Coastal and water plants seed germination and seedling development under the influence of zinc sulphate

The effect of zinc sulfate (1-500 mg/l) on Alisma plantago-aquatica L., Sium latifolium L. and Juncus effusus L. seed germination and seedling development was studied. We collected seeds from plants in August and September 2008 in Yaroslavl oblast, on humid banks of small rivers, the Ild' and the Latka. Then, after a cold wet stratification for 4-5 months, we germinated 25 pieces in lyuminostate in petri dishes at the temperature of 20-25°C on filter paper soaked with solutions of salts ZnSO₄*7H₂O at different concentrations. There were three replicates, illumination 3200 lux, photoperiod 9/15 (light/dark). The experiment lasted for 15 days. Control - distilled water. We determined laboratory germination and carried out monitoring of seedling development. We found out that low concentrations (1-10 mg / l) stimulated germination in all species. At concentrations of 25-500 mg/l, Alisma plantago-aquatica L. laboratory germination rate remained high, i.e. the seeds of this species proved to be resistant to the action of the studied TM. Sium latifolium L. seeds were marked by germination process slowing at 250 mg/l and more. Juncus effusus L. laboratory germination decreased sharply, starting with 50 mg/l. At 250 and 500 mg/l the seeds of this species did not germinate. It should be noted that Alisma plantago-aquatica L. seeds germinated faster than in control for almost all concentrations of zinc sulfate, Juncus effusus L. - at 1 and 25 mg/l and Sium latifolium L. as in control - at 1-25 mg/l. All three species showed normal development of seedlings at 1-25 mg/l. They had cotyledon leaves and well-developed roots. With the option of 10 mg/l, Sium latifolium L. seedlings leaf color was more intense than in the control, and at 25100 mg/l these seedlings and those of Alisma plantago-aquatica L. were marked by a decrease in intensity of the color and the size of cotyledons. We did not fix any changes of Juncus effusus L. leaf color intensity at any concentration which did not hinder their development. Concentrations at 50 and 100 mg/l caused leaves and roots necrosis of seedlings of all species. At concentrations of 250 and 500 mg/l, Sium latifolium L. seedlings died (shortly after the embryo root pipping the seed cover). However, at 50-100 mg/l, Alisma plantago-aquatica L. and Juncus effusus L. seedlings died earlier. In general, Juncus effusus L. seedlings were less resistant to zinc sulfate - already at 100 mg/l and they did not show cotyledon greening and they did not have cotyledon leaves.

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