Abstract:
Disadvantages of the use of OTCs for assessing the effects of 03 on the growth of plants include relatively high cost, the need for electrical power, and potential effects of the chambers themselves on the growth of the plants. In many cases, no chamber effects can be detected, and because most studies compare against a control, chamber effects would have a minimal effect on interpretation of results. The protective antioxidant chemical ethy lenedi urea (N42-(2-oxo-l-imidagolidinyl) ethyll-N2- phenylurea), often abbreviated to EDU, is currently the best known systemic antioxidant and has been used extensively to study the effects of ambient ozone on agricultural crops and trees in the field. This technique is relatively easy to employ and less costly than chamber filtration systems, however, it is essential to establish the correct dosage for protection from 03, without direct effects of EDU on the plant, and an estimate of the level of protection from 03 achieved. Ethylene diurea is known to be phytotoxic, so studies under controlled 03 conditions to establish an effective level of protection without phytotoxicity are essential before EDU can be used as an assessment tool.
