皇竹草生长和生理特性对疏浚土含水量变化的响应

Response of growth and physiological characteristics of Pennisetum hydridum to water content change in dredged soil

【目的】研究在不同含水量疏浚土中皇竹草Pennisetum hydridum的生长、生理特性及动态变化规律,探明皇竹草在疏浚土上生长的最适含水量,为新近吹填疏浚土的生态固化提供理论依据。【方法】选用皇竹草为供试植物,通过盆栽试验,设置20%(T1)、30%(T2)、40%(T3)、50%(T4)4个含水量(w)处理,分析皇竹草的生长、养分吸收、水分蒸腾、叶片和根系生理特性。【结果】皇竹草在T2处理中生长表现最佳,T2处理的株高(152 cm)、单株干质量(88.51 g)以及单株氮、磷、钾吸收量(505.72、99.39、1703.45 mg)等数值均显著高于其他处理(P<0.05)。随着疏浚土含水量的增加,皇竹草的日耗水量、耗水速率、净光合速率、气孔导度和蒸腾速率均呈先升后降趋势,且均在T2处理达到最大值,并显著高于其他处理(P<0.05);皇竹草酶活性指标在T1和T4处理均高于其他处理,在T2处理达到最低。综合评价结果表明,皇竹草生长对疏浚土含水量(w)适应性强弱排序为:30%>40%>50%>20%。【结论】综合各项指标,30%(w)疏浚土含水量最有利于皇竹草的生长、养分吸收和蒸腾耗水,皇竹草在水淹胁迫(T3、T4)中的各项生长指标优于干旱胁迫(T1)。以上结果可供实际生产应用中疏浚土的浅层固化、植物资源利用等参考。

【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(505.72,99.39,1703.45 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.