EFFECTS OF GAMMA-RADIATION ON POLY ISOBUTYLENE

Radiological parameters such as Mass attenuation coefficient (μm), effective atomic numbers (Zeff), electron densities (Neff), total cross-section (σt) & electronic cross-section (σe) have been computed and investigated for poly-isobutylene using NaI (Tl) scintillation counter and XCOM program. The gamma ray photons were detected by using NaI (Tl) detector with resolution of 8.2 % at 662 keV, using radioactive gamma ray sources 57Co, 133Ba, 137Cs, 54Mn, 60Co and 22Na. Values of μm for the poly-isobutylene decrease with increasing energy. An experiment is done to avail the radiological data on poly- isobutylene and to check the effects of gamma radiation produced on material with different energy ranges. It is found from the present investigation that the investigated results found immense importance in radiation industry, dosimetry, polymer industry etc

Does morphological and anatomical plasticity during the vegetative stage make wheat more tolerant of water deficit stress than rice?

Water scarcity and the increasing severity of water deficit stress are major challenges to sustaining irrigated rice (Oryza sativa) production. Despite the technologies developed to reduce the water requirement, rice growth is seriously constrained under water deficit stress compared with other dryland cereals such as wheat (Triticum aestivum). We exposed rice cultivars with contrasting responses to water deficit stress and wheat cultivars well adapted to water-limited conditions to the same moisture stress during vegetative growth to unravel the whole-plant (shoot and root morphology) and organ/tissue (root anatomy) responses. Wheat cultivars followed a water-conserving strategy by reducing specific leaf area and developing thicker roots and moderate tillering. In contrast, rice ‘IR64’ and ‘Apo’ adopted a rapid water acquisition strategy through thinner roots under water deficit stress. Root diameter, stele and xylem diameter, and xylem number were more responsive and varied with different positions along the nodal root under water deficit stress in wheat, whereas they were relatively conserved in rice cultivars. Increased metaxylem diameter and lower metaxylem number near the root tips and exactly the opposite phenomena at the root-shoot junction facilitated the efficient use of available soil moisture in wheat. Tolerant rice ‘Nagina 22’ had an advantage in root morphological and anatomical attributes over cultivars IR64 and Apo but lacked plasticity, unlike wheat cultivars exposed to water deficit stress. The key traits determining the adaptation of wheat to dryland conditions have been summarized and discussed