A Note on Methods Measuring the Internal Water Status in Leaves of Sunflower Plants (Helianthus annuus L.)

Abstract

Leaf water content of the sunflower plants was estimated using Stocker's technique proposed in 1929 as well as Weatherley's equation developed in 1950. In the latter method entire leaves were used instead of leaf discs for determining relative turgidity (R.T.). Because of the objections raised against the use of the relative turgidity term, the relative water deficit (R.W.D.) was calculated as 100-R.T. Attempts were made to correlate the calculated values of R.W.D. with the values of water saturation deficit (W.S.D.) obtained by adapting Stocker’s technique. Correlation (r) and regression (b) coefficients between R.W.D. and W.S.D. were found to be highly significant and reached unity ( +0.999 for r and +0.997 for b). Although modifications were introduced to Weather-ley’s technique, calculated water deficit was identical with that obtained by Stocker’s method.