Abstract
Velvet bean (Mucuna pruriens L.) is known to have strong allelopathic property. We hypothesized that allelopathy would be modified under altered gravity. We examined the gravitational effects on allelopathy by exposing a plant-plant system to pseudo-microgravity, which was generated by a 3D-clinostat. It has already been shown that the degree of suppression on the lettuce root growth by velvet bean was less on the 3D-clinorotation. L-DOPA (L-3,4-dihydroxy-phennylalanine) is known to be the major substance in the allelopathy of velvet bean, released from its root. Since L-DOPA is a precursor of melanin pigment, and is easily converted to melanin by oxidation, locality of L-DOPA production in the plant body can be seen through pigmentation. The distribution of L-DOPA in the root was also different under pseudo-microgravity. The detail of relationship between distribution of L-DOPA in root of velvet been plant and gravity was discussed by histological and histochemical methods.
