锰胁迫和性别竞争交互处理下沙棘雌雄幼苗生理响应特征

Physiological response characteristics of Hippophae rhamnoides seedlings under interaction of Mn stress and sexual competition

关键词:  土壤修复, 锰胁迫, 沙棘, 性别竞争, 生理响应

Key words:  soil remediation, Mn stress, sea buckthorn(Hippophae rhamnoides), sexual competition, physiological response

摘要:

沙棘(Hippophae rhamnoides)是重要的雌雄异株人工林防护树种,但对其环境胁迫的性别响应差异研究不足,性别竞争与胁迫因子的交互效应响应特征尚不清楚。为了探讨锰胁迫和性别竞争交互处理下沙棘雌雄植株的生理响应特征和耐受能力,旨在为沙棘修复土壤重金属污染提供实践指导,该文研究了锰胁迫(4 000 mg·kg^-1)和3种不同性别组合模式(雌雄、雌雌、雄雄)处理下沙棘的生理响应,分别测定雌雄沙棘叶片中叶绿素、过氧化物酶(peroxidase,POD)、超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondialdehyde,MDA)、总酚(total phenols, TP)、游离脯氨酸(free proline,Pro)、可溶性糖(soluble sugar,SS)、甜菜碱(glycine betaine, GB)以及锰含量。结果表明:(1)锰胁迫下,在所有竞争组合中,性间竞争的雄株(M/FM)SOD活性最高,而MDA含量与对照相比未有明显升高,表明雄株的抗氧化能力更好,膜氧化损伤程度更小。(2)锰胁迫时M/FM积累了更多的游离脯氨酸,表现出更好的渗透调节能力和耐受能力。(3)交互效应分析显示性别互作和锰胁迫交互处理显著影响了沙棘雌雄叶片的光合色素、抗氧化酶活性和渗透调节能力; 主成分分析显示SOD、POD、MDA、叶绿素b(chlorophyll b, Chlb)、SS、Pro可作为重要的生理响应指示参数。该研究结果对于利用沙棘修复土壤重金属污染可提供一定的参考。

Abstract:

Sea buckthorn(Hippophae rhamnoides)is an important dioecious tree species of protective plantation with insufficiently documented on the sexual responses difference to environmental stress as well as the interaction between sexual competition and heavy metal stress. In order to provide the practical guidance for repairing heavy metal pollution in soil, the physiological responses and tolerance of male and female sea buckthorn plants under Mn stress and different sexual competition interaction patterns were discussed. The physiological responses of sea buckthorn under Mn stress(4 000 mg·kg^-1)and three different sexual combinations(female × female, male × male, female × male)were determined, including the contents of chlorophyll, peroxidase(POD), superoxide dismutase(SOD), malondialdehyde(MDA), total phenols(TP), free proline(Pro), soluble sugar(SS), glycine betaine(GB)and manganese in male and female leaves. The results were as follows:(1)Under Mn stress, the SOD of male plants(M/FM)was the highest in all competition combinations, while the MDA content was not significantly increased compared with the control, indicating that the male plants had better antioxidant capacity and less membrane oxidative damage.(2)M/FM accumulated more free proline and showed better osmotic adjustment ability under Mn stress, indicating that male plants under sexual competition showed better tolerance to Mn stress.(3)The study indicated that male-female interaction and Mn stress interaction significantly affected the physiological response characteristics of sea buckthorn leaves, such as chlorophyll content, antioxidant enzyme activity and osmotic adjustment. Principal component analysis showed that the contents of SOD, POD, MDA, chlorophyll b(Chlb), SS and Pro in leaves could be used as the main physiological response indicators. The results can be used as a reference for the remediation of soil heavy metal pollution by sea buckthorn plants.