Cell volume ratios of natural and of induced tetraploid and diploid flowering plants.

Abstract

Many volume ratios between tetraploid and diploid guard cells of stomata and between diploid and haploid pollen grains were compiled from the literature and from own unpublished results. The sources of possible errors are discussed. No difference was found between induced auto- and allotetraploids. Some of the ratios with tetraploids of the C0 generation, but less so of later generations, were extremely high. The medians of the ratios were highest in the C0 generation (pollen grains 2.0-2.1, guard cells 2.4) and smaller in later generations (pollen grains 1.9, guard cells 2.1). The ratios of tetraploids from nature were 1.5-1.8 and thus significantly smaller than 2. The reduction may be a result of a selection for cell size during evolution, or of a physiological self-adjustment.The length/width ratios of guard cells were on average greater, but those of anisodiametric pollen grains smaller in induced tetraploids than in diploids, with a broad range of variation. The finding for guard cells is at variance with a widely held opinion.