Abstract Extensive green roof architecture is an effective and low-maintenance solution to reduce energy cost of heating or cooling the buildings, and can be used to mitigate several urbanization problems such as heat island effect, lack of green space, and excessive stormwater runoff. However, designs and vegetation selections of the extensive green roofs have primarily been based on the studies conducted in the temperate areas. This study aimed to assess the suitability of ten groundcover plants in a tropical area using quantitative physiological parameters of plants, including relative water content (RWC), stomatal opening rate, maximum quantum yield of photosystem II (Fv/Fm), soil moisture, and leaf surface temperature. Upon severe drought stress, RWC could distinguish non-tolerant from tolerant species as early as 3 days after drought treatment (DAD). The drought-tolerant species had >80 % RWC at 5 DAD. For non-tolerant species, Fv/Fm decreased to an undetectable level, whereas only 5.45 % reduction was found for the tolerant species at 5 DAD. Three plant species Sesuvium portulacastrum, Evolvulus nummularius and Callisia repens maintained >80 % stomatal opening at 5 DAD, but E. nummularius was not considered a tolerant species based on the RWC and Fv/Fm characteristics. Interestingly, under drought stress C. repens maintained >50 % soil moisture at 7 DAD and maintained canopy surface temperature comparable to the well-watered condition. Together the results suggest that these physiological parameters are useful for the assessment of drought tolerance ability of groundcover plants, and S. portulacastrum and C. repens should be considered for extensive green roof architecture in the tropical areas.

中文翻译：

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评估生理参数以确定热带地区广泛的绿色屋顶建筑的植物耐旱性

摘要 广泛的绿色屋顶建筑是降低建筑物供暖或制冷能源成本的有效且低维护的解决方案，可用于缓解热岛效应、绿地不足和雨水径流过多等城市化问题。然而，广泛的绿色屋顶的设计和植被选择主要基于在温带地区进行的研究。本研究旨在利用植物的定量生理参数，包括相对含水量 (RWC)、气孔开放率、光系统 II 的最大量子产量 (Fv/Fm)、土壤水分和叶面温度。在严重干旱胁迫下，RWC 早在干旱处理 (DAD) 后 3 天就可以区分非耐受物种和耐受物种。耐旱物种在 5 DAD 时具有 >80% RWC。对于非耐受物种，Fv/Fm 降低到无法检测的水平，而耐受物种在 5 DAD 时仅发现 5.45% 降低。三种植物物种马齿苋、Evolvulus nummularius 和 Callisia repens 在 5 DAD 时保持 > 80% 的气孔开口，但基于 RWC 和 Fv/Fm 特征，E. nummularius 不被视为耐受物种。有趣的是，在干旱胁迫下 C. repens 在 7 DAD 时保持了 > 50% 的土壤水分，并保持了与充足浇水条件相当的冠层表面温度。