Handbook of Plant and Crop Physiology

to have evolved a variety of mechanisms that contribute to yielding ability under those conditions. For in-
stance,T.aestivum,Secale cereale, and Aegilops squarrosahave an efficient K/Na selectivity character
because of the D genome but are less tolerant than crop species such as H.vulgareandT.durum, which
are less efficient in K/Na selectivity but more efficient in their compartmentation ability [147,148]. Sim-
ilarly, such differences can be observed among genotypes within a crop species, which is reflected in con-
tradictory reports for various crop species either confirming or disputing direct correlation between K/Na
selectivity and level of salinity tolerance [5].

870 SUBBARAO AND JOHANSEN

Figure 4 Relationships between shoot dry matter and tissue Na, Cl, K, and K/Na levels (a–d) and between
Cl and Na levels in root and shoot (e and f). (Plant samples were collected for growth and chemical analysis 55
days after sowing; plants were grown at 0, 4, 6, 8, and 10 dS/m salinity levels.) (From Ref. 181.)