华亭大黄幼苗对入侵植物野莴苣胁迫的生理响应

Physiological Responses of Huating rhubarb seed⁃lings to the stress of invasive plant Lactuca serriola

【目的】研究华亭大黄幼苗对入侵植物野莴苣胁迫的生理响应,为华亭大黄人工种植中防治入侵植物提供理论依据和方法。【方法】采用水浸法制备野莴苣植株浸提液,浸提液设置5个质量浓度[0(CK)、20、40、60、80 mg/mL],分别处理华亭大黄幼苗30、40、50和60 d,研究在特定质量浓度野莴苣浸提液胁迫下,华亭大黄幼苗的形态指标、生理指标、PSⅡ光能转换效率及净光合速率的响应变化。【结果】野莴苣浸提液对华亭大黄幼苗生长的影响表现为“低促高抑”,具体表现为:当浸提液浓度为20mg/mL时,华亭大黄幼苗的苗高、鲜重、单位长度生物量均高于其他浓度处理组;当浸提液浓度为40mg/mL时,华亭大黄幼苗MDA含量下降到最小值,SOD活性达到最大值,净光合速率达到最大值;当浸提液浓度为60、80 mg/mL时,华亭大黄幼苗苗高、鲜重、单位长度生物量均低于对照组,80 mg/mL浸提液处理时,净光合速率低于对照组。且随处理天数增加其作用增强,处理50 d时此作用最强,随后减弱。【结论】野莴苣浸提液对华亭大黄幼苗生长具有一定影响,在华亭大黄的田间种植过程中,应避免大量野莴苣植株存在,可以人工除去,以保证大黄正常生长。

【Objective】The aim of the study is to investigate the physiological responses of the seedlings of Huat⁃ing rhubarb to the stress of Lactuca serriola,and to provide theoretical basis and methods for the control of invasive plants in the artificial planting of Huating rhubarb.【Method】Lactuca serriola plant extracts were prepared by water extraction method.The extracts were set at 5 mass concentrations(0(CK),20,40,60,80 mg/mL)and Huating rhu⁃barb seedlings had been treated for 30,40,50 and 60 days respectively.The changes of morphological indexes,physi⁃ological indexes,PSⅡlight energy conversion efficiency and net photosynthetic rate of Huating rhubarb seedlings were studied under the stress of Lactuca serriola extracts at specific mass concentrations.【Result】The effect of wild lettuce extract on the growth of Huating rhubarb seedlings was manifested as"low promotion and high depression",which was manifested as following facts.When the concentration of extract was 20 mg/mL,the seedling height,fresh weight and biomass per unit length of Huating rhubarb seedlings were higher than those of other concentration treat⁃ment groups.When the concentration of extract was 40 mg/mL,the MDA content of Huating rhubarb seedlings de⁃creased to the minimum value,the SOD activity reached the maximum,and the net photosynthetic rate reached the maximum.When the concentration of extract was 60 and 80 mg/mL,the seedling height,fresh weight and biomass per unit length of Huating Rhubarb seedlings were lower than those in the control group,and the net photosynthetic rate was lower than that of the control group when treated with 80 mg/mL extract.The effect increased with the in⁃crease of treatment days,and this effect was strongest after 50 days of treatment,and then decreased.【Conclusion】Lactuca serriola plant extracts have a certain influence on the growth of Huating rhubarb seedlings,and a large num⁃ber of wild lettuce plants should be avoided during the field planting process of Huating rhubarb,which can be manu⁃ally removed to ensure the normal growth of Huating rhubarb.