Response of the accumulation of proline in the bodies ofPopulus euphratica to the change of groundwater level at the lower reaches of Tarim River

Abstract

The content of proline in the plant bodies is closely related to the converse-succession-resistant capability of the plants. In this paper, the relationship between the proline accumulation in the bodies ofPopulus euphratica and the change of groundwater level is analyzed by takingPopulus euphratica, the main community-building species of the desert riparian forests along the Tarim River, as the research object. The research results show that the accumulation of proline in the bodies ofPopulus euphratica is closely related to the change of groundwater level gradient under drought stress, it increases with the drawdown of groundwater level and the increase of moisture stress degree; the accumulation of proline in the bodies ofPopulus euphratica has two extremely high points at the groundwater depth ranges of 3.64–5.14 m and 9.46–10.16 m. Combining the field investigation and the analysis of the plots, it is considered that the groundwater level of 3.5–4.5 m is rational for the growth ofPopulus euphratica. The stress groundwater depth for the normal growth and the critical one for the survival ofPopulus euphratica are below 4.5 m and 9–10 m respectively at the lower reaches of the Tarim River.