采煤沉陷区模拟侵蚀破坏对小叶锦鸡儿光合生理特性的影响

为明确半干旱矿区植物生长及生理特性对侵蚀破坏的响应机制，以小叶锦鸡儿为对象，分析其枝叶生长、光合生理指标及水分利用效率在根系不同程度断裂损伤后的变化特征。结果表明，根系损伤对小叶锦鸡儿生长产生明显抑制作用，随损伤程度增大，抑制作用越明显，重度损伤后株高、冠幅、枝条长度和直径增长率相比对照分别降低了62.5%、61.1%、73.3%和74.4%；根系损伤对小叶锦鸡儿的各项光合指标均存在明显的抑制作用，同样具有根系损伤程度越大，叶片光合指标越低的变化趋势，以净光合速率为例，表现为对照(22.40 μmol·m^-2·s^-1)>轻度损伤(20.44 μmol·m^-2·s^-1)>中度损伤(17.33 μmol·m^-2·s^-1)>重度损伤(15.20 μmol·m^-2·s^-1)，而且根系损伤对光合指标的抑制作用在损伤形成后将长期存在，持续弱化叶片的光反应能力；根系损伤会改变小叶锦鸡儿叶片的水分利用效率，损伤程度越大，水分利用效率越高，表现为重度损伤(4.30 μmol·mmol^-1)>中度损伤(3.97 μmol·mmol^-1)>轻度损伤(3.61 μmol·mmol^-1)>对照(3.52 μmol·mmol^-1)。综合分析说明，在侵蚀破坏造成根系损伤后，小叶锦鸡儿会通过减缓生长和光合速率，降低水分需求，实现维持自身生存、生长和再生产的生存策略。

Effects of Simulated Erosion Damage on Photosynthetic and Physiological Characteristics of Caragana microphylla in Coal Mining Subsidence Area

In order to clarify the response mechanism of plant growth and physiological characteristics to erosion damage in semi-arid mining areas,Caragana microphylla was taken as the research object,and the changes of branches and leaf growth,photosynthetic and physiological indexes and water use efficiency were analyzed after different degrees of root damage.The results showed that root damage had a significant inhibitory effect on the growth of C.microphylla,and the inhibitory effect was more obvious with the increase of damage degree.Compared with the control,the growth rates of plant height,crown width,branch length and diameter after severe damage reduced by 62.5%,61.1%,73.3% and 74.4%,respectively.Root damage had a significant inhibitory effect on photosynthetic indexes of C.microphylla,and the greater the degree of root damage,the lower the photosynthetic indexes of the leaves.The net photosynthetic rates were in the order of control (22.40)> mild injury (20.44)>moderate damage (17.33)>severe damage (15.20 μmol·m^-2·s^-1).Moreover,the inhibition of root damage on photosynthetic indexes would persist for a long time after the formation of root damage,and continue to weaken the light response capacity of the leaves.Root damage could change the water use efficiency (WUE) of the leaves,and the greater the damage degree,the higher the WUE,presenting the order of severe damage (4.30)>moderate injury (3.97)>mild injury (3.61)>control (3.52 μmol·mmol^-1).In conclusion,after root damage caused by erosion,C.microphylla could realize survival strategy to maintain its own survival,growth and reproduction by slowing down the growth and photosynthetic rates and reducing water demand.