Toxic Effects of Paclobutrazol on Developing Organs at Different Exposure Times in Zebrafish

Abstract

To enhance crop productivity and economic profit, farmers often use pesticides that modulate plant growth and prevent disease. However, contamination of ecosystems with agricultural pesticides may impair the health of resident biota. Paclobutrazol (PBZ), an aromatic-containing triazole, is widely applied to many crops in order to promote flowering and fruit setting, while also regulating plant growth and preventing fungus-related diseases. Due to its high mobility, high stability and potential for bioaccumulation, the risks of PBZ to the health of organisms and ecological systems have become a serious concern. In previous studies, we documented the toxicity of PBZ on developing heart, eyes, liver, pancreas and intestine of zebrafish. In this study, we sought to further understand the developmental stage-specific impacts of PBZ on digestive organs and other tissues. Zebrafish were exposed to PBZ beginning at different embryonic stages, and the toxic effects on organs were evaluated at 120 hpf (hours post-fertilization) by in situ hybridization staining with tissue-specific marker genes, such as liver, intestine and pancreas. Unsurprisingly, early-stage embryos exhibited higher sensitivity to PBZ-induced death and developmental hypoplasia of digestive organs. Interestingly, the developing liver and pancreas were more sensitive to PBZ than intestine when embryos were exposed at early stages, but these tissues showed lower sensitivity at later stages. Our delineation of the differential toxic effects of PBZ on developing organs at different exposure timings can serve as a powerful reference for further studies into the mechanisms of PBZ organ toxicity.

In vitro induction and identification of polyploid Neolamarckia cadamba plants by colchicine treatment

“…PBZ derived from an aromatic compound, trizol is a plant growth regulator with many uses in agriculture. Among others, it is used to induce flowering, fruiting and prevent fungal infections ( Wang, Chang-Yi Wu & Lonameo, 2019 ). PBZ has many uses in in vitro culture for different plants, such as shoot multiplication medium MS + 5 mgL −1 in Phoenix dactylifera ( Awadh, Abdulhussein & Almusawi, 2019 ), rooting medium 1/2 B5 + 0.1 mgL −1 in N. cadamba ( Mok & Ho, 2019 ) and rooting medium MS + 1.5 mgL −1 in Zygopetalum crinitum ( Gimenes et al, 2018 ).…”

Paclobutrazol and Its Use in Fruit Production: A Review

“…Recent studies have demonstrated that the residual nature of PBZ affects soil microbial life (reduction in the number of fungi, bacteria, actinomycetes and earthworms), which impairs plant growth and development [21]. In addition, leaching and contamination of aquifers can occur [8,17].…”

“…The life of PBZ in water is shorter (i.e., no longer than 3 weeks), but it can cause potential damage to the flora and fauna [37]. The presence of PBZ in water can cause various physiological effects in fish (survival rate, embryonic hatching, failure in the development of the skeleton of the head and eyes) [21,51]. Such is the case of Daphnia magna (water flea) which showed physical deformities when exposed to 240 μg L -1 of PBZ in the embryonic stage [39].…”

“…The use of PBZ contributes to increase production value (yield and fruit quality), however, there is evidence of its residual effects and its negative effect on consumers' health [20]. In addition, there is information that it can cause environmental pollution (groundwater and soil) [21]. The aim of this paper was to collect, analyse and summarise information on the use of PBZ in the production of some economically important fruit trees and their possible risks to the environment.…”

Peer Review #2 of "In vitro induction and identification of polyploid Neolamarckia cadamba plants by colchicine treatment (v0.1)"

“…PBZ derived from an aromatic compound, trizol is a plant growth regulator with many uses in agriculture. Among others, it is used to induce flowering, fruiting and prevent fungal infections (Wang et al, 2019). PBZ has many uses in in vitro culture for different plants, such as shoot multiplication medium MS + 5 mgL -1 in Phoenix dactylifera (Awadh et al, 2019), rooting medium 1/2 B5 + 0.1 mgL -1 in N. cadamba (Mok & Ho, 2019) and rooting medium MS + 1.5 mgL -1 in Zygopetalum crinitum (Gimenes et al, 2018).…”