How to Recognize Ozone Symptoms

The following general guidelines can be given to identify ozone symptoms in plants

Symptoms identification for crops species

Visible ozone-like symptoms can be identified and distinguished from symptoms caused by other biotic/abiotic factors by following the general guide lines as described below:

Symptoms are more severe on mid-aged and older leaves than on younger leaves. Older leaves are the first to develop symptoms (age effect).

Shaded portions of the leaves (i.e. if two leaves overlap) usually do not show any injury (shade effect).

Visible ozone injury normally does not go through the leaf-tissue. Visible symptoms are most likely confined to the upper leaf surface, typically expressed as a discoloration, bronzing, reddening or stippling

Different gradation of ozone symptoms in upper surface of broccoli leaves (Photo: M.J. Sanz)

Undersides of the above leaves, note than despite the severe injury showed in the upper side of the leaves its lower side remain unaffected (Photo: M.J. Sanz)

Both, discolouration and even stippling only occur between the veins (interveinal) and do not affect the veins.

Typical interveinal ozone symptoms induced in spinach leaf (Photo: E. Calvo)

Typical pigmented sttipling induce by ozone exposure in OTC of bean plants (Photo: E. Calvo)

Last Updated on Friday, 26 February 2010 13:55