Previous studies have revealed that blue light stimulates coiling and prehaustoria development in young de-etiolated dodder seedlings prior to host attachment. In this study, the Ca²⁺ and H⁺ flux kinetics that are associated with blue light-mediated coiling and prehaustoria development in de-etiolated dodder seedlings were measured uninvasively using the ion-selective, vibrating microelectrode ion flux system. The findings showed that blue light induces rapid transient changes in the net Ca²⁺ and H⁺ fluxes. A clearly pronounced lag of about several minutes was observed between the blue light-induced changes in the Ca²⁺ and H⁺ fluxes, with H⁺ being a leading ion. The addition of 1 mol L⁻¹ vanadate, a known blocker of the plasma-membrane H⁺-ATPase, to the bathing solution completely prevented both the H⁺ and the Ca²⁺ flux responses and inhibited coiling and prehaustoria development, suggesting a causal relationship between the blue light-induced changes in the net Ca²⁺ and H⁺ fluxes and seedling movements. It is concluded that the plasma-membrane H⁺-ATPase plays a key role in a dodder's parasitic mode of growth and its adaptive response to the environment.

Item Type:	Refereed Article
Keywords:	weed, light, signalling, blue light, dodder, H+-ATPase, ion fluxes
Research Division:	Biological Sciences
Research Group:	Plant biology
Research Field:	Plant physiology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the biological sciences
UTAS Author:	Shabala, S (Professor Sergey Shabala)
ID Code:	105130
Year Published:	2015
Deposited By:	Tasmanian Institute of Agriculture
Deposited On:	2015-12-09
Last Modified:	2017-11-06
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