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Title: Physiology of metal ion-induced effects on germination and seedling growth in cereals
Author: Mahwood, T.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1995
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The effects of zinc, lead and copper ions, at concentrations up to 10 mM, on germination and seedling vigour of wheat, barley and rice were investigated. Percentage germination was unaffected by lead and zinc ions in the three species tested. The highest concentration of copper ions (10 mM) decreased the percentage germination in rice. Rice seedlings were grown in controlled environment cabinets using a nutrient culture technique. A copper ion concentration of 8 μM in the culture solution was found to inhibit the elongation of the longest root. Seedlings were grown in nutrient solutions at pH 5.5, 5.0 and 4.5, and three concentrations of copper ions. The reduction in all the growth parameters was highest at pH 4.5 in all copper ion treatments. The amount of chlorophyll in the uppermost fully-expanded leaves of the seedlings grown at pH 4.5, was considerably less than that in comparable leaves of the control seedlings. The effect of copper ions on root plasma membranes of the seedlings was estimated by measuring K+ leakage from intact roots. A larger amount of K+ leaked from roots when seedlings were incubated with high (16 μM) copper ion concentrations than when seedling roots were incubated in water. Similarly, the effect of copper ions on root lipid peroxidation as measured by TBA-rm(2-thiobarbituric acid-reactive material) accumulation, showed that more TBA-rm was accumulated in copper ion treated roots than in control roots. The effect of various copper ion concentrations on the morphology and ultrastructure of the roots was studied using light and scanning electron microscopy. The results showed that copper ions caused a reduction in the length of the root hair zone and of root hair length, a reduction in the size of the root cells, and initiation of lateral root closer to the root tip, compared to seedlings grown in control solutions.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available