UBC Theses and Dissertations
Growth, mineral uptake and phosphorus metabolism of Pisum sativum L. as influenced by air and soil temperatures, phosphorus nutrition and growth retarding chemicals Adedipe, Nurudeen Olorun-Nimbe
In greenhouse and controlled environment experiments, the influences of temperature, P nutrition-, and foliar sprays of 3 growth retarding chemicals on the growth, yield and mineral composition of Pisum sativum L. cv. Dark Skin Perfection were investigated. The utilization of P under 4 air and soil temperature regimes within the physiological range was also studied. The dwarfing effect of high temperature was related to that due to relatively high concentrations of growth retarding chemicals. Banded P fertilizer, applied at rates of up to 352 lb. per acre, increased plant growth, pea yield and the uptake of N, P, K, Ca and Mg. P increased the total contents of all 5 minerals in all 3 tissues (vine, pod and pea seed), but had multiple effects on mineral concentrations. Efficiency of P in producing pea yield increase was maximum at the 44 lb. per acre rate. The high air temperature of 30° decreased growth, pea yield, and total mineral uptake, compared with a temperature of 21°. The high soil temperature of 18° increased these 3 groups of variables, as compared with a temperature of 10°. Increases in mineral concentration at the high air temperature were largely due to "concentration effects'' resulting from smaller plants. Increases due to the high soil temperature were absolute because they occurred even in bigger plants. Increase in mineral uptake at the high soil temperature was not due to increased root growth, but was a result of increased metabolic activity. The effect of soil temperature on total absorption was greater than on translocation into the pea seed. (2-chloroethyl) trimethylammonium chloride (Cycocel) at 1 ppm was the most effective in terms of growth and yield stimulation. 2,4-dichlorobenzyl tributylphosphonium chloride (Phosfon) at 100 ppm was the most effective with respect to growth retardation, but markedly decreased pea yield. N-N-dimethylamino succinamic acid (B-Nine) at concentrations of 1 and 100 ppm was ineffective in altering growth pattern. Effects of the growth retarding chemicals on mineral uptake largely reflected plant size differences, and were not absolute effects. Cycocel and Phosfon at low concentrations are promising for use in arresting excessive vegetative growth and its attendant problems, and in increasing pea yield without deformative effects. The effects of relatively high concentrations of Cycocel and Phosfon were similar to those of high temperatures with respect to plant dwarfing, changes in mineral composition and alteration in the levels of Glucose, G-l-P, G-6-P, F-6-P, Fl,6-P, ADP and ATP. It appears that high concentrations of growth retarding chemicals and high temperatures depress plant growth by reducing the utilization of ATP in the phosphorylation of sugars, in the glycolytic sequence. The nearest-optimal air and soil temperature regime for plant growth and mineral uptake was the 21/13/18° day/night/soil. For uniformity in the nomenclature of plant growth regulators, it is suggested that growth retarding chemicals be called "RETARDINS".
Item Citations and Data