730
78. In Arabidopsis the genes TRYPTYCHON and STICHEL are involved in determining
how closely trichomes will develop to each other.
whether or not trichomes are formed.
which side of a leaf will have trichomes.
how many branches a trichome will have.
cell division within trichomes.
79. Once a pollen tube lands on a compatible stigma
chemical cues guide the pollen tube from the stigma to the embryo sac of an ovule.
that pollen tube continues on to another ovule.
other pollen tubes are attracted to that ovule.
other pollen tubes can penetrate that ovule more easily.
the flower dies to prevent further pollination
80. Which statement best reflects the current understanding of pollen-tube elongation?
It is not even known if pollen tube growth uses chemical signals or is completely random.
Pollen-tube elongation will occur as long as the pistil provides moisture and energy.
While it is known that chemical cues from female tissues help guide pollen tube growth,
the identity of these chemicals is not known.
Nearly all of the details of the chemical interactions between the pollen tube and pistil
tissue are known.
Pollen-tube elongation will occur only when pistil chemical cues are suppressed.
MATCHING
Match each of the following flower parts with its description.
Encloses and protects all other flower parts before the flower opens
Female reproductive parts
Often showy parts that function in attracting bees or other animal pollinators
81. petals
82. carpels
83. sepals
84. stamens