Effects of light and mechanical stimulation on coiling and prehaustoria formation in Cuscuta spp.

Abstract

SummaryIrradiation of 4‐day‐old dark‐grown seedlings of Cuscuta campestris Yuncker and Cusctira indecara Choisy with I min of red light stimulated coiling and prehaustoria formation in excised upper 4‐cm segments of seedlings during a 48‐h dark period in which zeatin was applied. Coiling and prehaustoria development were completely reversed when irradiated with 2 min of far‐red light applied directly after red light. When deetiolated segments were subjected to prolonged exposure of pure blue light, or mixtures of ultraviolet‐A/far‐red, blue/far‐red or red/far‐red light, coiling and prehaustona development were induced. Blue light at photon fluxes lower than 1 μmol m‐2 s‐1 did not promote coiling and formation of prehaustoria. Mechanical stimulation caused tendrils to coil and form prehaustona in biue and blue/far‐red light, but not in darkness. Zeatin substituted for high irradiance blue light and mechanical stimulation caused coiling and prehaustoria formation.

Temperature effects on Cuscuta campestris Yunk. seed germination

“…The growth of weed seedlings could be affected by different factors, such as temperature, light, depth to which seeds are embedded in soil, seed storage conditions, soil bacteria and seed vigour (Haidar et al, 1997;Walters, 1998;Benvenuti et al, 2005;Li and Kremer, 2006). The growth C. campestris seedlings depends on seed vigour, which also determines whether a successful parasitic bond with the host plant will be established (Walters, 1998).…”

The biology of Canadian weeds. 133. Cuscuta campestris Yuncker, C. gronovii Willd. ex Schult., C. umbrosa Beyr. ex Hook., C. epithymum (L.) L. and C. epilinum Weihe.

“…Blue light was found to be more effective in inducing coiling than far-red light (Furuhashi et al 1995;Haidar et al 1997). Treatments with mixtures of ultraviolet/far-red, blue/far-red, red/far-red light determined both the twining and prehaustoria initiation (Furuhashi 1995;Haidar et al 1997). Blue light at photon fluxes lower than 1 µmol m -2 s -1 promoted neither coiling nor initiation of prehaustoria (Haidar et al 1997).…”

“…Treatments with mixtures of ultraviolet/far-red, blue/far-red, red/far-red light determined both the twining and prehaustoria initiation (Furuhashi 1995;Haidar et al 1997). Blue light at photon fluxes lower than 1 µmol m -2 s -1 promoted neither coiling nor initiation of prehaustoria (Haidar et al 1997). The effect of far-red light was completely reversed by a red light treatment (Tada et al 1996;Furuhashi et al 1997;Haidar et al 1997).…”

“…Blue light at photon fluxes lower than 1 µmol m -2 s -1 promoted neither coiling nor initiation of prehaustoria (Haidar et al 1997). The effect of far-red light was completely reversed by a red light treatment (Tada et al 1996;Furuhashi et al 1997;Haidar et al 1997). The action spectrum for induction of prehaustoria had a pronounced peak near 740 nm and a small peak at 420 nm, while reversal of prehaustoria induction had major a peak at 660 nm and a minor peak at 380 nm (Furuhashi et al 1997;Haidar et al 1997).…”

“…This would explain why seedlings of C. campestris that emerged under an established alfalfa crop had their attachment to host reduced by 90% (Dawson 1966). Blue light was found to be more effective in inducing coiling than far-red light (Furuhashi et al 1995;Haidar et al 1997). Treatments with mixtures of ultraviolet/far-red, blue/far-red, red/far-red light determined both the twining and prehaustoria initiation (Furuhashi 1995;Haidar et al 1997).…”