Figure 4.

TUNEL labeling in PR and LR during lethal salinity. Roots of Arabidopsis plants that were treated with 200 mM NaCl for 24 or 48 hours, were labeled with TUNEL as mentioned in methods. (a,b) Shown are the representative confocal microscopy images of TUNEL positive control of LR and PR that were treated with DNase-I for 20 min. The green punctate structure represents nuclei with fluorescein labelled nick and PI was used as a counterstain to locate cell nuclei. (c,d) Are the representative images of TUNEL labeled roots that were salt stressed for 48 hours (similar results were obtained during 24 HAS). The lack fluorescein labelling in the LR (c) and PR (d) clearly indicate the absence of DNA nicking in these tissue under toxic salinity conditions. The experiment was repeated twice (n = 7–10 plants).