ECOPHYSIOLOGICAL STUDY ON THE INVASIVE WEED Cynanchum acutum L.

Abstract

The invasive weed, Cynanchum acutum, was collected from nine different habitat sites from Damietta and Kaliobia governorates. There were 27 associated species with C. acutum belonging to 24 genera and related to 15 families. Analysis of variance indicated that soil variables were significantly different at 0.001 level except for pH. The same was also detected for the functional morphological traits of C. acutum; all of the traits were significantly different at a level less than 0.001. On the other hand, there were great differences in carbohydrates, phenolics, protein and proline contents among the studied sites. There were differential correlations between functional physiological traits of C. acutum and the soil variables in the studied sites. Phenolics content was positively correlated with soil chloride but negatively correlated with soil moisture content. On the other hand, proline content was positively correlated with both soil calcium carbonate and bicarbonate. In addition, there was a close correlation between protein content and soil calcium carbonate and bicarbonate. Meanwhile, soil organic matter and available phosphorus correlated well with various physiological variables. Anyway, there was a positive correlation between available phosphorus and protein content. These present results might provide information about the soil characteristics supporting the plant growth in addition to possible expectations of the plant internal composition. These close correlations tend to indicate that the variation in growth and physiological function of C. acutum might be a consequence of the varied edaphic factors.