Antitranspirants for improvement of water use efficiency of crops

Abstract

The use of antitranspirants may guarantee the establishment of seedlings transplanted under drought conditions or prolong the life of mature plants at sub-optimal moisture levels. Where water is really scarce they can reduce transpiration losses to the extent that irrigation intervals may be extended. Whilst, at present, known antitranspirants are relatively expensive, their use can be justified, for example, to prevent shrinkage in high-value fruits, or where crop survival is threatened.Plants need water; but they are profligate in its use. Roughly 1% of the water taken up by a plant is used for its growth and development while the remaining 99% is lost by transpiration. Whilst drainage and evaporation playa considerable part in water loss, it is clear that much of the water applied in irrigation is lost through transpiration alone. Often the rate of transpiration exceeds that of water absorption (particularly under conditions of high evaporative demand, and even when soil water is readily available) and the resultant water stress restricts plant growth. Reduction of transpiration, were it feasible, could minimize the irrigation water requirement and thus relieve the plant from water stress to a certain extent.

Film antitranspirants increase yield in drought stressed wheat plants by maintaining high grain number

“…The higher leaf turgor in AT-sprayed WD plants is consistent with the notion that AT film decreases water loss and enables prolonged turgor maintenance under WD conditions (del Amor et al, 2010;Feddema, 1954;Lipe and Skinner, 1979). This is supported by our results on plant water use and those reported in the literature (Das and Raghavendra, 1979;Fuehring and Finkner, 1983). Turgor loss in unsprayed WD plants occurred 2-4 days after drought imposition.…”

“…This is consistent with the notion that the film from AT restricts transpiration by providing a physical barrier to the stomata, thereby increasing stomatal resistance to water vapour diffusion (Anderson and Kreith, 1978;Das and Raghavendra, 1979;Feddema, 1954). Since stomata regulate both water vapour loss and carbon dioxide intake, a concurrent reduction in photosynthesis was expected.…”

“…Similarly, reduced yield from the application of AT under WW conditions was expected, since the AT film decreases leaf permeability to carbon dioxide exchange thus decreasing the supply of assimilates available for developing floret growth (Das and Raghavendra, 1979;Davenport et al, 1974;Gale and Hagan, 1966). The significantly higher grain yield observed in this study after AT application to WD plants just before booting (Z39) supports our study hypothesis and the field studies reported by Kettlewell et al (2010) on the effects of AT on yield in wheat.…”

Yield enhancement of droughted wheat by film antitranspirant application: rationale and evidence

“…Recent reviews of methods of improving crop water productivity [1,3,4] have omitted one agronomic method: the use of film antitranspirants to reduce water loss from plants. This omission is understandable, since the three main reviews of antitranspirants [5][6][7] and subsequently textbooks on plant water relations and on drought management [8][9][10] have concluded that film antitranspirants have very limited usefulness.…”

“…A detailed review tabulates the published effects of 23 film antitranspirants in concurrently reducing transpiration and photosynthesis across 13 plant species [7]. Reviews and textbooks have therefore concluded that antitranspirants are only of value for situations where photosynthesis is not important but where reduction in water loss is beneficial [5][6][7][8][9][10]. Most of these uses are on ornamental species, e.g.…”