Interference of three weed extracts on uptake of nutrient in three different varieties of paddy through radio tracer techniques.

Interference of three dominant weed extracts viz., Ageratum conyzoides L., Melilotus indica All. and Parthenium hysterophorus L. were examined on seed germination, seedling growth, and nutrient uptake (32P and 65Zn) in three different varieties (PD-10, PD-12 and PB) of paddy (Oryza sativa L.). Among the three different varieties irrespective of weed extracts, PD-10 and PD-12 were resistant and PB was susceptible in terms of seed germination, radicle length and plumule dry weight; and PD-12 and PB were resistant and susceptible, respectively, in terms of plumule length and total seedling dry weight. A. conyzoides caused maximum reduction in seed germination and M. indica in seedling growth in different varieties of paddy. The weed extracts interfered in uptake of both 32P and 65Zn and there was a gradual decrease in uptake of both nutrients with increasing concentration of extracts in both root and shoot. The uptake of 32P and 65Zn was more inhibitory with the extracts of A. conyzoides and M. indica, respectively in different varieties. The inhibition in seed germination, seedling growth and nutrient uptake may be due to the presence of phenolics and other secondary metabolities. The phenolics such as gallic, vanillic, protocatechuic and p-hydroxybenzoic acids were identified from these weed extracts.

Biokinetics of 65Zn in liver and whole body and its bio-distribution in nickel treated protein deficient rats.

This study was designed to determine the effect of nickel treatment on biological half-lives of 65Zn in whole body and liver as well as on distribution of 65Zn in different organs of protein deficient rats. Nickel sulfate at a dose level of 800mg/l in drinking water was administrated to normal control as well as to protein deficient rats for 8 weeks. A significant increase was found in fast and slow components of biological half lives of 65Zn in whole body and only fast component in liver of protein deficient rats. Interestingly, slow component in whole body and fast component in liver of nickel treated protein deficient rats were not different from normal controls though they were significantly elevated in protein deficient rats. On the other hand, slow component of 65Zn was also not altered in nickel treated protein deficient rats, which however, was significantly decreased in nickel treated rats. Protein deficiency led to a marked elevation in per cent uptake of 65Zn in brain and caused significant depression in liver, kidney and intestine. However, uptake of 65Zn in brain showed a significant depression in nickel treated rats, whereas the uptake was elevated in brain in nickel treated protein deficient rats. In conclusion, protein deficient conditions seem to be playing a dominant role in context with the distribution of 65Zn in different organs when nickel is administered to protein deficient rats. However nickel alone is seen to cause adverse effect on the distribution of 65Zn.