مهدی محمدی

Adverse effects caused by the overuse of chemical fertilizers have led to the development of natural biostimulants like seaweed and microalga extracts being used as an alternative, environmentally—friendly approach to improve crop growth and increase agricultural yields. The current research aimed to study the interactions between seaweed and microalga extracts priming on the seed germination parameters, and the growth of Calotropis procera. A petri—dish trial was conducted under a controlled growth room, where the experimental seeds were treated individually with the two biostimulant primings, seaweed liquid extracts (SLEs) and microalga liquid extracts (MLEs), and combinations of SLEs+MLEs at different levels (0, 0.5, 1, and 1.5%). The results of the germination experiment indicated that most germination parameters except seed vigor were significantly increased at all levels of SLE, and 0.5% of MLE. Also, the primary growth indices such as shoot length, root length, shoot and root fresh and dry weight were remarkably enhanced in lower levels of their combined primings. Our data about combined biostimulant treatments showed that SLE 0.5 and SLE 1%+MLE 0.5% led to increasing the germination and growth of primed seeds compared to control. Ultimately, SLE 1% and MLE 0.5% priming were found to be more successful and better candidates for developing effective biostimulants for improving seed germination parameters of milkweed. Therefore, the results maintain the concept of marine algae extracts as an agricultural biocatalyst, which could be applied as alternative biostimulants in improving growth performance for some plants.