Uptake and translocation of imidacloprid via seed pathway and root pathway during early seedling growth of corn

Abstract

BACKGROUND: A systemic seed treatment can be taken up into shoot tissues during early corn seedling growth. However, the pathway that a systemic compound is taken up, either from seed or root uptake to shoot tissues is not fully understood. To study the single contributions of seed pathway and root pathway for the uptake and translocation of imidacloprid seed treatment, two methods were developed: A seed treatment method and a growing media/hydroponic solution delivery method. The seed treatment method employed a live and dead seed separated with plastic wrap to provide a barrier. The growing media/ hydroponic solution delivery method quantified the capacity for uptake by seeds and roots. RESULTS: The seed pathway transported 1.9-2.5 times more imidacloprid into shoot tissues when compared to the root pathway at the same dosage rate. The higher amount of imidacloprid taken up and translocated by the seed pathway was attributed to the fact that the corn seeds were in direct contact with high provided concentrations of imidacloprid. However, the root pathway showed 7.9-9.5 times higher capacity for transporting imidacloprid into shoot tissues when compared with the seed pathway. Whenever imidacloprid was taken up by seed or root, amounts of imidacloprid were measured in both tissues of seed and root. CONCLUSION: The seed pathway transported more imidacloprid than the root pathway during early seedling growth since corn seeds were contacted by higher concentrations of imidacloprid. Both seed pathway and root pathway were occurring concurrently during early seedling growth of corn.

Trace determination of imidacloprid and its major metabolites in wheat‐soil system

“…Moreover, the concentration of the most active metabolite, IMI olefin, in the flag leaves was approximately 1.95 times that in the stem. These results are consistent with the predictions of the [45,46]. In addition, the high pKa value indicates that the pesticide was not ionized and could move freely between the phloem and xylem.…”

“…According to the Briggs model, the log K ow and transpiration stream concentration factors of IMI are 0.51 and 0.6, respectively, implying that IMI has considerably high xylem mobility. Imidacloprid is predominantly transported within xylem vessels [45, 46]. In addition, the high pKa value indicates that the pesticide was not ionized and could move freely between the phloem and xylem.…”

Potential Threat of Lead Oxide Nanoparticles for Food Crops: Comprehensive Understanding of the Impacts of Different Nanosized PbOx (x = 1, 2) on Maize (Zea mays L.) Seedlings In Vivo

“…However, the roots of germinated seeds will only access the compounds that diffused from the surface of the seeds and uptake them passively . Therefore, when the first embryonic root perforated the seed coat, the germinated seeds with the initial root became much higher in surface area than seeds at the seedling stage and potentially had a higher capacity for uptake . At this stage, more PbO 2 /PbO NPs would be diffused to and accumulated at the surface of germinated seeds with increasing NP concentrations.…”

“…46 Therefore, when the first embryonic root perforated the seed coat, the germinated seeds with the initial root became much higher in surface area than seeds at the seedling stage and potentially had a higher capacity for uptake. 45 At this stage, more PbO 2 /PbO NPs would be diffused to and accumulated at the surface of germinated seeds with increasing NP concentrations. Consequently, they are likely to agglomerate together and adhere to the surface of primary roots of intact seedlings, by which process the water uptake and water flux would be reduced to a certain extent.…”

“…Studies have demonstrated that corn seeds will directly take up a systemic compound by diffusing into corn seeds through its permeability of pericarp/testa. However, the roots of germinated seeds will only access the compounds that diffused from the surface of the seeds 45 and uptake them passively. 46 Therefore, when the first embryonic root perforated the seed coat, the germinated seeds with the initial root became much higher in surface area than seeds at the seedling stage and potentially had a higher capacity for uptake.…”