Evaluation of salinity-mediated end-point cytogenotoxicity in Germinating Roots of Lathyrus sativus L., Variety Mahatora.: Bio-assay guided biomarker studies

Abstract

Pulse crops are susceptible to salt stress as per different research reports but how far Lathyrus sativus L., responds to increasing salinity has been taken up in this work. Thus, the harmful effects of increasing salinity on plant cells at various phases of chromosomal integrity and nucleolus morphology have been evaluated in Lathyrus sativus L., variety Mahatora. Lathyrus sativus variety Mahatora seeds were subjected to seed priming with serially diluted concentrations of NaCl (500, 400, 300, 200 and 100 mM respectively) and germination percentage (72 hrs), root length inhibition (7 days) normal and abnormal MI (Mitotic Index) with 2% aceto-orcein staining, nucleolar morphometric cum frequency analysis (0.05% hematoxylin), total protein, POX and Electrolyte leakage from etiolated roots and root metabolic activity/dehydrogenase activity were measured (TTC staining). From 200 mM onwards, significant reduction in germination percentage and root length inhibition resulted and at 300 and 400 mM salt-priming significant reduction in normal MI%, increased Abnormal MI% showing both aneugenic and clastogenic responses were accounted. At 500 mM pre-exposed root tip cells were found to develop gradual blackening and root tip death and very less viable cells with highly necrotic, vacuolated with chromosomal erosions and nuclear dismantling and nuclear blobbing resulted apoptosis in addition to decreased POX and dehydrogenase activity (300–500 mM NaCl-treated test sets). NaCl stands out as a potential cyto-genotoxicant in Lathyrus sativus L., variety Mahatora. The maximum tolerance level (200–300 mM) and at 400–500 mM NaCl has been highly cytotoxic as per cytological and biochemical data. From 200 mM onwards, nucleolar volume and frequency were altered and at 500 mM pretreatment complete degradation of nuclear machinery was encountered. Out of salinity significant proportions of C-mitosis and polyploidy showing NaCl has a disruptive action in spindle fibre formation that in turn produced somatic diads and subsequent polyploidy formations (At 200 to 300 mM).