弱光条件下光质和光周期对水培生菜生长与品质的影响

在弱光条件的人工光植物生长室中，设置两种不同红蓝光比例光质和两种不同光周期，水培盆栽红叶生菜（R）、绿叶生菜（G）和紫叶生菜（P），采收后测定3种生菜的生物量指标以及抗氧化物、可溶性糖等营养品质指标，以研究弱光条件下光质和光周期对3种叶色水培生菜产量和品质的影响。结果表明：（1）生菜产量主要受光周期影响，营养品质指标受光质和光周期的综合影响。光照时间延长显著增加了3种生菜叶面积。绿叶生菜和红叶生菜单位叶面积鲜重在不同光质及光周期下无显著差异。紫叶生菜单位叶面积鲜重对光周期变化的反应则因光质环境而异。延长光周期使3种叶色生菜地上部鲜重提高一倍多，但3种生菜地上部鲜重受光质影响不显著。（2）延长光照时长对3种生菜营养品质的影响因光质而异。在红蓝1:2光质下，延长光照时长降低了绿叶生菜总酚和类黄酮相对含量以及抗坏血酸和可溶性蛋白含量，提高了红叶生菜花青素和可溶性糖含量，但降低了抗坏血酸和可溶性蛋白含量，紫叶生菜总酚相对含量得到提高，但抗坏血酸含量显著降低。在红蓝2:1光质下，延长光照时长显著提高了绿叶生菜总酚和类黄酮相对含量，抗坏血酸含量有所降低，红叶生菜总酚和类黄酮相对含量、抗坏血酸、可溶性糖和可溶性蛋白含量均显著降低，紫叶生菜总酚含量显著提高。说明在弱光条件下延长光照时长可以显著提高3种不同叶色生菜产量。在红蓝1:2光质下，延长光照时长使红叶生菜的花青素含量和可溶性糖含量得到显著提高。在红蓝2:1光质下，延长光照时长可以提高绿叶生菜和紫叶生菜营养品质。

Influence of Light Quality and Photoperiod on Growth and Nutritional Quality of Three Leaf-color Lettuce Cultivars under Weak Light

Three leaf-color lettuces were hydroponically cultivated in culturing room with artificial light in greenhouse to investigate the influence of light quality and photoperiod on their growth and nutritional quality. The results showed that the yield of three kinds of lettuce was mainly affected by photoperiod and the nutritional quality was primarily influenced by combined action of light quality and photoperiod. Extension of lighting period enlarged the leaf area of the three kinds of lettuce. Fresh weight unit leaf area of green lettuce and red lettuce didn’t changed much when the light quality and photoperiod altered. However, fresh weight unit leaf area of purple lettuce responded to the change of photoperiod differently with the variation of light quality. Shoot fresh weight of three lettuce improved more than 100% when the lighting period prolonged. The effects of photoperiod on nutritional quality of the three kinds of lettuce differed when the light quality varied. When under RB 1:2 light, total phenols and flavonoid relative contents, ascorbic acid and soluble protein contents dropped greatly after treated with lighting period extension. And anthocyanin and soluble sugar contents of red lettuce improved significantly when lighting period extended, while ascorbic acid and soluble protein contents decreased. Total phenols relative content of purplelettuce increased, but ascorbic acid content reduced. However, when under RB 2:1 light, total phenols and flavonoid relative contents of green lettuce increase remarkably, but ascorbic acid content lessened. And phenols and flavonoid relative contents, ascorbic acid, soluble sugar and soluble protein contents of red lettuce dropped strikingly. Total phenols relative content of purple lettuce improved significantly under treatment lighting period extension. To summarize，extending lighting period could enhance the yield of the three kinds of lettuce, and this phenomenon could be free from the effect of light quality. Extension of lighting period could lifted the contents of anthocyanin and soluble sugar of red lettuce under RB 1:2 light. While under RB 2:1 light, nutritional quality of green lettuce and purple lettuce could be improved greatly by lighting period extension.