Pearl millet (Pennisetum glaucum L. cv. HHB-67) seeds were pre-soaked in sulphydryl compounds (dithiothreitol, thioglycollic acid, thiourea, and cysteine). In plants at 59 and 67 d after sowing (DAS), activities of photosystem (PS) 2 (ferricyanide site) and PS1, both chloroplastic and total superoxide dismutase, glutathione reductase, and glutathione-S-transferase increased after all sulphydryl pre-treatments at both stages of plant development. Also dry matter of plant parts sampled at 55 DAS was higher after thiol-treatments in comparison with control. and N. K. Ramaswamy ... [et al.].
Wheat (Triticum aestivum L. cv. Sonalika) seedlings were grown in Hoagland solution. Primary leaves were harvested at 8, 12, and 15 d and cut into five equal segments. Contents of photosynthetic pigments and proteins, and photosystem 2 (PS2) activity increased from base to apex of these leaves. Chlorophyll (Chl) content was maximum at 12 d in all the leaf segments, but PS2 activity showed a gradual decline from 8 to 15 d in all leaf segments. In sharp contrast, the CO2 fixation ability of chloroplasts increased from 8 to 15 d. CO2 fixation ability of chloroplasts started to decline from base to apex of 15-d-old seedlings, where the content of ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (RuBPCO-LSU) increased acropetally. RuBPCO-LSU content was maximum in all the leaf segments in 12-d-old seedlings. This shows a distinctive pattern of PS2, Chl, CO2 fixation ability of chloroplasts, and RuBPCO-LSU content along the axis of leaf lamina during development and senescence. RuBPCO-LSU (54 kDa) degraded to fragments of 45, 42, 37, 19, and 16 kDa products which accumulated along the leaf axis during ageing of chloroplasts. Thus the CO2 fixation ability of chloroplasts declines earlier than PS2 activity and photosynthetic pigment contents along the leaf lamina. and F. Dilnawaz ... [et al.].