Salinity and proteolytic enzymes in germinating seeds of x Haynaldoticum sardoum (Poaceae)

The effect of salinity on germination, early seedling growth, and storage p rotein mobilization of x Haynaldoticum sardoum MELETTI & ONNIS seeds was in vestigated. Increased salinity affected more adversely the early germinatio n of the Culmo Pieno than Culmo Vuoto line seeds - the higher the temperatu re the greater the effect. The reduction in coleoptile and root growth appe ared to be more sensitive to increased salinity than germination; minor dif ferences between Culmo Pieno and Culmo Vuoto seedlings were found. The acti vity of some proteolytic enzymes involved in the mobilization of the endosp ermatic storage proteins was estimated: high salinity generally reduced the proteolytic activity. The inhibition of cysteine proteinase (EC 3.4.22) ac tivity was particularly interesting since this enzyme was involved in the i nitial and further degradation of gluten, and appeared to play a key role i n that process. The consequence of this inhibition could lead to the impair ed capacity of the seed to mobilize storage proteins, and hence deprive you ng seedlings of nutrients prior to the development of the autotrophic capac ity.