英文摘要 |
Design, construction and operation of an open-closed reversible system equiped with a Beckman 864-21-2-3 IRGA and a ten-inch strip chart recorder for absolute measurement are described. The preparation of standard gases, the introduction of outside clean air and its filtration, methods of adding CO2 to the gas handling system by a micrometric capillary valve, irradiance and illuminance of the lighting system equiped with a water tank as a heat barrier, and air conditioning of the leaf chamber are discussed. The IRGA used in the experiment is insensitive to H2O vapor. Thus the humidity problem in the system is discussed. Ten soybean lines and three Amaranthus cultivars were studied for their gross photosynthesis P(subscript G), net photosynthesis P(subscript N). post-illumination burst (PIB, R(subscript L)), dark respiration R(subscript D)Z and CO2 compensation point (CO2CP). The equipment is ideal for identification of C3 and C4 photosynthesis by their PIB and CO2CP nature. Factors affecting the photosynthetic rates and methods of preparing the detached leaf samples are discussed. |