Aquaponics, a circular agri-aquaculture system, offers the potential to enhance food production resilience across diverse environmental contexts. Plant physiological processes that regulate water and nutrient fluxes in decoupled aquaponics are responsive to environmental dynamics such as stomatal behaviour. In greenhouses, these dynamics are largely driven by changes in natural solar radiation. This research investigates plant physiological dynamics of lettuce traits to various natural light conditions in a fully climate-controlled environment mimicking geographic latitude-based light variations and lighting application modes. We explored the physiological and resource utilisation effects of these regimes as basis for a geographic-adjusted planning of climate-resilient aquaponic systems. For that, four lighting scenarios were applied in a climate chamber over a period of 21 days in decoupled aquaponic setups, involving two daily light integrals (DLIs) and two daily light dynamics (DLDs) for lighting application modes: North (LAT 59° 54' 41.37'' N) natural sunlight dynamics, North static, South (LAT 40° 25' 0.39'' N) natural sunlight dynamics (Sn), and South static (Ss). DLIs and natural sunlight dynamics were derived from Northern (Oslo, Norway) and Southern (Madrid, Spain) Europe in March 2022. Observed plant physiological variables were plant growth, chlorophyll and carotenoid contents, stomatal conductance and morphology, and net photosynthesis (P). Resource-use variables at leaf level, including CO, light, water, and nutrient utilisation, were also estimated. Latitude-dependent DLIs, in general, significantly affected lettuce growth, quality, and physiological responses; with lower latitudes (Sn, Ss) improving P by 68% compared to North-DLI treatments. Resource utilisation was also positively impacted in South-DLI treatments, e.g., light use efficiency was in average 2.2 times higher in South-DLI (0.75 g [CO] mol [PPFD]) than in North-DLI (1.62 g [CO] mol [PPFD]) treatments. Lighting modes had limited effects, and interactions between DLIs and DLDs were largely absent. These findings indicate the significance of geographic differences in natural solar radiation dynamics on designing climate-resilient aquaponics facilities, and highlight the influence of geography on crop productivity and resource efficiency.

中文翻译：

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解耦鱼菜共生系统中光照制度对生菜生理和资源利用的纬度相关影响

鱼菜共生是一种循环农业水产养殖系统，具有增强不同环境背景下粮食生产弹性的潜力。解耦鱼菜共生系统中调节水和养分通量的植物生理过程对环境动态（例如气孔行为）敏感。在温室中，这些动态很大程度上是由自然太阳辐射的变化驱动的。这项研究研究了在完全气候控制的环境中，模拟基于地理纬度的光变化和照明应用模式，生菜性状在各种自然光条件下的植物生理动力学。我们探索了这些制度的生理和资源利用影响，作为气候适应性鱼菜共生系统地理调整规划的基础。为此，在 21 天的时间里，在解耦鱼菜共生设置中在气候室中应用了四种照明场景，其中涉及照明应用模式的两个每日光积分 (DLI) 和两个每日光动态 (DLD)： 北（LAT 59° 54） ' 41.37'' N) 自然阳光动态、北静态、南 (LAT 40° 25' 0.39'' N) 自然阳光动态 (Sn) 和南静态 (Ss)。 DLI 和自然阳光动态源自 2022 年 3 月的北欧（挪威奥斯陆）和南欧（西班牙马德里）。观察到的植物生理变量包括植物生长、叶绿素和类胡萝卜素含量、气孔导度和形态以及净光合作用 (P) 。还估计了叶层的资源利用变量，包括二氧化碳、光、水和养分利用。一般来说，与纬度相关的 DLI 会显着影响生菜的生长、品质和生理反应；与 North-DLI 处理相比，低纬度地区（Sn、Ss）的 P 提高了 68%。 South-DLI 处理中的资源利用也受到积极影响，例如，South-DLI 的光利用效率（0.75 g [CO] mol [PPFD]）平均比 North-DLI（1.62 g [CO] mol [PPFD]）高 2.2 倍。 [PPFD]）治疗。照明模式的效果有限，并且 DLI 和 DLD 之间基本上不存在相互作用。这些发现表明自然太阳辐射动力学的地理差异对于设计具有气候适应性的鱼菜共生设施具有重要意义，并强调了地理对作物生产力和资源效率的影响。