ABSTRACT
The potential of in-situ monitoring of cytotoxic effects of chromium through root-tip assay was studied in a sugarcane cultivar CoLk 8102 (Saccharum spp. hybrid). Sugarcane setts supplied with graded concentrations of chromium (VI), exhibited a reduction of 85.92 and 95.10 % in mean root length at 40 and 80 ppm Cr dosages along with 61.25 and 82.50 % reduction in mean root number/node respectively. Mitotic index of root tip cells of treated setts declined and the frequency of aberrant mitotic phases increased pari passu to the increasing chromium concentration. To compare and quantify the effect of graded chromium dosages on frequency of chromosome aberrations vis-à-vis inhibition of mitotic activity, a ‘Decretion factor’ (D.F.) has been used for the first time. The value of DF increased with the increase in the chromium dosages. The increase in chromosome aberration frequency was low at low chromium dosages (1 or 2 ppm), but the high Cr dosages (40 and 80 ppm), induced sharp reduction in mitotic efficiency of root system along with anomalies in the process of cell division and induced chromosome aberrations in sugarcane root meristem, which in turn affected the over all plant growth.
ABSTRACT
Characteristics of crude and digested spent wash (distillery waste), and effect of their application on cyto-morphological attributes of settlings of eleven genotypes of sugarcane (Saccharum species hybrids) were studied. High concentrations of K, P, S, Fe, Mn, Zn and Cu contents and heavy metals were present in crude spent wash as compared to the digested one. Root meristem assay of settlings grown on crude and digested spent wash showed a detrimental effect on mitotic efficiency and also induction of de novo chromosomal aberrations viz. clump formation, chromosome stickiness, laggards and micronuclei formation etc. higher number of chromosomal abnormalities as compared to those of control conditions. Mitotic index of root-meristems of different genotypes showed a decline of 62.65 to 100% in crude spent wash treatment and 36.94 to 90.33% decline in digested spent wash treatments as compared to the control. However, an improvement to the extent of 27.73% was observed in the mitotic activity of root-meristems treated with diluted spent wash (1:5 v/V with water). Inhibitory effects of digested and crude spent wash were also visible on bud sprouting and settling height, but 1:5 aqueous dilution of spent wash stimulated the early growth attributes. Such beneficial effects of diluted spent wash were observed in most of the sugarcane genotypes.