Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA.
Plant Cell Environ. 2021 Aug;44(8):2466-2479. doi: 10.1111/pce.14056. Epub 2021 Apr 21.
The finely tuned balance between sources and sinks determines plant resource partitioning and regulates growth and development. Understanding and measuring metabolic indicators of source or sink limitation forms a vital part of global efforts to increase crop yield for future food security. We measured metabolic profiles of Cucurbita pepo (zucchini) grown in the field under carbon sink limitation and control conditions. We demonstrate that these profiles can be measured non-destructively using hyperspectral reflectance at both leaf and canopy scales. Total non-structural carbohydrates (TNC) increased 82% in sink-limited plants; leaf mass per unit area (LMA) increased 38% and free amino acids increased 22%. Partial least-squares regression (PLSR) models link these measured functional traits with reflectance data, enabling high-throughput estimation of traits comprising the sink limitation response. Leaf- and canopy-scale models for TNC had R values of 0.93 and 0.64 and %RMSE of 13 and 38%, respectively. For LMA, R values were 0.91 and 0.60 and %RMSE 7 and 14%; for free amino acids, R was 0.53 and 0.21 with %RMSE 20 and 26%. Remote sensing can enable accurate, rapid detection of sink limitation in the field at the leaf and canopy scale, greatly expanding our ability to understand and measure metabolic responses to stress.
源和汇之间的精细平衡决定了植物的资源分配，并调节着生长和发育。理解和测量源或汇限制的代谢指标是全球努力提高未来粮食安全作物产量的重要组成部分。我们测量了在碳汇限制和对照条件下生长于田间的南瓜（西葫芦）的代谢谱。我们证明，这些谱可以使用叶片和冠层尺度的高光谱反射率进行非破坏性测量。在汇限制的植物中，总非结构性碳水化合物（TNC）增加了 82%；叶面积比（LMA）增加了 38%，游离氨基酸增加了 22%。偏最小二乘回归（PLSR）模型将这些测量的功能特性与反射率数据联系起来，使对构成汇限制响应的特性进行高通量估计成为可能。叶片和冠层尺度的 TNC 模型的 R 值分别为 0.93 和 0.64，%RMSE 分别为 13 和 38%。对于 LMA，R 值分别为 0.91 和 0.60，%RMSE 分别为 7 和 14%；对于游离氨基酸，R 值分别为 0.53 和 0.21，%RMSE 分别为 20 和 26%。遥感可以在叶片和冠层尺度上准确、快速地检测田间的汇限制，极大地扩展了我们理解和测量代谢对胁迫响应的能力。
