Department of Geography and Atmospheric Science, University of Kansas, 1475 Jayhawk Blvd., Lawrence, KS, 66045, USA.
The Land Institute, 2440 East Water Well Rd., Salina, KS, 67401, USA.
Plant Sci. 2020 Jun;295:110279. doi: 10.1016/j.plantsci.2019.110279. Epub 2019 Sep 25.
Perennial crops have been proposed as a more sustainable alternative to annual crops, because they have extended growing seasons, continuous ground cover, reduced nutrient leakage, and sequester more carbon in the soils than annual crops. One example is intermediate wheatgrass (Thinopyrum intermedium), a perennial crop that has been used as a cool-season forage throughout the USA and Canada and also across its native range in Eurasia. Since the 1980's, intermediate wheatgrass has been under domestication to improve seed fertility and grain yield. Commercial products are being sold under the trade name Kernza, owned by The Land Institute, located in Salina, Kansas, USA. This review provides a comprehensive framework about the physical and biological aspects involving the water and carbon cycles in Kernza plants. The main aspects we highlight here are based on previous findings regarding Kernza: i) the ability of maintaining a relatively high water-use efficiency throughout the whole growing season, which is beneficial to mitigate water stress, representing an important physiological mean to acclimate under severe, unfavorable weather conditions, and ii) its higher evapotranspiration (ET) and net carbon uptake rates, particularly when compared to annual counterparts. Only a thorough multifaceted assessment of the repercussion for carbon and water fluxes of a shift from annual crops to Kernza will allow assessing the perspectives of such novel perennial crop to support food security and a number of ecosystem services, particularly under future climates.
多年生作物被认为是一种比一年生作物更可持续的替代选择，因为它们具有更长的生长季节、连续的地面覆盖、减少养分渗漏，并在土壤中固碳量比一年生作物更多。一个例子是中间偃麦草（Thinopyrum intermedium），这是一种多年生作物，在美国和加拿大以及欧亚大陆的原生范围内被用作冷季饲料。自 20 世纪 80 年代以来，中间偃麦草一直在进行驯化，以提高种子肥力和谷物产量。商业产品以美国堪萨斯州萨利纳的土地研究所（The Land Institute）拥有的商标 Kernza 出售。这篇综述提供了一个关于 Kernza 植物水碳循环物理和生物方面的综合框架。我们在这里强调的主要方面是基于之前关于 Kernza 的发现：i）在整个生长季节保持相对较高的水分利用效率的能力，这有利于缓解水分胁迫，代表了在恶劣不利天气条件下适应的重要生理手段，ii）其较高的蒸散（ET）和净碳吸收速率，特别是与一年生作物相比。只有对从一年生作物向 Kernza 转变对碳和水通量的影响进行全面的多方面评估，才能评估这种新型多年生作物支持粮食安全和许多生态系统服务的前景，特别是在未来的气候条件下。
