Reactive Oxygen Species, Oxidative Damage and Their Production, Detection in Common Bean (<em>Phaseolus vulgaris</em> L.) under Water Stress Conditions

Reactive oxygen species (ROS) being small and highly reactive oxygen containing molecules play significant role in intracellular signaling and regulation. Various environmental stresses lead to excessive production of ROS causing progressive oxidative damage and ultimately cell death. This increased ROS production is, however, tightly controlled by a versatile and cooperative antioxidant system that modulates intracellular ROS concentration and controls the cell’s redox status. Furthermore, ROS enhancement under stress serves as an alarm signal, triggering acclimatory/defense responses via specific signal transduction pathways involving H2O2 as a secondary messenger. Nevertheless, if water stress is prolonged over to a certain extent, ROS production will overwhelm the scavenging action of the anti-oxidant system resulting in extensive cellular damage and death. DAB (3,3′-diaminobenzidine) test serves as an effective assessment of oxidative damage under stress. It clearly differentiates the lines on the basis of darker staining of leaves under water stress. The lines showing greater per cent reduction in yield parameters show greater staining in DAB assay underlining the reliability of using this assay as a reliable supplement to phenotyping protocols for characterizing large germplasm sets

A rapid micropropagation protocol of <i>Atropa acuminata</i> Royle ex Lindl.―A threatened medicinal plant species of Kashmir Himalaya

576-580In the present study, different explants, viz., petiole and nodal explants, of Atropa acuminata Royle ex Lindl. were used to develop an efficient micropropagation protocol for the conservation of this medicinally important plant. The petiole explants produced the maximum amount of callus on MS medium supplemented with BAP (3 mg/L) within 18 d in 80% cultures. Further, shoot regeneration was obtained when these calli were subcultured onto MS medium supplemented with BAP (5 mg/L), with a mean shoot length of 2.2±0.19 cm in 40% cultures within 48 d. Similarly, from nodal explants, the maximum amount of callus was achieved on MS medium supplemented with BAP (2 mg/L) in 80% cultures within 17 d. When these calli were transferred onto MS medium supplemented with BAP (2 mg/L), shoot regeneration was obtained with a mean shoot length of 2.0±0.20 cm in 80% cultures within 14 d. Root differentiation with 100% response was obtained within 18 d in in vitro grown shoots on MS medium augmented with IBA (0.5 mg/L) with a mean number of 21.6±6.9 roots. The in vitro raised plantlets were then successfully acclimatized and hardened in compost under greenhouse conditions within 3 wk with 80% response. The hardened plants were successfully transferred to the field conditions