Ecophysiological and anatomical changes due to uptake and accumulation of heavy metal in Brachiaria decumbens

Scientia Agricola

Marcelo Pedrosa Gomes²  Teresa Cristina Lara Lanza De Sá E Melo Marques¹  Mariana De Oliveira Gonçalves Nogueira¹  Evaristo Mauro De Castro¹  Ângela Maria Soares¹ 

[1] ,UFMG Inst. de Ciências Biológicas Depto. de BotânicaBelo Horizonte MG ,Brasil

关键词: contaminated soil;    chlorophyll;    growth;    potencial photosynthesis;   

DOI  :  10.1590/S0103-90162011000500009

来源: SciELO

【 摘 要 】

The growth and developmental characteristics of grasses and their high biodiversity make such plants suitable for remediation of areas contaminated by heavy metals. Nevertheless, heavy metal toxic effect on the plants may cause alteration in their metabolic pathways, such as photosynthesis, respiration, and growth, modifying plant anatomy. This work aimed to evaluate the effect of levels of soil contamination (0, 7.5 % and 15 % m³ m-3) on biomass production, on photosynthetic characteristics and on anatomical changes in roots and leaves of brachiaria (Brachiaria decumbens Stapf.). After seeds were planted, seedlings were uprooted and replanted in vases containing soil at different contamination levels, being left to rest for 120 days. At the end of that time, plants presented reduced yield of root and shoot dry matter, contents of chlorophyll a, chlorophyll b, total chlorophyll and potential photosynthesis with increased of soil contamination. The cell layers of endodermis and exodermis in the root tissues and the cell walls of the xylem and cortical parenchyma all thickened as contamination increased. In the leaf tissues, the adaxial and abaxial epidermis presented increased thickness while the leaf blade presented reduced thickness as contamination increased with consequent change in the root growth rate. In general, the effects of heavy metal increased with the metal concentration. Some results indicate that B. decumbens seems to have some degree of heavy metal tolerance.

【 授权许可】

CC BY   
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