Variations in Proline Content of Salt Cedar (<i>Tamarix chinensis</i>) in Different Habitats of the Yellow River Delta, China

Abstract

Understanding relationships between vegetation and its substrate environment is helpful for protection of ecosystem integrity. Substrate has been proved as one of good indicators to reveal the inherent interactions between wetland vegetation and its environment. A study was thus conducted to investigate the suitable soil environment for salt cedar (Tamarix chinensis) in order to predict its distribution in the Yellow River Delta in whichTamarix chinensishas been spreading in recent years. This study analyzed the soil parameters as environmental variations, and at the same time used proline content as a physiological indicator to illuminate the condition of theTamarix chinensis. The habitats were classified into 3 clusters at 95% confident level with K-mean clustering algorithm. The differences in soil conductivity, Cl-, NO3-, Na+and Mg2+among the three clusters were significant as revealed by ANOVA results. The distribution of these clusters and their soil variations were consistent, implying that the clustering illuminates the differences physically. Finally, a range ofTamarix chinensisleaf proline was settled and compared with the clustering results, and it was found thatTamarix chinensiscould have positive growth dynamic under moderate soil water and salinity conditions.