Figure 7

Anticipated model of SeNPs induced germination in rice by the following mechanisms. Hydroprimed seed with slow water uptake and low metabolic activity. In hydroprimedseeds the hydrolysis of starch occur gradually and thus available sugars is low in the initialphase, exhibiting slow germination. But in case of SeNPnanopriming at first,during the initial phase of imbibition, SeNPspenetrate the seed coat creating small pores and facilitating water uptake intoseeds which in turn emulsify the stored nutrients of endosperm and transport them to embryo via theepithelial cells of the scutellum after increased water uptake and up-regulation of theexpression of aquaporin genes involved water uptake. Secondly, in the second phase, the α-amylase could possibly interact with functional groups ofbiomolecular ligands on the surfaceofSeNPs through the thiol linkages as NPs-amylase complex leading to higher metabolicactivity by increasing starch hydrolysis and generating large amount soluble sugarsand hence lowering the osmotic potential and water potential. This drives more water uptakeand creates high mechanical resistance in whole tissues of cell wall causing its loosening. Thirdly, in the last stage, aquaporins facilitate H₂O₂ or ROS diffusion acrossbiological membranes. SeNPs mediated ROS elevation is tightly controlled by seed antioxidantsystems to maintain ROS in optimum range of oxidative window which help in its functioning as signalling molecules. The ROS participate in cell wall loosening and endosperm weakening and also trigger essentialmetabolic activity of seed for promoting seed germination.