不同土壤环境对紫茎泽兰种子存活的影响

Effect of different storage conditions on the viability of Eupatorium adenophora seeds

紫茎泽兰(Eupatoriumadenophora)是我国西南地区广泛分布的检疫性入侵杂草,研究其种子在土壤中的存活规律对进一步明确入侵机制和综合防治具有重要意义。本研究通过室内培养试验,持续6个月监测了不同土壤温度(10、20、30℃)、湿度(20%、50%、80%)、深度(0、2、4、6、8 cm)、pH(4、7、10)、盐胁迫(240 mmol·L^(-1))、干旱胁迫(-0.6 MPa PEG)条件下紫茎泽兰种子的存活率。结果表明:贮藏温度、贮藏湿度、贮藏时间对紫茎泽兰种子存活率影响极显著(P<0.01),且存在极强的交互作用。紫茎泽兰种子存活率随贮藏时间的延长呈下降趋势,贮藏6个月后,高温(30℃)高湿(80%)条件下紫茎泽兰种子存活率仍高达82.22%,高温(30℃)低湿(20%)下种子存活率低于3%。种子存活率随埋藏深度的增加而升高,贮藏6个月后,土表(0 cm)紫茎泽兰种子的存活率下降到60%,而8 cm埋藏深度的种子存活率仍高达92.22%。紫茎泽兰种子在pH为7的土壤中贮藏6个月存活率仍能达88.9%,贮藏在pH为4和10的土壤中,紫茎泽兰种子存活率降至70%左右。紫茎泽兰种子对NaCl胁迫和干旱胁迫环境有较强耐受能力,贮藏6个月存活率仍分别高于60%和75%。由此可见,紫茎泽兰种子对土壤环境有较强的适应性。这是其在我国西南地区入侵成功并成为优势种群的原因,因此适当免耕或少耕有助于减少紫茎泽兰土壤种子库密度。

Eupatorium adenophora is a widely distributed quarantine invasive weed in southwestern China,and the study of its seed survival in soil is essential for further clarifying its invasion mechanism and comprehensive control.In this study,we monitored the survival rate of E.adenophora seeds under different soil temperatures,humidity,depth,pH,salt stress,and drought stress conditions through indoor incubation tests for 6 months.The results showed that storage temperature,storage humidity,and storage time had significant effects(P<0.01)on the viability of E.adenophora seeds,and there was a strong interaction effect.The seed viability of E.adenophora showed a decreasing trend with the increase of storage time,and after 6 months of storage,the seed viability of E.adenophora under high temperature(30℃)and high humidity(80%humidity)was as high as 82.22%,whereas seed viability under high temperature(30℃)and low humidity(20%humidity)was less than 3%.Seed viability increased with the increase of burial depth,and after 6 months of storage,the viability(0 cm)of E.adenophora seeds on the soil surface decreased to 60%,while the viability of seeds buried at 8 cm depth was as high as 92.22%.The survival rate of E.adenophora seeds stored in soil at pH 7 for 6 months was 88.9%,while the survival rate of E.adenophora seeds was reduced to approximately 70%when stored in pH 4 and 10 environments.Furthermore,E.adenophora seeds were tolerant to NaCl stress(240 mmol·L^(-1))and drought stress(-0.6 MPa PEG),and the survival rate was still higher than 60%and 75%,respectively,after 6 months of storage.As such,strong adaptability of the seeds to the soil environment may be a reason for its successful invasion and becoming a dominant population in the southwestern part of China.Appropriate no-tillage or less tillage can help reduce the density of the seed bank of the soil of E.adenophora.