Table 3.

Correlation between Conditions of the Naked Embryo Sac and the Arrival of Pollen Tubes

Condition of the Naked Embryo Saca
Wholly DisruptedCC RemainingCC and EC RemainingCC, EC, and 1 SY RemainingCompleteReceiving PT
Ovules from unpollinated flowersb
Frequency (%)c74.7 ± 11.31.1 ± 1.011.2 ± 5.12.6 ± 1.48.8 ± 7.31.5 ± 1.8
Number of arrivalsd0 (0%)0 (0%)2 (1%)4 (2%)197 (97%)0 (0%)
Ovules from pollinated flowerse
Frequency (%)c79.2 ± 9.80.5 ± 0.85.7 ± 1.51.8 ± 1.36.1 ± 3.56.7 ± 6.0
Number of arrivalsd0 (0%)0 (0%)0 (0%)0 (0%)53 (100%)0 (0%)
  • a Conditions of the naked embryo sac are classified into six types based on the survival of the four gametophytic cells, namely, the egg cell (EC), the two synergids (SYs), and the central cell (CC). An embryo sac in which one synergid had received a pollen tube and degenerated but other gametophytic cells remained intact was scored as the embryo sac receiving the pollen tube (PT).

  • b Ovules were excised from unpollinated flowers.

  • c Frequencies of each type of embryo sac were investigated 14 hr after the start of cultivation by monitoring 100 embryo sacs in each culture. Values are means ±sd of values from 21 experiments (ovules from unpollinated flowers) and from 11 experiments (ovules from pollinated flowers).

  • d The condition of embryo sacs was scored within 2 hr of the arrival of the pollen tube at the naked embryo sac. The numbers within parentheses give the relative frequency of the arrival of pollen tubes to each type of embryo sac with respect to the total number of arrivals (203 among ovules from unpollinated flowers and 53 among ovules from pollinated flowers).

  • e Ovules were excised from pollinated flowers 10 hr after pollination. Some ovules had already received a pollen tube in the ovary (Higashiyama et al., 1997).