Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, Limassol, Cyprus.
J Sci Food Agric. 2018 Dec;98(15):5861-5872. doi: 10.1002/jsfa.9139. Epub 2018 Jun 27.
Potassium (K) deficiency in leafy vegetables such as lettuce is a major concern regarding quality. Seaweed (SW) extracts, as biostimulants, are biodegradable materials and have become increasingly popular as they are reported to enhance crop growth and yield.
In order to overcome K deficiencies (i.e. 375 vs 125 mg L ), alternative foliar applications with extracts of Ascophyllum nodosum SW or K were examined using lettuce plants which were grown hydroponically. Potassium deficiency (at 125 mg L ) reduced plant biomass, photosynthetic rate, leaf stomatal conductance, lettuce potassium content and tissue antioxidant capacity as compared with the higher K level (375 mg L ). Application of SW increased the relative growth of lettuce in the low-K treatment. The K level and/or SW application altered the plant's enzyme protective activity (superoxide dismutase, SOD; catalase, CAT; peroxidase, POD) against oxidative stress and hydrogen peroxide (H O ) production. Spray applications of SW mitigated the effects of K deficiency on indicators of enzyme activity and plant damage, back to levels of high K content (375 mg L ). The high K level, but also SW application, increased the antioxidant activity of the processed lettuce before storage. Foliar application of the SW extract increased the quality of cut lettuce grown in 125 mg L K conditions by reducing the rate of respiration and increasing consumer preference.
The SW application could alter the detrimental effects of K deficiency during lettuce growth and storage of processed products. © 2018 Society of Chemical Industry.
叶菜类蔬菜（如生菜）中的钾（K）缺乏是一个主要的质量问题。海藻（SW）提取物作为生物刺激素，是可生物降解的材料，由于其被报道能增强作物的生长和产量，因此越来越受欢迎。
为了克服 K 缺乏症（即 375 与 125mg/L），使用水培生菜植物检查了用 Ascophyllum nodosum SW 或 K 的提取物进行的替代叶面应用。与较高的 K 水平（375mg/L）相比，K 缺乏症（在 125mg/L 时）降低了植物生物量、光合速率、叶片气孔导度、生菜 K 含量和组织抗氧化能力。SW 的应用增加了低 K 处理中生菜的相对生长。K 水平和/或 SW 应用改变了植物对氧化应激和过氧化氢（H₂O₂）产生的酶保护活性（超氧化物歧化酶，SOD；过氧化氢酶，CAT；过氧化物酶，POD）。SW 的喷雾应用减轻了 K 缺乏对酶活性和植物损伤指标的影响，使其恢复到高 K 含量（375mg/L）的水平。高 K 水平，甚至 SW 应用，增加了在 125mg/L K 条件下生长的加工生菜的抗氧化活性，从而降低了呼吸速率并增加了消费者的偏好。
SW 应用可以改变生菜生长和加工产品储存过程中 K 缺乏的不利影响。 © 2018 化学工业协会。
