Objective To study the growth, physiological characteristics and their dynamic changes of Pennisetum hydridum in dredged soils with different water contents, find out the optimal water content for the growth of P. hydridum in dredged soils, and provide a theoretical reference for the ecological solidification method of newly blown and filled dredged soil.

Method Four water content (w) treatments of 20% (T1), 30% (T2), 40% (T3) and 50% (T4) were set up to analyze the growth, nutrient absorption, water transpiration, leaf and root physiological characteristics of P. hydridum through potting experiment.

Result The growth performance of P. hydridum was the best in T2, and the plant height (152 cm), dry mass per plant (88.51 g) and N, P and K uptake per plant (505.72, 99.39, 1 703.45 mg) of T2 were significantly higher than those of other treatments (P<0.05). The daily water consumption, water consumption rate, net photosynthetic rate, stomatal conductance and transpiration rate of P. hydridum all increased first and then decreased with the increase of soil water content, and all reached the maximum in T2 and were significantly higher than those of other treatments (P<0.05). The enzyme activity indexes of P. hydridum were higher in T1 and T4 than those of other treatments, and reached the lowest in T2. The comprehensive evaluation results showed that the growth adaptability of P. hydridum to water content in dredged soil was as follows: 30% > 40% > 50% > 20%.

Conclusion Based on the various indicators, the water content of 30% in dredged soil is the most conducive to growth, nutrient absorption and transpiration and water consumption of P. hydridum, and the growth performance of P. hydridum in flooding stress (T3, T4) was better than that of drought stress (T1). These results can be used as a reference for shallow solidification of dredged soil and utilization of plant resources in practical production applications.