Kalcsits Lee A
Tree Fruit Research and Extension Center, Washington State UniversityWenatchee, WA, USA; Department of Horticulture, Washington State UniversityPullman, WA, USA.
Front Plant Sci. 2016 Apr 5;7:442. doi: 10.3389/fpls.2016.00442. eCollection 2016.
Calcium and potassium are essential for cell signaling, ion homeostasis and cell wall strength in plants. Unlike nutrients such as nitrogen and potassium, calcium is immobile in plants. Localized calcium deficiencies result in agricultural losses; particularly for fleshy horticultural crops in which elemental imbalances in fruit contribute to the development of physiological disorders such as bitter pit in apple and cork spot in pear. Currently, elemental analysis of plant tissue is destructive, time consuming and costly. This is a limitation for nutrition studies related to calcium in plants. Handheld portable x-ray fluorescence (XRF) can be used to non-destructively measure elemental concentrations. The main objective was to test if handheld XRF can be used for semi-quantitative calcium and potassium analysis of in-tact apple and pear. Semi-quantitative measurements for individual fruit were compared to results obtained from traditional lab analysis. Here, we observed significant correlations between handheld XRF measurements of calcium and potassium and concentrations determined using MP-AES lab analysis. Pearson correlation coefficients ranged from 0.73 and 0.97. Furthermore, measuring apple and pear using handheld XRF identified spatial variability in calcium and potassium concentrations on the surface of individual fruit. This variability may contribute to the development of localized nutritional imbalances. This highlights the importance of understanding spatial and temporal variability in elemental concentrations in plant tissue. Handheld XRF is a relatively high-throughput approach for measuring calcium and potassium in plant tissue. It can be used in conjunction with traditional lab analysis to better understand spatial and temporal patterns in calcium and potassium uptake and distribution within an organ, plant or across the landscape.
钙和钾对于植物的细胞信号传导、离子稳态及细胞壁强度至关重要。与氮和钾等养分不同，钙在植物体内难以移动。局部缺钙会导致农业产量损失；对于肉质园艺作物而言尤其如此，果实中的元素失衡会导致生理病害的发生，如苹果的苦痘病和梨的栓皮病。目前，植物组织的元素分析具有破坏性、耗时且成本高昂。这限制了与植物钙相关的营养研究。手持式便携式X射线荧光光谱仪（XRF）可用于无损测量元素浓度。主要目的是测试手持式XRF是否可用于完整苹果和梨的钙和钾的半定量分析。将单个果实的半定量测量结果与传统实验室分析结果进行比较。在此，我们观察到手持式XRF对钙和钾的测量结果与使用微波等离子体原子发射光谱仪（MP-AES）实验室分析测定的浓度之间存在显著相关性。皮尔逊相关系数范围为0.73至0.97。此外，使用手持式XRF对苹果和梨进行测量，可确定单个果实表面钙和钾浓度的空间变异性。这种变异性可能导致局部营养失衡的发生。这凸显了了解植物组织中元素浓度的空间和时间变异性的重要性。手持式XRF是一种相对高通量的方法，用于测量植物组织中的钙和钾。它可与传统实验室分析结合使用，以更好地了解器官、植物或整个区域内钙和钾吸收及分布的空间和时间模式。
