12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > A small-scale controlled environment chamber fo...
View graph of relations

« Back

A small-scale controlled environment chamber for the investigation of the effects of pollutant gases on plants growing at cool or sub-zero temperature

Research output: Contribution to journalJournal article

Published

Journal publication date1990
JournalEnvironmental Pollution
Journal number2
Volume64
Number of pages14
Pages155-168
Original languageEnglish

Abstract

A new, small-scale controlled environment plant growth chamber is described, which permits accurately controlled temperatures from ambient (c. 20°C) down to −5°C in the day or −15°C at night. The system also allows controlled injection of pollutant gases.

The chamber is based on a modified commercial chest freezer with temperature control achieved through by-passing the cooling coils in the inner walls of the freezer. This by-pass is controlled by a BBC microcomputer which gives nominal temperature control to 0·1°C over definable diurnal temperature profiles. Photoperiod is also controlled by the microcomputer. The chamber forms a virtually closed system to which pollutant gases are added by injection from low concentration cylinders, regulated using mass flow controllers. The accuracy with which pollutant concentrations are controlled is increased by filtration of the air-stream after passing over the experimental plants: i.e. a ‘single-pass’ system is adopted.

In operation air temperatures across the chambers are controlled to within 1-1·5°C of the pre-set value over the range 25 to −10°C. Leaf temperatures are 2·5-3·0°C above air temperatures during the day, with a total energy input of c. 180 Wm−2 from two 400 W metal halide lamps. The lamps provide a photon fluence rate of 270±30 μmol quanta PAR m−2 s−1 at plant height. During the dark, leaf temperatures deviate less than 1·0°C from air temperature. Soil temperatures are controlled separately from air temperature and are held above zero at all times. To date, fumigation, with NO2 and SO2 has been confined to the daytime. At pre-set concentrations of 20 nl litre−1 variations during fumigation were less than 2·0–2·5 nl litre−1 and 0·5 nl litre−1, respectively.