Study on the release routes of allelochemicals from Pistia stratiotes Linn., and its anti-cyanobacteria mechanisms on Microcystis aeruginosa.

Allelochemicals in Pistia stratiotes Linn. have a strong anti-cyanobacteria effect on Microcystis aeruginosa. To further determine the release routes of allelochemicals in P. stratiotes and understand their anti-cyanobacteria mechanisms, we aimed to systematically investigate the allelopathic effects of leaf leachates, leaf volatilization, root exudates, and residue decomposition of P. stratiotes on M. aeruginosa. The influences of P. stratiotes allelochemicals on the physiological properties of M. aeruginosa were also studied. Root exudates of P. stratiotes exhibited the strongest inhibitory effect on M. aeruginosa growth. The residue decomposition and leaf leachates exhibited a relatively strong inhibitory effect on M. aeruginosa growth. By contrast, the leaf volatilization stimulated M. aeruginosa growth. Therefore, root exudation was determined to be the main release route of allelochemicals from P. stratiotes. The mixed culture experiment of P. stratiotes root exudates and M. aeruginosa showed that the allelochemicals released from root exudation had no effect on the electron transfer of M. aeruginosa photosynthetic system II. However, it reduced the phycocyanin (PC) content and phycocyanin to allophycocyanin (PC/APC) ratio in the photosynthetic system. As the root exudates concentration increased, the electrical conductivity (EC) and superoxide anion radical (O2(*-)) values in the M. aeruginosa culture fluid increased significantly, indicating that the allelochemicals released from the root of P. stratiotes inhibited algae growth by affecting the PC and PC/APC levels in photosynthesis, destroying the cell membrane, and increasing O2(*-) content to result in oxidative damage of M. aeruginosa.

Severe destruction of the upper respiratory structures after brief exposure to a dieffenbachia plant.

Dieffenbachia is a common domestic plant. Oral contact with the plant generally causes slight effects, but when chewed it may result in painful oropharyngeal edema. Even though the mechanism through which this plant causes toxicity is not known, calcium oxalate crystals (rhaphides) and protease in the idioblast of the plant are considered to be the causes. Our aim was to show the lethal effects of a common domestic plant named Dieffenbachia.A 70-year-old male patient applied to our clinic with aphasia, dysphagia, sialorrhea, wounds on the lips and tongue, and swelling on the face. There was edema on his tongue, soft palate, uvula, anterior pharyngeal plica, epiglottis and aryepiglottic fold, and ulceration on the right side of his tongue, the right cheek mucosa, right-lower gingival, soft palate, tongue base, epiglottis anterior surface, and free edge.Dieffenbachia toxicity presents both minimal and serious problems, which can be life threatening, as in our case. Toxic cases resulting in serious clinical pictures due to Dieffenbachia are rare.