The effects of lead [Pb(NO₃)₂] on the growth and chlorophyll content of sea grass [Thalassia hemprichii (ehrenb.) Aschers.] ex situ

This study aimed to determine the effects of heavy metals Pb exposure on growth rate of shoots, chlorophyll content, new roots length, and level Pb accumulation in root and leaf of Thalassia hemprichii were cultured ex situ condition. A total of 40 ramets T. hemprichii were divided into 4 treatment groups: K0 (control), and different concentrations of Pb(NO₃)₂ as K1 (10 ppm), K2 (25 ppm), and K3 (50 ppm). The observation of growth rate was occured for 40 days. Chlorophyll contents and Pb content of 8 ramets from each group were measured at day 41. During study, it was not found any new shoot that growth in all groups. The result of chlorophyll contents showed that the lowest value found in K3 group (chlorophyll a= 1.106 ± 0.205 mg/L; chlorophyll b= 0.746 ± 0.151 mg/L; and total of chlorophyll= 1.861 ± 0.190 mg/L). There was significantly influence of Pb on total chlorophyll content among all groups (p=0.006). It is also known that chlorophyll b was more affected than chlorophyll a as result of lead effect. There were growth and elongation of roots however no significantly difference between the groups. Highest level of Pb accumulation on root and leaf was shown by K3 group (2.55 ± 0.09 ppm on root and 1.80 + 0.11 ppm on leaf).