Table 2.

Frequency of the Arrival of Pollen Tubes at the Micropylar End of the Naked Embryo Sac of Ovulesa

Culture ConditionsNo. of Pollen TubesNo. of OvulesNo. of Experiments
Pollen TubesOvulesTotalReached Embryo SacsbTotalContact with Pollen Tubesc
In vitroIntact19300 (0%)37900 (0%)10
Semi–in vitroIntact6804273 (4.0%)8190210 (2.6%)21
Semi–in vitroHeat treatedd29921 (0.03%)34761 (0.03%)11
Semi–in vitroMixed (intact/heat treated)147560 (4.1%)1520/145045 (3.0%)/0 (0%)5
  • a Frequency was investigated 24 hr after the start of cultivation.

  • b The numbers within parentheses give the relative frequency of pollen tubes reaching the micropylar end of naked embryo sacs with respect to the total number of pollen tubes.

  • c The numbers within parentheses give the relative frequency of ovules making contact with pollen tubes with respect to the total number of ovules.

  • d Whole ovaries were heat treated at 90°C for 5 min before the excision of ovules.