Nonylphenol, an industrial endocrine disrupter chemical, affects root hair growth, shoot length and root length of germinating cos lettuce (Lactuca sativa)

Nonylphenol (NP), an industrial plasticiser and surfactant, has caused behavioural and physiological abnormalities in mammals, however few studies have explored its action on plants. Recent studies indicate that NP may reduce crop yield and adversely impact food quality. The aim of this study was to use lettuce as a model plant to evaluate effects of NP on seed germination and seedling growth as well as to determine the locus of activity. A total of 2100 seedlings were examined for their response to NP exposure in a laboratory experiment. A germination efficiency index (GEI) was developed as a complimentary assessment tool to germination percentage, seedling length and mass. Nonylphenol targeted the root maturation zone and impaired seedling growth when applied at 800 μg L^-1 and higher. While shoot lengths were shorter, root lengths were longer compared with control seedlings. The GEI was a valuable tool that should be examined further in similar crop studies. This investigation highlights the importance of understanding the effects of endocrine disrupters on germinating plants. Since NP is still broadly used in developing countries due to increased industrialisation and agricultural intensification, adverse effects on crops may impact negatively on the already compromised food security dilemma of these countries.