SEE PROFILE

ABSTRACT specific cellular functions, irrespective of turgor (Paleg et al., 1985; Shen et al., 1997).Osmotic adjustment (OA) is a major component of drought resis-Substantial genotype diversity for OA was observedtance. Four different methods for measuring OA in plants are in general use, but there is no information on the comparative perfor- in wheat (Triticum aestivum L.) (Morgan, 1977; Morgan mance of these methods. Two similar experiments were designed to et al., 1986), sorghum (Sorghum spp.) (Blum and Sulli-evaluate the four methods for measuring OA in diverse indica and van, 1986; Santamaria et al., 1990; Basnayake et al., 1993; japonica cultivars of rice (Oryza sativa L.) subjected to a drying cycle Tangpremsri et al., 1995), chickpea (Cicer arietinum L.) in large pots in the greenhouse. The four methods were: (i) derivation (Morgan et al., 1991), field pea (Pisum sativum L.) (Rod-of OA from regressions of leaf relative water content (RWC) on leaf rigues-Maribona et al., 1992), black spruce [Picea mari-osmotic potential (OP); (ii) estimation of OA from OP of stressed ana (Mill.) B.S.P.] (Tan and Blake, 1997), sunflowerplants calculated to rehydrated state; (iii) estimation of OA from OP (Helianthus annuus L.) (Jamaux et al., 1997), and vari-of stressed plants that have been rehydrated; and (iv) estimation (from ous turfgrasses (Qian and Fry, 1997). Osmotic adjust-data used in Method 1) of OA capacity by the sustained RWC at a ment occurs in rice subjected to water deficit (Cutler etgiven OP of 23.5 MPa. Method 1 was a priori considered as the bes