Date of Award:

5-1967

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Department name when degree awarded

Plant Nutrition and Biochemistry

Committee Chair(s)

George W. Welkie

Committee

George W. Welkie

Committee

Herman H. Wiebe

Committee

David R. Walker

Abstract

A method has been described to suspend seedling wheat roots in a saturated atmosphere. Wheat (Triticum vulgate, L.) seeds were germinated in aluminum trays and the seedlings transferred to seedling chambers. After a day's growth, the roots were treated with various concentrations of solutions containing CaSO4, KCl, KF, NaCL, NaF, CH3COONa, FCH2COONa, K2C2O4 and Na2EDTA and observations were recorded 24 and 48 hours after treatment. The new root growth was described with respect to root hairs, root tissue collapse and root discoloration. Total length and length of the root hair zone of the primary roots were measured after the 48 hour observations.

Evidence is obtained to show that fluoride ion was more inhibitory to root growth than chloride and corresponded to symptoms resulting from lack of supplied calcium or treatment with oxalate which could precipitate calcium or EDTA which could chelate calcium. The resulting root response has been ascribed to displacement of available calcium by the univalent cations in the solution, or to an interaction of calcium with the anions, or both. Depletion of available calcium by fluoride ion is discussed as the formation of an insoluble precipitate of CaF2. Organic fluoride ion was found to be less inhibitory to root growth than the inorganic fluoride ion and the possibility of in vivo conversion of the organic fluoride to the inorganic fluoride is considered.

Better root growth was observed in double salt solution containing calcium and potassium than that found in single salt solution containing only calcium, and the loss of available calcium due to displacement by K+ was considered to be less in the former than in the latter. With higher calcium levels, higher potassium levels were necessary for maximum root growth; but with lower calcium levels, higher potassium levels resulted in inhibition of root growth.

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