High-Resolution Measurements of Transient Changes in the Growth Rate of Intact Lupin Seedlings

Abstract

Measurements of the growth rate of intact lupin seedlings were made under steady-state conditions and as the environment was altered. Although the growth rate frequently changed smoothly with the new condition, there were several cases where periodicity or oscillations in the growth rate were observed. These cases included growth oscillations induced by: the solution in which the roots were immersed being changed back from a mannitol solution to water; the replacement of anaerobic conditions by air or oxygen; the tension being increased on the hypocotyl; and, under some condi- tions, the addition or removal of high CO2 concentrations. The observed periodicity is more complex than is accounted for by a simple relationship of the minimum yield stress increasing or decreasing with the growth rate, but more information is needed to develop a better model.

Endogenous Rhythmicity of Ethylene Production in Growing Intact Cereal Seedlings

“…The early observations of Liptay and Davidson (11) suggest that different embryos of germinating barley are in different physiological states. Recently, it has been shown that lack of synchronicity of individual seedlings in a representative group may disturb a typical response (12). ACKNOWLEDGMENT We thank Sandra Jansone and Zigmunds Voicehovics for expert technical assistance.…”

Wall extensibility: its nature, measurement and relationship to plant cell growth

“…This type of nonlinearity probably accounts for occasional reports of turgor-independent growth (Shackel & Matthews, 1987;Termaat et al, 1985; an extreme example in Chara observed by Zhu & Boyer, 1992). Because plants often show a rather complicated growth response to step changes in turgor or wall stress (Marshall & Penny, 1976;Kuzmanoff & Evaxis, 1981;Cosgrove, 1988), it is likely that a complicated adaptation mechanism underlies this type of limited turgor independence.…”