Abstract:

To illustrate whether the toxicity of cadmium to chrysanthemum on the growth and physiological metabolism could be reduced or not by exogenous β-aminobutyric acid（BABA），chrysanthemum‘Zhongshan Jinkui’（Cd tolerant）and‘Zhongshan Dangui’（Cd sensitive）were subjected to hydroponic culture in 1/2Hogland nutrient solution supplemented with 200 μmol · L-1 Cd，200 μmol · L-1 Cd with 0.2 mmol · L-1 BABA. The morphology and biomass，Cd accumulation and transportation，Cd fluxes on root tip and relative electrolyte conductivity，contents of MDA，chlorophyll，proline in leaves were measured. The results showed that Cd stress inhibited the growth，biomass and chlorophyll synthesis，destroyed the integrity of the cell membrane，and induced membrane lipid peroxidation damage in both varieties.‘Zhongshan Jinkui’suffered less membrane lipid peroxidation，thereby showed better integrity of the cell membrane than‘Zhongshan Dangui’，it could synthesis a large number of osmotic adjustment substances such as proline to alleviate the toxicity of Cd stress. BABA improved the growth，biomass of chrysanthemum under Cd stress. Meanwhile，BABA reduced the increase of MDA content and relative conductivity in leaves，but no increase in proline were observed with the presence of BABA. Cd tolerant variety‘Zhongshan Jinkui’has a larger Cd fluxes than the Cd sensitive cultivar‘Zhongshan Dangui’，the tolerant cultivar accumulated higher Cd than the sensitive one，especially in the base mature leaves. BABA accelerated the absorption of Cd in both varieties and promoted transportation of Cd from root to aboveground，but has no effect on distribution of Cd in different leaf positions，inferring application of BABA could contribute to the phytoremediating of cadmium contaminated soil by chrysanthemum.

Key words: chrysanthemum, cadmium tolerance, BABA, Cd flux, NMT