Study on the instrumental error of the portable photosynthesis system

Combined measurement error of average photosynthesis rate is comprised of the instrumental error．the measurement error and the characteristics of leaf photosynthesis．The instrumental error comes from CO₂ analyzer，flowmeter．temperature thermometer and barometer．The error is different with different measuring methods or leaf photosynthesis rates．The photosynthesis rate is stronger，the error is smaller．The error in open system is about 8％～ 20％，and is about 2．5％～ 15％ in closed system ．The main eror is owing tO CO₂ analyzer and flowmeter．