Evaluation of the effect of a single dose of ammonia on lettuce photosynthesis in a hermetically sealed phytotron
Berkovich, Y.A.; Sled' V.D.
Kosmicheskaia Biologiia i Aviakosmicheskaia Meditsina 23(2): 67-70
1989
ISSN/ISBN: 0321-5040 PMID: 2716273 Document Number: 328510
The threshold of the phytotoxic effect (PTE) of ammonia at a concentration of 10 to 20 mg/m3 on 28-day lettuce plants was evaluated during a single 2-hour exposure. The rate of Hill's reaction, level of energization of chloroplast membranes during leaf illumination as well as visible photosynthesis of lettuce plants from the beginning of fumigation to vegetation day 31 were recorded. Similar changes in the above parameters induced by ammonia were seen. This suggests that photosynthesis was inhibited already at light stages. As a measure of PTE, 10 per cent decrease of the photosynthetic productivity of plants exposed to fumigation was recommended in comparison with controls during the vegetation period. According to this measure, the PTE of ammonia amounted to 20 mg/m3 in the above experimental conditions.