Rujira Suebsimma. Influence of soil amendments on growth and cadmium accumulation in Ocimum Gratissimum (African Basil) and O Tenuiflorum (Holy Basil). Master's Degree(Environmental Biology). Mahidol University. : Mahidol University, 2008.
Influence of soil amendments on growth and cadmium accumulation in Ocimum Gratissimum (African Basil) and O Tenuiflorum (Holy Basil)
อิทธิพลของสารปรับปรุงดินต่อการเจริญเติบโตและการสะสมแคดเมียมของ Ocimum Gratissimum (ต้นยี่หร่า) และ O. Tenuiflorum (ต้นกะเพรา)
Abstract:
The objective of this study was to determine the suitability of the aromatic
plants, Ocimum specie, as an alternative crop that could be grown in heavy metal
contaminated soil. A hydroponic study was conducted to compare growth
performance, Cd and Zn tolerance and accumulation by two aromatic crops, Ocimum
tenuiflorum (holy basil) and O. gratissimum (African basil), grown in nutrient solution
containing various concentrations of Cd and Zn (control, Cd 2.5 and 5 mg L-1 and Zn
10 and 20 mg L-1) for 15 days. The results showed that O. gratissimum had a higher
tolerance (Tolerance index, TI > 1) and growth performance. O. gratissimum also
accumulated higher Cd and Zn concentration in its tissues. As a result, O. gratissimum
was selected for further study.
A pot experiment was performed to examine the influence of hydroxyapatite
(HA) (0.75%and 1.5 % w/w) and cow manure (10% and 20 % w/w) amendments on
growth and Cd and Zn accumulation in O. gratissimum grown in contaminated soil for
3 months. Cow manure application showed the maximum dry biomass production of
O. gratissimum and significantly reduced DTPA extractable Cd and Zn concentration
in soils. Hydroxyapatite amendment did not improve growth of O. gratissimum but
was effective in reducing the mobility of both Cd and Zn. Both HA and cow manure
could reduce the Cd and Zn concentrations in both roots and shoots. Moreover, Cd
concentration in leaves of O. gratissimum grown on soil amended with 20 % cow
manure decreased to 0.29 mg kg-1, which slightly exceeded the maximum level (ML)
for Cd set by the Commission of the European Communities and the Codex
Alimentarius Commission (0.2 mg kg-1 DW for leafy vegetables and fresh herbs).
Therefore, growing O. gratissimum in combination with soil amendments as an
alternative cash crop on slightly heavy metal contaminated agricultural soils is
economically and environmentally feasible.