36. Plant Reproduction

In an environment that is very stable, with reliable moisture and temperature, what type of reproduction would be most advantageous for a plant, and why?

Which statement below accurately describes the role of S-genes in plants?

Evaluate these statements about double fertilization. Select True or False for each sentence.T/FTwo zygotes are formed, but only one survives.T/FOne sperm fuses with an egg while the other sperm fuses with polar nuclei.T/FIt results in the formation of a diploid embryo and triploid endosperm.T/FBoth sperm involved in double fertilization form within the same pollen tube.

Double fertilization means thata. flowers must be pollinated twice to yield fruits and seeds.b. every egg must receive two sperm to produce an embryo.c. one sperm is needed to fertilize the egg, and a second sperm is needed to fertilize the polar nuclei.d. every sperm has two nuclei.

In angiosperms, each pollen grain produces two sperm. What do these sperm do? a. Each one fertilizes a separate egg cell. b. One fertilizes an egg, and the other is kept in reserve. c. Both fertilize a single egg cell. d. One fertilizes an egg, and the other fertilizes a cell that develops into stored food.

In angiosperms, are sperm and eggs produced by mitosis or meiosis? Which cells are spores? Which structures are gametophytes?

Match questions 3–8 with options a–f. 3. Attracts pollinator 4. Develops into seed 5. Protects flower before it opens 6. Produces sperm 7. Produces pollen 8. Houses ovules a. pollen grain b. ovule c. anther d. ovary e. sepal f. petal

Some plant species produce male and female individuals in which the males have an XY genotype and the females have an XX genotype. After double fertilization, what would be the genotypes of the embryos and endosperm nuclei? (A) embryo XY/endosperm XXX or embryo XX/endosperm XXY (B) embryo XX/endosperm XX or embryo XY/endosperm XY (C) embryo XX/endosperm XXX or embryo XY/endosperm XYY (D) embryo XX/endosperm XXX or embryo XY/endosperm XXY

Some dioecious species have the XY genotype for male and XX for female. After double fertilization, what would be the genotypes of the embryos and endosperm nuclei?a. embryo XY/endosperm XXX or embryo XX/endosperm XXYb. embryo XX/endosperm XX or embryo XY/endosperm XYc. embryo XX/endosperm XXX or embryo XY/endosperm XYYd. embryo XX/endosperm XXX or embryo XY/endosperm XXY

In a species showing sporophytic incompatibility, which type(s) of pollen could successfully fertilize an S2S3 flower? (A) S1 pollen from an S1S3 flower (B) S2 or S3 pollen from an S2S3 flower (C) S3 pollen from an S1S1 flower (D) S1 pollen from an S1S1 flower

A small flower with green petals is most likelya. bee-pollinated.b. bird-pollinated.c. bat-pollinated.d. wind-pollinated.

What are the advantages and disadvantages of self-fertilization versus those of outcrossing?

DRAW IT Draw and label the parts of a flower.

Make a sketch of a simplified flower with all four organs, and indicate how the pattern of expression for just two genes (e.g., 'D' and 'E') could, hypothetically, regulate the development of each organ. Consider that what's important is whether a gene is on or off and that a structure can be specified when neither gene is expressed.

Most flowering plants can achieve pollination in several different ways. Those that produce pollen and carpels on the same plant may be self-pollinated, but they may also be cross-pollinated by insects or other pollinators. The cape gooseberry (Physalis peruviana) shown here is able to produce seed whether it is self- or cross-pollinated. Is one type of pollination better for reproductive success than the other?Considering the gooseberry flower shown here, what types of cues might attract bees to the plant? What type of rewards do bees seek?