Rawashdeh Rabeah Yousef, Harb Amal Mohammad, AlHasan Asma Mahmoud
Department of Biological Sciences, Yarmouk University, Irbid, Jordan.
Heliyon. 2020 May 29;6(5):e03983. doi: 10.1016/j.heliyon.2020.e03983. eCollection 2020 May.
Seed germination is a critical stage in plant life, and recent practices use nanomaterials for the improvement of plant seed germination indices. This study was conducted to assess the effect of laboratory prepared zinc oxide nanoparticles on the physiological and biochemical changes of lettuce seeds.
Lettuce seeds were soaked in a suspension of moderately polydisperse zinc oxide nanoparticles at two different concentrations (25 ppm or 50 ppm) and shaken for 3 h at 25 °C. Seeds treatment was followed subsequently by two to three days drying at ambient conditions. Treated seeds were stored for 3-4 weeks, at ambient conditions and then tested for germination in petri dishes. Germination was observed on daily basis and seedling length was measured. After imbibition and before the start of the visible germination, seeds were examined for topography and surface analysis using the scanning electron microscope and zinc uptake was measured by using the atomic absorption spectrometry and the energy dispersive X-ray. The pattern of mobilization of biomolecules was analyzed to detect any differences among different seed groups.
There was no loss of viability for the nanoparticles treated seeds. Indeed their germination was enhanced and their biomass increased. The activated performance of the nanoparticles imbibed seeds has been found to be correlated with an increased level of Zn inside lettuce seeds. The recorded measurements show a significant enhancement of seedling length. Interaction of zinc oxide nanoparticles with lettuce seeds mediates a variation in the biochemical processes. Changes detected in treated seeds were as following: reduced levels of the total carbohydrates (including simple saccharides and polysaccharides), higher capacity of protein synthesis, an elevated level of starch as well as an increased activity of antioxidant enzymes.
Lettuce seeds primed with ZnO nanoparticles were found not only to maintain seed viability but even to exhibit a detectable level of germination enhancement compared to the control seeds. Overall, the promoted response of lettuce seeds during early stages of seed growth is encouraging for the application of ZnO NPs for seed priming for better germination indices.
种子萌发是植物生命中的关键阶段，最近的实践中使用纳米材料来改善植物种子的萌发指标。本研究旨在评估实验室制备的氧化锌纳米颗粒对生菜种子生理和生化变化的影响。
将生菜种子浸泡在两种不同浓度（25 ppm或50 ppm）的中等多分散性氧化锌纳米颗粒悬浮液中，在25°C下振荡3小时。种子处理后，在环境条件下干燥两到三天。处理过的种子在环境条件下储存3 - 4周，然后在培养皿中进行发芽测试。每天观察发芽情况并测量幼苗长度。在吸胀后且在可见发芽开始之前，使用扫描电子显微镜检查种子的形貌和表面分析，并使用原子吸收光谱法和能量色散X射线测量锌的吸收。分析生物分子的动员模式以检测不同种子组之间的任何差异。
纳米颗粒处理过的种子没有活力丧失。事实上，它们的发芽得到增强，生物量增加。已发现吸收纳米颗粒的种子的活化性能与生菜种子内锌水平的增加相关。记录的测量结果显示幼苗长度显著增加。氧化锌纳米颗粒与生菜种子的相互作用介导了生化过程的变化。在处理过的种子中检测到的变化如下：总碳水化合物（包括单糖和多糖）水平降低、蛋白质合成能力提高、淀粉水平升高以及抗氧化酶活性增加。
发现用氧化锌纳米颗粒引发的生菜种子不仅能保持种子活力，而且与对照种子相比，甚至表现出可检测到的发芽增强水平。总体而言，生菜种子在种子生长早期阶段的促进反应对于将氧化锌纳米颗粒应用于种子引发以获得更好的发芽指标是令人鼓舞的。
