Leaf number, dry weight, and nutrient composition of Lactuca sativa L. cv. Waldmann's Green leaves were compared following 9 days of treatment in a controlled environment room under various combinations of photosynthetic photon flux (PPF:350 vs 800 micromoles m-2 s-1), atmospheric CO2 level (ambient vs 1500 micromoles mol-1), and single-strength (1X:15 mM) vs double-strength (2X:30 mM) nitrogen (N) as NO3- alone or as NH4(+) + NO3- (1:5 molar ratio). CO2 enrichment greatly enhanced leaf number under all PPF and N conditions, but increased leaf dry weight only at high PPF. Conditions favoring high photosynthesis enhanced leaf starch content 3-fold, and protein content increased as much as 64% with 2X NH4(+)+NO3-. Free sugar content was 6 to 9% of leaf dry weight for all treatment combinations, while fat was 1.5 to 3.5%. Ash content varied from 15 to 20% of leaf dry weight. Modified controlled environments can be used to enhance the nutritional content as well as the yield of crops to be used for life support in space-deployed, self-sustaining human habitats. Leaf lettuce is a useful model crop for demonstrating the potential of nutritional value added by environmental manipulation.

中文翻译：

---

环境对“Waldmann's Green”产量和营养成分的影响叶用生菜


莴苣 (Lactuca sativa L. cv.) 的叶数、干重和营养成分。在受控环境室中处理 9 天后，在光合光子通量（PPF：350 与 800 微摩尔 m-2 s-1）、大气 CO2 水平（环境与 1500 微摩尔 mol-1）、以及单强度 (1X:15 mM) 与双强度 (2X:30 mM) 氮 (N)，单独为 NO3- 或 NH4(+) + NO3-（摩尔比为 1:5）。在所有 PPF 和 N 条件下，CO2 富集极大地增加了叶片数量，但仅在高 PPF 下增加了叶片干重。有利于高光合作用的条件使叶片淀粉含量提高了 3 倍，蛋白质含量在 2X NH4(+)+NO3- 下增加了 64%。所有处理组合的游离糖含量为叶干重的 6% 至 9%，而脂肪含量为 1.5% 至 3.5%。灰分含量为叶干重的 15% 至 20%。改良的受控环境可用于提高农作物的营养成分和产量，这些农作物可用于太空部署、自我维持的人类栖息地的生命支持。生菜是一种有用的模型作物，可以展示通过环境操纵增加营养价值的潜力。