UBC Undergraduate Research

Some morphological and physiological differences between a normal Sitka spruce and a yellow mutant Scott, G.R.


Sun and shade foliage was collected from a normal and mutant Sitka spruce (Picea Sltchensis Bong. Carr) and analyzed as to morphological and physiological differences. The amount of chlorophyll a, cnbrophyll b, and carotene pigments was determined; needle length and width, length of last year's growth, and number of needles on last year's were measured. Pigment content was measured on top and bottom half of a golden scion to indicate within scion variation. Some mutant needles were cut in half, and pigment content measured in both halves to indicate within needle variation. Results indicate that the sun foliage of the mutant contains about five times less chlorophylls and slightly more carotene than ntSrmal sun foliage. In shade foliages, the mutant contained about 1.5 times more of the three pigments. The morphological studies show that the mutation causes a stunting of some needle characteristics in the mutant foliage. Previous studies indicate that this genetic mutation either disrupts the production of normal proteinous grana within the chloro-4 plasts or slows the rate of production of the chlorophylls. In the mutant either mechanism is activated by direct sunlight.

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