Developing plant-based strategies for the sustainable remediation of salinized soils

土壤和淡水盐碱化的影响广泛而巨大。联合国粮农组织估计，世界上6.5%的可耕地已经盐碱化或盐碱化。在本提案中，植物修复（利用植物修复土壤）被探索作为一种减轻受影响地点盐的有害影响的手段。被称为“盐生植物”的耐盐植物因其修复盐碱化土壤和防止盐浸出到地表水和地下水中的潜力而受到评估。虽然大多数植物对盐敏感，但盐生植物已经发展出耐受和在这些条件下茁壮成长的机制。“积累盐生植物”在其组织中吸收盐，而“再盐生植物”通过其叶片表面的特殊腺体分泌多余的盐。这两种类型的植物在植物修复方面都是有用的。在前者中，必须收获植物并处理受盐污染的生物质，而在后者中，盐可以通过称为“盐传导”的过程在风中分散。本提案将研究：i)修复机动车道路上道路盐的蓄积盐植物，以及ii)修复工业盐碱化土壤的更广泛的再盐植物。加拿大目前在盐消费方面处于世界领先地位，每年使用150万吨道路用盐。将采用温室和实地研究来调查本地植物物种，以修复盐碱化的路边，并将确定收获的含盐植物生物量是否可以重新利用为可用的副产品（例如饲料、堆肥或生物炭）。从理论上讲，再生盐生植物的使用比积累盐生植物有优势，因为排泄的盐可以通过风的作用分散，从而消除了植物收获的需要。具有讽刺意味的是，虽然高浓度的盐是有害的，但低浓度的盐对动植物物种都是必需的营养物质，因此分散后可能是有益的。重点将是探索加拿大的休闲盐植物，目的是提供一种可行和可持续的替代植物技术来修复盐污染场地，同时成本低，易于实施。将植物整合到任何修复设计中都有以下好处：最大限度地减少土壤退化，通过植物物质中的碳储存缓解气候变化，为本地物种创造栖息地，改善场地美学。记录最佳做法的研究结果将被公布，最终将一项新的环境技术交到加拿大人手中。在5年的时间里，该提案将支持和培训12名HQP。HQP将获得批判性思维和规划、实验室分析技术、实地工作组织和动员以及沟通技巧（口头和书面）方面的技能，所有这些都是学术、工业或私营部门潜在雇主积极寻求的技能。

Impacts of soil and freshwater salinization are widespread and substantial. The Food and Agriculture Organization of the United Nations estimate that ~6.5% of the world's arable soils are already saline or sodic. In this proposal, phytoremediation (using plants to remediate soils) is explored as a means of mitigating the harmful effects of salt at affected sites. Salt-tolerant plants known as `halophytes' are evaluated for their potential to remediate salinized soils and prevent leaching of salts into surface and ground waters. While most plants are sensitive to salt, halophytic plants have developed mechanisms to tolerate and thrive in these conditions. `Accumulator halophytes' sequester salts in their tissues, while `recretohalophytes' secrete excess salts through specialized glands on their leaf surfaces. Both types of plants are useful in the context of phytoremediation. In the former, plants must be harvested and the salt-contaminated biomass disposed of, while in the latter, salts may be dispersed on the wind in a process referred to as `haloconduction'. This proposal will study: i) accumulator halophytes to remediate road salt on motor ways, and ii) recretohalophytes for the broader remediation of industrially salinized soils. Canada currently leads the world in salt consumption, applying >5 million tonnes of road salt annually. Greenhouse and field studies will be employed to investigate native plant species for remediation of salinized roadsides, and will determine if the harvested salt-laden plant biomass may be repurposed into useable by-products (e.g. fodder, compost, or biochar). In theory, the use of recretohalophytes has an advantage over accumulator halophytes as excreted salt may be dispersed through wind action, thus removing the need for plant harvesting. Ironically, while salts are hazardous at high concentrations, low levels are essential nutrients for both flora and fauna species, and hence may prove to be beneficial when dispersed. The focus will be on exploring Canadian recretohalophytes with the goal of providing an alternative phytotechnology for remediating salt-contaminated sites that is feasible and sustainable, while also being low-cost and easy to implement. The integration of plants into any remediation design has the benefits of minimizing soil degradation, mitigating climate change through carbon storage in plant matter, creating habitat for native species, and improving site aesthetics. Findings documenting best practices will be published, ultimately putting a new environmental technology into the hands of Canadians. Over a 5-year period, this proposal will support and train 12 HQP. HQP will gain skills in critical thinking and planning, laboratory analytical techniques, field work organization and mobilization, and communication skills (both oral and written), all of which are actively sought after by prospective employers be they academic, industrial or private sector.