Role of sulphur availability on cadmium-induced changes of nitrogen and sulphur metabolism in maize ( Zea mays L.) leaves

• Autor: Astolfi, Stefania ; Zuchi, Sabrina ; Passera, Calvino
• Assuntos: Adaptation, Physiological - drug effects ; Adaptation, Physiological - physiology ; adenosine triphosphate ; Agronomy. Soil science and plant productions ; ATP sulfurylase ; Biological and medical sciences ; Cadmium ; Cadmium - administration & dosage ; Cadmium - toxicity ; Chelating Agents - metabolism ; chlorophyll ; corn ; Cysteine Synthase - metabolism ; Economic plant physiology ; enzyme activity ; Fundamental and applied biological sciences. Psychology ; glutamate dehydrogenase ; Glutamate Dehydrogenase - metabolism ; glutamate-ammonia ligase ; Glutamate-Ammonia Ligase - metabolism ; Glutathione ; grain crops ; heavy metals ; leaves ; Metalloproteins - biosynthesis ; Mineral nutrition ; nitrate reductase (NADH) ; Nitrate Reductases - metabolism ; Nitrogen - metabolism ; nutrient availability ; nutrient solutions ; Nutrition. Photosynthesis. Respiration. Metabolism ; O-acetylserine sulfydrylase ; phosphoenolpyruvate carboxylase ; Phosphoenolpyruvate Carboxylase - metabolism ; Phytochelatins ; Plant Leaves - chemistry ; Plant Leaves - drug effects ; Plant Leaves - enzymology ; Sulfate Adenylyltransferase - metabolism ; sulfates ; Sulfates - pharmacology ; sulfur ; Sulfur Compounds - metabolism ; Sulphur ; Sulphur metabolism ; Zea mays ; Zea mays - chemistry ; Zea mays - drug effects ; Zea mays - enzymology ; Zea mays L
• É parte de: Journal of plant physiology, 2004-07, Vol.161 (7), p.795-802
• Descrição: The interactions between sulphur nutrition and Cd exposure were investigated in maize ( Zea mays L.) plants. Plants were grown for 12 days in nutrient solution with or without sulphate. Half of the plants of each treatment were then supplied with 100 μM Cd. Leaves were collected 0, 1, 2, 3, 4 and 5 days from the beginning of Cd application and used for chemical analysis and enzyme assays. Cd exposure produced symptoms of toxicity (leaf chlorosis, growth reduction) and induced a noticeable accumulation of non-protein SH compounds. As phytochelatins are glutamate- and cysteine-rich peptides, the effect of cadmium on some enzyme activities involved in N and S metabolism of maize leaves was studied in relation to the plant sulphur supply. In vivo Cd application to S-sufficient plants resulted in a drop of all measured enzyme activities. On the other hand, S-deficient plants showed a decrease in nitrate reductase (NR; EC 1.6.6.1) and glutamine synthetase (GS; EC 6.3.1.2) activity, and an increase in NAD-dependent glutamate dehydrogenase (GDH; EC 1.4.1.2) and phosphoenolpyruvate carboxylase (PEPc; EC 4.1.1.31) activity as a result of the Cd treatment. Furthermore, in the same plants ATP sulphurylase (ATPs; EC 2.7.7.4) and O-acetylserine sulphydrylase (OASs; EC 4.2.99.8) showed a particular pattern as both enzymes exhibited a transient maximum value of activity after 4 days from the beginning of Cd exposure. Results provide evidence that the increase of ATPs, OASs, GDH and PEPc activities, observed exclusively in S-deficient Cd-treated plants, may be part of the defence mechanism based on the production of phytochelatins.
  
• Editor: Jena: Elsevier GmbH
  
• Idioma: Inglês