more importantly, these parameters can be precisely controlled to create the environmental conditions desired.for example, the temperature of the chamber block is controlled by peltier coolers to any level within +- 6 c of the air temperature. light can be adjusted at any level from 0 to more than 2000 umol m-2 s-1, and co2 from 0 to 200 umol as well. artifical light is optionally supplied by a "cold" lamp (LED type,670 nm) . the selected level of co2 are supplied by a co2 injector system. any combination of light and co2 level can also be measured with an optional sensor.