Khalil A M, Murchie E H, Mooney S J
School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, UK.
College of Agriculture, University of Duhok, Duhok-Kurdistan Region, Iraq.
AoB Plants. 2020 Jul 26;12(5):plaa036. doi: 10.1093/aobpla/plaa036. eCollection 2020 Oct.
The potential increased frequency and severity of drought associated with environmental change represents a significant obstacle to efforts aimed at enhancing food security due to its impact on crop development, and ultimately, yield. Our understanding of the impact of drought on crop growth in terms of plant aerial tissues is much more advanced than knowledge of the below-ground impacts. We undertook an experiment using X-ray Computed Tomography that aimed to support measurements of infrared gas exchange from plant shoots with quantification of 3D root architecture traits and the associated soil structural characteristics. Winter wheat (cv. Zebedee) was assessed at two early growth stages (14 and 21 days) under four water treatments (100, 75, 50 and 25 % of a notional field capacity (FC) and across two soil types (sandy loam and clay loam)). Plants generally grew better (to a larger size) in sandy loam soil as opposed to clay loam soil, most likely due to the soil structure and the associated pore network. All plants grew poorly under extreme water stress and displayed optimal growth at 75 % of FC, as opposed to 100 %, as the latter was most likely too wet. The optimal matric potential for root and shoot growth, inferred from the water release curve for each soil type, was higher than that for photosynthesis, stomatal conductance and transpiration suggesting root and shoot growth was more affected by soil water content than photosynthesis-related characteristics under water deficit conditions. With incidences of drought likely to increase, identification of wheat cultivars that are more tolerant of these conditions is important. Studies that consider the impact of water stress on both plant shoots and roots, and the role of the soil pore system such as this offer considerable potential in supporting these efforts.
与环境变化相关的干旱发生频率和严重程度增加，这对旨在加强粮食安全的努力构成了重大障碍，因为干旱会影响作物生长，最终影响产量。我们对干旱对作物地上组织生长的影响的理解比对地下影响的了解要先进得多。我们进行了一项使用X射线计算机断层扫描的实验，旨在通过量化三维根系结构特征和相关土壤结构特征来支持对植物地上部分红外气体交换的测量。在四个水分处理（分别为理论田间持水量（FC）的100%、75%、50%和25%）以及两种土壤类型（砂壤土和粘壤土）条件下，对冬小麦（品种Zebedee）在两个早期生长阶段（14天和21天）进行了评估。与粘壤土相比，植物通常在砂壤土中生长得更好（长得更大），这很可能是由于土壤结构和相关的孔隙网络。在极端水分胁迫下，所有植物生长不良，在FC的75%时表现出最佳生长，而不是100%，因为后者可能太湿。根据每种土壤类型的水分释放曲线推断，根系和地上部分生长的最佳基质势高于光合作用、气孔导度和蒸腾作用的最佳基质势，这表明在水分亏缺条件下，根系和地上部分的生长比与光合作用相关的特征更容易受到土壤含水量的影响。随着干旱发生率可能增加，识别更耐受这些条件的小麦品种很重要。像这样考虑水分胁迫对植物地上部分和根系的影响以及土壤孔隙系统作用的研究，在支持这些努力方面具有很大潜力。
