malachite green to visualize pollen walls and fuchsin acid to stain
cytoplasm and mitochondria. Aborted pollen grains appear colored
in pale green, while viable ones are shown in purple-red. The
capability of viable pollen grains to produce a pollen tube (pollen
germination) and to carry the two sperm cells toward ovules can be
studied both in vitro and in vivo. Liquid and solid media have been
optimized for in vitro pollen germination [6], and decolorized
aniline blue (DAB) staining of pollinated pistils is usually applied
to observe in vivo pollen tube growth [7]. DAB contains a fluorochrome that bind glucans present in pollen tube cell walls and
ABERRANT FLOWER MORPHOLOGY?
MALE GAMETOPHYTE (POLLEN) AFFECTED?
OVULE OR FEMALE GAMETOPHYTE (EMBRYO
SAC) AFFECTED?
SEED DEVELOPMENT AFFECTED?
Silique length
Seed set
Segregation
distortion
2
3
4
1
5
Pistils, sepals, petals
Flower
organs
Stamens / anthers
Ovule morphology
Development of
embryo sac cells
PHENOTYPIC / GENOTYPIC ABNORMALITIES?
Morphology
Viability
In vitro
germination
In vivo
germination
Seed size /
shape / color
Aberrant embryo
Aberrant endosperm
Seed coat defects
Fig. 2 Suggested guideline for successive and systematic studies of reproductive
defects in Arabidopsis thaliana
Identifying Reproductive Mutations in Arabidopsis
373