Abstract:

Flooding stress, which prevents normal plant growth, is a prominent bottleneck constraining the existing wetland restoration techniques. Changes in root morphology are an adaptive strategy used by plants to cope with adverse environmental conditions. To demonstrate the feasibility of the restoration route of root morphology ectopic pre-construction-transplantation, we compared the growth status and soil erosion resistance of Typha orientalis Presl. bred at three inundation depths (5, 10, and 40 cm) with three root domain limitation intensities (5, 10, and 40 cm), and clarified the effects of root morphology ectopic pre-construction on improving plant tolerance to inundation and soil erosion resistance. The growth status and soil erosion resistance under the three flooding depths (0, 20, and 40 cm) clarified the role of root morphology ectopic pre-construction in improving plant flooding tolerance and the mechanical properties of root-soil complexes. The results showed that, under the three root restriction intensities, p. cuspidata cultivated with 10 cm vertical space restriction had the best root morphology, and its root-crown ratio, root porosity, and root volume were 31.9%, 18.6%, and 51.14% higher than that of p. cuspidata cultivated without vertical space restriction, and after transplanting, under the most unfavourable condition of flooding depth of 40 cm, its light energy trapping capacity, photoelectron transfer efficiency, and root oxygenation capacity were higher than that of p. cuspidata cultivated without vertical space restriction. The light energy capture capacity, photoelectron transfer efficiency and root oxygen secretion capacity were increased by 12.8%, 12.6% and 17.0%, respectively, compared with those cultivated without vertical space, which enhanced the oxygen production and oxygen transfer capacity of p. cuspidata, alleviated the problem of oxygen deficiency of plant roots caused by inundation, and also increased the antioxidant capacity of p. cuspidata after transplanting, and improved the adaptability of p. cuspidata to the inundated environment. By measuring the root mass density and shear resistance of the root-soil complex after the transplantation of Dandelion officinalis with different root morphologies, it was found that the root mass density of Dandelion officinalis transplanted after 10 pendant restriction cultivation was 2.36 times higher than that of the Dandelion officinalis transplanted after no pendant restriction cultivation, and at the same time, the shear resistance, cohesion and internal friction of the root-soil complex of Dandelion officinalis transplanted after pendant restriction cultivation was 2.36 times higher than that of Dandelion officinalis transplanted after 10 pendant restriction cultivation. The root-soil complexes were also more resistant to shear, cohesion, and internal friction angles, which enhanced the soil erosion resistance. The combination of ectopic root pre-construction and transplantation can provide a new approach for the restoration of wetland vegetation in a more rapid, stable, and efficient manner.

Key words: cattail, flooding, ectopic cultivation, physiological response, root-soil complex, root characteristics

摘要：

淹水胁迫阻碍植物正常生长是制约现有湿地修复技术的突出瓶颈。根系形态的变化是植物应对不良环境的适应性策略，为论证根系形态异位预构建－移栽这一修复路线的可行性，通过比较3种根域限制强度（5、10、40 cm）育成的香蒲（Typha orientalis presl.）在3个淹水深度（0、20、40 cm）下的生长状态和土壤抗侵蚀能力，明确了根系形态异位预构建对提高植物淹水耐受性和根土复合体力学性能的改善作用。结果表明，在3种根域限制强度下，10 cm垂向空间限制培育的香蒲具有最佳的根系形态，其根冠比、根孔隙度和根体积较未垂向空间限制培育的香蒲提高了31.9%、18.6%、51.14%。移栽后，在淹水深度40 cm的最不利条件下，其光能捕获能力、光电子转移效率和根系泌氧能力较无垂向空间培育的香蒲分别提高了12.8%、12.6%和17.0%，增强了香蒲的氧气产量和氧气传输能力，缓解了淹水导致植物根部缺氧问题，还增大了香蒲移栽后的抗氧化能力，提高了香蒲对淹水环境的适应性。通过对不同根系形态的香蒲移栽后的根土复合体根质量密度和抗剪切能力的测定，发现10 cm垂向限制培育后再移栽的香蒲根质量密度是无垂向限制培育后再移栽香蒲的2.36倍，同时，相较于未经垂向空间限制培育后再移栽的香蒲，垂向空间限制培育后再移栽香蒲的根土复合体的抗剪切能力、粘聚力和内摩擦角均有所提升，增强了其土壤抗侵蚀能力。根系形态异位预构建－移栽这一组合种植方式可为湿地植被修复提供一条更加快速、稳定、高效的新思路。

关键词: 香蒲, 淹水, 异位培育, 生理响应, 根土复合体, 根系特性