Reference

The relative efficiency of nitrogen fixation in pea root nodules

The relative efficiency of nitrogen fixation in pea root nodules. Dixon, R. O. D.; Blunden, E. A. G. (Edinburgh EH9 3JH, UK). Plant Soil, 75(1), 131-8 (English) 1983. CODEN: PLSOA2. ISSN: 0032-079X. DOCUMENT TYPE: Journal CA Section: 11 (Plant Biochemistry) Section cross-reference(s): 10 Expts. were performed to investigate the causes of low relative efficiency, RE, in legume root nodules. N-fixing activity and RE varied with time of incubation of nodules and with different temps. and O concns. The effects of N concn. and CO2 concn. 124-38-9 and 9013-04-1 are also in the experiment. were also examd. In each case the RE was inversely related to N-fixing activity, measured by acetylene redn. Increasing the N concn. had no effect on either N-fixing activity or RE. Expts. with isolated bacteroids gave higher RE values than the whole nodules from which they were isolated. All results were consistent with H inhibition of nitrogenase within the nodule being the cause of low RE. .

Studies on carbon flow in Crassulacean acid metabolism during the initial light period

Studies on carbon flow in Crassulacean acid metabolism during the initial light period.Some chemicals with cas registry numbers like 6915-15-7 and 124-38-9 are also used. Fischer, A.; Kluge, M. (Inst. Bot., Tech. Hochsch., Darmstadt D-6100, Fed. Rep. Ger.). Planta, 160(2), 121-8 (English) 1984. CODEN: PLANAB. ISSN: 0032-0935. DOCUMENT TYPE: Journal CA Section: 11 (Plant Biochemistry) In the Crassulacean acid metab. (CAM) plants Kalanchoe tubiflora and Sedum morganianum, a shift in the pathways occurs by which external CO2 enters the metab. during the initial light period (phase II of the diurnal CAM cycle). At the beginning of phase II, CO2 is fixed mainly by the C4 pathway; during late phase II, however, it is fixed mainly via the C3 pathway. The C3 pathway contributes to the phosphoenolpyruvate-carboxylase-mediated CO2 fixation by the provision of C3 skeletons. Since the shift in the C flow pathway is delayed after a CO2-free night when malic-acid accumulation in the vacuoles is prevented, it is very likely that the amt. of malic acid in the vacuole is integrated in the mechanism which controls CAM during the initial light period. A light-on signal at the beginning of phase II is not required to bring about the shifts in the C flow pathways, as is shown by the reaction of plants to a prolonged dark period. A model of C flow during phase II is proposed. .