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Maize ( Zea mays ) seeds can detect above‐ground weeds; thiamethoxam alters the view
Author(s) -
Afifi Maha,
Lee Elizabeth,
Lukens Lewis,
Swanton Clarence
Publication year - 2015
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.3936
Subject(s) - thiamethoxam , germination , phytochrome , agronomy , biology , zea mays , far red , horticulture , pesticide , botany , red light , imidacloprid
BACKGROUND Far red light is known to penetrate soil and delay seed germination. Thiamethoxam as a seed treatment has been observed to enhance seed germination. No previous work has explored the effect of thiamethoxam on the physiological response of buried maize seed when germinating in the presence of above‐ground weeds. We hypothesised that the changes in red:far red reflected from above‐ground weeds would be detected by maize seed phytochrome and delay seed germination by decreasing the level of GA and increasing ABA . We further hypothesised that thiamethoxam would overcome this delay in germination. RESULTS Thiamethoxam enhanced seed germination in the presence of above‐ground weeds by increasing GA signalling and downregulating DELLA protein and ABA signalling genes. An increase in amylase activity and a degradation of starch were also observed. CONCLUSIONS Far red reflected from the above‐ground weeds was capable of penetrating below the soil surface and was detected by maize seed phytochrome. Thiamethoxam altered the effect of far red on seed germination by stimulating GA and inhibiting ABA synthesis. This is the first study to suggest that the mode of action of thiamethoxam involves both GA synthesis and ABA inhibition. © 2014 Society of Chemical Industry