The aim of this study was to dissect the response of melatonin under different mode of application with series of concentrations in pea plants for growth, photosynthesis and antioxidant system. Surface sterilized seeds of Pisum sativum were soaked in deionized water (control), 50, 100, and 200 M of melatonin for 4, 8, and 12 h (shotgun approach). In another mode of application, same concentrations of ML applied through foliage of plants and were allowed to grow for 30 days. At this stage of growth, plants were sampled to assess the various growths and photosynthetic traits as well as selected biochemical characteristics. The results indicated that growth characteristics, net photosynthetic rate, antioxidants system, and proline content showed diverse response for different concentrations and mode of application. Foliar application excelled over the seed soaking and 100 M of ML proved best in enhancing activity of antioxidant system and proline accumulation in comparison to control plants. The up-regulation of antioxidant enzymes as well as proline triggered by melatonin could have great potential for improving crop yield and act as an eco-friendly plant growth regulator for sustainable agriculture practices.
