Figure 2.

Pollen viability and germination are dysfunctional in dwf1-1. A, Example of wild-type (WT) pollen that has been stained with 4′,6-diamidino-phenylindole to show the three-nucleated pollen grain and spherical shape. nu-g, Germinative nuclei; nu-v, vegetative nuclei. Bar = 10 μm. B, Representative example of dwf1-1 pollen highlighting internally collapsed surface, absence of nuclei, and aberrant spherical shape. Bar = 10 μm. C, Viability of pollen grains determined by a modified Alexander stain (n = 100; error bar is sem of three technical replicates). Asterisks indicate significance by Student’s t test. **, P = 0.01. Light micrographs of pollen germination determined in the wild type (D) and dwf1-1 (E). In the wild type, evidence of the protruding annulus (an) and the germinating pollen tube (PT) is noted, but they are absent in dwf1-1. Bar = 10 μm. F, Germination rate determined as the percentage of pollen that developed the pollen tube (error bars represent sem; n = 3 independent replications [100 counts each]). Asterisks indicate significant difference. ***, P = 0.001.