mohamed soliman khater

The present work aimed to address the effects those might be taken place to the
chemical constitution of Mentha piperita due to foliar spraying of 10 ppm ascorbic acid,
iron (III) chloride and sodium bicarbonate combined with exposure to different light
irradiation, ultra violet –A (UV-A), White light (W), Mixed light ( UV-A+W) and control
(C). Rhizomes of Mentha piperita L. were transplanted in 16cm plastic pots (12 pots for
each treatment) in a controlled chamber. The experimental results in general revealed that,
the tested concentrations of ascorbic acid, iron (III) chloride and sodium bicarbonate
significantly deceased the content of chlorophyll a, chlorophyll b, total amino acids, total
phenols and total sugars. While the carotenoids significantly increased. The major effects
were observed with the combination between UV-A and the tested materials especially
ascorbic acid. That can be correlated to that ascorbic acid has absorption band in UV region
which increase the effect of the UV-A more than the use of ultra violet alone. Also the
lower rates of chlorophyll synthesis may be attributed to reducing gene expression
encoding chlorophyll binding proteins or break down of structural integrity of chloroplasts
and also decreasing total amino acids and total phenols respectively.