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

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

Studies on the role of abeisie acid as antiranspirant on growth, chemical analysis and yield components of cowpea plants in presence of soil conditioners

Cowpea plants were grown in newly reclaimed soil mixed with three different types of soil conditioners, the plants were sprayed twice after 30 and 37 days from sowing, with different concentrations of Abscisic acid [ABA]. As a result of the foliar ABA application on plants grown in the absence of the soil conditioners, there were a slight increase in respect to the plant height, number of branches, number of leaves, the fresh and dry weight of the whole plants and the seed yield/ Feddan. These increments followed the gradual increase of ABA concentration. The ABA treatments induced a potent effect in reducing the stomatal number and width on both leaves surfaces, chlorophyll, carotenoids and sugar contents while there was an increase in the nitrogenous constituents in the leaves. The effect of the soil conditioners [only] showed a significant increase in respect to all mentioned parameters when compared with ABA treatments and the untreated plants. The interaction treatments [ABA and the soil conditioners] increased significantly all the mentioned parameters and also reduced the stomatal number and width compared with the respective control of the soil conditioners and the untreated plants but not in respect of ABA treatments