Role of putrescine on growth, regulation of stomatal aperture, ionic contents and yield by two wheat cultivars under salinity stress

ABSTRACT

Amelioration of salinity stress at different levels [0.0, 2000, 4000, 8000 and 12000 mg/l] in two wheat cultivars Giza 168 and Gimeza 9 was investigated. Foliar application of diamine putrescine at different concentrations [1.25, 2.5 and 5mM] in pot experiments was conducted during two successive seasons [2001 and 2002]. Exogenous application of putrescine on salt stressed plants considerably increased shoot growth [number of tillers, number of leaves, area of leaves, fresh and dry weight] and grain yield/plant. Foliar application of putrescine also induced a potent effect in reducing the stomatal aperture and slightly increased the stomatal number on both leaf surface in the two cultivars. Furthermore putrescine treatment decreased degradation of chlorophyll and increased soluble sugar contents. Application of putrescine inhibited Na and Cl uptake and accelerated the accumulation of K, Ca, Mg and P in the shoots of salt stressed plants. Moreover, a higher solute concentration contributing to osmotic adjustment was observed in shoots of salinity treated Gimeza 9 than in those of Giza 168. This response together with the higher accumulation of inorganic solutes in Gimeza 9 and organic solutes [soluble sugars] in Giza 168 indicated different salt tolerance mechanisms operating in the two cultivars