Threshold effect of the groundwater depth on the photosynthetic efficiency of Tamarix chinensis in the Yellow River Delta

Aims Groundwater is a major factor that affects the growth and distribution of Tamarix chinensis in the Yellow River Delta (YRD). The response relationship between the photosynthetic physiological processes of T. chinensis and the depth to groundwater (DGW) remains unclear. This paper aims to elucidate the response pattern of photosynthetic efficiency to the DGW and to determine the suitable DGW for the growth of T. chinensis.