An ozone molecule contains three of oxygen atoms (O3) which included the molecular oxygen (O2) that is important in our life in order to survive. Ozone is also the form of UV rays (sun) from the upper parts of atmosphere which is called stratosphere. Another name for stratosphere is protective ozone layer because it can help to protect human from the harmful effect of the ultra-violet radiation (UV ray) by absorbing it. But the lower part of atmosphere which name troposphere, can easily causes harmful or damage to a lung tissues of human and also the leaves tissue of plants because of the strong oxidizing agent. However when sunny or warm days, an ozone that formed by nitrogen oxides (NOx) in the lower parts of atmosphere will react with volatile organic compounds (VOCs). Any combustion by a product will causes nitrogen oxides released into the atmosphere. Example when forest on fire, effect of the burning vegetation will cause released of the nitrogen oxides.
Ozone can enter the plant leaves through stomata (during gas exchange) and oxidizes the tissue of plant which can cause the process of biochemical and physiological change. Injury of foliar can easily observed when the plant cells on the process of dying. Example in the case of broadleaf plants, it can easily observe through the symptoms of interveinal necrotic on the leaves surface, that also called “oxidant stipple”.
(1) After it enters the leaves through the stomates, it will directly affects the cellular in vegetation by damaged it especially to mesophyll cells.
(2) Before enters the cells themselves, it will dissolves in the water that surrounding the cells.
(3) Change of membrane permeabilities are the effect damage of cellular. It will or will not easily observe by the injury or growth of reduction.
(4) Stomata will open when response to the warmth and light, however, will close when response to water stress, high CO2 and aridity (dry condition).
Not all ozone can enters the leaves through the stomata but small amount of ozone can easily enter the leaves by absorb directly from the exterior surfaces on the leaf. Uptakes of ozone are strongly depending on the conductance of stomatal by variety of the climatic and also the conditions of atmosphere. However, reducing of root growth will normally increase water stress when the stomatal conductance reduced by ozone. There are many studies proved that a drought conditions have less damage of ozone because the dependence of stomatal conductance. But other studies have proved that more sensitivity of ozone was exhibited by plants under stress condition (moisture). In the experiments of T. A. Mansfield et. al. (1993), it shown that ozone may reduce stomatal conductance in the moist conditions, by the other way, it may also increase stomatal conductance in drought stress. However, reduction of the ozone damage is possible due to a lower stomatal conductance which is under fertilization of the higher CO2...