ISOPlexis Genebank, University of Madeira, Campus da Penteada, 9020-105, Funchal, Madeira, Portugal.
ISOPlexis Genebank, University of Madeira, Campus da Penteada, 9020-105, Funchal, Madeira, Portugal.
J Plant Physiol. 2019 Jan;232:100-106. doi: 10.1016/j.jplph.2018.11.024. Epub 2018 Nov 28.
Taro (Colocasia esculenta L. Schott) is an important staple food crop in tropical and developing countries, having high water requirements. The purpose of this study was to evaluate the feasibility of using carbon and nitrogen isotopic composition (δC and δN) as a physiological indicator of taro response to drought, and elucidation of the relationship between the water use efficiency (WUE) under drought conditions and carbon isotope discrimination (ΔC). As an alternative to WUE determination, obtained by measuring plant growth and water loss during an entire vegetative cycle, we have used ΔC to determine the tolerance of C taro plants to drought. Seven taro accessions from Madeira, Canary Islands and the Secretariat of the Pacific Community (Fiji) collections were grown under greenhouse conditions and subjected to different watering regimes during a one-year cycle. Total plant biomass (TPB), WUE and δN were determined at the whole-plant level (WP). Corms and shoots were evaluated separately for nitrogen content (N), δC, ΔC and δN. WUE showed positive correlation with TPB (r = 0.4) and negative with ΔC (r = -0.3); Corm δN showed positive correlations with WP δN (r = 0.6) and corm N (r = 0.3). Accordingly, the taro plants with enhanced WUE exhibited low ΔC and δN values as a physiological response to drought stress. The approach used in the present study has developed new tools that could be used in further research on taro response to environmental stresses.
芋头（Colocasia esculenta L. Schott）是热带和发展中国家的重要主食作物，需水量大。本研究旨在评估碳氮同位素组成（δC 和 δN）作为芋头对干旱响应的生理指标的可行性，并阐明干旱条件下水分利用效率（WUE）与碳同位素分馏（ΔC）之间的关系。作为测定整个营养生长期植物生长和水分损失来确定 WUE 的替代方法，我们利用 ΔC 来测定 C 型芋头植物对干旱的耐受能力。在温室条件下种植了来自马德拉群岛、加那利群岛和太平洋共同体秘书处（斐济）收集的七个芋头品种，并在一年的周期内进行不同的浇水处理。在整个植株水平（WP）上测定总植物生物量（TPB）、WUE 和 δN。分别对块茎和地上部分进行氮含量（N）、δC、ΔC 和 δN 的评估。WUE 与 TPB 呈正相关（r=0.4），与 ΔC 呈负相关（r=-0.3）；块茎 δN 与 WP δN（r=0.6）和块茎 N（r=0.3）呈正相关。因此，增强 WUE 的芋头植株表现出低 ΔC 和 δN 值，作为对干旱胁迫的生理响应。本研究中使用的方法开发了新的工具，可用于进一步研究芋头对环境胁迫的响应。
