匍匐茎外来入侵植物及其同属本地种胁迫信号的克隆整合差异

Differences in clonal integration of stress signal between a stoloniferous invasive plant and its congeneric native one

关键词:  氧化损伤, 抗氧化能力, 渗透调节, 种间差异, 克隆整合

Key words:  oxidative damage, antioxidant capacity, osmotic regulation, interspecific differences, clonal integration

摘要:

相比于同属本地种,外来入侵克隆植物在资源物质的克隆整合中获益更大,但非资源物质(如胁迫信号、防御信号)的克隆整合对外来入侵克隆植物及其同属本地种生长表现的影响尚不清楚。该文选取匍匐茎外来入侵植物南美蟛蜞菊(Sphagneticola trilobata)及其同属本地种蟛蜞菊(S. calendulacea)的克隆片段(包含3个相连分株),实施均质性水分胁迫处理,结合局部喷施外源脱落酸(ABA)和匍匐茎连接/切断处理,研究外源ABA诱导克隆片段的系统性抗性及其对生长表现的影响。结果表明:(1)通过克隆整合,局部喷施外源ABA显著缓解南美蟛蜞菊和蟛蜞菊克隆片段相连分株叶片的氧化损伤,增强叶片的抗氧化酶活性和渗透调节物质的含量。(2)相比于蟛蜞菊,局部喷施外源ABA显著增加南美蟛蜞菊克隆片段的第三分株(幼年分株)的脯氨酸含量和可溶性蛋白含量(Pro)和第二分株(成熟分株)的超氧化物歧化酶(SOD)活性。(3)相比于蟛蜞菊,局部喷施外源ABA显著增加南美蟛蜞菊克隆片段的总生物量,对南美蟛蜞菊的根冠比没有显著影响。综上认为,外来入侵植物南美蟛蜞菊从局部喷施外源ABA所诱导的胁迫信号克隆整合中获益更大,同时更高的地上生物量分配可能有助于进一步增强其入侵性。

Abstract:

Under heterogeneous resource supply, alien invasive plants with clonal growth can benefit more from clonal integration of resource substance than their native congeneric ones. However, clonal integration of non-resource substance(like stress or defensive signal)and its effects on growth performance between alien invasive plants and their native congeneric ones remains unclear. Clonal fragments(including three successive ramets)of invasive stoloniferous plant Sphagneticola trilobata and its native congeneric one S. calendulacea subjected to homogeneous water stress were used to investigate effects of local abscisic acid(ABA)application on systematic resistance and growth performance within clonal network when stolon between interconnected ramets was severed or retained intact. The results were as follows:(1)With clonal integration, local ABA application significantly alleviated foliar oxidative stress of both S. trilobata and S. calendulacea, increased foliar antioxidant enzyme activity and osmotic regulatory substance content.(2)Compared to S. calendulacea, local ABA application significantly increased content of proline(Pro)and soluble protein contents in third ramets of S. trilobata and superoxide dismutase(SOD)activity in second ramets of S. calendulacea compared to S. trilobata.(3)Compared to S. calendulacea, local ABA application significantly increased the total biomass of S. trilobata, but had no significant effect on the root-shoot ratio of S. trilobata. In conclusion, alien invasive plant S. trilobata may benefit more from clonal integration of stress signal induced by local ABA application than its congeneric native one S. calendulacea. In addition, it is suggested that greater biomass allocation to aboveground may be helpful for successful invasion of S. trilobata.