MINERAL NUTRITION AND FLOWER TO FLOWER POLLEN SIZE VARIATION

Bell , C. Ritchie . (U. of North Carolina, Chapel Hill.) Mineral nutrition and flower to flower pollen size variation. Amer. Jour. Bot. 46(9): 621–624. 1959.—Mineral nutrition appears to affect the amount of variability of pollen size in both clone and heterozygous seedling material grown on 6 different, deficient, nutrient solutions. In no case did the controls on complete nutrient solution have the largest mean pollen size. No pattern of pollen-size variation related to blooming date or to type of mineral deficiency could be detected in this experiment: the largest mean pollen size for tomato clone 1 came from plants on the —N solution, the smallest from plants on the –S solution (a 5.4 μ difference); for petunia clone 1, largest on –K, smallest on –S (a 2.3 μ difference); petunia clone 2, largest on –N, smallest on –P (a 1.9μ difference); dill set 1, largest on –K, smallest on –N (a 2.9μ difference); dill set 2, largest on –S, smallest on –N (an 8.2μ difference); portulaca (both sets presumably heterozygous) set 1, largest on –Mg, smallest on Ca (a 9.7μ difference); portulaca set 2, largest on –N, smallest on –Mg (a 13.6μ difference), note that set 1 was largest on –Mg. In the case of petunia pollen, there was greater size variation from flower to flower on the same plant than between flowers from different plants of the same clone on different nutrient solutions. Such variation offers further proof of the danger of using pollen size as an indicator of polyploidy or as a taxonomic characteristic until such correlations have been proven, in each separate instance, to be valid.