The Application of Systemic Linguistics in University Textbooks (A Case Study of General Biochemistry)

The research at hand discusses about the mode of text and textual properties in a university textbook from a systemic linguistic point of view. The corpus of the study includes the texts of a book titled General Biochemistry (by Maleknia and Shahbazi) and the research was carried out through an analytic method. The results indicate that the textual properties of the book are such that in theme position, different constituents were used to express different meanings. In this position, constituents from different grammatical categories are present and change the meaning of the clause by themselves. Some of these themes are textual themes, with a high frequency (52.77%). They have a textual function and hence have led text development and more cohesion. Other themes (17.55%) are marked and are topicalized to express emphasis, intensity or contrast of meanings. Thus, such structural clues are tools for handling meanings, and clarify the intended purpose of the authors of the book. It means that, meaning has been affected by mode. The main message of textual metafunction, which is mode, is to regard and apply such special structural elements that are very effective in perception. In this study, the findings confirmed the importance of theme-rheme structure and its role in text writing and a change of meaning. Such findings can be considered by authors and particularly by editors in writing academic books and can help improve the quality of university textbooks.