Source: SEAMEO BIOTROP's Research Grant | 2018
The experiment aimed to examine the photosynthetic response, physiology and growth of the five weed species in response to the treatment of Hg and Pb. Five weed species (Branchiaria mutica, Cyperus kyllingia, Ipomea aquatica, Mikania micrantha, and Paspalum conjugatum) were grown in water culture and subjected to Hg(NO3)2 and PB(NO3)2 at 0.25 and 0.5 mM for 3 weeks. Photosynthetic rate, growth and some physiological parameter were observed during the treatments. The result showed that Hg treatment reduced photosynthetic rate dramatically under different photosynthetic photon flux density suggesting that heavy metal Hg until 0.5 mM caused the damage of photosynthetic apparatus almost all species. Both Hg and Pb induced growth decrease, but the decrease was far higher in Hg than in Pb treatment. Hg and Pb treatment caused dramatic increase in leaf MDA content, which was associated with the decrease of chlorophyll content significantly. Only Hg treatment that induced higher proline content in the leaves of threated plants, not Pb suggesting that proline may have a role as alarm stress.
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