ISHS Acta Horticulturae 768: XXVII International Horticultural Congress - IHC2006: International Symposium on The Role of Postharvest Technology in the Globalisation of Horticulture
EFFECT OF CADMIUM ON NITROGEN ACCUMULATION AND ACTIVITIES OF NITROGEN ASSIMILATION ENZYMES IN PAKCHOI |
| Authors: | G.W. Sun, Z.J. Zhu, X.Z. Fang, R.R. Chen, H.C. Liu |
| Keywords: | pakchoi, cadmium, nitrogen accumulation, NH4+-N, NO3-N, nitrate reductase, glutamine synthase, glutamate synthase, glutamate dehydrogenase |
| Abstract:
Plants of two cultivars (cv. Huqing 1 and cv. Hangyoudong) of pakchoi (Brassica campestris L. spp. chinensis) were grown in nutrient solution of either 0 or 10 mg•L-1 cadmium (Cd) to determine the effects of Cd on growth, N-accumulation and activities of the nitrogen assimilation enzymes. Cd strongly inhibited plant growth and significantly decreased chlorophyll content and water uptake of both cultivars. Cd induced toxic symptoms were smaller chlorotic leaves and brown roots. Cd caused a significant reduction of N-content in shoots of both cultivars; however, N-content was significantly increased in cv. Huqing 1 roots, whereas it decreased in cv. Hangyoudong roots. N accumulation in shoots and roots of both cultivars was dramatically reduced by Cd. NO3--N concentration was decreased and NH4+-N concentration was increased in the leaves of both cultivars exposed to Cd. Activities of nitrate reductase (NR, EC 1.6.6.1), glutamine synthase (GS, EC 6.3.1.2) in both cultivars and glutamate synthase (GOGAT, 1.4.7.14) in cv. Hangyoudong were significantly decreased, but glutamate dehydrogenase (GDH, EC 1.4.1.2) activity of both cultivars was significantly enhanced when exposed to 10 mg•L-1 Cd. | |
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