DISC ELECTROPHORETIC STUDY OF POLLEN PROTEINS FROM NATURAL POPULATIONS OF BETULA POPULIFOLIA IN NEW JERSEY

Pollen proteins from individual trees of eight natural populations of B. populifolia Marsh. located in diverse physiographic provinces of New Jersey were separated by disc electrophoresis with 7 % acid and basic acrylamide gels. Specific stains and substrates for detecting general proteins, esterase, and leucine aminopeptidase isoenzymes were utilized. Average Rp values, 95 % confidence intervals, and percentage similarity values were calculated. Dendrograms were constructed to illustrate protein similarity among populations. The effects of increasing the concentration of protein samples subjected to electrophoresis and storage of pollen (4 C over 16 months) were investigated. After statistical analysis we concluded that: each protein system investigated revealed different amounts of intra- and interpopulation variation, different population ranking (determined by amount of variation), and different population similarity groupings; conclusions based on the comparisons of numbers of protein bands were not always valid; disc electrophoretic data revealed information about natural selection and gene flow; the effect of increasing pollen protein concentration was quantitative; with storage pollen proteins increased in overall positive charge.