Causes
Chlorosis is typically caused when leaves do not have enough nutrients to synthesise all the chlorophyll they need. It can be brought about by a combination of factors including:
- a specific mineral deficiency in the soil, such as iron or magnesium
- deficient nitrogen and/or proteins
- a soil pH at which minerals become unavailable for absorption by the roots
- poor drainage (waterlogged roots)
- damaged and/or compacted roots
- pesticides and particularly herbicides may cause chlorosis, both to target weeds and occasionally to the crop being treated.
- exposure to sulphur dioxide
Of course, the exact conditions would be different for different plants. For example, Azaleas prefer unusually acidic soil and rice isn't troubled by waterlogged soil.
- ozone injury to sensitive plants
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