Exogenously applied melatonin stimulates root growth and raises endogenous indoleacetic acid in roots of etiolated seedlings of Brassica juncea.
Exogenous melatonin was applied to etiolated seedlings of wild leaf mustard (Brassica juncea) and the effect on root growth and endogenous indole-3-acetic acid (IAA) levels determined. The results show that 0.1microM melatonin has a stimulatory effect on root growth, while 100microM is inhibitory. Furthermore, the stimulatory effect was only detectable in young seedlings (2-d old). Older seedlings (4-d old) appear to be less susceptible to both the stimulatory and the inhibitory effect of melatonin. Exogenous application of 0.1microM melatonin also raised the endogenous levels of free IAA in roots, while higher concentrations had no significant effect. The specific mechanism that causes exogenous melatonin to increase the amount of free IAA in roots, paired with a stimulation of root growth, remains to be uncovered.
Chen
Qian
Q
State Key Laboratory of Vegetation and Environmental Changes, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, PR China.
Qi
Wen-bo
WB
Reiter
Russel J
RJ
Wei
Wei
W
Wang
Bao-min
BM
D007210:Indoleacetic Acids / Q000378:metabolism*; D008550:Melatonin / Q000494:pharmacology*; D009149:Mustard Plant / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*
D007210:Indoleacetic Acids; C030737:indoleacetic acid; D008550:Melatonin