Germination and electrical conductivity tests on artifcially aged seed lots of 2 wall-rocket species

Abstract

The aim of this study was to determine whether the loss of germinability and vigour in wall-rocket seed lots was related toelectrolyte leakage. Ten seed lots of 2 wall-rocket species (9 of Diplotaxis tenuifolia and one of D. erucoides (Brassicaceae)) were storedat 45 °C and 70% relative humidity and electrolyte leakage was measured using the conductivity test. Small diferences in longevity werefound among species or seed lots, suggesting that a similar relative longevity might be expected within the genus Diplotaxis afer artifcialageing, and that it will be above the average of that found in other species of the same family at similar storage conditions. Electrolyte losswas strongly related to loss of seed viability. Tere was a negative linear relationship between conductivity and seed germination (R2 =0.85), and a positive relationship with T50 (R2 = 0.77). Small diferences were found among species or seed lots regarding the correlationbetween electrolyte leakage and seed germination and vigour. Our results indicate that the conductivity method is able to predict theviability of wall-rocket seeds stored at 45 °C and 70% RH, with the same regression equation of conductivity and germination ( 33.97x+ 135.59) being able to predict the viability of diferent seed lots and species. A conductivity level ranging from 1.4 to 2.2 mS g 1 DWwould indicate that the potential of a Diplotaxis seed lot to germinate has decreased to 80%. Te correlation between electrolyte leakageand seed germination provides a valuable means for early detection of seed viability in wall-rocket seeds.