Chilling of drought-hardened and non-hardened plants of different chilling-sensitive maize lines Changes in water relations and ABA contents

Abstract

The effect of chilling acclimation by drought was investigated in two maize ( Zea mays L.) inbred lines differing in chilling sensitivity. Two-leaf-stage seedlings of the two lines were drought-hardened or not and then chilled. Subsequent recovery was evaluated. Plant growth parameters, water status, transpiration, root water uptake and ABA levels were measured. Chilling produced a greater decrease in relative growth rates (RGR) and net assimilation rates (NAR) in Penjalinan than in Z7. This was also observed in non-drought-hardened plants versus drought-hardened ones. Drought-hardening decreased chilling-induced water deficit. At the end of chilling, relative water content and leaf water potential were higher in drought-hardened plants than in non-drought-hardened ones. The beneficial effect of drought-hardening was more evident in the chilling-sensitive line. Penjalinan. Osmotic potential at full turgor showed the absence of osmotic adjustment. Root water uptake decreased similarly in drought-hardened as in non-drought-hardened plants. However, transpiration of drought-hardened plants during chilling was lower. During chilling, root and leaf ABA content was higher in drought-hardened plants, while no differences were observed between lines. At the end of the recovery, nearly all measured parameters reached control values. The beneficial effect of drought-hardening on plant growth and water status during chilling is discussed on the basis of ABA content and its effect on transpiration.