Dipartimento di Scienze Agrarie e Ambientali (DISAA), Università degli Studi di Milano , via Celoria 2, 20133 Milano, Italy.
J Agric Food Chem. 2016 Jul 6;64(26):5317-23. doi: 10.1021/acs.jafc.6b01377. Epub 2016 Jun 23.
Together with stomatal conductance and root conductivity, the stem water reserve and transport systems could be regulatory mechanisms able to participate in the regulation of the plant water status. Lianas, such as Vitis spp., minimize the trunk support role, and stems have evolved to improve their ability in water transport. In this work, stems of 10 different Vitis species were studied in relation to their expected drought tolerance using reflectance spectroscopy. Spectra were measured before (T0) and after coloration with Sudan IV dye. The T0 spectral signature showed characteristic species features. The partial least squares (PLS) regression and the self-organizing map (SOM) neural network analysis were able to predict the expected drought tolerance score; thus, reflectance spectroscopy was demonstrated to be a useful technique for drought tolerance phenotyping. These methods could be applied for the preliminary selection of new rootstocks/cultivars. Wood composition variation appeared to be correlated with the water stress susceptibility. To clarify this relationship, the attention was focused on the wood hydrophobicity. Sudan IV is a microscopy dye traditionally used to underline suberin, waxes, and, in general, hydrophobic substances. Differences between rough and colored spectra evidenced the absorption band of Sudan IV with a maximum at 539 nm. The coloration intensity was used to develop a hydrophobicity index. The obtained values were correlated with the expected drought tolerance score. Therefore, hydrophobic compounds seem to play an important role in water use efficiency, and an hydrophobic barrier in the xylem tissue appears to be a protective mechanism against water stress.
与气孔导度和根导率一起，茎水储备和运输系统可能是能够参与植物水分状况调节的调节机制。藤本植物，如葡萄属植物，最小化了树干的支撑作用，茎进化为提高其水分运输能力。在这项工作中，研究了 10 种不同葡萄物种的茎，以用反射光谱法研究其预期的耐旱性。在（T0）用苏丹 IV 染料染色之前和之后测量光谱。T0 光谱特征显示出特征物种特征。偏最小二乘（PLS）回归和自组织映射（SOM）神经网络分析能够预测预期的耐旱性评分；因此，反射光谱被证明是一种用于耐旱性表型分析的有用技术。这些方法可用于新砧木/品种的初步选择。木材成分的变化似乎与水分胁迫的敏感性有关。为了澄清这种关系，重点关注木材疏水性。苏丹 IV 是一种传统上用于强调类脂体、蜡质和一般疏水性物质的显微镜染料。粗糙和着色光谱之间的差异表明苏丹 IV 的吸收带在 539nm 处具有最大值。着色强度用于开发疏水性指数。获得的值与预期的耐旱性评分相关。因此，疏水性化合物似乎在水分利用效率中起着重要作用，木质部组织中的疏水性屏障似乎是一种防止水分胁迫的保护机制。
