Influence of protection from grazing on carbohydrate and nitrogen metabolites of three range species in the western Mediterranean coastal region of Egypt

Abstract

Helianthemum lippii, Plantago albicans and Cutandia dichotoma are three range species which grow in non-saline depressions along the Mediterranean coast of Egypt west of Alexandria. The present study investigates the effect of protection from grazing on the contents of total available carbohydrates, soluble sugars, crude protein and soluble nitrogen in various organs of these species. In Helianthemum lippii, protection during the growing season promoted the accumulation of total available carbohydrates in all organs, soluble sugars in reproductive organs and crude protein in aerial parts (vegetative and reproductive organs). On the other hand, protection during the dry season promoted the accumulation of soluble sugars in roots and crude protein in aerial organs. In Plantago albicans, protection during the growing season resulted in the increase in the contents of both total available carbohydrates and soluble sugars in aerial parts, and the content of crude protein in roots. During the dry season, protection resulted in the increase in the contents of both crude protein and soluble nitrogen in vegetative organs. In Cutandia dichotoma, protection promoted a remarkable decrease in the contents of soluble sugars during winter and of crude protein during winter and spring.