 1998     

Airborne Pollen Grains of Gurdur,Turkey

Ｔｈｃ ｐｏｌｌｅｎ ｇｒａｉｎｓ ｉｎ ｔｈｅ ａｔｍｏｓｐｈｅｒｅ ｏｆ Ｂｕｒｄｕｒ ｈａｖｅ ｂｅｅｎ ｓｔｕｄｉｅｄ ｆｏｒ ａ ｔｗｏ－ｙｅａｒ ｐｅｒｉｏｄ（１９９６ｔｈｒｏｕｇｈ １９９７）ｗｉｔｈ ａ Ｄｕｒｈａｍ ｓａｍｐｌｅｒ．Ａ ｔｏｔａｌ ｏｆ １１ ８８１ ｐｏｌｌｅｎ ｇｒａｉｎｓ ｂｅｌｏｎｇｉｎｓ ｔｏ ３９ ｔａｘａ ｈａｖｅ ｂｅｅｎ ｉｄｅｎｔｉ－ｆｉｅｄ     

Exogenous application of nitric oxide modulates osmolyte metabolism,antioxidants, enzymes of ascorbate-glutathione cycle and promotes growth under cadmium stress in tomato

Experiments were carried out to investigate the role of nitric oxide (NO) in ameliorating the negative effects of cadmium stress in tomato seedlings. Plants treated with cadmium (CdCl₂, 150 μM) showed reduced growth, biomass yield, pigment content, chlorophyll fluorescence, and gas exchange parameters. Exogenous application of NO donor (sodium nitroprusside) with nutrient solution protected chlorophyll pigments, restored chlorophyll fluorescence and gas exchange parameters, and caused significant enhancements in growth and biomass yield. Cadmium triggered the synthesis of proline and glycine betaine; however, application of NO caused further enhancement of their accumulation, reflecting an obvious amelioration of the cadmium-induced decline in relative water content. Activities of the antioxidant enzymes superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase, monodehydroascorbate reductase, dehydroascorbate reductase, and other enzymatic activities of ascorbate-glutathione cycle were enhanced following the application of NO, as compared with those in untreated seedlings under control and cadmium stress conditions. NO increased the flavonoid and total phenol content in Cd-stressed tomato plants. Moreover, NO application restricted the uptake of cadmium and enhanced the accumulation of nutrients in different parts of tomato plants. On the basis of the findings of the present study, we propose that NO has a potential role as a growth promoter for tomato under cadmium stress.     

Modification of Osmolytes and Antioxidant Enzymes by 24-Epibrassinolide in Chickpea Seedlings Under Mercury (Hg) Toxicity

Journal of Plant Growth Regulation - The effects of 24-epibrassinolide (EBL, 10−6 M) on mitigation of mercury (Hg, 15&nbsp;μM and 30&nbsp;μM HgCl2) toxicity on growth,...     

Possible influences of a macroalgal bloom in eelgrass beds on fish assemblages in the lower Knysna Estuary,South Africa

The occurrence of a macroalgal bloom at eelgrass (Zostera capensis) sampling sites in the summer of 2014/2015 provided an opportunity to use underwater video cameras to monitor the possible effects of environmental change on fish diversity and abundance in the lower reaches of the Knysna Estuary. A General Linear Model (GLM) showed that there was a significant difference in the abundance of fish before and after an invasion of the sampling sites by the macroalga Ulva lactuca. The eelgrass bed fish abundance was more affected by the macroalgal bloom than the bare substratum fish abundance, with the Ulva impacting negatively on the relative abundance of Mugilidae in the former habitat. The hypothesis that macroalgal invasions have a negative effect on fish diversity and abundance is therefore supported by this preliminary study.