为揭示半干旱采煤沉陷区水土保持植物的逆境生存策略,以2~3 a生黑沙蒿(Artemisia ordosica)为试验材料,对其根部进行原位根系断裂试验模拟土壤侵蚀胁迫,设置重度胁迫(P1)、中度胁迫(P2)、轻度胁迫(P3)及对照(CK)四个处理,研究黑沙蒿生长指标、光合特性及生理应激反应对胁迫的响应变化.结果表明:(1)土壤侵蚀胁迫显著抑制黑沙蒿生长速率,侵蚀破坏程度越大,生长抑制越显著,重度胁迫后黑沙蒿株高、冠幅、枝条长度、枝条直径增速较对照组平均下降36.91%、43.90%、69.76%、66.76%.(2)土壤侵蚀胁迫对黑沙蒿光合作用形成明显的负面作用,且侵蚀破坏程度越大,负反馈越强烈,重度胁迫后黑沙蒿叶片净光合速率、气孔导度、胞间二氧化碳浓度、蒸腾速率、叶绿素含量较对照组分别降低39.86%、59.26%、7.82%、51.55%、12.33%.(3)侵蚀破坏发生70d内,黑沙蒿叶片SOD活性、POD活性和CAT活性与对照组相比呈先升高后降低随后趋于平稳趋势,MDA含量在一定范围内波动,冗余分析表明SOD活性对黑沙蒿光合特性的影响最为显著.综合分析说明,采煤沉陷区土壤侵蚀破坏造成的黑沙蒿根系断裂会降低其生长速率,并抑制叶片光合作用,但黑沙蒿可通过调节自身抗氧化酶活性来维持其基本生长,是具有优良抗逆性与适应性的侵蚀区生态修复植物种.
To reveal the survival strategy of plants in semi-arid coal mining subsidence areas faced with soil erosion stress,2-3-year-old Artemisia ordosica plants were used as the test materials and in-situ root structure destruction tests were carried out at four levels:severe stress(P1),moderate stress(P2),mild stress(P3),and control(CK).The changes in growth indices,photosynthetic characteristics,and physiological traits of A.ordosica were measured.The results showed that soil erosion stress significantly inhibited the growth rate of A.ordosica,and that the greater the degree of simulated damage,the more significant the growth inhibition.After severe stress,the growth rates of plant height,crown width,branch length,and branch diameter of A.ordosica decreased by an average of 36.91%,43.90%,69.76%,and 66.76%,respectively,compared to control plants.Soil erosion stress also conferred a significant negative effect on the photosynthesis of A.ordosica,and the greater the degree of damage,the stronger the negative effect.After severe stress,the net photosynthetic rate,stomatal conductance,intercellular carbon dioxide concentration,transpiration rate,and chlorophyll content of A.ordosica decreased by 39.86%,59.26%,7.82%,51.55%,and 12.33%,respectively,compared to control plants.After 70 days of erosion stress,the activities of superoside dismutase(SOD),peroxidase(POD),and oxidoreductase(CAT)in A.ordosica initially increased and later decreased,and tended to be stable when compared with the control.The malondialdehyde(MDA)content fluctuated within a certain range.Redundancy analysis showed that the level of SOD activity had the most significant effect on the photosynthetic characteristics of A.ordosica.Comprehensive analysis showed that the root fracture of A.ordosica caused by soil erosion in coal mining subsidence areas will reduce its growth rate and inhibit photosynthesis.However,A.ordosica can maintain its growth by regulating the activity of its antioxidase systems and can therefore be considered to be an ecological restoration plant species due to its excellent resistance and adaptability in erosive areas.