Physiological Studies with Heavy Water. II. Germination and Growth Inhibition of Barley by D₂O

Abstract

Seed germination and barley seedling growth in various D2O concentrations have been studied. It was observed that the emergence of root and shoot was delayed, there being greater delay in shoot than in root emergence. A complete block was observed in germination in pure D2O and the germination rate was slowed down significantly in lower concentrations.An initial germination delay by different D2O concentrations seemed to cause a subsequent retardation in the growth measured as shoot and root length. A comparison of root and shoot length with their respective dry weights suggested that the growth by cell division/elongation might have been affected more than the transport of food materials from the endosperm to the embryo.Analysis of the total sugars of the endosperm and the embryo at 8 hour intervals showed that while the hydrolysis of starch to sugars was progressively decreased by increasing D2O concentrations, the transport rate from endosperm to embryo showed a sharp inhibition in 50 "/o D-)O and above. This indicated that the inhibition in the transport of materials, besides less hydrolysis of reserve food materials, may also be a causal factor of germination and growth inhibition in DoO.

D2O Labeling to measure active biosynthesis of natural products in medicinal plants

“…56,57 In barley, D 2 O concentrations up to approximately 37.5% by volume are relatively well-tolerated, but above that level, growth attenuation and germination arrest increase significantly with D 2 O concentration. 58 As shown in the first two case studies, using a D 2 O concentration lower than this allows for readily detectable incorporation of label over an extended experiment (greater than one month). Surprisingly, excised Menispermum leaves tolerated 100% D 2 O reasonably well, as metabolic activity and label incorporation could be detected for up to 15 days.…”

Quantification of root water uptake and redistribution using neutron imaging: a review and future directions

“…L. ev. Winter) (Waber, 1975) and germination of barley (Bhandarkar et al., 1971). The impact of D 2 O on plant growth is concentration‐ and time‐dependent.…”